AN EXPERT TUTOR IN ORGANIC SYNTHESIS

PAMELA WYNNE MYNOTT B.Se. Ph.D.

A Master's by Course Dissertation submitted in partial fulfilment of the requirements for the award of the degree of MSe in Computer Education of Loughborough University of Technology, Januar¥ 1988.

Supervisor a D R GREEN, B.Se., M.Sc., M.Ed .• Ph.D.

~ b¥ PAMELA .WYNNE MYNOTT 1988

PAGE 1 ABSTRACT

This dissertation describes the development of an educational package for 'A' level Chemistry students. The package is intended to aid the understanding of organic synthesis routes. It comprises an interactive computer program in BBC Basic which functions as an expert tutor. and accompanying notes. The user is given the freedom to choose the ways in which the synthesis problems are posed, the degree of difficulty o~ the synthesis problem and the type of help given. A feature of the program is its ability to compute if requested a route between any compounds 1n the database. The dissertation includes a consideration of educational aims and a description of the way in which the program and the user interface were designed to meet these aims. It also contains copies of the screen displays obtained during two interactive sessions. The program is compared with three others and the advantages and drawbacks of each are detailed. The conduct of tests to evaluate the program are described and the conclusions drawn from these tests are given. The dissertation contains a fllll description of the program and a listing together with lists Of procedures and vari~bles. Copies of notes for students and teachers are provided. The=e include a description of the sllggested use of the program in its educational context.

PAGE 11 Acknowledgments

I should like to acknowledge the help I have received in writing this dissertation from a number of people. In particular my thanks are due to the following:-

Firstly to Dr. D. R. Green of CAMET for the interest and support he has given me as my supervisor.

Secondly to Dr. C. R. Sutton o~ the School o~ Education.

Leicester University for help in arranging the testing o~ the program.

Finally to my husband Dr. P. H. Mynott for preparing the diagrams, for help in producing the copies of the dissertation and for his unfailing support and encouragement.

PAGE iii DECLARATION

I declare that the program described in this dissertation and the dissertation itself are entirely my own work.

Pamela W. Mynott

January 1988

PAGE IV CONTENTS Abstract Page ii Acknowledgments Page iii Declaration Page iv

Chapter 1 Educational aims

1.1 Summary of aims Page 1 1.2 Amplification of aims Page 2 1.3 Description of the chemistry content Page 6

Chapter 2 Program design and implementation

2.1 Design of user interface p~ge 11 2.2 Description of the program Page 111 2.3 Demonstration of the program running Page 20

Chapter 3 Comparison with other programs

3.1 Introduction Page 36 3.2 Comparison with the program "ORGANIC SYNTHESIS by P.M. Smith Page 36 3.3 Comparison with· the program "ORGANIC CHEMISTRY" (synthesis of aliphatic substances) by G. Hall .Page 39 3.11 Comparison with the program "ORGANIC CHEMISTRY part 1" by Salisbury Chemistry Page 112

Chapter li Testing

li.1 Design of tests Page 115 li.2 Preliminary testing Page 115 11.3 Final testing Page .li7 li.3 Conclusion Page 52

PAGE V Chapter 5 Program design

·5.1 Data structure Page 511 5.2 Introduction to program Page 56 5.3 Help menu Page 611

6 Appendices

6.1 Reaction diagrams Page 75 6.2 Program listing Page 79 6.3 List of Procedures Page 911 6.11 List of variables Page 96 6.5 Students' notes Page 97 6.6 Teachers' notes and questionnaire Page 102

PAGE VI CHAPTER 1. Educational Aims

1.1 Summary of educational aims

The educational aims of the program are as follows:-

1) To provide a program which enables students to h~ve experience of devising organic synthetic routes and to become familiar with the reactions that these involve. 2) To enable the students to have as much control as possible over their learning. 3) To enable students to experiment and make choices without incurring penalties or jeopardising their chances of successfully completing the synthesis. A) To provide a user interface which is as friendly as possible, so that students who are not familiar with computers can easily use the program. 5) To ensure that the names of the chemical compounds are consistent with the rules of the International Union of Pure and Applied Chemistry and that the chemistry content is accurate.

PAGE 1 ~.2 Amplification of aims

1.2.1 Devising synthetic routes

The concept of devising a route from one organic compound to another is not di~ficult. However. students often experience problems both in devising an overall route and in selecting appropriate reagents for each step. It is obviously time consuming and expensive to provide practical training in the laboratory. A computer is well suited to coping with the problem of route selection and to storing the data on compounds and their reactions with a series of reagents. A report by the chief examiners for Nuffield 'A' level

chemistry (~983) highlighted the difficulties students encounter in organic chemistry. tt Organic chemistry stands out as an area of concern, and this comment is not a new one. The present Nuffield 'A' level course contains about 50 basic organic reactions. .These could be said to form the core of factual knowledge necessary for the average candidate before he can operate ·with confidence at higher levels in organic chemistr~.n My program is intended to give help in applying this core of knowledge and in developing the higher level skills of devising routes for organic syntheses. A working party for the Royal Society of Chemistry reported recently on the use ot microcomputers in school chemistry

(~986). It saw the main areas of potential for computer programs for post-16 courses as being those applying to problem solving and organising chemical knowledge. Devising organic routes is clearly a problem solving activity. In order to help the students organise their chemical knowledge I

provided the chart given on page ~o which shows the relationships between compounds. I also grouped the chemical reactions used in the program into four classes.

PAGE 2 1.2.2 Learner Control To enable the students to have as much control as possible over their learning they should be able to choose either the compounds at the start and £inish or the level o£ di££iculty of the synthesis. This level of difficulty is determined by the minimum number o£ steps needed to get from the starting compound to the end product and whether the end product has a different number of carbon atoms from the starting compound. They should. in addition be able to select,- a) The level of help needed at any stage i.e. whether they wish to see the reactions of the starting compound. or ways to make the end product or the complete steps (compounds and reagents) from the starting compound to the end product. b) The amount of information displayed and type of information displayed at any stage. Thus at the end of the program they should be able to decide whether to see the preferred route for the synthesis, or the route that they have used (showing either all the reagents and compounds they used or showing just the compounds). c)The route taken by the program. Thus they should be able to decide at any stage to continue with the current synthesis. to restart with the original starting compound. to start another synthesis. or to end the program completely.

PAGE 3 1.2.3 Encouraging students to experiment freely

The report by a working part~ on the use microcomputers in school chemistry for the Royal Society of Chemistry (1986, p.7) expressed disappointment that little use was made of programs that allow students to prepare and test their own models. I decided to include comprehensive help facilities in the program so that students can explore different s~nthesis routes. The program is always able to provide them with sufficient help to complete the synthesis whatever the route taken. It is possible with any computer based learning system to include various methods for assessing performance. However. these generally act to discourage divergent thinking. Therefore I decided to omit such assessment and to include means to help students to recover from mistakes by enabling them to return to a previous compound. Thus they can retrace their steps· along the route.

PAGE 1I 1.2.U Friendly user interface

My aim was to provide a user interface which is was friendly as possible. so that students who are not familiar with computers can easily use the program. This involves the following considerations:- a) Limiting the keyboard input to single keys presses and grouping the keys to be used in a logical way. b) Ensuring that all input is validated and that the program is protected against accidentally pressing the escape or break keys. c) Keeping the screen disPlay as clear as possible. d) Ensuring that the students can see the names of all the compounds and reagents to which they ,need to refer.

1.2. 5 Chemical names consistent with IUPAC The rules for naming organic compounds have been drawn up by the International Union of Pure and Appplied Chemistry. They are usually known as the IUPAC rules and are gradually replacing the older. less systematic way of naming organic compounds.

PAGE 5 1.3 Description of Chemistry content

Our school uses the Nuffield 'A' level Chemistry syllabus. The present syllabus contains about fifty basic organic reactions. together with the names and formulae of the compounds involved. The majority of these reactions are a1iphatic reactions (i.e. they involve organic compounds which are not derivatives of benzene). Some of the older. more traditional chemistry syllabuses contain more than twice this number of reactions. I decided to limit the reactions used in the program to the a1iphatic organic reactions contained in the Nuffie1d s¥11abus, so that the program cou1d be used b¥ my own students. It can be used by students of other 'At level syllabuses, but will not cover all" the reactions that they need to know about. Nevertheless it should give them valuable experience of organic Syntheses. It is probable that the factual content of many syllabuses will be reduced to cope with the advent of students who have fo11owed GCSE courses. For instance, it is 1ike1¥ that reactions involving the addition of an extra carbon atom will be omitted from the Nuffield syl11abus. I have, therefore. put reactions involving such addition as a separate. option on the initia1 menu. Teaching scheme for the Nuffie1d s¥11abus The complete course is divided into two sections. The first section consists Of eighteen topics. four of which involve the chemistr¥ of carbon compounds (organic chemistr¥). The second section is an extended study of a special topic se1ected from five possib1ities. The eighteen topics of the basic course are elaborated in two students' books. one for each year of the course. Each book contains experimental work. discussion on underlying theory. background reading and problems. There are also two teachers' guides. A11 four books are edited b¥ B.J. Stokes (198U). The course aimed to break down the traditional boundaries between inorganic. organic and physical chemistry. However. the originators of the Nuffie1d course acknow1edged that it

PAGE 6 was advisable to deal specifically with carbon compounds. Thus Teachers' Guide 1 by B.J. Stokes (1981 p.x) states that "some time shall be devoted to a concentrated investigation of carbon compounds". Organic chemistry is introduced in topic 9. which starts with the rules for naming organic compounds. The compounds are divided into classes according to the groups they contain e.g. a1cohols all possess the hydroxyl group. OH. Groups such as the hydroxyl group are known as functional groups. Reactions of organic compounds are determined by the reactions of the functional groups they contain. The compounds are also named according to the groups they contain. A summary chart is given at the end of each organic topic to show the main reactions covered in the topic. It consists of a block diagram displaying the compounds involved in the reactions and indicating routes from one compound to another by arrows. For instance part of the chart surveying topic 11 reactions in Students' Book 1. B.J. Stokes (1981. p. 108) 1s as follows:-

ALCOHOLS IALDEHYDES I

ESTERS ACIDS

Students are asked to record on the chart details of the reagents and the types of chemical reaction involved. Some of the different types of reactions and reagents are detailed at the end of topic 9 in Students' Book 1. B.J. Stokes (1981. pp.319-320). For instance a substitution reaction is a reaction in which one group replaces another. an addition reaction is one in which one or more groups are added to a molecule to give a single product and an eli~ination reaction is one in which one or more groups are removed from a molecule. The students are also introduced to the terms to describe these reactions. such as nucleophilic Bubstitution and

PAGE 7 electrophilic addition. Nucleophilic substitution is substitution by a nucleophile- a compound (often with a negative charge) which has a pair o~ electrons available to form a new bond. Electrophilic addition is addition by a an electrophile- a compound (often with a positive charge) with a vacancy for a pair of electrons. Topic 17, the last topic on organic chemistry, ends with a section on routes for making organic compounds. This section is intended to provide opportunities to revise the reactions of the functional groups and of the reagents. and to provide knowledge of simple synthetic routes. Students' Book 2. 8.J. Stokes (198n. pp.321-325) gives the methods of preparation for ten different types of compound and gives a chart showing the inter-relationships between these compounds. I have provided a chart based on this 1n the students' guide to my program. However. the chart in the Nuffield Students' Book 1. B.J. Stokes 198n) does not display all the inter-relationships between the ten compounds. I have added the missing ones to my chart and have also added an extra compound, ammonium ethanoate, as it is a useful intermediate compound in a reaction sequence. The chart is shown on page 10. The program contains data on sixteen compounds which are members of one of the ten classes of compounds as follows:- compounds compound functional class group ethanoic acid. methanoic acid carboxylic acid COOH ethanal aldehyde HC~O ethanol, methanol alcohol OH ethene alkene HC=CH ethylamine. methylamine amine NH2 ethanamide amide CONH2 ethanenitrile nitrile CN ethylethanoate ester RCOOR' chloro- & bromoethane. chloro- & bromomethane halogenoalkane RX ethanamide acyl chloride COCl

PAGE 8 I have also indicated on the chart and in the program the type of reaction needed for the various conversions. This was done in order to encourage the students to think about the type of reaction they were using at each stage of the synthesis. I a~so hoped that the se~ection of the correct reagent would be easier if they were grouped according to the type of reaction they bring about.

I have used four reaction types:- i) redox (oxidation-reduction) reactions ii) e~1mination reactions iii) hydro~ysis and e~ectrophi~ic addition reactions iv) nuc~eophi~ic SUbstitution reactions. At the end of topic 17 students can be given an opportunity to plan and undertake a two or three step organic reaction in the laboratory. Even such a simple synthesis can take more than a week of laboratory time and some schools omit this practical experience of organic synthesis. In such a case a computer simulation of an organic synthesis is an obviouB alternative.

PAGE 9 Reaction routes for organic synthesis

I aldehyde l' ,,' .&" ...... ". '. , ".,... '" ,,,. .~, '" ,. ... " '" ... '"

acid •. , · . ~· '. . '" I I · \ ...... '''''. ! , I I I \ )$J~ I . . I I I \ .. : I I I chloride

I ~.

redox elimination hydrolysis and electrophilic addition nucleophilic substitution

PAGE 10 CHAPTER 2. Program desizn and implementation

2.1 Design of the User Interface

The main ways in which the user can interact with 8 pro~ram a~e by aialo~ue ¥OP BeQuentia1 pPo2ramB. by keyworas for command driven pro~rams and b~ single key presses, mice. cursors or joysticks ~or menu driven programs.

I wanted to allow the Users to have as much control as possible over their route throu~h the program and so did not consider using 8 sequential or linear structure for the program. I also decided not to use a command driven structure for the following reasons. Command driven programs are often difficult to operate at first when the user is unfamiliar with the keywords. They are best suited to a suite of programs. Also the keywords have either ~o be typed 1n full. represented by a single letter or abbreviated. If users have to enter full keywords they need to be fairl~ proficient typists and I wanted the program to be easily operated by students unfamiliar with keyboard layout. If users have to enter single letters they to need to be informed what the letters represent even if the intitial letter of a word is used to represent it. I wanted to keep the user documentation to a minimum and so decided to give this information on screen as each input ls requested. My main reason for not using a command driven structure is that it can be difficult for students to get a clear picture of the complete range of options open to them at different stages of the program. I felt that this could best been shown b~ a menu of options, which is also quick and simple to use.

I decided against using input b~ joysticks or mouse because again the user needs some familiarit~ with their usage. Also I wanted the program to be ss portable ss possible. This left me with the choice of two methods of selecting options from the menu. One is by the use of single keys for input. The other is by the use of cursor keys (or the spacebar) to cycle through the menu options, the chosen one being highlighted and its selection confirmed b~ using the return key. Ideall~ I would have likedt6 be able to allow

PAGE 11 the students to choose for themselves which of these methods they preferred. However. as the memory of the BBC computer is limited it was necessary to keep the program fro becoming too long. Moreover. I had insufficient time to develop both methods. Although the cycling menu is particularly easy to use I developed a program which selected options by single key input as this is a more common form of input. I chose to use the numeric keys to input choices which have a marked effect on the program as these are the easiest keys to use. Thus the choices of the difficulty of the synthesis. of the reactions and of the reagents use is made by numbers. I reserved the letter keys, which are harder for an inexperienced typist to find. to select further menus. The letters employed are the initial letters of the menu or action required so that they are easy to remember. H is used for the help menu. R for the reaction menu and M for the main menu. E is used to exit or end the program. G is used to give in or go back to a previous compound and N is used to start a new synthesis. These letter keys are also grouped on the keyboard. which makes them fairly simple to find.

Q w.lilIiil T Y U lOP

A S 0 F BIN J K L

ZXCBN[3 Grouping the keys in this way may Cause an inexperienced typist to choose an unwanted option through hitting the wrong key. For this reason I ensured that the user could always return to the main menu whatever the option selected. The only time they cannot do this is when deciding to give in. They are then warned that they will be unable to return to the menu if they choose this option. For my design of the control interface I used a check-list of design considerations given by K. Alexander and D. Blanchard (1985). Thus I tried to keep the user interface consistent within the program. The cursor only appears on the screen

PAGE 12 when a ,single key input is expected. The return key has to be pressed after such input and all input is validated. The cursor is disabled when the user has only to press the spacebar to continue to the next screen. All the menus are of the same form. The heading is given in green text, ~ollowed by the input requested in yellow text. The options available are detailed in cyan with their numbers in yellow. Finally a reminder of the input requested is given in blue lettering on a yellow bar. The Questions are always placed at the bottom of the screen. If the wrong input is given the reminder is repeated until the correct form of input is made. A window is used to hold the entire menu on the screen, so that it is not overwritten however many times the wrong input is made. I gave some thought to the way in which the single key input should be entered. I wrote a standard entry procedure whiCh used an input command. This meant that a user had to press return after making an entry. Thus an inexperienced user who might easily press the wrong key could quickly correct a wrong entry. The alternative was to use a get statement which accepts a single key press without the need to press return. Two experienced users commented that they preferred this alternative. Therefore I changed the program to allow users to select the form of input they wanted. The range of colours throughout the program is restricted. White, yellow, green and cyen are used for text. These colours have a high or medium perceived brightness. Black and blue are used as background colours as they have the lowest perceived brightness. I checked that the colours chosen gave a satisfactory display on two monochrome monitors, one green, one black and white. I also checked the colours with a table of recommended colour pairings given by D. Watson (1987).

