Problems and Solutions in Organic ChemistryPress Subrata Sen Gupta Formerly, Reader in Chemistry R.P.M.University College, West Bengal Oxford © Oxford University Press. All rights reserved. PSOC_FM.indd 1 12/30/2015 5:30:48 PM 3 Oxford University Press is a department of the University of Oxford. It furthers the University’s objective of excellence in research, scholarship, and education by publishing worldwide. Oxford is a registered trade mark of Oxford University Press in the UK and in certain other countries. Published in India by Oxford University Press YMCA Library Building, 1 Jai Singh Road, New Delhi 110001, India © Oxford University Press 2014 The moral rights of the author/s have been asserted. First published in 2014 All rights reserved. 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Oxford © Oxford University Press. All rights reserved. PSOC_FM.indd 2 12/30/2015 5:30:49 PM Preface Though chemical compounds are visible to the naked eye, discussed, students would get specific information on the their constituent atoms and bonds are invisible even under a types of reactions these two different classes of carbonyl very powerful microscope. When one tries to visualize the compounds take part in. Such an approach to learning formation of a compound, one has to depend on the infor- the subject is more pragmatic as it helps readers get mation available in related literature, confirmed through acquainted with the relevant reactions within a class of time-tested experiments. Therefore, when a student comes organic compounds. across a new problem, the solution can only be rationalized as a ‘plausible’ explanation or by concluding that ‘results KEY FEATURES have to be confirmed by experiments and investigations’. • Problems on the nomenclature of the different classes Organic chemistry is a mind-boggling field of chemistry, of organic compounds based on IUPAC rules, and in the sense that nature has produced thousands of organic the answers to these molecules with unimaginable complexities. Fascinated by • A plethora of problems on the classes of compounds this area of study, chemists are observing and following with plausible mechanisms and rationalization, nature to synthesize many new compounds in their labora- where necessaryPress tories, many of which have changed our lifestyle in unim- • Illustrative reaction mechanisms through well-drawn aginable ways. diagrams with supportive explanations and com- Young learners must realize that to excel in any science ments wherever needed course, they must develop the habit of solving problems. • Problems on stereochemistry, spectroscopy, and per- To gain confidence in this, they would initially need the icyclic reactions assistance of books that contain a large number of solved • Over 1500 solved problems addressing various topics problems. It is with this objective in mind that Problems on the subject and Solutions in Organic Chemistry was conceived. The • Includes 700 chapter-end exercise problems to aid book is designed as a self-study material, to expose stu- self-evaluation dents to the various facets of organic chemistry. University CONTENTS AND COVERAGE ABOUT THE BOOK The book has 21 chapters. A short description of the nature Problems and Solutions in Organic Chemistry is primar- of problems included in each chapter is given here. ily written for undergraduate students who have opted for Chapter 1, Nomenclature of Organic Compounds, provides an Honours course in chemistry. It will also be useful for problems on the naming of various aliphatic, alicyclic, aro- students pursuing postgraduation in chemistry and those matic, fused polynuclear, spiro, heterocyclic, and bridged preparing for competitive examinationsOxford such as the Joint compounds. The nomenclature of many unique unsatu- Admission Test for Masters (JAM), National Eligibility rated aliphatic compounds and compounds with a variety Test (CSIR–UGC NET), and Graduate Aptitude Test in of functional groups have been discussed. End-chapter Engineering (GATE). exercises discussing certain interesting chemical structures Most problems in each chapter have been discussed have also been included. on the basis of traditional functional groups present in organic compounds. This will help students get an idea of Chapter 2, Physical Organic Chemistry, deals with prob- the types of problems based on a particular class of com- lems based on the concepts and theories in organic chemis- pounds. For example, alcohols can participate in elimi- try, such as acid–base reactions, dipole moments, reaction nation reactions, etherification reactions, esterification rates, tautomerism, reaction kinetics, and aromaticities. reactions, and are reagents in nucleophilic substitutions Chapter 3, Stereochemistry, includes a large number of as well. Therefore, if we separately discuss the problems problems on various aspects of stereochemistry involving on alcohols, we can get an idea of the different types of organic molecules. Problems on both static and dynamic reactions these compounds take part in. Similarly, the stereochemistry have been demonstrated. properties of aliphatic carbonyl compounds and aromatic carbonyl compounds differ in many reactions. Therefore, Chapter 4, Aliphatic and Alicyclic Hydrocarbons and if problems on these compounds are individually their Halides, elucidates problems on both saturated and © Oxford University Press. All rights reserved. PSOC_FM.indd 3 12/30/2015 5:30:55 PM iv Preface unsaturated compounds in addition to those on aliphatic Chapter 16, Carbohydrates, has problems dealing with and alicyclic hydrocarbons. naturally occurring typical monosaccharides, disaccha- rides, and polysaccharides. Chapter 5, Alcohols and Ethers, throws light on typical problems on alcohols and aliphatic ethers. Chapter 17, Amino Acids, Proteins, and Nucleic Acids, deals with a variety of problems on important biomole- Chapter 6, Aliphatic Carbonyl Compounds, deals with a cules such as amino acids, proteins, and nucleic acids. wide array of interesting problems on aliphatic aldehydes and ketones. Chapter 18, Molecular Rearrangements, analyses prob- lems associated with molecular rearrangements encom- Chapter 7, Aliphatic Acids and their Derivatives, describes passing all the classes of organic compounds. problems on aliphatic acids and their derivatives, such as esters, amides, and acid halides. Chapter 19, Conversions and Syntheses of Organic Compounds, gives a clear picture on the mechanisms Chapter 8, Aliphatic and Alicyclic Amines, Nitriles, related to conversions among organic molecules and also Isocyanides, Ylides, Diazocompounds, and Organometallic talks about the synthesis of organic molecules from typical Compounds, discusses a host of interesting problems on compounds and reagents. these classes of compounds. Chapter 20, Constitutional Problems on Organic Chapter 9, Aromatic Carbonyl Compounds, explores the Compounds, has a diverse range of problems on the iden- typical problems associated with these compounds. tification of compounds based on a sequence of reactions. Chapter 10, Aromatic Acids, Amines, Nitro-compounds, Chapter 21, Miscellaneous Problems, presents a large num- and Diazo-compounds, comprises a large number of prob- ber of interesting problemsPress based on the different classes of lems on these staggering classes of compounds. organic compounds and a variety of organic reactions we Chapter 11, Phenolic Compounds, Benzoquinones, and encounter in organic chemistry. Aromatic Ethers, deals with specific and interesting prob- Appendix A, Abbreviations of a Few Reagents Used in lems on these compounds to understand their reactions Chemical Literature, lists out the abbreviations and the better. corresponding chemical structures of some frequently used reagents in organic reactions. Chapter 12, Benzenes, Polynuclear and Alicylic Hydrocarbons, explains problems on benzene and substi- Appendix B, Reducing and Oxidizing Agents Commonly tuted benzenes, polynuclear aromatic hydrocarbons, and Used in Organic Chemistry, lays emphasis on the various some additional problems on alicyclic compounds, which reducing and oxidizing agents, along with their chemical have not been discussed in Chapter 4. Universitycomposition, preferred solvent, and reaction mixture. Chapter 13, Pericyclic Reactions, deals with problems on ACKNOWLEDGEMENTS this special class of organic reactions. These include reac- I express my deepest gratitude to Oxford University Press tions such as electrocyclic reaction, cycloaddition reaction, India for accepting this book for publication. I am particu- sigmatropic reaction,