IUPAC NOMENCLATURE OF ORGANIC COMPOUNDS Part I. HYDROCARBONS

1. ALKANES (Saturated chain hydrocarbons)

Names of hydrocarbon chains C1-C20: C1 - methane C6 - hexane C11 - undecane C16 – hexadecane C2 - ethane C7 - heptane C12 – dodecane C17 - heptadecane C3 - propane C8 - octane C13 – tridecane C18 - octadecane C4 - butane C9 - nonane C14 - tetradecane C19 – nonadecane C5 - pentane C10 - decane C15 - pentadecane C20 - eicosane

Names of alkyl substituents:

Suffix -ane of parent alkane is replaced by suffix -yl. Accepted common names of alkyl groups C1-C5, (common abbreviations and systematic names are given in brackets)

CH3- methyl, (Me); CH3CH2- ethyl, (Et); CH3CH2CH2- propyl, (Pr); (CH3)2CH- isopropyl, (i-Pr); CH3CH2CH2CH2- butyl, (n-Bu); CH3CH2(CH3)CH- sec-butyl, (s-Bu), (1-methylpropyl); (CH3)2CHCH2- isobutyl, (i-Bu), (2-methylpropyl); (CH3)3C- tert-butyl, (t-Bu), (1,1-dimethylethyl); CH3CH2CH2CH2CH2- pentyl; (CH3)2CHCH2CH2- isopentyl, (3-methylbutyl); CH3CH2(CH3)2C- tert-pentyl (1,1-dimethylpropyl); (CH3)3CCH2- neopentyl (2,2-dimethylpropyl);

Alkane name formation:

1. We are looking for the longest carbon chain. 2. Carbon atoms are numbered starting from the end closer to the first branching point. 3. We identify substituents and list them in alphabetical order. 4. The number of the same substituents is indicated by prefixes: di- (2); tri- (3); tetra- (4); penta- (5); heksa- (6); hepta- (7);..etc. 5. Behind the last substituent parent name of hydrocarbon chain is written.

7-tert-butyl-4-ethyl-3-methylundecane 6-isopropyl-2,9-dimethyltetradecane 7-(1,1-dimethylethyl)-4-ethyl-3-methylundecane

Names of branched alkyl substituents are formed in similar way as alkanes names, remembering that: a) Numbering of carbon atoms in substituent always starts from carbon linked to the parent skeleton. b) The longest chain is numbered. c) Substituents are listed in alphabetical order. d) The suffix –ane (for alkane) is replaced by suffix –yl (for alkyl). e) Name of such substituent is placed in brackets.

2. CYCLOALKANES (Saturated ring hydrocarbons)

To the alkane name indicating number of carbon atoms, the prefix cyclo- is added.

cyclopropane cyclobutane cyclopentane cyclohexane cycloheptane cyclotetradecane

1 3. ALKENES, ALKYNES, CYCLOALKENES, CYCLOALKYNES (Unsaturated hydrocarbons)

Multiple bonds (C=C – double bond, CC – triple bond) are regarded in unsaturated hydrocarbons as functional groups. For alkenes the suffix -ene, indicates the presence of C=C bond, for alkynes the suffix –yne indicates the presence of CC bond. In compounds containing both types of multiple bonds the order of suffixes is: -en-yne.

Naming of unsaturated hydrocarbons:

1. The longest chain containing the highest number of multiple bonds must be found. 2. Numbering begins from the end closer to the multiple bond. In molecules containing both kinds of bonds, double bond has priority before triple bond. 3. Before suffixes -ene or –yne the number indicating position of the bond has to appear. 4. In cycloalkenes and cycloalkynes numbering begins from one multiply bonded carbon and goes through the second multiply bonded carbon..

4-(2,3-dimethylpropyl)- 6-ethyl-7-methyl-1-nonene 5-cyclopentyl-2-methyl-2-octen-6-yne 6-ethyl-7-methylnon-1-ene 1-cycloheptene 5-cyclopentyl-2-methyloct-2-en-6-yne

7,9-dimethyl-5-propyl-8-decen-1-yne 1-vinyl-1,3,5-cyclodecatriene 3-(2-propenyl)-14-propyl- 7,9-dimethyl-5-propyldec-8-en-1-yne 1-ethenylcyclodeca-1,3,5-triene cyclotetradeca-1,8-diyne

Commonly used non-systematic names of alkenes and alkynes:

CH2=CH2 ethylene (ethene) CH2=C=CH2 allene (propadiene) HCCH acetylene (ethyne)

Unsaturated substituents with accepted common names:

CH2=CH- vinyl (ethenyl) CH2=CHCH2- allyl (2-propenyl) CH2= methylene CH2=C(CH3)- isopropenyl

4. AROMATIC HYDROCARBONS (ARENES)

Accepted common names:

benzene toluene o-xylene m-xylene p-xylene mesitylene

p-cymene styrene naphthalene anthracene phenantrene

2 Substituent derived from benzene, (C6H5-) is called phenyl, phenylmethyl group (C6H5CH2-) is called benzyl.

Substituted arene derivatives are named in similar way as other hydrocarbons. Numbers indicating the positions of substituents and the names of substituents are placed in alphabetic order before the name of parent hydrocarbon.

Examples:

1-isobutyl-2-methylbenzene (2,3-dimethylbutyl)benzene 3-ethyl-1-methylnaphthalene

Parts of systematic name:

2-isopropyl-4,10,11-trimethyl-5-phenytrideca-1,6-dien-12-yne

     locant substituent name parent name endings

prefixes parent skeleton suffixes

Systematic name formation when structural formula is given:

1. Find the parent hydrocarbon framework and write its name. 2. Identify substituents linked to the chosen framework, by their names and write them in alphabetic order. 3. Number the carbon atoms in parent skeleton according to the rules. 4. Write the systematic name in the following order: a) All substituents in alphabetic order must be preceded with numbers indicating position of linking to parent skeleton. b) If there are 2 or more identical substituents, the same number of locants has to appear before substituent name. c) Write the parent hydrocarbon name behind all substituents. d) Write locants and suffixes indicating position, number and kind of multiple bonds.

Write systematic names for following compounds:

1. 2. 3.

3 4. 5. 6.

7. 8. 9.

10. 11. 12.

13. 14. 15.

16. 17. 18

19. 20 21.

22. 23. 24.

25. 26. 27.

4