PAGE 13 2.2 Description of the program

Students are posed the problem of converting one organic compound to another by selecting appropriate reactions and reagents. The data is stored for each compound as any array consisting of its formula and reactions, if any, with each of sixteen reagents. The reagents are split into four groups according to the type of reaction they bring about. These reaction types are given in section 3 of chapter 1 and the information is shown in tabu~ar form in appendix 6.5. The degree of difficulty of the conversion depends on the number of reaction steps required. The program is able to select a conversion which takes the number of reaction steps stipulated by the user.

A major feature of the program is its abi~ity to work out the optimal route between any pair of the seventeen compounds for which data is stored. It disp~ays a~~ the compounds and reagents involved in the route. Students can request this information at any stage of their synthesis route. The program then starts looking for a one step reaction route. This exists if one of the reaction products of the current compound· corresponds to the end product. Should the program fail to find a one step route it must then seek a two step route. In order to do this it searches for a one step route between each of the reaction products of the current compound and the end product. If this exists the conversion can be achieved in a total o~ two steps. I~ this search ~ails the program must look for a three step route. In order to do this it stores a~~ the precursors to the end product. These are compounds which can react in one step to make the end product. It then searches for a two step reaction between the current compound and each of the precursors. If this exists the conversion can be achieved in three steps. A search for a four step reaction commences when the search for a three step reaction ~ails. To do this the program finds a~~ the compounds which can be converted in one step to the precursors. Such compounds are two steps away ~rom the end product. The program then looks to

PAGE 14 see if any of them can be synthesised in two steps from the current compound. If this search succeeds the program has found a four step synthesis route. Thus the sequence of the search is as follows. First the program looks one step forward from the current compound. then two steps forward from it. then one step back from the end product and two steps forward from the current compound. ending with a search two steps back from the end product and two steps forward from the current compound. The program then displays the compound and reagent for each step in the reaction route. There are a few reaction routes in the program that take more than four steps. These all involve an end product which has one more carbon atom than the starting compound. To add an extra carbon atom a halogenoalkane (with one carbon atom) must be reacted with potassium cyanide to make ethane nitrile which has two carbon atoms. If the search fails to find a four step route the reaction must involve ethane nitrile as an intermediate compound. Thus the program initially seeks for the shortest route from the current compound to ethane nitrile. Then it lOOkS for the shortest route from ethane nitrile to the end product. It is able by this method to display the seven compounds and six reagents involved in a six step reaction route. The search for the optimum route is described in detail in section 3 of chapter 5. The program is driven by a series of menus which allow the user to select various options. These options are described in the following sections.

PAGE ~5 ) > 2.2.1 Selection o~ compounds Initiall}' the user is able either to determine the complex! ty of the synthesis route, ,which can invel ve from one

to six reaction steps. or to select one or both o~ the

compounds involved. I~ the}' opt to select one compound the program selects the other one. If they decide on a conversion in which the end product has more carbon atoms than the starting compound the program selects the appropriate

compounds. The ~irst compound is selected ~rom the ~irst eleven compounds which contain two carbon atoms. The end

product is selected ~rom the last ~ive compounds which contain only one carbon atom. If they stipulate the minimum number of steps in the s}'nthesis the selection of compounds is more complicated. The program has to find two compounds such that

the ~ollowing conditions are satis~ied i)the starting compound can be converted to the end product in

the required number o~ steps il)the conversion cannot be carried out 1n a smaller number of steps.

PAGE 16 2.2.2 Selection Of reagents

Once the compounds have been determined the user is asked to convert-the starting c~mpound to the end product and shown the main menu. The main menu allows the user to give UP. to request help or to select one out of four types of organic reaction. He can return to this menu at sny time if he needs to request help or wants to give In. If a reaction type is chosen from the main menu a further menu is displayed. This shows the four reagents appropriate for the chosen type of reaction. The user can opt to react the current compound with one of these four reagents. Al.ternativel.:? he can request to see the reactions Of the current compound with all four reagents. The program then checks whether the reagent reacts with the compound. If there is no reaction information to this effect is displ.a:?ed. If there is a reaction the program has to ascertain whether the reaction product can be used further in the synthesis. This involves establishing whether the reaction product corresponds to one of the seventeen compounds for which data ls stored. The user is informed if a reaction product cannot be used any further in the reaction scheme. The program then returns to the main menu to allow another reaction type to be chosen for the current compound or for help to be requested. The program must also check whether a reaction product corresponds to the end product. If the end product has been reached the message "Route completedtt is displayed and user is shown the end menu. If the reaction product does not correspond to the end product the user is returned to the main menu. They are then asked to convert the reaction product to the end product.

PAGE l.1 2.2.3 SeLection of heLp The heLp menu is dispLayed when heLp is requested. It allows the user to request the type of help needed. He can ask to see all the reactions of the current compound. or to see the methods of preparation of the end product. or to see all the steps to get from the current compound to the end product. After seLecting the type of heLp he is returned to the heLp menu and can request more help, or give up the current problem or return to the main menu.

2.2.U Decision to give up If the user decides to give up he is given the option of returning to a previous stage of the synthesis, returning to the main menu or giving up completely. He is warned that if the Last option is chosen he wiLL be unabLe to continue with the current synthesis problem. If he opts to return to a previous step 1n the reaction scheme all the compounds involved in their scheme are displayed. He is then asked to select one of these compounds. The curent compound is also dispLayed so that he can continue with this if he decides not to select one of the earlier compounds. The new current compound is set to the selected compound. The step number is altered to the steps from the starting compound to the new current compound. Finally the user is returned to the main menu.

PAGE L8 2.2.5 Options in end menu The end menu is displayed if the user decides to completely give up or reaches the desired end product. It gives the option of seeing the reaction steps taken and the reagents used. or of seeing the shortest possible route. or of ending the current synthesis problem. If the current problem ls ended the user can decide whether to end the program or to select a further conversion.

2.3 Demonstration of program running

The following section shows the screen displays as the program runs. Pages 20 to 36 are the screen dumps for a run in which the user is able to synthesise the end product without using the help facilities. A second run is presented on pages 37 to the end of the section. This run displays full use of all the options available to the user and especially the help facilities.

PAGE 19 You will be asked to convert one organic co~pound to another. The route for this ~ay take several steps. In the hardest one the end product has one ~ore carbon ato~ than the first co~pound.

You can ~ake your own choice of starting co~pound. Rlternativel~ you can select the degree of difficulty by choosing the ~ini~u~ nu~ber of steps required for the conversion. There is no penalty if you take ~ore steps than this. You can ask for help at any stage, or go back to a previous co~pound, and still continue with the synthesis.

Type the nu~ber for the choice wanted.

1 to pick a one step t~eact i on. 2 to pick a two step t~eact i on.

3 to pick t ht~ee Ot~ 11'0 t~ e steps. 4 to add a cat~bon atoM in the t~out e. t 5 to pick YOUt~ own COlllPO unds .

?3

PAGE 20 Convert ethyl ethanoate CH3COOC2H5 to a~~oniu~ ethanoate CH3COOHH4 Type the nUfflber of the reaction, or H for help, or G to give in. 1 Redox reactions 2 EliMination reactions 3 Hydrolysis & electrophilic reactions 4 Hucleophilic substitution

Convert ethyl ethanoate CH3COOC2H5 to afflffloniuffl ethanoate CH3COOHH4 Type the nUfflber of the reaction or R to see reaction products or M for the fflenu

9 heat+ acid 10 heat+ aqueous potassiuM hydroxide 11 add conc. sulphuric acid and water 12 treat+ sodiuM broMide&sulphuric acid

?10

PAGE 21 Convert ethyl ethanoate CH3COOC2H5 to a~~oniu~ ethanoate CH3COOHH4

Step 1 ethyl ethanoate heated + aqueous potassiuM hydroxide gives ethanol

Convert ethyl ethanoate CH3COOC2H5 to a~~oniu~ ethanoate CH3COOHH4 via ethanol C2H50H

Type the nu~ber of the reaction, or H for help, or G to give in or go back. 1 Redox reactions 2 EliMination reactions 3 Hydrolysis & electrophilic reactions 4 Nucleophilic substitution

, - /, ,-

PAGE 22 Con~ert ethyletflanoate CH3COOC2H5 :to aMMoniuM ethanoate CH3COOHH4 via ethanol C2H50H Type the nUMber of the reaction or R to see reaction products or M for the Menu

1 reflux+ excess cone. chroMic acid 2 heat+ dil. chroMic acid & distill 3 treat+ lithiuM aluMiniuM hydride 4

11

Convert ethyl ethanoate CH3COOC2H5 to aMMoniuM ethanoate CH3COOHH4 via ethanol C2H50H

step 2 et hano 1· t'ef 1 uxed + excess cone. chrOMic acid gives ethanoic acid 4-

PAGE 23 Convert ethyl ethanoate CH3COOC2H5 to a~~oniu~ ethanoate CH3COOHH4 via ethanoic acid CH3COOH

Type the nu~ber of the reaction, or H for help, or G to give in or go back. 1 Redox reactions

2 Eli~ination reactions 3 Hydrolysis & electrophilic reactions 4 Nucleophilic substitution

Convert ethyl ethanoate CH3COOC2H5 to a~~oniu~ ethanoate CH3COOHH4 viaethanoic acid CH3COOH

Type the nu~ber of the reaction or R to see reaction products or M for the ~enu

13 treat+ phosphorus pentachloride

14 treat+ a~Monia 1

114

PAGE 2U Convert ethyl ethanoate CH3COOC2H5 to aMMoniuM ethanoate CH3COOHH4 via ethanoic acid CH3COOH

Step 3 ethanoic acid treated + aMMonia gives aMMoniuM ethanoate We II done!! You have COMpleted the synthesis

Convert ethyl ethanoate CH3COOC2H5 to aMMoniuM ethanoate CH3COOHH4 via aMMoniuM ethanoate CH3COOH Route COMPleted!! Type the nUMber of the inforMation you require or type E to end.

1 f Ot' your reaction steps. 2 for your steps and reagents. 3 for the shortest route. 6

PAGE 25 Convert ethyl ethanoate CH3COOC2H5 to a~~oniu~ ethanoate CH3COOHH4

a~~oniu~ ethanoate can be ~ade fro~ ethyl ethanoate in 3 steps. 1.ethyl ethanoate is reacted + lithiuM aluMiniuM hydride to ~ake ethanol. 2.This is reacted + excess cone. chroMic acid to Make ethanoic acid. 3.This in turn is reacted + aMMonia to give aMMoniuM ethanoate.

Convert ethyl ethanoate CH3COOC2H5 to a~~oniuM ethanoate CH3COOHH4 Type the nu~ber of the inforMation you require or type E to end.

1 fot~ your reaction steps. 2 for your steps and reagents. 3 for the shortest route. 7

PAGE 26 Convert ethyl ethanoate CH3COOC2H5 to ammonium ethanoate CH3COOHH4 WELL DONE!! You took 3 steps The route you took was ethyl· ethanoate (reacting + aqueous potassi~M hydroxide ) ->ethanol (reacting + excess cone. chromic acid) ->ethanoic acid (reacting + aMMonia) ->ammoniuM ethanoate

Convert ethyl ethanoate CH3COOC2H5 to amMonium ethanoate CH3COOHH4 Type the number of the inforMation you require or type E to end.

1 f Ot~ your reaction steps.

2 f ot~ your steps and reagents.

3 f Ot~ the shortest route. B :: !

PAGE 27 GOODBYE

PAGE 28

/ Type the nu~ber for the choice wanted.

1 to pick a one step reaction. 2 to pick a_two step reaction.

~ to pick three or ~ore steps. 4 to add a carbon atoM in the route. 5 to pick your own cOMPounds.

Type the nu~ber of the choice wanted

1 to choose YOUt~ stat~ting cOMPound.

2 to .. choose YOUt~ end cOMpound.

3 to choose both co~pounds.

PAGE 29 Give the nUfflber of ~our first cOfflpound chosen froffl the list below.

1 ethanoic acid 10 ethano~l chloride 2 ethanal 11 aMMoniuM ethanoate 3 ethanol 12 Methanol 4 ethene 13 Methanoic acid 5 chloroethane 14 chloroMethane 6 broMoethane 15 broMoMethane 7 ethanaMide 8 ethanenitt~ile 9 ethyl ethanoate

Your first cOMpound is Methanoic acid

Give the nUMber of ~our end cOMPound chosen froM the list below.

1 ethanoic acid 10 ethano~l chloride 2 ethanal 11 aMMoniuM ethanoate 3 ethanol 12 eth~laMine 4 ethene 5 chlot~oethane 6 bt'OMoet hane 7 ethanaMide 8 ethanenitt~ile 9 ethyl ethanoate

PAGE 30 >

Convert Methanoic acid HCOOH to ethene CH2=CH2 Type the nUMber of the reaction wanted or H for help or G to give in . . . ' 1 Redox reactions 2 EliMination reactions 3 Hydrolysis & electrophilic reactions 4 Nucleophilic substitution

Convert Methanoic acid HCOOH to ethene CH2=CH2 Type the nUMber of the help wanted .."- or M for the fflenu or G to give in. 1 for reactions of Methanoic acid 2 for ways to Make ethene 3 to see all the reaction steps ? :f,::mllmi~mmmmmmmml,:mmil:mmmmm::m:::~iY:R:~:::i:ii::l:ll::~mi:i;m~i'~mi!l:mi~ii~iiimiiii,m:mmi~itlmmiii(1immmmimii:mm~mm~mmr~m:~mimmimm:m

PAGE 31 Methanoic acid reacted

1 + excess cone. chroMic acid-} -,.. cat~bon dioxide ". " 1 + lithiuM aluMiniuM hydride -} Methanol 2 + alcoholic potassiuM hydroxide-} potassiuM Methanoate 3 + aqueous potassiuM hydroxide-} potassiuM Methanoate

Further reactions of Methanoic acid 4 + phosphorus pentachloride-} Methanoyl chloride """ 4 + aMMonia-} aMMoniuM Methanoate 4 + ethanol & acid-} ethyl Methanoate mm::m~mm~m:!mm::lli:mi:~i:l:~~~lI:U:liE:S:Sim~mS:e,a:p:E:e\ai8:i~lmJ);(lim:mlPJ):"i~iJ;:UlU:E::~ij~;~mm~fwmmi:~~imf,lill

PAGE 32 Convert Methanoic acid HCOOH to ethene CH2=CH2 Type the nUMber of the help wanted or M for the Menu or G to give in. 1 for reactions of Methanoic acid 2 for ways to Make ethene 3 to see all the reaction steps

l' ~ll[m~~~ill~m~illm:m~~~mm~mm~~~ill~~~~~~mlmY;Bj~u~~ml~~mwmii2l[~~i~]u~m3.i]~~mmmm.mj!~jQ~ijjm~:Glml[mmlim]~m[im~~lm~mmmm~l~~~~mm~m "'.-."-

Convert Methanoic acid HCOOH to ethene CH2=CH2 ethene can be Made 2 by reacting ethanol + hotpot or aluMina 2 by reacting chloroethane + alcoholic potassiUM hydroxide 2 by reacting broMoethane + alcoholic potassiUM hydroxide

mm!tm~mm~mm~:!!mtm!!:m!!!:imm~:B!E!S!S!m!!ms:~!aJ::;!6!QlalB!mm!![!Qlm~mC,Ql"!m!;r;:tJlU:6~~~i~r~milii~ll~~mmm~!~m

PAGE 33 Conu~rt Methanoic acid HCOOH to ethene CH2=CH2 Type the nUMber of the help wanted or M for the Menu or 6 to give in. 1 for reactions of Methanoic acid 2 for ways to Make ethene 3 to see all the reaction steps

Convert Methanoic acid HCOOH to ethene CH2=CH2 This reaction takes More than 4 steps. To increase the nUMber of carbon atoMs you MUSt Make a halogenoalkane and then • react it with sodiuM cyanide in order to. Make ethanenitrile. - .

PAGE 3/( 1.Methanoic acid is reacted + lithiuM aluMiniuM hydride to Make Methanol. 2.This is treated + phosphorus pentachloride to Make ch I Ot~OMet hane . 3.This in turn is treated + alcoholic sodiuM cyanide to give ethanenitt~ile. Please riote down these interMediates

,! ~; ~. .~ ~. e ene can e rOM e anenitrile steps. 1.ethanenitrile is reacted + acid to Make ethanoic acid. 2.Thls is treated + lithiuM aluMiniuM hydride to Make ethanol. 3.This in turn is treated + hot pot or aluMina to give ethene. Please note down these interMediates 1~~m::m:m~~mmmmmm[i~~mm:m:R:8:El$.:S:[im:ilS:R:A:elE[B[6i8[iim:lmlmQmmii:eiQ:tJm:J;,U,U:Eim~;;;mmil~mm~mmltm[j]m

PAGE 35 Chapter 3. Comparison with other software

3.1 Introduction

I have been able to obtain three other programs which give students experience in solving organic synthesis problems. All three programs are available from AVP Computing. Chepstow. The t'irst two programs, "ORGANIC SYNTHESIS" by P.M. Smi th (1987) and "ORGANIC CHEMISTRY" by Salisbury Chemistry (1985) are each on a single disc. "ORGANIC CHEMISTRY PART 1. ALIPHATIC REACTIONS", by G.Hall (1986) is supplied on two discs, one ot' which holds a database on organic reactions.

All three programs. like m~ own. ask the user to convert a starting compound to an end product via a series of reactions. The main differences between the programs are in the amount of control the user has in choosing the synthesis problem and in the help t'acilities available. Each program is reviewed in turn. The review consists of a short description of the program. followed by an assessment to see how well it fulfills the educational aims stated in Chpater 1.

3.2 Comparison with "ORGANIC SYNTHESIS" by P.M. Smith (1987) The package consists ot' a disc, a short, three page booklet and a loose sheet containing loading instructions for the BBC

Master series The two t~pes of program avai~able are :- 1. Organic synthesis on the screen. 2. Printed questions using an Epeon FX printer. It is suggested that students should start with the printed questions as they are generally easier than the conversions. I attempted to use the second program which gives printed questions, but the program crashed at'ter printing the t'irst Question. so I was unable to test it further.

Description ot' "ORGANIC SYNTHESIS" by P.M. Smith (1987)

The program is menu driven. but only uses three menus compared with the eight menus in my program. The user can select three levels ot' questions. Level 1 restricts the selection to 6 compounds and 15 reagents. Level 2 selects t'rom four compounds and 25 reagents. Level 3 uses all the rea~ents and compounds with two functional groups.

PAGE 36 Once one of three levels has been selected the screen clears to show the synthesis problem. The screen display is divided into four sections. The first section shows the current compound. Underneath this is the section giving a list of instructions for input. Next the conversion problem is displayed on a coloured bar e.g.CONVERT bromoethane to ethanoyl chloride. Finally the reaction sequence so far is displayed. The only help the user can request is to see the reactions of the current compound. If the start option is requested the synthesis problem restarts with the original compound.

Assessment of "ORGANIC SYNTHESIS" by P.M. Smith (1987) i) Learning and experiencing organic synthetic routes The stated aim of the program is to help students learn the organic reactions required for 'A' level Chemistry. It does allow students to practise organic reactions. However, I feel, that it does not meet my first stated aim which is to enable students to become familiar with organic synthesis. The routes selected on the easiest level can involve up to six steps. Even very able students are unlikely to succeed in following routes of such complexity and thus completing a synthesis. The average student would be completely lost and the program does not allow students to ask to see the correct route. so they are unable to learn by their mistakes. ii)Learner Control This program does not give students much control over their learning. This program, 1n contrast to mine. does not enable students to select particular compounds, whose reactions or synthesis they need to practise. Nor can they select the degree of difficultY.of the synthesis route i.e. the number of steps involved. They are only able to choose the range of reagents and compounds from which the program selects. As mentioned above the help available is restricted to seeing the reactions of the current compound. The user does not have the facilities available in my program to see the ways of

PAGE 37 preparing the end product or the best route to it. Nor has the user any control over the amount of information displayed at any stage. With only two menus to use the learner has little control over the route taken by the program. The user can. however. request to restart the synthesis. beginning again with the initial compound. They cannot. as in my program. reQuest to go back to one of the intermediate compounds in the reaction route.

iii)Experimenting Students can tryout different reactions and, as mentioned above, restart the synthesis.

iv)User interface Keyboard input is limited to single Key presses followed by return. The keys used are not grouped on the keyboard, but this is probably not necessary when so few keys are used. The program does not accept lower case letters and users are not warned to ensure that the caps lock is off. The escape key is disabled. but the breaK Key is not. The screen display was rather distracting. The flashing arrow at .the bottom of the screen drew attention away from the input cursor which looked lost in the middle of the screen! The chemical formulae for the compounds in the reaction sequence are well displayed. but the user cannot choose whether or not to Bee them. One of the worst features of the program was that it was Quite difficult to list the reagents available. They should certainly have been given in the user guide and have been more accessible within the program. In order to select a reagent the user has to enter a single number representing it. Its name of the reagent is not shown on the screen.

v) Organic Names and Chemistry Content In several cases the names used were not consistent with the accepted IUPAC names e.g. propanonitrile was given rather than

PAGE 38 propanenitrile and ethanamine rather than ethylamine.

As fa~ as I COUld ascertain the Chemistry of the pro~ram was correct. The reactions and compounds went ~ar beyond the scope of the Nuffield Chemistry syllabus. Because of this. the general complexity of the synthetic routes. and the limited help facilities I felt the program would not be useful to my students.

3.3 Comparison with "ORGANIC CHEMISTRY PART 1. Aliphatic Reactions" by G. Hall (1986)

The package has been reviewed by P.E. Catermole (1987) . It consists of documentation and two discs. One disc contains the program for the organic synthesis problems. The other disc contains a data base of information on all the main classes of aliphatic compounds. This database- can be accessed at any stage during a preparation sequence. There is also a similar package for aromatic compounds and the two packages can be purchased together or separately.

Description of the program "ORGANIC CHEMISTRY PART 1." by G. Hall (1986) The program is menu driven. Like my own program, but unlike the "ORGANIC SYNTHESIS" program by P.M. Smith (1987), it uses

a large number o~ menus. The initial menu gives a choice o~ a

preparation sequence or of using the database. I~ the database is selected the databse disc has to be loaded. The user then has a choice of classes of compounds. Once a class has been selected the user can call up either reactions or preparation of the chosen class. Problems at two levels of difficulty can be selected by the program or by the user. Once a problem has been chosen the main menu is displayed. It displays clearly the starting

PAGE 39 compound. the end compound and the current compound. It also gives the user a choice of 60ptions:- 1. Display structures of compounds 2. Carry out next step of synthesis 3. List sequence so far. U. See a so1ution to this prob1em 5. Se1ect a different svnthesis 6. Go back to previous intermediate The database can be accessed at all stages.

Assessment of "ORGANIC CHEMISTRY PART 1." bv G. Ha11 (1986)

i) Learning and experiencing organic synthetic routes

This program does allow students to practise organic reactions, but does pose routes which are far too difficult for the average student to complete. Some of the routes took six steps. The review bV P.E. Catermo1e (1987) points out that the easiest level cou1d prove taxing for an • S· 1eve1 candidate. The program does. however, provide a fair amount of he1p if a user needs it.

ii)Learner contro1 The program provides a reasonable degree of learner control. but with several important omissions. The user is not restricted to syntheses picked bV the computer as in the "ORGANIC SYNTHESIS" program bv P.M. Smith (1987). He can se1ect from a 1ist of svntheses with a stated starting and end compound. My program, however. allows the user to select either or both of these compounds. The main lack of learner control is in the selection of the degree of difficu1tv of the synthesis. Whereas my program enables the user to stipulate the number of steps needed to complete the synthesis. this program only permits a choice of two levels of difficu1tv. Nor does it exp1ain the difference between the two levels. I assume that the more difficult one uses more compounds and reagents.

PAGE UO Ttle J)l"o~rSJn, 1ike my own, haB COnlDl"etlenB1ve tlel.D f'a.cil.i t1ee. It allows the user to look at reactions of the current compound and at methods of preparation of the end product. However. if the user requests a solution to the problem they are only given a route from the original starting compound to the end product. It is not able to provide a route from the current compound to the end product as my program does. The learner is not always able to control the amount of information displayed. If a reaction is selected the user is asked to load the database disc. They are then given several screens of information about the chosen reaction, which they may not wish to see. The preparation sequence disc then has to be reloaded. When the user asks to use a reagent the list of reagents available is restricted to those which react with the current compound. Unfortunately this list scrolls over the display showing the current status i.e. starting compound, current compound and end product). It would have been very easy to keep this vital information on display in a text window. The learner does have control over the general route taken by the program. They can abandon the synthesis at any stage. They can also go back, as in my program, to any previous intermediate. iii) Experimenting Students can experiment freely within the program. Unfortunately. as mentioned previously. they are restricted to seeing a solution to the shortest route rather than the route they select themselves. My program does allows them to see a solution to their own route.

iv)User interface Students who are not familiar with computers would probably have some difficulty in using the program. if their computer was equipped with a single disc drive. The program uses both discs and this involves a fair amount of changing discs. The program is particularly easy to use 1n some respects as all input is limited to numeric key. All input is validated.

PAGE In It is. however. quite easy to stop the program running as neither the escape nor break keys are protected. The program also stops if it is unable to access the database when needed. This could happen if the wrong disc is in the drive. On one occasion it crashed with the correct disc in use. The screen display is very good. The reaction sequences are very clearly shown using displayed formulae. In this respect this program is much superior to "ORGANIC SYNTHESIS" by P.M. Smith (1987). The only fault with the display was the one mentioned previously i.e. vital information is lost from the screen due to scrolling. v) Organic Names and Chemistry Content The chemical names used are consistent with the IUPAC rules. However, some of the chemical information within the program is incorrect. Aqueous potassium manganate(7) is used as an oxidising agent and ammonia is said to react with esters to give amines. Neither of these reactions are correct.

3.U Comparison with "ORGANIC CHEMISTRY (synthesis of aliphatic substances)" by Salisbury Chemistry (1986)

The package consists of brief documentation and a disc

tt containing two programs. One, ttOrganic Nomenclature • is on the naming of organic compounds. The other. "Synthesis of aliphatic SUbstances". like the previous two programs and my own program, poses aliphatic synthesis problems.

Description of "ORGANIC CHEMISTRY" by Salisbury Chemistry (1986)

The program starts with a menu which allows the user to see information about both programs or to them. There is a lengthy pause if the synthesis program is selected and the user is warned that it takes about 12 seconds to read the data and to work things out. The program then displays details of the help

PAGE U2 facl~lties avai~ab~e. The program starts by giving the starting compound. the end product and the minimum number of steps needed to get from one to the other. The user has to enter the name of the compound in the next stage of the synthesis. A list of sixteen reagents is then displayed and the user has to select the appropriate reagent to prepare the compound. They are informed if they select the wrong reagent and the correct reagent is displayed. The program continues until the user either decides to exit or manages .to synthesise the end product. In the latter case their intermediate compounds are displs¥ed together with the details of their score, number of mistakes and requests for help. Finally the intermediate compounds in the optimum route are given.

Assessment of "ORGANIC CHEMISTRY"

by Sa~isbury Chemistry (1986) i) Learning and experiencing organic synthetic routes Few students will be able to complete the organic synthesis problems posed by this program. A number of the compounds selected by the program are rather obscure and the synthesis routes often involved a very large number of steps. for instance seven and eight step routes were selected by the program.

ii) Learner control This program. unlike my own, does not allow the learner to exercise much control over their learning. They cannot easily

se~ect the degree of difficu~ty of the synthesis. The introduction to the program suggests that the user selects

this by pressing break unti~ they hit upon a synthesis with the required number of steps. The user cannot opt to practise the synthesis or reactions of particular types of compounds. Some help facilities are available, but users are discouraged from using them as points are deducted from their final score if help is requested. As in my program reactions of the current compound can be requested. Similarly the user

PAGE A3 can ask to see compounds from which the end product can be prepared. The program does not show a route from any compound to the end compound at any stage of the route as my program does. It only displays the shortest route from the starting compound to the end product when the s~nthesis has been completed or given up. iii) Experimenting The students are not discouraged from experimenting since they are not penalised if they use a long route from the starting compound to the end product. However. the program does not give sufficient he~p faci~ites to a~~ow them to experiment freely. iv) User interface

I found this program the most difficu~t of the three to use.

The program did not a~ways disp~a¥ the names of the current compound and the end product as the other two programs and my own program do. In a long synthesis the user might well forget what stage had been reached. The program also asked for input without reminding the user what the numbers and letters represented e.g. "Enter 1.2 or Cif. The disp1ay was not always clear. In particular the red letters on a black background did not show up well.

V) Organic Names and Chemistr¥ Content Unlike my program and the other two programs. this program gives and accepts both the revised IUPAC names and the older, non-systematic names for chemical compounds. The IUPAC names

are usua~IY given first with the other name in brackets. However the program did not always adhere to this order, for instance ethyl ammonia. the non-systematic name, was followed

b¥ eth¥~amine. the IUPAC name. The chemistry content was correct apart from one mistake- the

reaction of alcohols with h~drogen halides was not recognised b¥ the program.

PAGE UU Chapter a.Testins U.1. Design of tests

I agree with the view of Deryn Watson (1987 p.129), that a trial has more relevance if the program is tested at the time when the teacher is tackling that part of the curriculum. I would like to have been able to test program at such a time. The program is intended to complement the work on organic synthesis in Topic 17 of Nuffield 'A' level chemistry which is normally covered towards the end of the spring term. This would have been the ideal time to test the program. but an impossible one as this project was started inthe summer and had to be completed by the following January. Therefore I had to compromise and decided to test a preliminary version o~ the program at the beginning of the summer term with students

~rom my school who were revising for the 'A' level examinations. This would give me Borne idea of how suitable the program was and what modifications were needed to improve it.

I then asked colleag~es at my school and other schools to test the finished program in the autumn term using students who had covered the basic organic reactions needed for the program. Unfortunately these students had not by then reached the stage of tackling the organic Bynthesis problems. Thus the program introduced them to the concept of organic synthesis rather than reinforcing the work they were doing on it with their teachers. In order to evaluate the program I designed a Questionnaire to send to teachers. with a scale of rating 1 to 5 for each question. I decided to use this type of Questionnaire, rather asking for written comments, because the Quality and depth of written replies can vary so much and I wanted to obtain a consistent picture of teachers' reactions. I left space on the questionnaire for additional comments and suggestions, so that I would still be able to obtain detailed responses from anv teacher who wished to provide additional information.

U.2 Preliminarv testing

The program tested at this stage differed from the final program in several respects. The main differences were in the degree of help available to the students and in the degree of

PAGE U5 control they had over selecting suitable synthesis problems. The help facilities were limited to displaying the reactions of the current compound and the methods of preparation of the end product. The program was not able to compute routes from the current compound to the end product. The choice of synthesis problem was limited to selecting from the following:- 1) a one step reaction, 2) a two step reaction, 3) one involving two to four steps or 4) one involving the addition

of a carbon atom. Students were not able to select speci~ic compounds. There was no guide for teachers or students at this stage. The preliminary program was used by two of my colleagues at

Grob~ Communit~ College, Mrs. J. Craig and Ms. L. Ta~lor, with

groups of their seventh ~ear students. I also observed one of the groups using the program. Ms. Taylor pointed out two errors in the names of the organic compounds and these were corrected in the final version of the program. Ms. Craig felt that the program was best suited for use by individual students or small groups. She noticed that the less able students in a large group did not contribute to the general discussion about which reactions to use. Therefore. when I wrote the teachers' guide I recommended that the program was used by small groups or by individuals. Mrs. Craig also pointed out that students need to have done a fair amount of revision before using the program. If they have not got this background knowledge she felt that using the program could make them more confused. She had noticed that some students became involved in long syntheses more by luck than judgement!

Ms. Taylor suggested that a preliminar~ program was needed to revise basic organic reactions. I also observed that less confident students did not tackle the multi-step routes, but

requested only single step preparations. Thus the~ were using the program to revise organic reactions rather than to

practise organic synthesis. Two students asked me to modif~ the program so that they could practise the reactions of

specific compounds. I added this faci1it~ to the program.

PAGE ~6 4.3 Fina~ testing

The later version of the program was tested by my two colleagues and by a student from our school working at home. by Mr M.W. Frew of Longs~ade Co~~ege. Birsta~~, and by Mr. N.

Chapman, a student at Ash Lawn High Schoo~, Rugby. They a~~

comp~eted the questionnaire about the program and had the students' and teachers' guides. I also had some comments on

the program from Dr. C. Sutton of the Schoo~ of Education, Leicester University Some more modifications were made to the program as a . result of the feedback I received. The answers to the'Questionnaires were as follows:-

Question A.l

Do you consider that the program was best suited to use by

a)individua~ students

b)sma~~ groups

c)a who~e c~ass?

One rep~ied individua~ students and sma~~ groups, stipu~ating

"NOT who~e c~ass", one rep~ied individua~ students and three

rep~ied sma~~ groups. One of the students who used it on his own thought it best for sma~~ groups, whereas the other one thought it best for use by individua~s.

Question A.2

Which of the above used the package?

Two answered individua~ students, three rep~ied sma~~ groups. question A.3

Did the program generate discussion? (omit if on~y used by (a)

PAGE 47 Question A.7

Are they familiar with computer packages?

Everyone said yes to this.

Question A.8

What. if any. problems occurred whilst using the program?

Two teachers pointed out that students were sometimes given the same one-step reaction a second time. There are over thirty possible one-step reactions. so I did not think originally that repetition would be a problem. In response to this information I modified the program to ensure that there was no repetition of any of the synthesis problems. Educational Content

Please use the following ratings when completing the rest of the form:-

i-unacceptable/not at all lI-well 2-poor 5-very well 3-average 6-not tried/not relevant

Question B.1

How well do your students usually cope with this topic?

The answers to this ranged from poor to very well!

PAGE 118 Question B.2

Do ~ou think the program assists students with their understanding of organic synthesis reactions? The answers to this were evenly divided between well and very we~~.

Question B.3

How do you think the program assists students with their recall of organic synthesis reactions?

Again the answers to this were evenly divided between well and very well.

Question B.1I

Do you think the package meets its stated aims?

Three replied very well and two well.

Question B.5

How appropriate is the package ~or the task?

The answers to this were evenly divided between good and very good.

Question B.6

The program was designed to be as flexible as possible so that students can control 'their own learning. How well does the program meet this aim? Three replied ver¥ well and two replied well.

PAGE 119 Question B.7

Please give any changes that you think would improve this fexibility·or the program in general.

One teacher asked for more one-step reactions. In fact all the one-step reactions summarized in chapter 17 of Nuffield 'A' 1eve1 Chemistry Book 2 (?) are inc1uded in the program. The same teacher asked me to ensure that synthesis problems did not repeat. As mentioned previously this change was made to the program at a later stage. One student said that he did not like pressing the return key after each input. Therefore I modified the program to allow the user to dtermine the mode of input used.

Question B.8

Is the chemical content of the package accurate? Please detail any errors.

No errors were reported in the later version.

Presentation and ease of use

Question C.1

How easily can the package be used by a student with 1itt1e experience of computers?

Four answered very easily and one answered average.

Question C.2

How easy was the menu structure to use?

Three answered very good, one good and one average.

PAGE 50 Question C.3

How did you find the help option?

All rated this very good. One colleague had rated the help option on the preliminary program as poor.

Question C.1l

How well did the program deal with wrong responses?

Two said very well. one said well and one said average.

Question C.5

How 'clear was the overall screen presentation?

Three replied good, one very good and one average.

Question c.6

How easy was it to fPol1ow the program instructions?

Three said very easy and two said easy.

Question C.7

How useful was the teachers· guide?

One teacher said very useful. one said useful and one said it was not needed as all the information was in the students' guide.

PAGE 51 Question c.B

How useful was the students' guide?

Only one person thought that the students' guide was useful. The others pointed out that students invariably ignore program documentation.

Further suggestions for improving the package

It was suggested that more one step react~ons from the first year of the course might be added. The same teacher also suggested that the chart displaying the ~eactions between all the compounds should be available within the program as students rarely consult program documentation. Such a display would need windowing facilities which are not available on the BBC microcomputer.

4.4 Conclusions

My program has two main features which none of the three programs reviewed in Chapter 3 possess. Firstlv it allows the user to determine either the degree of difficultv of the synthesis or the compounds involved in the synthesis. Students can select a synthesis involving one step, two steps. three or four steps. or one that necessitates adding a carbon atom (this could be up to six steps long). Alternativelv thev can select either the starting compound. the end product or both compounds. Secondly it allows the user to see the optimum route from any compound they have synthesised to the end compound. Another feature of my program not possessed by the others is that it groups the reagents according to the type of reaction thev bring about. This encourages the students to think about the type of reaction involved at each stage of the svnthesis and makes it easier to select a suitable reagent. The results from the trials at a small number of schools

PAGE 52 were very encouraging and surprising~y consistent. They indicated that my program was suitab~e for use either by individual students or small groups. When used in small groups it generated discussion within the group. My own impression Prom my observations was that the program was more SUccess full with students of above average ability. They often used it for long periods. The student who rated himself as as more able ran the program for three hours without a break! However. all the users thought that it was suitab~e for the who~e abi~ity range. The program was considered to assist students with their understanding and recall of organic synthesis. It was also felt that it met my other educational aims.

The he~p option was rated high~y by a~~ the users. They also considered that the clearness of" the instructions and the flexibilit¥ of the program were above average. Most users also thought it above average in the following respects:- ease of

use of menu structure 9 overall screen presentation, ability to deal with wrong responses and the ease of use by stUdents with

~itt~e experience of computers (in fact no students in this category used the program). A majority of users fe~t that it was not necessary to supply a students' guide. This justifies my initia~ decision to put as much information as possib~e within the program rather than in the stUdents' guide. The teachers' guide was generally thought to be useful.

The overall success of the program can be gauged by the following comment by one of the teachers who tested the program. Mr M.W. Frew (~987)_ "The program was 'student friendly' and allowed them to obtain help or move on from their failures. I was very impressed by the program and the value of its use as a student self revision tool. The program was extreme~y friend~y. Especia~~y encouraging was the fact that students cou~d get out of prob~emsand obtain he~p at any point."

PAGE 53 CHAPTER 5. Program Design

5.1 Data Structure

The data is organised to store the details of seventeen compounds and their reactions. if any. with sixteen reagents. These details are stored as a two dimensional array. The sixteen reagents are 8S follows:­

1- treat$(1 ) exess chromic acid 2. treat$(2)' dil chromic acid 3. treatt(3) lithium aluminium hydride U. treatt(U) hydrogen & metal catalyst 5. treat$(S) strong heat 6. treat$(6) phosphorus pentoxlde 7. treat$(7) alcoholic potassium hydroxide S. treat$(S) porous pot or alumina 9· treatt(9) acid 10.treatt(10) aqueous potassium hydroxide 11.treat$(11) conc. sulphuric acid then water 12.treat$(12) sodium bromide&sulphuric acid 13.treat$(13) phosphorus pentachloride 1U.treatt(lU) ammonia 15.treat$(15) ethanol & acid 16.treat$(l6) alcoholic sodium cyanide The sixteen reagents are divided into four groups of four. according to the type of reaction they bring about.

The reaction types are grouped as follows:- 1. type$(l) Redox reactions 2. typet(2) Elimination reactions 3. typet(3) Hydrolysis and electrophilic reactions U. type$(U) Nucleophilic substitution.

The data is read in by the procedure PROCdata. This sets up the text colours and sets step%. the number of steps from the starting compound to the end product, to zero. It also sets check$, the string storing the numbers of the chosen compounds, to a nul string. It then assigns the total number of compounds, cmpdtotal%, to 17 and the total number of

PAGE SU reagents. reactotal%. to 16. Next it reads the four reaction types. followed by the conditions for the sixteen reactions. start$(1) to start$(16) and the sixteen reagents. type$(1) to type$(16). Finally the procedure reads the array of compounds and their products with the 16 reagents. FOR cmpd%=1 TO cmpdtotal% READ formula$(cmpd%) FOR react%=O TO reactotal% READ item$(cmpd%.react%) NEXT react% NEXT cmpd% The first element of the array. when cmpd%=l. is as follows:- "CH3COOH". ethanoic acid. D. O. ethanol. 0. 0. 0. 0. potassium ethanoate. 0. potassium ethanoate. 0. 0. ethanoyl chloride. ammonium ethanoate. ethyl ethanoate. 0 CH3COOH. formula$(1). is the formula of the first compound and ethanoic acid. item$(1.0). is its name. Then follows the reactions of ethanoic acid with each of the sixteen reagents. Zero indicates that no reaction occurs. For instance ethanoic acid does not react with the first two reagents. so item$(l.1) and item$(1.2) are both equal to zero. Ethanoic acid does react with the third reagent. lithium aluminium hydride to make ethanol and with the fourth reagent to make ethanal. Thus item$(1.3) is ethanol and item$(l.U) is ethanal.

The seventeen compounds are:- 1. ethanoic acid. 2. ethanal, 3. ethanol. U. ethene. 5. chloroethane. 6. chloroethane. 7. bromoethane, 8. ethanamide. 9. ethyl ethanoate. 10. ethanoyl chloride. 11. ammonium ethanoate. 12. ethylamine. 13. methylamine. lU. methanol. 15. methanoic acid, 16. chloromethane, and 17. bromomethane. Two of the compounds. ethylamine and methylamine, do not react with any of the reagents. They can only be used as end compounds, not as starting compounds. The chart in appendix 6.1 shows the relationships between the starting compounds. reagents and reaction products.

PAGE 55 5.2 Introduction to the prOgram

PROCintro gives the introduction to the program as fOllows. ORGANIC SYNTHESIS

"You will be asked to convert one organic compound to another. The route for this may take several steps. In the hardest one the end product has one more carbon atom than the first compound."

The user is then asked to press the spacebar. After this has been done the next part of the introduction is given.

"You can select your own compounds. A1ternatively you can select the degree of difficult~ b~ choosing the minimum number of steps required for the conversion. There is no penalty if you take more steps than this." The user is again asked to press the spacebar and the end of the introduction is given.

"You can ask for help at any stage or go back to a previous

I compound and still continue with the synthesis. '

The next screen gives the user the OPtion of pressing return after an entry. The screen is cleared and the stepmenu is displa~ed. This gives the user the choice of selecting compounds, (start compound, or end compound. or both) or selecting the degree of difficult~ (one step, two steps, three or more steps, or a synthesis requiring a carbon atom to be added). The structure diagram for the step menu is shown overleaf.

PAGE 56 STRUCTURE DIAGRAM FOR 'STEPHENU'

STEP -MENU

enter 1-5 5

want choose own 2step 3atep menu

enter 1-3 1-3 pick pick pick pick own EJown latep lstep lstep latep falae 0<.' true false false EJ 1.2

find prior ~ EJ

seek precu step2 -rsor

found 2step

PAGE 57 5.3 Selection of start and end compounds Option 1.0ne step reactions If the user selects a one step reaction then the procedure pick~step(TRUE) is ca~~ed.

DEF PROCpick~(boolean) REPEAT

step(~)=FALSE

IF pick%=n now%=RND(n)+~3 ELSE now%=RND(~2)-~ IF now%=O now%=2

end%=RND(~2)

FOR react%=~ TO ~6

IF item$(now%.react%)=item$(end%.O) step(~)=TRUE NEXT react%

UNTIL end%<>now% AND step(~)=boolean ENDPROC

Step(~) is set to false snd now%. the index of the starting compound. is selected randomly. For a one step reaction now% is chosen from numbers between 1 and 11. Compounds twelve and thirteen cannot be used as starting products. Compounds fourteen to seventeen have one carbon atom less than the other compounds in the data. These are selected if pick%=n i.e. the user wants to add a carbon atom during the synthesis. The end product is then selected from the first twelve compounds which are all compounds with two carbon atoms. The index of the end product is end%. The progrsm then checks if the initial compound. item$(now%.O). reacts with any of the sixteen reagents to produce the end product. item$(end%.O). If this is the case step(~) is set to true by the line IF item$(now%.react%)=item$(end%.O) step(~)=TRUE. The procedure is repeated until step(~) is true. the indices of the starting and end compounds are different and have not been stored together in check$ i.e. this pair of compounds has not been selected previously.

PAGE 58 Option 2. Two step Reactions

If a two step reaction is requested then the program has to select two compounds such that one can be converted into the other in two steps. but not in one step. The procedure picK1step(FALSE), described above, is used to picK such a pair of compounds such that the starting compound "and step(2) is set to false. Each of the reaction products of the starting compound, trY$. has to be checked to see whether it has any reactions i.e. if it corresponds to one of the first eleven

compounds in the data base. This is carried out b~ the

procedure PROCfind(tr~$,end$).

DEF PROCfind(tr~$,end$)

FOR cmpd%~1 TO 17

IF item$(cmpd%,O)=tr~$ PROCseeK2step NEXT cmpd% ENDPROC

If this procedure identifies the reaction product, tr~$, with a compound, item$(cmpd%,O) it calls the proced1ure PROCseeK2step. This checKs whether this compound can be

converted into the end compound ~n one step i.e. whether any of its reaction products corresponds to the end product.

DEF PROCseeK2step

tr~%~cmpd% FOR act%=1 TO reactotal%

IF item$(tr~%,act%)=end$ PROCfound2step NEXT act% ENDPROC If a two step reaction is found then the procedure PROCfound2step is called. This stores the compounds and reagents required for the two step reaction and sets step(2) to true.

PAGE 59 Option 3. Three or more steps

If the third option is se1ected then a pair of compounds must be found such that one cannot be converted to the other in either one or two steps. For such compounds, providing the starting compound is selected from the first eleven compounds. the conversion will take either three or four steps. Conversions taking more steps than this involve the addition of a carbon atom as detailed 1n the next section.

The procedure PROCchoose3step ~irst calls pick1step(FALSE) to select a conversion taking more than one step. Step(2) is set

to ~alse. PROCprior is called and this in turns calls PROCprecursor. These two procedures respectively find and store the array of compounds, prior$(tot%), and of reagents, endreact$(tot%), prior to the end product, item$(end%,O).

DEF PROCprior tot%=O FOR cmpd%=l TO 17 FOR react%=l TO 16 IF item$(cmpd%,react%)=item$(end%,O) PROCprecursor NEXT react% NEXT cmpd% ENDPROC

DEF PROCprecursor tot%=tot%+l prior$(tot%)=item$(cmpd%,O) endreact$(tot%)=treat$(react%) ENDPROC The procedure choose3step checKs each of the reaction products

o~ the starting compound in turn to see i~ they match one o~ the precursors. If they do a two step reaction has been found. step(2) is set to true and the loop control variables, react% and no% are set to stop the loops. Count controlled loops are used rather than REPEAT UNTIL loops to speed up the search.

PAGE 60 CnooBe3Btep repeats tne 8ea~Cn until. a pail' of! comDoundB naB been :f'ound fol' wnicn one and two step conversions are not possible.

DEF PRoccnoose3step REPEAT step(2)=FALSE

PROC~i~kl~t~~(FAL§E) PROCprior FOR react%=l TO 16 FOR no%=l TO tot% IF item$(now%,react%) = prior$ (no%) THEN step(2)=TRUE:no%=tot%+1:react%=17 NEXT no% NEXT react% UNTIL NOT step(2) ENDPROC

Option U. Adding a carbon atom.

If! tnis option is selected tnen tne stal'ting compound nas to have one carbon atom less tnan tne end product and tne conversion nas to take more than one step. Pick1step(FALSE) is used to select the starting compound. item$(now%.O), from the last four compounds 1n the data base. These compounds. which only contain one carbon atom. are picked by setting now% to RND(U)+13.

Option 5. User picks their own compounds.

If! this option is selected a menu of possible choices is displaved. The user has to decide whether to choose 1. the starting compound. 2. the end product or 3. both compounds. If they decide to pick only the end product start% is set to

~alse otherwise it ls true. The procedure ownpick is called. This displavs possible compounds and asks the user to select

PAGE 61 one. If start% is true the range o~ compounds displayed as possible starting compounds is compounds 1 to 17. with compounds 12 and 13 omitted. If start% is false the range of end products displayed is compounds 1 to 12. If the user only wants to choose one compound the procedure random is called to select the other compound. Otherwise ownpick is used again, with start% set to ~alsel for the user to select an end product. If the user selects the same start and end compounds err is set to true and PROCerr is called. This points out their mistake and asks them to choose again. PROCstepmenu is repeated until err is ~alse.

Storing variables

When the start and end compounds have been selected PROCvar is called. This stores the initial compound as beginS, the end compound as seeK$ and the first compound used as act$(O). If necessarv it calls PROCprior and PROCprecursor to find out and store the precursors and reagents leading to the end product. Reaction sequences involving the addition of one carbon atom can take up to six steps. If help is requested with such a conversion the search for the reaction steps will be slow. PROCprior and PROCprecursor are used at this stage in order to save time when such help is requested. The major part of the program now commences with the main menu displayed by calling PROCmenu. The structure diagram for this is shown overleaf.

PAGE 62 STRUCTURE DIAGRAM FOR THE MAIN MENU

MENU

G

Enter React Help 1 - 11 -ants H • G

Products Help menu

Enter 1 - 3 M • G

1 2 G

Reacts Route Aid in steps Menu

Enter M,R.G

Main No Back end menu steps menu

Aid steps

PAGE 63 5.3 Help menu

If help is requested PROChelp is called and the help menu is displayed as shown on the screen display on page 33. The user is returned to the help menu until they e1 ther type "M" to return to the main menu or type "G" to give up.

DEF PROChelp help=TRUE REPEAT PROChelpmenu IF answer$="l" PROCreacts IF answer$="2" PROCroutes IF answer$="3" PROCaidsteps IF answer$<>"M" OR answer$<>"G" PROCspace UNTIL answer$="M" OR answer$="G" ENDPROC

The help menu gives the user the option of:- 1. calling PROCreacts to see the reactions of the current compound - item$(now%.O).

2. calling PROCroutes to see ways to make the end product - item$(end%,O)

3. calling PROCaidsteps to see all the reaction steps between the two compounds.

Alternatively they can choose to return to the main menu or to give up or go back to a previous compound.

PAGE 611 Reactions of the current compound

PROCreacts is called. This looks at the reaction product of the current compound with each reagent in turn. When a reaction product is found PROCviewreacts is called. This procedureincrements the count of reaction products. It also d l svl a~!; I.hfo~ t"eaction prc1du.:t e..nd ttl-= rE'BC+?l1t ttl·9.t i;:o. n-=-=,jE-':! for its preparation.

DEF PROCreacts count%=O FOR react%=1 TO reactotal% IF item$(now%.react%)<>"O" PROCviewreacts(react%) NEXT react% PROCspacebar ENDPROC

DEF PROCviewreacts(J%) count%=count%+l

IF count%/5 = INT(count%/5) PROCnewpage("reactions".item$(now%.O) PRINT ;vellow$;FNreaction(3%); PRINTcyan$;"+ ";treat$(J%);arrow$ PRINTcyan$;" ";item$(now%.J%) ENDPROC

If more than five such products are displayed on the screen PROCnewpage is invoked to hold the display on the screen until the space bar is pressed. The screen is then cleared and the remaining reaction products and reagents are displayed.

PAGE 65 Ways to make the end product

The algorithm to display the ways to prepare the end product is similar to that which displays the" reactions of the current compound. PROCroutes is called. This looks at the reaction products of the starting compound with each reagent in turn. When a reaction product is found which matches the end product PROCgiveinfo is called. This procedure increments the count and displays the compound and the reagent needed to react with it to make the end product.

DEF PROCroutes CLS PRINT'green$;seek$;" can be made" count%=O FOR cmpd%=l TO cmpdtotal% FOR react"=l TO reactotal% IF item$(cmpd%,react%)=seek$ PROCgiveinfo NEXT react" NEXT cmpd% PROCspacebar ENDPROC

DEF PROCgiveinfo count%=count%+l IF count%/S=INT(count%/S) PROCnewpage("preparations",seek$) PRINT';yellow$;FNreaction(react%);cyan$;

PRINT"by treating ";item$(cmpd%.O);" with I' PRINTcyan$;treat$(react%) prior$(count%)=item$(cmpd%,O) ENDPROC

PAGE 66 The steps between the starting and end compound

PROCaidsteps is called if the user asks to see the shortest route between the current compound and the end product. In order to find this optimum route the program first must look for a one step reaction. If this fails it must search for a two step route. If this search is unsuccessful it must try for a three step route. Should it fail to find this. it must seek for a four step route. Before starting these searches PROCin1t sets all the steps to false.

DEF PROCinit FOR N%=O TO U step(N%)=FALSE NEXT N% ENDPROC

The structure diagram for the search is shown overleaf on page 70. PROCaidsteps calls PROCinit and then PROClooklstep. This procedure looks for a match betwen the reaction products of the current compound and the end prOduct. If such a match is found it calls the procedure lstep.

DEF PROClooklstep FOR react%=l TO reactotal% IF item$(now%.react%) = seek$ PROClstep NEXT react% IF NOT step(l) PROClook2step ENDPROC

PROClstep displays the one step reaction. sets step(l) to true and stops the search by setting the loop control variable. react%. to reactotal%+l. If looklstep fails to find a one step reaction it calls PROClook2step to seek a two step reaction.

PAGE 67 STRUCTURE DIAGRAM FOR PROCEDURE 'AID STEPS'

AID STEPS

In1t step

step(l} step(l} TRUE FALSE

look c::J 2step step(2) step(2)

I:::!p I~ __FS_:_~T:_E ____ ~ J 3s tep

step(3) step(3) TRUE FALSE

try llstep

query lletep

step(ll) step(ll) TRUE FALSE

~ind L_f_1_n_d___ --I L_~_~_:_!_:_ __I l-_f_1_n_d__ -, L_~_~_:_~r:__ .J c::J

give Ilstep

PAGE 68 DEF PROClook2step FOR react%=l TO reactotal% IF item$(now%.react%)<>"O'·PROCfind(item$(now%.react%).item$(end%. o ) ) NEXT react% IF step(2) PROC2step ELSE PROCseek3step ENDPROC

Look2step takes each reaction product of the current compound in turn. It uses PROCfind(try$.end$) to see whether these products have any reactions i.e. if they correspond to one of the first eleven compounds in the data.

DEF PROCfind(try$.end$) FOR cmpd%=l TO cmpdtotal% IF try$=item$(cmpd%.O) PROCseek2step NEXT cmpd% ENDPROC If this procedure identifies the reaction product. try$. with a compound, item$(cmpd%.O) it calls the procedure

PROCseek2step. This determines whether ~his compound can be directly converted to the end product.

DEF PROCseek2step try%=cmpd% FOR act%=l TO reactotal% IF item$(try%.act%)=end$ PROCfound2step NEXT act% ENDPROC If look2step fails to find a two step reaction it invokes seek3step to search for a three step reaction. Seek3step looKs for a two step route between the current compound and each of the precursors, prior$(no%), to the end product. Hence it 1s very similar to look2step, but involves two loops instead of one.

PAGE 69 DEF PROCseek3step FOR nO%=1 TO tot% FOR react%=1 TO reactotal%

IF item$(now%.react%)<>"O'~ PROCfind(item$(now%.react%}.item$(prior$(no%}} NEXT react% NEXT no% IF step(3} PROCbeginstep ELSE PROCtry4step(tot%) ENDPROC

PROCbeginsteps displays all three steps of a three step route and the first three steps of a four step route.

PROCtry4step(tot%} identifies the compounds. item$(compd%, 0). from which the precursors to the end product can be made. These are compounds two steps away from the end product. It then looks for a two step route from the current compound to these compounds.

DEF PROCtry4step(tot%) FOR no%=l TO tot% FOR compd%=l TO cmpdtotal% FOR agent%=l TO reactotal% IF item$(compd%,agent%)=prlor$(no%) PROCquery4step(item$(compd%.O) NEXT agent" NEXT compd%

IF NOT step(4) PROCxtra ENDPROC

PAGE 70 If PROCtryUstep finds a compound. item$(compd%.O). which is two steps from the end product. it only remains to see whether this compound can be made from the starting compound in two steps. This search is performed by PR()Cg\j(!r·'y"ll!;t(~j..I('ooi-;.$) whi(!h is virtuaLLy identicaL with Look2step.

DEF PROCqueryUstep(Look$) FOR react%=l TO reactotal% IF item$(now%.react%)<>"O" PROCfind(item$(now%.react%).Look$) NEXT react% IF step(2) PROCyesUstep ENDPROC

PROCyesUstep stops the three Loops by setting the Loop controL variables. it stores the steps and reagents to the end product.

It can be seen from the reaction routes diagram on page 10 that it is possible to get from any compound to a compound with the same number of carbon atoms in four steps or less. If more than four steps are involved the required route must invoLve the addition of a carbon atom. This is achieved by heating either chloromethane or bromoethane with alcoholic potassium cyanide to form ethanenitrile. In such a case the program uses the PROCxtra to split the route into two. This procedure searches for ways to get from the current compound to ethanenitrile and then for ways to get from ethanenitrile to the endproduct. In order to do this it has to store the indices of the current starting compound and the current end product as temporary variables.

PAGE 71 DEF PROCxtra REM Route has more than II steps & goes via ethanenitrile. tempnow%=now% tempend%=end%

CLS VDU 23.1.1;0;0;0; PRINTcyan$:item$(now%.O);" to "jseek$ PRINT'cyan$:"This reaction takes more than U steps." PRINT'cyan$;"To increase the number of carbon atoms" PRINT'cyan$;"yoU must make a halogenoalkane and then" PRINTcyan$;"react it with sodium cyanide in order" PRINT'cyan$:"to make ethanenitrile." end%=8:item$(end%.O)="ethanenitrile" PROCspacebar PRINTcyan$;"Stage 1"; PROCprior PROCl.ookl.step PROCspacebar now%=8 end%=tempend%:via$="t. PRINTcyan$;"Stage 2"; PROCprior PROCinitstep PROCl.ookl.step now%=tempnow% via$="tt PROCspacebar ENDPROC

The procedure PROCxtra sets the end compound to ethane nitrile and searches for a route to prepare it from the current compound. It first calls PROClooklstep to search for a one step reaction. The search continues until a route is found. This is then displa¥ed and. the end compound is restored to the original one. The current compound is set to ethanenitrile. PROCinit is cal.l.ed to set the step variabl.es to fal.se.

PAGE 72 PROClook1step is again called to start the search for the shortest route from ethane nitrile to the end product. This is displayed when it has been found and the current compound is restored to its original form.

PAGE 73 Bibliography

Chief Examiners (1983), Examiners' Report for Nuffield 'A' level Chemistry, University of London. Stokes B J (1984), Revised Nuffield Advanced Chemistry, Students' Books I and 11 and Teachers' Guides I and 11, Longman Group Ltd. Alexander K and Blanchard D (1985), Educational Software a creator's handbook-. Tecmedla. Salisbury Chemistry (1985), Organic Chemistry, Synthesis of Aliphatic Substances, BBC Disc COM 21, AVP Computing. Hall G (1986), Organic Chemistry, Part 1. Aliphatic reactions, Science Education Software Ltd. Smith P M (1987), Organic Synthesis, BBC Disc COM 64, AVP Computing. Working group for The Royal Society of Chemistry (1986), THE USE OF MICROCOMPUTERS IN SCHOOL CHEMISTRY, Council for Educational Technology Watson D (1987), Developing CAL: Computers in the Curriculum, Harper EdUcation Series.

PAGE 74 6.1 Reaction diagrams

REDOX REACTIONS

Chrom~c ac~d Chrom~c ac~d Li thium Alum. Hydrogen • metal (excess. cone) (d~lute) Hvdride catal~st

Ethanoic o o Ethanol o acid

Ethanel IEthanoic acid IEthanoic acid I Ethanol o I I I

Ethanol IEthanoic acid I Ethanal o o I I

Ethene I Ethene diol I Ethene diol Ethane o I I

Chloro o o Ethane o -ethane

Bromoethanel o o Ethane o I

Ethanamide I o o Ethylamine o I

Ethane . I o o Ethvlamine o -nitrile I

Ethvl o o Ethanol o ethanoate I

Ethanoyl o o Ethanol Ethanel chloride

Ammonium o o o o Ethanoate I

Ethylamine I o o o o I Methyl o o o o -amine

Methanol IMethanoic acidl Methanal o o I I

Methanoic ICarbon dioxidel o Methanol o acid I I

Chloro o o Methane o -methane

Bromo o o Methane O' -methane

PAGE 75 HYDROLYSIS AND ELECTROPHILIC REACTIONS

Acid Potassium Cone. Sul.ph. Sodium bromide hydroxide acid, then & sulphuric (aqueous) . water. acid

Ethanoic o Potassium o o acid ethanoate

Ethane1 IEthane! trimerl Ye1l.ow resin I o o 1 1 1

Ethanol. o o o I Bromoethane 1

Ethene o o Ethanol I Bromoethane 1

Chl.oro o Ethanol o o -ethane I

Bromoethanel o Ethanol o o 1

Ethanamide I Ethanamlde Potassium o o I h~drochloridel ethanoate

Ethane I Ethanoic acidl Potassium o o -nitril.e 1 1 ethanoate

Ethyl. o Ethanol. o o ethanoate I

Ethanoyl. 1 Ethanoic acidl Ethanoic acidl o o chl.oride 1 1 1

Ammonium o Potassium o o Ethanoate 1 ethanoate

Ethyl.amine 1 o o o o 1 Methyl. o o o o -amine

Methanol o o o I Bromomethane I 1 1

.. ~ Methanoic o Potassium o o acid methanoate , Chloro o Methanol. .1 o o -methane 1

Bromo o Methanol. o o -methane

PAGE 76 ELIMINATION REACTIONS

Stronst heat Phosphoros Potassium Porous pot pentoxide hydroxide or a1umina (alcohoLic)

Ethanoic o o o Potassium acid ethanoate

Ethana1 o o o I Tribromo I -ethane

Ethano1 o o o Ethene

Ethene o o o o

Ch1oro o o Ethene o -ethane I

Bromoethanel o o Ethene o 1

Ethanamide I o Ethane o 1 Methylamine . I -nitrile I

Ethane o o o o -nitrile

Ethyl o o o o ethanoate I

Ethanoyl o o o o 1 chloride 1

Ammonium 1 Ethanamide 1 Ethanenitrilel o o Ethanoate 1 1 1 Ethylamine 1 o o o o I

Methyl o o o o -amine

Methanol o o o o

------Methanoic o o o I Potassium acid I methanoate ------·Ct11oro o -I o o o -methane 1 '-. Bromo o o o o -methane

PAGE 77 NUCLEOPHILIC SUBSTITUTION

Phosphorus Ammonia Ethanol. Sodium cyanide PentaChl.oride and ac:1d (al.cohol.ic)

Ethano1c Ethanoyl Ammonium Ethyl. o acid chloride ethanoate ethanoate

Ethanal. IDich1oroethanel A pol.ymer Acetal Ethana! I I cyanhydrin

Ethanol. I Chl.oroethane I o o o I I

Ethene o o o o

Chl.oro o Ethy1amine o IPropanenitril.el -ethane I I I

Bromoethanel o Ethyl.amine o IPropanenitrilel I I I

Ethanamide I o o o o I

Ethane o o o o -nitril.e

Ethyl. o Ethanamide o o ethanoate I

Ethano.vl o Ethanamide Ethyl o ch10ride ethanoate

Ammonium o o o o Ethanoate I

Ethyl.amine I o o o o I Methyl. o o o o -amine

Methanol. I Chl.oromethanel o o o I I

Methanoic Methanoy1 Ammonium Ethyl o acid ch10ride methanoate methanoate

Ch1oro o Methylamine I o I Ethanenitril.el -methane I I I

Bromo o Methylamine I o I Ethanenitrilel -methane I I I

PAGE 78 6.2 Program listing

10 CLEAR 20 DIM ite.'I17,17), starll(17), acll I17) , fortulal117l 30 DIMreactl!I7), treats !Ill , usedll171 40 DIM typel141, priorlllOI, stepl41, endreactlllOI 50 MODE7 60 tn 200,1 70 REM disable escape 80 tV,EY 10 OLD MRUN M:REM disable break 90 PROCdata lOO REPEAT 110 VDU26 120 PROCintro 130 REPEAT 140 PROCstep.enu 150 UNTIL NOT err 160 PROCvar 170 REPEAT 180 REPEAT 190 REPEAT 200 REPEAT 210 PROC.enu 220 UNTIL replyl()'H' OR replyl='S' 230 IF replyl()'S' PROCreactants 240 UNTIL replyl()'H' OR reply'='S' 250 IF replyl='R'PROCproduct5 260 UNTIL repIyl()'M' OR replyl='S' 270 IF replyl()'S'PROC5taqes ELSE PROCqivein 280 UNTIL found OR an50er'='S' 290 REPEAT 300 PROCendlenu 310 UNTIL an5Merl='E' 320 PROC.indo.121 330 PROCcontinue 340 UNTIL ans.erl='E' 350 END 360 370 OEF PROCerror 380 PROCcontinue 390 IF an5.erl='E' THEII ENO 400 ENDPROC 410 420 DEF PROCdata 430 qreenl=CHRI130:yello.,=CHRI131:bluel=CHRI132:cyanl=CHR1134 440 backl=CHRI157:doublel=CHRI141 450 arro.'='_)':copdtotal7.=17:reactotal!=16:5tepl=0:err=FALSE:checkl=" 460 FOR NI=I TO 4 470 READ typellNZI 480 HElTNl 490 FOR N7.=1 TO reactotall 500 READ startIIH!I,treatIINll 510 HElTNl 520 FOR copd7.=1 TO copdtotall 530 READ for.ulallcopdll 540 FOR reactl=O TO reactotal! 550 READ ite.'lcopdl,reactll 560 NEXT reactl 570 NEXT copdl 580 ENOPROC

PASE 79 590 600 DEF PRDCwindo.llineZI 610 RE" clears a text window of lineZ lines. 620 YDU 26 630 VDU 28,O,24,39,IineZ 640 CLS . 650 ENDPROC 660 670 DEF PROCtitleltextl,groundl,titlel1 680 RE" Title in double height letters centred on coloured bar 690 length!=LENltitlell 700 space7.=134-lengthZI/2 710 FOR NZ=I TD 2 720 PRINTdoublel;groundl;b,ckl;text';SPCsp,ceZ;titlel 730 NEXT )IZ 740 ENDPROC 750 760 OEF PROCbarltextl,groundl,titlel1 770 REM title centred on coloured bar 7BO lengthX=LENltitlell 790spaceX=136-lengthII/2 BOO PRINT·groundl;backl;te,tl;SPCspace7.;titlel BIO ENDPROC B20 830 OEF FNreactionIJ7.I=INT!.7S'JI/41 840 OEF FNuppercaselreplyll=CHRIIASCreplyl-321 850 860 OEF PROCenterlentryl1 870 RE" Sets text HindoH.lnputs ,nd checks entry 880 VOU 28,0,24,39,18 890 REPEAT 900 PROCb,rlyelloHl,bluel,'Type "entryll 910 VDU 23,I,I;0;0;0;:RE" cursor on 920 IF returnI INPUT ans.erl ELSE ,ns.erl=6ETI:PRINTans.erl 930 ,ns.erl=LEFTllans.erl,11 940 IF ASCans.erl)96 THEN ans.erl=FNuppercaselans.erll 950 UNTIL INSTRlentryl,ans.erll)O 960 VDU 23,I,OjOjOjOj:RE" cursor off 970 PROC.indo.151 980 ENOPROC 990 1000 DEF PROCspacebar 1010 PROCbarlyello.I,bluel,'PRESS SPACE BAR TO CONTINUE'I 1020 ans.erl=6ETI 1030 CLS 1040 ENDPROC 1050

PA6E 80 1060 OEF PROCintro 1070 YOU 23,I,O;0;0;0;:RE" cursor off 1080 CLS 1090 PROCtitl.ly.lloHt,blu.I,'OR6ANIC SYNTHESIS') 1100 PRINT"'You Hill b. ask.d to conv.rt on. organiccolpound to anoth.r, '; 1110 PRINT'Th. rout. for this .ay take s.v.ral st.ps,'; 1120 PRINT' In the hard.st on. the .nd product has on. lor. carbon atol than the first coopound,' 1130 PROCbarly.lloHt,blu.I,'PRESS SPACE BAR TO CONTINUE') 1140 ansH.rl=6ETI 1150 PROC.indoHIIO)

1160 PRINT'·You can select the compounds, or you canselect the I j 1170 PRINT'd.gr •• of difficulty of the conv.rsion by picking the oini.u. nu.b.r of st,ps it tak.s, Th.r. is no p.nalty if you take .or. st.ps than this,' 1180 PROCHindoH(18) 1190 PROCspac.b.r 1200 CLS 1210 PRINT'You can ask for h.lp at any stag', or go back to a pr.vious ccopound, and still continu. Hith the synthesis,- 1220 PROCspac.bar 1230 PROCHindoH(2) 1240 PRINT"'To lak. your choic.s you n•• d only type on. I.tter or nuob.r, You can d,cid. if you Hant to pr.ss r.turn aft.r an .ntry,' 1250 PRINT'lf you can oak. an .ntry corr.ctly you oay pr.f.r not to have to pr.ss r.turn .ach ti •• , Do you Hant to press it each tile?- 1260 REPEAT 1270 PROCbarly.lloHt,blu.t,'Typ' Y or N') 1280 ansH.rt=6ETI 1290 UNTIL INSTRI'yyNn',ansH.rl)O 1300 IF ansH.rt='Y' OR ansH.rl='y' r.turn%=TRUE ELSE r.turn%=FALSE 1310 PROCHindoH(2) 1320 ENDPROC 1330 1340 DEF PROCvar 1350 RE" s.ts start variabl.s, If n.c.ssary calls PROCprior 1360 found=FALSE 1370 b.ginl=it •• tlnoHi.,O) 1380 firstforol=foroulatlno.%) 1390 acttIO)=b.gint 1400 s•• kt=it •• II.nd%,O) 1410 IF NOT st.plll AND pickl()3 PROCprior 1420 PROCHindo.(4) 1430 ENDPROC 1440 1450 DEF PROC.rr 1460 .rr=TRUE 1470 PROC.indoH(2) 1480 PRINT'y.lloHI;'You have chos.n the sao.' 1490 PRINTy.lloHI;'starting and .nd cO'pounds,' 1500 PRINT'y.lloHI;'You lust chaos. again,' 1510 PROCspacebar 1520 ENOPROC 1530

PAGE 81 1540 DEF PROCpicklst.p(bool.an) 1550 RE" IF bool.an=TRUE ch.cks for 1 st.p r.action. 1560 RE" IF bool.an=FALSE ch.cks for lor. than 1 st.p 1570 REPEAT 1580 ,t.p(I)=FALSE" 1590 IF pick%=4 nOH7.=RND(4)'13 ELSE nOHl=RND(II) 1600 .nd7.=RND(12) 1610 nOMI=STRlnoMl 1620 .ndl=STRI.ndI 1630 FOR r.actl=1 TO r.actotall 1640 IF it.o$(.ndI,O)=it •• '(noMI,r.act,) st.p(I)=TRUE 1650 RE" true if it.o$(.ndI,O) is a product of it ••'(no.7.,O) 16~0 NEXT r.actl 1670 UNTIL .nd%()noH7. AND st.p(I)=bool.an AND (INSTR(ch.c",no.!'.nd$))=Q 1680 ch.c'$=ch.ck$'no.$'.ndl 1690 ENDPROC 1700 1710 DEF PROCMant2st.p 1720 RE" Ch.eks .ach product until a 2 step reaction found 1730 REPEAT 1740 PROCpicklstep(FALSE) 1750 step(2)=FALSE 1760 FOR reactl=1 TO reactotal1 1770 IF ite.'(noH',react,)(),O' PROCfind(it.ol(noM',reactI),ite.$(endI,O)) 1780 NEXT reactl 1790 UNTIL step(2) 1800 CLS 1810 ENDPROC 1820 1830 DEF PROCfind(tryl,endl) 1840 RE" Finds if the products are starting coopounds 1850 FOR eopd'=1 TO 17 1860 IF it •• $(elpd',O)=try$ PROCs"'st.p2 1870 NEXT copdI 1880 ENDPROC 1890 1900 DEF PROCs"'st.p2 1910 RE" Finds if the product of a starting coopound is the .nd eoopound 1920 try,=clpdl 1930 FOR aet7.=1 TO 16 1940 IF it •• $(try7.,actI)=.nd$ PROCfound2st.p 1950 NEXT aet7. 1960 ENOPROC 1970 1980 DEF PROCfound2st.p 1990 RE" stor.s cOlpounds &r.ag.nts for a 2 st.p r.action 2000 st.p(2)=TRUE 2010 via$=it •• S(tryI,O) 2020 us.dl(I)=tr.atS(r.actI) 2030 usedS(2)=tr.atS(actI) 2040 IF us.dl(2)='dil. chrolic acid L distill' THEN us.dl(2)=us.dl(2).'.d' 2050 clpdI=17 2060 actI=17 2070 ENDPROC 2080

PASE 82 2090 DEF PROCchoose3,tep 2100 REPEAT 2110 step 121;FALSE 2120 PROCpicklsteplFALSEI 2130 PROCprior 2140 FOR reactI;1 TO 16 2150 FOR noI;1 TO totI 2160 IF ite.llnooI,re,ct%l;priorllnoII stepI21;TRUE:noI;totl+l:react%;17 2170 NElTnoI 21BO NEITre.ctI 2190 UNTIL NOT stepl21 2200 ENOPROC 2210 2220 OEF PROCoonpick 2230 RE" User picks starter, o.itting ethylaoinel121 and .ethylalinel131 2240 RENor user picks end compound 2250 IF .ant1.;3 AND NOT st.rt% PRINTyelloofj'Your first co.pound is 'jite.llnooI,OI 2260 PRINTyelloolj'Give the nu.ber 01 your'j 2270 IF start, PRINTyelloolj'lirst coopound' ELSE PRINTyelloolj'end coopound' 22BO PRlIHyelloolj'chosen Iroo the list belo.,' 2290 PROC.indool61 2300 IF startI endI;2 ELSE end%;3 2310 REPEAT 2320 PRINT 2330 FOR c.pd%;1 TO end% 2340 PRINTjyello.ljcopd1.jcyanljite.llcopd1.,0IjTABI17Ijyello0Ijcopd%+9jcy.nljite.llc.pd%+9,01 2350 NEIT 2360 FOR copd%;end%+1 TO 9 2370 PRINTjyello.ljclpdljcyanljite.Slcopd%,Olj 23BO IF clpd%+9<16 AND start% PRINTjyello.ljTABIIBljc.pd%+9jcy.nljite.licopd%+11,01 ELSE PRINT 2390 NEXT c.pd, 2400 PRINT' 2410 VDU 2B,0,24,39,IB 2420 VDU 23,1,ljOjOjOj:REH cursor on 2430 IF start% fin%=15 ELSE lin%;12 2440 REPEAT 2450 PRINT'blueljbackljyello.lj' Enter a nUlber fro. I to 'jlin% 2460 INPUT replyl 2470 no,=VALlreplyll 24BO UNTIL no7.>O AND noI11 AND st.rtI no%=noI+2:pickI;4 2500 CLS:PRINT" 2510 PRINTyelloolj'You have chosen 'jite.llno%,OI 2520 PRINTyello.ljlor.ul.llno,lj' Is this correct?' 2530 PROCenterl'Y,N'1 2540 UNTIL .ns.erl='Y' 2550 IF st.rtI nooI;no% ELSE end%;no% 2560 IF 0.nt%<>3 PROCr.ndo. 2570 PROCoindo.121 25BO ENOPROC 2590 2600 OEF PROCr.ndol 2610 REM picks r.ndol cOlpound 2620 REPEAT 2630 IF st.rt% end%;RNDI121 ELSE no.1.;RNDI171 2640 UNTIL endI<>no.% AND nooI<>12 AND noo%<>13 2650 ENOPROC 2660

PAGE B3 2670 OEF PROCslep.enu 2680 RE" AlloNs a choice of nUlber of sleps 2690 PRINT"y,lloNS;'Type Ihe nUlber for Ihe choice Nanled,' 2700 PRINT"yelloNS;'I';,yanS;'lo pick a one slep reaclion,' 2710 PRINT'yelloNS;'2';cyanS;'lo pick a INO slep reaclion,' 2720 PRINT'yelloNS;'3';cyanS;'10 pick Ihree or .ore sleps,' 2730 PRIHT'yelloNS;'4';cyanS;'lo add a carbon alol in Ihe roule,' 2740 PRINT'yelloNS;'s';cyanS;'lo pick your Don coopounds,' 2750 PROCenlerl'l, 2, 3, 4 or 5') 2760 pick!·YALlans.erS) 2770 PROC.indo.(2) 2780 IF pick!" PRIIH'cyanS;'Picking compounds, Please .ail' 2790 YOU 23,1,0;0;0;0; 2800 IF pickl·j PROCpickislep!TRUE) 2810 IF pickl'2 PROC.anl2slep 2820 IF pickl'3 PROCchoose3slep 2830 IF pickl·4 PROCpicklsleplFALSE) 2840 IF pickl'5 PROCo.n.enu 2850 EIIOPROC 2860 2870 OEF PROCo.n.enu 2880 RE" user picks one or both cOlpounds 2890 e"'FALSE 2900 PRIHT'yelloNS;'Type Ihe nu.ber of Ihe choice .anled' 2910 PRINT'yelloM'j·l·;cyanSj·to choose your starting compound,' 2920 PRINT'yello.S;'2';cyanS;'lo choose your end co.pound,' 2930 PRIIH'yel1oNS; '3';cyanS; '10 choose bolh coopounds,' 2940 PROCenlerl'l, 2 or 3') 2950 .anll·YALlansNerl) 2960 IF .anll·2 slarll'FALSE ELSE slarIX'TRUE 2970 PROC.indo.12) 2980 PROCoNnpick 2990 IF Nan1I'3 slarl'FALSE:PROCoHnpick 3000 IF endI'no.! PROCerr 3010 EHDPROC 3020 3030 DEF PRDC.enu 3040 RE" Choice of reaclion Iype, help or give in 3050 help·FALSE 3060 PRDCoindo.12) 3070 PRINTgreen$j'Convert ';beginf;' ';firstforaS 3080 PRINTgreenS;'lo ';ile.Slend7.,O);' ';forlulaSlendl) 3090 IF beginS(}ile.Slno.l,O) PRINTgreenS'v;a ';;leoSlnool,O);' ';forouIaSlnoH!) 3100 PRINT'yello.S;'Type Ihe nuober of Ihe reaclion .anled' 3110 PRINTyellooS;'or H for help or S 10 give up'; 3120 IF slep!)O PRINT'yelloNS;'or go back,' ELSE PRINT',' 3130 FOR H!'I TO 4 3140 PRINT'yeIIo.S;HI;:PRINTcyanS;lypeSIHI) 3150 NEXT HI 3160 PROCenlerl'l, 2, 3, 4, H or S') 3170 replyl'ansoerS 3180 IF replyS"H' PROChelp 3190 ENOPRDC 3200

PASE 84 3210 DEF PROChelp.enu 3220 REM Choice of type of help 3230 PRINT'yelloNlj'Type the nUlber of the help Nanted' 3240 PRINT'yelloNlj'or Mfor the lenu or S to give up'j 3250 IF stepI}O PRINT'yelloNlj'or go back,' ELSE PRINT',' 3260 PRINT'yelloMlj'I'jcyanlj'for reactions of 'jitelllnoNI,O) 3270 PRINT'yelloNlj'2'jcyanlj'for Nays to .,ke 'jitelllendI,O) 3280 PRINT'yelloNlj·3·jcyanlj·to 5ee ,11 the reaction steps' 3290 PROCenterl'l, 2, 3, Mor S') 3300 IF ,nsNerl='S' THEN replyl='S' 3310 ENDPROC 3320 3330 DEF PROCendlenu 3340 RE" Choice of seeing reaction steps or shortest route 3350 CLS 3360 IF found PRINTgreenlj'Route coapleted'!' 3370 PRINT'yelloNlj'Type the nu.ber of the infor.,tion you' 3380 PRINTye!1oMlj 'require or type E to end,' 3390 PRINT'yello,lj'I'jcy,nlj'for your re,ction steps,' 3400 PRINT'yelloNlj'2'jcyanlj'for your steps ,nd reagents,' 3410 PRINT'yelloNlj'3'jcy,nlj'for the sho~te5t route,' 3420 PROCenterl'l, 2, 3 or E') 3430 IF IVALlansNer$)(3 AND stepI=O AND .nsNerIO·E·) PROCnosteps 3440 IF IVALI.n5MerI){3 AlID stepI)O AND an'NerIO'E') PROCdi'pl.y 34S0 IF ,n"erl='3' PROClookfirst 3460 EHDPROC 3470 3480 DEF PROCgivein 3490 REMSive in, continue or return to previous coopound 3500 PRINT'yelloMlj'Type Mto return to the· •• in oenu' 3510 PRINTyelloMlj'or type R to return to. coopound' 3520 PRINTyelloNlj'or type S to give up,' 3530 PRINT"cy.nlj'lf you do give up you can no longer' 3540 PRINT'cy.nlj'continue Kith this synthesis,' 3550 PROCenterl'M, R or S·) 3560 IF ,nsKerl='R' AND stepI{1 PROCnosteps 3570 IF .nsMerl='R' AND stepI}O PROCback 3580 EHDPROC 3590 3600 DEF PROCre.ctants 3610 REM Choice of seeing reaction products or return to .enu 3620 REM lets the user see reaction products or return to the .enu, 3630 noI=VALlreplyl) 3640 PRINTgreenljtypellno1) 3650 PRINT'yelloKlj'Type the nUlber of the reaction or R to' 3660 PRINTyelloKlj'see reaction products or Mfor the .enu· 3670 no7.=no7.*4-3 3680 IF pickl()4 AND an'Ner$='4' fini,hI=no%+2 ELSE finish%=no%+3 3690 FOR N1=no1 TO finish1 3700 PRINT'yello.ljN1jTABI3)jcy,nljst,rtIINI)jtre.tIIH7.) 3710 NEXT N% 3720 VDU 28,0,24,39,IB 3730 REPEAT 3740 PRIHT 3750 PROCtitlelyello,l,bluel,'Sive the nu ob er "nted or R or M') 3760 INPUT repl yl 3770 choseX=VALlreplyl) 3780 UNTIL replyl='R' OR replyl='"' OR Ichose1}no%-1 AND chosel{fini,hI+I) 3790 PROCKindo,(5) 3BOO ENDPROC

PASE 85 3810 3820 DEF PROCproducts 3830 RE" allo.s the user to choose. reaction or to return to the .ain .enu, 3840 PRINT'yello.I;'Type the reaction nuaber or " for the .ain .enu,' 3860 PRINTgreenl;actllsteptl 3880 FOR NI=nol TO finishI 3890 PRINTyeIlowl;NI;','jcy.nl;startIINII;'ed'j 3900 IF ILEN ISTRI INIII fLENI treaU WIll fLElH start! INIII 1}34 THENPRINT 3910 PRINT cyanl;tre.tIINII 3930 IF ite.llnow',N%I='O'PRINT;cyanl;'doesn't react,' ELSE PRINTcy.nl;'_)';ite.SlnowZ,N%1 3940 NElT 3950 VDU 28,0,24,39,18 3960 REPEAT 3970 PRINT·blu~.jbackSjyelloHtj· Type a number from -jno!j- to ·jfinishlj· or n- 3980 INPUT replyl 3990 chose7.=VALlreplyll 4000 UNTIL choseI)noI-1 AND choseI(no%f5 OR replyl='"' 4010 PROCwindowl51 4020 ENDPROC 4030 4040 DEF PROCstages 4050 RE" Displ.ys the reaction step. 4060 PRINTgreenlj'Step 'jstepHl 4070 PRINTcyanS;.ctllstepII' treated oith' 4080 PRINTcy.nl;treatslchose7.lj' gives' 4090 IF ite.Slnoo7.,chose'l=seekl PROCfound 4100 IF ite.llnowI,choseI,='O' THEN PRINTcy.nlj'no re.ction' 4110 IF ite.llnooI,chose'I()seekS ANO ite.Slnoo',chose,I()'O' THEN PROCcheckproduct 4120 PROCspacebar 4130 IF beginl()iteallnow"OI PRINTgreenl'vi. ';ite.SlnooI,OI;' ';foroul.llnoo7.I:PROC.indooI51 4140 ENOPROC 4150 4160 DEF PROCnosteps 4170 RE" No steps to show 4180 CLS 4190 PRINT"cyanl;'You have not done .ny re.ctions'" 4200 PROCsp.cebar 421 °ENDPRDC 4220 4230 DEF PROCb.ck 4240 REMShows previous coopounds to pick 4250 entryl=" 4260 PROCwindowl21 4270 PRINTyeIIooSj'Enter the nu ob er of the co.pound' 4280 PRINTyeIIool;'you wish to return to' 4290 FOR NI=O TO step7.-1 4300 PRINTyeIIooljNIfljcy.nl;.ctIINl) 4310 IF NI)O entryl=entry\f' or 'f5TRIINIfl) ELSE entryl=entrylfSTRIINlfll 4320 NEXT 4330 PROCenterlentryl1 4340 neol=VALI.nswerl'-1 4350 FOR clpdl=1 TO clpdtot.ll 4360 IF ite.llcopdl,O)=actllneo'l nowl=clpdl 4370 NEXT clpdI 4380 stepI=newl 4390 ENDPRDC 4400

PAGE 8b 4410 DEF PROClooklir.t 4420 RE" check. il the currenl coo pound i. Ihe .Iarting coopound 4430 lir.I=FALSE 4440 nooZ=O 4450 REPEAT 4460 nooZ=no01'1 4470 IF ile.Slno.Z,Ol=beginS lirsl=TRUE 4480 UNTIL lir,t 4490 PROCaid.leps 4500 ENDPROC 4510 4520 DEF PROClound 4530 10und=TRUE 4540 PRINTcyanSj.e,kf 4550 PROC.alched 4560 acISI.lep7.}=ile.Slno.Z,chosell 4570 ENDPROC 4580 4590 DEF PROC.alch,d 4600 RE" .Ior,s co'pound and reagenl lor a reaclion slep 4610 .lepl=slep7.+1 4620 act$lslep7.}=it,.flno.Z,O} 4630 reacl$I.lep7.l=lrealflchoseIl 4640 ENDPROC 4650 4660 DEF PROCcheckproducl 4670 RE" Sees il a producl .ake. co.pounds in the .che.e, 4680 .atch=FALSE 4690 listed=FALSE 4700 PRINT'cyan$jile.$lno.7.,choseIl 4710 copdl=O 4720 REPEAT 4730 copdI=copdl+l 4740 IF ileoflcopdl,O}=ileoflnool,chosell PROCdoesprodr,acllcopdll 4750 UNTIL li.led OR copdl=clpdtolall 4760 IF NOT .alch PRINTgreenSj'Thi. cannot be u.ed furlher' ELSE PROC.alch,d 4770 ENDPROC 4780 4790 DEF PROCdoesprodreacllnol} 4800 RE" check. il a cODpound reacl. oilh a reagent, 4810 li.led=TRUE 4820 FOR reacll=1 TO reaclolall 4830 IF iteoSlnol,reacll}()'O' THEN .alch=TRUE:noo7.=nol 4840 NEXT reacll 4850 ENDPRDC 4860 4870 DEF PROCdi.play 4880 RE" di.plays Ihe reaclion .Iep., 4890 PROCoindool2} 4900 IF found PRINT'cyanlj'WELL DONE!!' 4910 PRINT'cyanfj'!ou look 'j.lepI' .Iep'j 4915 IF .lep%>1 THEN PRINT'.' 4920 PRINTcyanlj'The roule you look Ha.' 4930 PRINTyelloHSjbeginf 4940 FOR .lagel=1 TO .lepI 4950 IF ansoerS='2' PRINTcyanSj'lu.ing 'jreaclll.lagellj'l' 4960 IF .lageI/5=INT.lageI/5 AND an •• erf='2' THEN PROC.pacebar:CLS 4970 PRINT'yellooSjarroHSjaclSI.lagell 4980 NEXT .Iagel 4990 PROC.pacebar

PA6E 87 ) 5010 5020 OEF PROCcontinue 50.30 stepI:O 5040 REPEAT 5050 VOU26:CLS 5060 PROCtitlelyello.$,blue.,'TYPE E TO EXIT THE PROSRA" OR') 5070 PROCtitlelyelloo$,blue$,'TYPE N FOR A NEW SYNTHESIS,'I 50BO ansoer$;SET$ 5090 UNTILans.er$:'E' OR ans.erl:'N' 5100 IFan ..er$;'E' THEN PRIIIT" "SOOOBYE' 5110 CLS 5120 ENOPROC 5130 5140 OEF PROChelp 5150 RE" help requested 5160 help:TRUE 5170 REPEAT 51BO PROChelp •• nu 5190 IF anso.r.:'I' PROCr.acts 5200 IF ans •• r$:'2' PROCroutes 5210 IF ansoerl:'3' PROCaidsteps 5220 IF ansoerl()'"' ANO ans.erl()'S' PROCspacebar 5230 UNTIL ans.erl:'"' OR ans.erl:'S' 5240 ENDPROC 5250 5260 OEF PROCinitstep 5270 FOR NI:O TO 4 52BO stepINI):FALSE 5290 NEXT 5300 ENOPROC 5310 5320 DEF PROCaidsteps 5330 RE" finds the steps needed to get to end product, 5340 PROC.indoo(2) 5350 PROCinitstep 5360 PROClooklst.p 5370 PROCspacebar 53BO ENDPROC 5390

PASE BB 5400 DEF PROC,lr. 5410 RE" Roule h.s lore Ih.n 4 sleps &goes vi. elhanenilrile, 5420 lelpnow';no.I 5430 le.pendI;endI 5440 CLS 5450 VDU 23,1,1;0;0;0; 5460 PRINTcyanS;ileIS(nowI,OI;' 10 ';5ee,S 5470 PRINT'cyanS;'This reaclion 1"e5 lore Ihan 4 sleps,'

54BO PRINT'cyanSj'To increase the nusber of carbon atoms I 5490 PRINT'cyanS;'you lusl .ake a halogeno.I'ane and Ihen' 5500 PRINTcyanS;'reacl il .ilh sodiuI cyanide in order' 5510 PRINT'cy.nS;'lo .ake elhanenilrile,' 5520 end,;8:ile.S(end',OI;'elh.nenilrile' 5530 PRDCspacebar 5540 PRINTcy.nS;'Slage ;'; 5550 PROCprior 5560 PROClooklstep 5570 PROCspacebar 5580 no.7.;8 5590 endI;le.pendI:vial;" 5600 PRINTcyanl;'Slage 2'; 5610 PROCprior 5620 PROCinitstep 5630 PROCloo,lslep 5640 no.I;te.pno.t 5650 vi.I;" 5660 PROCspacebar 5670 ENDPROC 5680 5690 DEF PROCloo,lstep 5700 RE" looks for a I step reaction 5710 FOR reactI;1 TO 16 5720 IF ite.S(no.I,reactII;seekS PROCIstep 5730 NEIT reaclI 5740 IF NOT step(11 PROClook2step 5750 ENDPROC 5760 5770 OEF PROClstep 5780 RE" displays the 1 step re.ction 5790 CLS 5800 PRINT'cyanl;ile.S(endI,OI;' can be .ade fro.' 5810 PRINT'cyanS;ite.S(now',OI;' in one step' 5820 PRINT'cyanS;'by Ireating it with' 5830 PRINT'cyanS;lreatS!re.ctII;',' 5840 reaclI;17 5850 step(II;TRUE 5860 ENOPROC 5870 5880 DEF PROClook2step 5890 RE" looks for a 2 slep reaclion 5900 FOR reacl,;1 TO 16 5910 IF ite.S(no.',reacltl()'O' PROCfind(ite.S(no.I,reacIII,ile.S(endI,OII 5920 NEIT 5930 IF slep(21 PROC2slep ELSE PROCseek3slep 5940 ENDPROC 5950

PAGE 89 5960 DEF PROC2sl.p 5970 RE" ShoHs the 2 st.p r ••clion, 5980 CLS 5990 PRINT'cy.nl;it ••llnoHI,O);" 10 ";il,"II.ndl,O) 6000 PRINT'cy.nl;"This conv.rsion c.n b•• chi.v.d' 6010 PRINT'cy.nl;"by first r ••cting ";il.ollnoHZ,O);" +" 6020 PRINT'cy.nl;usedlll);' to I.k.'; 6030 IF LENus.dllll+LENvi.I)29 PRINT 6040 PRINTcy.nl;vi.I;',' 6050 PRINT'cy.nl;"This in turn is r •• cl.d with' 6060 PRINT'cy.nl;usedI(2);' to •• ke'; 6070 IF LENus.dI121+LENs •• kl)29 THEN PRINT' 6080 PRINTcy.nl;s.ekl;',' 6090 ENDPROC 6100 6110 DEF PROCprior 6120 RE" s•• ks pr.cursors to .nd producl 6130 10tI:O 6140 FOR c.pdI:1 TO 17 6150 FOR r •• cII:1 TO 16 6160 IF it ••llcopdI,r •• ctI):il ••II.nd7.,OI PROCpr.cursor 6170 NEXT r •• ctl 6180 NEXT clpdI 6190 ENDPROC 6200 6210 DEF PROCs •• k3sl.p 6220 RE" looks for. 3 sl.p r •• ction 6230 PRINTcy.nl;'Looking for rout.s,PI •• s. H.it,' 6240 vi.II:"' 6250 FOR noI:1 TO totI 6260 FOR r •• cII:1 TO 16 6270 IF it ••llno.7.,r •• clll()'O' PROCfindlil •• llno.7.,r •• cIII,priorllno!11 6280 IF sl.pl21 AND vi.II:" PROCfound3sl.p 6290 NEXT r •• cII 6300 NEXT noI 6310 IF sl.pI3) PROCb.ginsl.ps ELSE PROCtry4slepllolI) 6320 ElmPROC 6330 6340 DEF PROCfound3sl.p 6350 RE" slor.s inl.r ••di.t. coopounds ~ r"g.nls, 6360 st.pI31:TRUE 6370 vi.lI:vi.1 6380 vi.21:priorllnoI) 6390 us.dI131:.ndr •• clllno7.1 6400 noI:toU+1 6410 r •• cII:r •• clol.lI+1 6420 ENDPROC 6430 6440 DEF PROCpr.cursor 6450 RE" stor.s .11 Ih. pr.cursors 10 Ih ••nd coopound 6460 1011:1011+1 6470 priorllloIII:it •• llclpdI,O) 6480 .ndr •• cllllotII:lr •• lllr •• ctII 6490 ENDPROC 6500

PAGE 90 6510 DEF PROCb.ginst.ps 6520 RE" Shows st.rt 01 3 &4 st.p r •• etions, 6530 CLS 6540 PRINTgr •• n';it •• 'I.ndI,OI;' can b. I.d. Iro.' 6550 PRINTgreenS;iteIS(nowZ,O)j' in 'j 6560 IF st.pl41 PRINTgr •• n';'4 st.ps,' ELSE PRINTgr,.n';'3 st.ps,' 6570 PRINT'ey.n';'I,';it •• 'lnowI,OI;' is r.,et.d with' 6580 PRINTey,n';us.d'II';' to I.k. '; 6590 IF LENus,d'III+LENvi.S)29 PRINT 6600 PRINTey,,';vi.S;',' 6610 PRINT'ey,nS;'2,This is tr.,t.d with' 6620 PRINTey,nS;u,.dSI2I' to •• k.'; 6630 IF ILENus.dSI21+LENvi,2')291 PRINT 6640 PRINTey.nS;vi,2S;',' 6650 PRINT'ey.n';'3,This in turn is tr •• t.d with' 6660 PRINTey,nS;us.dSI31;' to giv.'; 6670 IF ILEllu ..dS(3)+LEN".kI>291 THEN PRINT 6680 IF ,t.p141 PROCgiv.45t,p ELSE PRINTey.nl;s •• 'S;',' 6690 IF h.Ip PRINT'y.llowS;'PI •• " not, down th." int,r •• di.t,,'; 6700 ENDPROC 6710 6720 DEF PRDCtry4,t'pltotII 6730 REM checks for conpounds from Khich the precursors can be lade 6740 FOR noI=1 TO totI 6750 FOR eoopdI=1 TO elpdtot.II 6760 FOR .g.nt7.=1 TO r"etot,II 6770 IF it.oSleo.pdI,'g.ntII=prior'lnoII PROCqu.ry4st'plit"SlcompdI,011 6780 NEXT 'g,ntI 6790 NEXT coopdI 6800 NEXT noI 6810 IF NOT st.pl41 PROC,tr, 6820 ENDPROC 6830 6840 DEF PROCqu.ry4st,pllook', 6850 RE" eh.eks il th, lin.l product c.n b. I.d. fro. eurr.nt on" 6860 vi .IS=" 6870 FOR RI=I TO 16 6880 IF it ••SlnowI,RXI()'O'PROClindlit ••SlnowI,RII,IookSI 6890 IF st.pl21 AND vi.IS=" THEN PROCy.s4st.p 6900 NElT 6910 EN DPROC 6920 6930 DEF PROCy.s4st,p 6940 REM stor.s the int.r •• di.t. coopounds .nd r •• g.nts 6950 st.pI41=TRUE 6960 vi.2S=it ••SlcoopdI,01 6970 vi.3S=priorSlnoII 6980 end'= ...kS 6990 s•• k'=it •• 'leoopdI,OI 7000 us.dSII'=tr"t'IRI' 7010 us.dI131=tr •• tll.g.ntII 7020 us.dSI41=.ndr •• ctSlnoXI 7030 noI=totI+1 7040 eoopdI=18 7050 .g.nt7.=17 7060 RI=17 7070 PROCb.ginst.ps 7080 ENDPROC 7090

PAGE 91 7100 DEF PROCgive4slep 7110 RE" Displays end slep of four, 7120 PRINTcyanSivia3Si',' 7130 PRINT'cyanSi'4, Finally Ihis is reacted with' 7140 PRINTcyanSjusedS(4lj' to oake'j 7150 IF lENusedS(4)'lENseekS)29 PRINT 7160 PRINTcyanSiile.S(endX,O) 7170 ENDPROC 7180 7190 DEF PROCreacls 7200 RE" looks for the reaclions of Ihe currenl compound, 7210 counlX=O 7220 ClS 7230 PRINT'greenSi'R.aclions of 'iile.S(nowI,O) 7240 FOR reaclI=1 TO reaclotall 7250 IF ile.S(noMX,r.acII)()'O' PROCvi.Mreacls(re.cIX) 7260 NEXT r.aclI 7270 PROCspac.bar 7280 EllDPROC 7290 7300 DEF PROCvieMreacls(JX) 7310 RE" displays the reaclion producls 7320 counll=counll'l 7330 IF counII/5=INT(countI/S) PROCneMpag,('reactions',il,.S(noMX,O)) 7340 PRINT' i yell OOSi FNreaction (n) i 7350 PRINTicyanSilreal$(Jl)jarrowS 7360 PRINTcyanSj' 'iileoS(nool,J7.) 7370 ENDPROC 7380 7390 DEF PROCnewpage(lypeS,ladeS) 7400 RE" Slarls a neM page 7410 PROCspacebar 7420 ClS 7430 PRINTjgreenSi'Furlher 'j 7440 PRINTlypeSj' of 'jladeS 1450 ENDPROC 7460 7470 DEF PROCroules 7480 RE" Seeks Mays of .aking Ihe end producl, 7490 counU=O 7500 FOR clpdl=! TO clpdlolall 7510 FOR reacll=! TO reaclolall 7520 IF ileIS(copdl,reacll)=seekS PROCgiv,info 7530 NEXT reactX 7540 NEXT clpdl 7550 PROCspacebar mo ENDPROC 7570 7580 DEF PROCgiveinlo 7590 RE" Shows all oays 01 .aking Ihe end product, 7600 ClS:PRINTgreenSjseekSj' can be .ade' 76!0 counll=count7.'1 7620 IF counII/5=INT(countl/S) PROCn,opage('preparations',seekS) 7630 PRINT'jyellowSjFNreaction(reactl)jcyanSj 7640 IF INSTR(starIS(NI),'heal')O PRINT'by heating'jiteIS(cmpdX,O) ELSE PRINT'by r.acting 'jitell(clpdl,O) 7650 PRINTcyanSjlreatS(reactl) 7660 priorS(countl)=iteoS(clpd7.,O) 7670 ENDPROC 7680

PASE 92 7690 DATA Redox reactions,Elilination reactions 7700 DATA Hydrolysis ~ .I.ctrop~ilic r.actions,Nucl.op~ilic substitution 7710 DATA reflux,+ excess conc. chrolic acid 7720 DATA ~.at,' dil. c~ro.ic acid ~ distill 7730 DATA tr.at,' lithiuI aluliniuG hydride 7740 DATA ~.at,' hydrog.n ~ •• tal catalyst 7750 DATA tr.at,' v.ry strong h.at 7760 DATA h.at,' p~osphorus p.nto,id. 7770 DATA ~.at,' alco~olic potassiu. hydroxide 7780 DATA ~.at,' porous pot or aluoina 7790 DATA h.at,' acid 7800 DATA h.at,' aqu.ous potassiut hydro,id. 7810 DATA add,'conc.sulphuric acid th.n .at.r' 7B20 DATA tr.at,' sodium bro.id.~sulp~uric acid 7830 DATA treat,+ phosphorus pentachloride 7840 DATA tr •• t,' , •• oni, 7850 DATA h.at,' .t~anol &,cid 7B60 DATA tr.at,' ,Icoholic sodium cyanid. 7870 DATA ·CH3COOH', ethanoic acid, 0, 0, ethanol, 0, 0, 0, 0, potassiul ethanoate, 0, potassiulI ethanoate, 0, 0, ethanoyl chloride, amloniul ethanoate, ethyl ethanoate, Q 7880 DATA ·CH3CHO., ethanal, ethanoic acid, ethanoic acid, ethanol, 0, 0, 0, 0, tribrolloethane, ethanal triller, yellow resin, 0, 0, dichloroethane, a polymer, acetal, ethanal cyanhydrin 1 7890 DATA ·C2H50H , ethanol, ethanoic acid, ethanal, 0, 0, 0, 0, 0, ethene, 0, 0, 0, brolloethane, chloroethane, 0, 0,

°7900 DATA 'CH2=CH2', .t~.n., .th.n. diol, .th.n. diol, .t~'n., 0, 0, 0, 0, 0, 0, 0, .t~anol, bro.o.t~an., 0, 0, 0, ° 7910 DATA 'C2H5CI', chloro.t~an., 0, 0, .than., 0, 0, 0, .t~.n., 0, 0, .thanol, 0, 0, 0, .thyl,ain., 0, propan.nitril. 7920 DATA ·C2H5Br., brolloethane, 0, 0, ethane, 0, 0, 0, ethene, 0, 0, ethanol, 0, 0, 0, ethyl amine, 0, propanenitrile 7930 DATA 'CH3COIlH2', .thanalid., 0, 0, .thylalin., 0, 0, .than.nitril., 0, •• thylaain., .thanalid. hydrochlorid., potasiul ethanoate, 0, 0, 0, 0, 0, 0 1 7940 DATA IC2H5CN , ethanenitrile, 0, 0, ethyl amine, 0, 0, 0, 0, 0, ethanoic acid, potassium ethanoate, 0, 0, 0, 0, 0, o 7950 DATA 'CH3COOC2H5', .t~yl .thanoat., 0, 0, .thanol, 0, 0, 0, 0, 0, 0, .thanol, 0, D, 0, .t~ana.id., 0, ° 7960 DATA 'CH3COCI', .thanoyl chlorid., 0, 0, .t~anol, .t~anal, 0, 0, 0, 0, .t~anoic acid, .th,noic arid, 0, 0, 0, ethanamide, ethyl ethanoate, 0 7970 DATA 'CH3CDDNH4', a•• oniuo .thanoat., 0, 0, 0, 0, .thana.ide, .than.nitril., 0, 0, 0, potassiu ••thanoat., 0, 0, 0, 0, 0, 0 7980 DATA 'C2H5NH2', .thyl,"in., 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 7990 DATA 'CH3NH2', l.thyl,.in.,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O 8000 DATA 'CH3DH', •• thanol, •• thanoic acid, •• thanal, 0, 0, 0, 0, 0, 0, 0, 0, 0, bro,ol.than., chloro •• than., 0, 0,

°8010 DATA IHCOOH·, lethanoic acid, carbon dioxide, 0, methanol, 0, 0, 0, 0, potassium lethanoate, 0, potassiul lethanoate, 0, 0, lethanoyl chloride, a.loniul lethanoate, ethyl lethanoate, 0 8020 DATA 'CH3CI', chlorol.than., 0, 0, •• than., 0, 0, 0, 0, 0, 0, •• thanol, 0, 0, 0, ..thyla.in., 0, .than.nitrile B030 DATA 'CH3Br', brotol.t~an., 0, 0, •• than., 0, 0, 0, 0, 0, 0, •• thanol, 0, 0, 0, .ethyla.in., 0, .than.nitril.

PAGE 93 6.3 List of procedures

PROCaidsteps finds the steps needed to get to end product. PROCback shows all the previous compounds to returned to. PROCbar(text$,ground$,title$) prints the title centred on a coloured bar. PROCbeginsteps displays the start of 3 and U step reactions. PROCcheckproduct sees if a product makes compounds in the scheme. PROCchoose3step selects a three step reaction. PROCcontinue asks if user wants to continue with the program. PROCdata reads in the initial data. PROCdoesprodreact(no%) finds if a compound reacts with a reagent. PROCdisplay displays the reaction steps in the synthesis. PROCendmenu gives a choice of seeing user's own reaction steps or the optimum route. PROCenter(entrY$) sets text window. Inputs and checks entry. PROCerr gives error if user picks the same start and end compounds. PROCfind(try$,end$) finds if the products are start compounds. PROCfound sets found to true and calls PROCmatched. PROCfound3step stores steps in a 3 step route. PROCfound2step stores steps in a 2 step route. PROCgivein allows user to give UP. continue or return to previous compound. PROCgiveUstep displays end step of four. PROCgiveinfo shows all ways of making the end product. PROChelp help requested. PROChelpmenu gives choice of type of help. PROCintro gives instructions. PROClookfirst checks if the current compound is the starting compound. PROClooklstep looks for a 1 step reaction. PROClook2step looks for a 2 step reaction. PROCmatched stores compound and reagent for a reaction step.

PAGE 9U PROCmenu choice of reaction type 9 help or give 1n. PROCnewpage(t¥pe$.made$) starts a new page.

PROCnosteps no steps to displ~. PROCownmenu lets user pick compounds. PROCownpick user picks start and/ or user end compound. PROCpicklstep(boolean) checks for 1 step reactions if boo lean is true. Otherwise it checks for more than 1 steps. PROCprecursor stores all the precursors to the end compound. PROCprior seeks precursors to end product. PROCproducts lets user pick a reaction or go to main menu. PROCquer¥Ustep(look) checks if the final product can be made from current one. PROCreactants lets user see products or return to the menu. PROCrandom picks random compound. PROCrescts looks for the reactions of the current compound. PROCroutes seeks ways of making the end product. PROCseek3step looks for a 3 step reaction. PROCseekstep2 finda if the product of a starting compound is the end compound.

PROCstepmenu allows a choice o~ number of steps. PROCstages displa¥s the reaction steps. PROCtitle(text$.ground$.title$) prints title$ in double height letters centred on coloured bar. PROCtr¥Ustep(tot%) checks for compounds from which the precursors can be made. PROCvar stores the start variables. PROCviewreacts(J%) displa¥s the reaction products. PROCwant2step checks each product until a 2 step reaction is found. PROCwindow(line%) clears a text window of 11ne% lines. PROCyesUstep stores the intermediate compounds and reagents. PROCxtra called if route has more than U steps and thus goes via ethanenitrile. PROClstep displa¥s the 1 step reaction. PROC2step shows the 2 step reaction.

PAGE 95 6.u List of variables act$(17) Array of compounds used 1n the reaction sequence begin$ Starting compound check$ String used to stop repetition. It holds the indices for pairs of compounds picked previously cmpdtotal" Total number o~ stored compounds endreact$ Array of reactions leading to end product end" Index of end compound end$ End compound err Boolean.True if same start and end compounds f'irst Boolean.True if current compound is initial one firstform$ Formula of starting compound formula$(17) Array of formulae for the compounds help Boolean. True if help requested item$(17,17) Array of compounds and reaction products listed Boolean. True if a product is a listed compound match Boolean. True if a reaction of a compound found now"" Index of current compound in synthesis pick" Integer indicating choice of compounds e.g. pick%=l for a one step reaction prior$(10) Arra¥ storing the precursors to the end product return" SooleanaTrue if user opts to use return for input react$(17) Arrav of the reactions used in a svnthesis reactotal% Total number of reactions stored seek$ End compound start" Soolean. True if user opts to piCk first compound start$(17) Array of stored reaction conditions e.g. heat step(U) Array of booleans indicating number of steps in a synthesis e.g. step(l) is true if' there is 1 step tot" Total number of precursors to end compound treat$(17) Array of stored reaction conditions type$(U) Array of' four dif'ferent types of' reaction used$(17) Array of reaction conditions used in a synthesis want" Number indicating userts choice of compounds via$ Intermediate compound 1n a two step reaction vial$ First compound in a multistep synthesis via2$ Second compound in a multistep synthesis via3$ Third compound in a multistep synthesis

PAGE 96 6.5 Students' Notes ORGANIC SYNTHESIS PROGRAM STUDENTS' GUIDE Before you start the program

The pro~ram "ORGANIC" is designed to help you to tackle organic synthesis problems. During the program you are asked to design a route to convert a starting compound to a given end product. Thus before you run the program you need to know which organic reactions are useful for producing a particular functional group such as an OH group or a eOOH group. These ·reactions are summarised on pages 321 to 32U of the Chemistry Students' Book 2. You are supplied with a chart showing the inter-relationships between all the types of compounds used in the program. This chart is similar to the one on page 325. but has more links shown. It will help vou i~ vou copv the chart and write on it the reagents and reaction type needed for each conversion. The reagents you can use 1n the program are grouped into four classes as follows:- i) Redox (oxidation-reduction) Reactions 1. Reflux with an excess of concentrated chromic acid. made from sodium chromate (VI) and concentrated sulphuric acid. 2. Heat excess of the compound with dilute chromic acid. made

~rom sodium chromate (VI) and dilute sulphuric acid. Then immediatelv distill o~~ the product. 3. Treat with lithium aluminium hvdride. 4. Heat with hVdrogen and a nickel catalvst. ii) Elimination reactions 5. Heat stronglv. 6. Heat with phosphorus pentoxide.

7. Heat with an alcoholic solution o~ potassium hvdroxide. 8. Heat with porous pot or aluminia.

PAGE 97 iii) Hydrolysis and electroph1lic Substitution reactions 9. Heat w1th a dilute acid. 10. Heat with an aqueous solution of potassium hydroxide. 11. Add concentrated sulphuric acid and then add water. 12. Treat with sodium bromide and sulphuric acid. (These react together to give hydrogen bromide gas.

Please note that hydrolysis reactions involving the negative hydroxide ion are nucleophilic substitution reactions. They are included in the same group as the electrophl1ic addition reactions for convenience. The reaction of alcohols with sodium bromide in the presnce of sulphuric acid is treated as an electrophilic addition reaction. This is because it is thought to start with the addition of a proton. The reaction of alkenes with the same reagents is an electrophl1!c addition reaction. iv) Nucleophilic substitution reactions 13. Treat with phosphorus pentachloride. 1U. Treat with ammonia. 15. Heat with alcohol in the presence of an acid catalyst. 16. Treat with a solution of sodium cyanide in alcohol.

The compounds you will meet in the reaction scheme are as follows:- ethanoic acid, ethanel, ethanol. ethanoyl chloride. choroethane, bromoethane, ethanamide. ethane nitrile. ethyl ethanoate. ammonium ethanoate. ethene. ethylamine (end product only). methylamine (end product only). methanol. methanoic acid. choromethane and bromomethane.

PAGE 98 Loading the program

The program is loaded by holding down the shift key and at the same time tapping the break key until the following message appears on the screen in large yellow letters:-

P~~ee th~ ~~d f~~cti~~

to lo~d th~ p~~g~~~_

Press this key and you are then ready to start the program.

Running the program

The program has been designed to give you as much ~reedom to make your own choices as possible. If you make mistakes or wrong choices you will not be penalised in an¥ way and you will still be able to synthesise your end product. The choices you have to make are presented to you via a series of menus. You only have type in one letter or number to make your choices. followed by pressing the return key. a) Choosing the starting and end compounds

At the start of the program you are presented with a menu which allows you to select either the degree of difficulty of the synthesis or a starting compound. If you make your own choice of starting compound you will not know the number of steps in the optimum route. Alternatively you can determine the number of steps the synthesis takes, or whether it involves adding an extra carbon atom (by reacting a halogenoalkane with sodium cyanide). Once the starting and end compounds have been selected the route taken by the program will depend entirely on your decisions.

PAGE 99 bl Selecting a reagent

The main menu allows you to select one o~ the four reaction classes, to request help or to give 1n. I~ you request a reaction class you will be shown the reagents available to you. You can select one of these. or request to see all the reactions Of the current compound with the reagents in this class, or you can return to the main menu. You may request a reagent that either does not react with the current compound or reacts to form a compound which cannot be used further in the scheme. If this happens the information is displayed on the screen and you are able to return to the main menu to start to select another reaction instead. If your compound does react with your chosen reagent you can carry on with further reactions until the end product is reached. cl Requesting help

I~ you request help then a further menu is displa¥ed. This allows you to look at all the reactions of the current compound. or to see all the ways of making the end product, or to be given a11 the steps and reagents in the best route to the end product. Or alternatively you can give in or go back to the main menu. You can use the help option as much as ¥ou feel is necessary.

PAGE 100 d) Giving up

You can give in at any stage. If you do this you will be asked to confirm this choice. If you decide not to you can return to the main menu. If you do confirm that you are giving up the current synthesis problem 1s ended. You can. however. opt to start a new one

e) Ending the current synthesis problem The end is reached when you either give in. or succeed 1n reaching the end product. The steps and reagents you have used, and/or the best route, can then be shown. If you wish you can go on to select another synthesis.

PAGE 101 6 .. Teachers' Notes

ORGANIC SYNTHESIS PROGRA~ TEACHERS' GUIDE Program details The program, "ORGANIC", is intended to help students to tackle simple problems in organic synthesis. They are presented with a starting compound and asked to convert it to an end product. The reactions and compounds used are detailed in the students' guide. Ideally. the students should have completed Topic 17 of the revised Nuffield 'A' level Chemistry course before tackling the program. It is designed to complement the work on simple synthetic routes at the end of this topic. However. it could be used as a revision excercise when students have completed topic 13. At this stage they will have covered all the compounds and reagents used within the program. The reactions used are grouped into four classes:­ l)redox reactions 2)elimination reactions 3)hydrolysis and electrophilic addition U)nucleophilic sUbstitution Although hydrolysis is clearly nucleophilic sUbstitution it is grouped, for convenience. with electrophl1ic addition reactions. The reaction of alcohols with sodium bromide in the presence of sulphuric acid is also included in this class rather than under nucleophilic substitution. This is because the initial reaction of the alcohol is thought to be protonation. which is then followed by attack by the nucleophilic bromide ion. Moreover. the reaction of these reagents with an alkene is electrophilic addition. A chart is provided which shows the inter-relationship betwen the compounds. This is based on figure 17.22 in topic 17. but it has been expanded to show all the possible links. Some of these links are not shown in the original chart.

PAGE 102 Educational Aims 1) To provide a program which enables students to become familiar with organic synthetic routes and the reactions they involve" The Chemistry content of the program is to be limited to that of the revised Nuffield 'A' level syllabus.

2) To enable the students to have as much control as possible over their learning. They should be able to make the following choices:- a) The level of difficulty of the synthesis i.e. the minimum

number of steps needed to get from the starting com~ound to

the end product and whether the end product has a dif~erent

number o~ carbon atoms to the starting compound. b) The level of help needed at any stage i.e. whether they wish to see the reactions of the starting compound, or ways to make the end product or the complete steps (compounds and reagents) from the starting compound to the end product. c) The amount of information displayed at the end of the program i.e. whether they wish to see the preferred route for the synthesis,or the route that they have used ( displaying either all their reagents and compounds or just the compounds) .

3) To encourage students to experiment and to make decisions. safe in the knowledge that a mistaken choice will neither incur penalties nor jeopardise their chances of success:rully completing the synthesis. 11) To provide a user interface which is as friendly as possible. That students who are unfamiliar with either computers or the layout of keyboards can easily use the program.

Loading and running the program

The program disc supplied requires a 110 track drive. The program is loaded by booting the disc (holding down the shift key. whilst tapping the break key). The user is then asked to press the red function key fO. When this is done the main

PAGE 103 program is loaded. The disc also contains the program listing as a Wordwise file "ORGTEXT".

Using the program

Once the program is loaded the escape "and break keys are disabled. If it is necessary to stop the program the end option within the program can be called up. This gives the option of ending the program or selecting a new synthesis. Alternatively the control and break keys can be pressed simultaneously and the program reloaded if' necessary.

Previous testing has indicated that the program is most successful when used by single students or by two or three students of similar ability working together. The program has been designed to give students as much control over their use of it as possible. They are able to select the difficulty of the synthesis i.e the number of steps it takes to make the end product from the starting compound and whether the synthesis involves increasing the number of carbon atoms. However, previous trials have shown that some students stay with the simple, one step reactions and may need encouraging to tackle the more difficult syntheses. The students are able to ask the program for help whenever they feel it is needed and can select the type of help they need i.e. reactions of' the current compound, ways of synthesing the end product or the complete steps to get from the former to the latter. Again it was found that some students were reluctant to use the help option and needed to be reminded of this facility.

PAGE lOll Evaluation o~ Organic Synthesis Program Your opinions will be a great help to me in evaluating and modi~ylng the program. Please help by completing and returning the form to:- Mrs. p.W.Mynott, Groby Community Colege, Ratby Road,Groby, Leics. Please complete the following:­ Evaluating teacher Evaluating school

MODE OF USE A.i) Do you consider that the program was best suited to use by a) individual students b)small groups c)a whole class?

A.2) Which of the above used the package?

A.3) Did the program generate discussion? (omit if only used by (a).)

A.U) Ability range of pupil/s? a)more able b)average c)less able d)mixed ability

PAGE 105 A.5) If vou think the program is suitable for all abilitv ranges enter all. I~ not give the Buitable range or ranges.

A.6) How long did each group or student spend on the package?

A.7) Are thev familiar with computer packages?

A.8)What. if anv. problems occurred whilst using the program?

Please use the following ratings when completing the rest of the form:-

1-unacceptable/not at all a-good 2-poor 5-verv good 3-average 6-not tried/not relevant

Please use the blank page if you need more space for comment, particularly when using ratings 1 or 2. The word package includes the program and Bupporting material provided.

Educational Content

B.l) How well do vour students usuallv cope with this topic? 1 2 3 a 5

B.2) Do vou think the program assists them with their understanding of organic synthesis reactions? 1 2 3 a 5

PAGE 106 B.3) Do ¥ou think the program assists them with their recall of organic synthesis reactions? 1 2 345

B.4) Do ¥ou think the package meets its stated aims?

1 234 5

B.5) How appropriate is the package for the task? 1 234 5

B.6) The program was designed to be as flexible as possible so that students can control their own learnin~. How well does the program meet this aim? 12345

B.7) Please give an¥ changes that ¥ou think would improve this fexibilit¥ or the program 1n general.

B.8) Is the chemical content of the package accurate? Please detail any errors.

PAGE 107 Presentation and ease of use

Col) How easily can the package be used by a student with little experience of computers? 1 2 3115

C.2) How easy was the menu structure to use? 1 2311 5

Co3) How did you find the help option? 1 2 3115 c.U) How well did the program deal with wrong responses? 1 2 3115 c.S) How clear was the overall screen presentation? 1 2 3115

C.6) How easy was it to fOllow the program instructions? 1 2 3115 c.?) How useful was the teachers' guide? 1 2 3115

CoB) How useful was the students' guide? 1 2 3115

Further suggestions for improving the package are particularly welcome.

PAGE loB