E-Book Content
ORGANIC CHEMISTRY FOR GENERAL DEGREE STUDENTS V O L U M E 2: A R O M A T I C
CHEMISTRY
by
P. W. G. SMITH, A. R. TATCHELL,
P H . D . ,
Senior Lecturers
D.i.c, M . S C ,
in Organic
The Woolwich
A . R . C . S . ,
P H . D . ,
A . R . I . C .
F . R . I . C .
Chemistry
Polytechnic
PERGAMON PRESS OXFORD · LONDON · EDINBURGH · NEW YORK TORONTO · SYDNEY · PARIS · BRAUNSCHWEIG
Pergamon Press Ltd., Headington Hill Hall, Oxford 4 & 5 Fitzroy Square, London W.l Pergamon Press (Scotland) Ltd., 2 & 3 Teviot Place, Edinburgh 1 Pergamon Press Inc., Maxwell House, Fairview Park, Elmsford, New York 10523 Pergamon of Canada Ltd., 207 Queen's Quay West, Toronto 1 Pergamon Press (Aust.) Pty. Ltd., 19a Boundary Street, Rushcutters Bay, N.S.W. 2011, Australia Pergamon Press S.A.R.L., 24 rue des Ιcoles , Paris 5*" Vieweg & Sohn GmbH, Burgplatz 1, Braunschweig Copyright © 1969 Pergamon Press Ltd. First edition 1969 Library of Congress Catalog Card No. 64-66138 Printed in Great Britain by Thomas Nelson (Printers)
Ltd.
Edinburgh
This book is sold subject to the condition that it shall not, by way of trade, be lent, resold, hired out, or otherwise disposed of without the publisher's consent, in any form of binding or cover other than that in which it is published. 08 012947 1 (flexicover) 08 012948 X ( h a r d cover)
PREFACE THE scope and the manner of treatment of the subject-matter of this text book of Organic Chemistry are outHned in the preface to Volume 1. In this volume we have endeavoured to cover the im portant fundamental aspects of aromatic chemistry, including simple heteroaromatic systems, to a level which, broadly speaking, is adequate to meet the requirements of students reading for a B.Sc. General Degree and for examinations of a similar standing. The decision to separate the aromatic section from the aliphatic was intentional rather than one of convenience. We felt that in a course of this level the interests of the student are best served by a systematic study in the first instance of the chemistry of functional groups, based on their structural characteristics, in aliphatic systems. The study of aromatic compounds can then begin with the properties of the aromatic nucleus followed by a consideration of the manner in which interaction with the aromatic system may modify the reactivity of functional groups. On the basis that the student has already acquired some familiarity with the basic concepts of reaction mechanisms from the material presented in Volume 1, we have taken the opportunity, in this volume, of extending the treatment of selected mechanistic topics to a some what greater depth. Woolwich Polytechnic London, S.EA8
P. W. G. S. A. R. T.
VII
CHAPTER 1
BENZENESTRUCTURE AND REACTIVITY Introduction As has been mentioned in the introduction to Volume 1, organic chemistry has from an early date been broadly divided into ali phatic and aromatic branches. This classification was largely one of convenience since aromatic compounds (so named because many of the earliest examples isolated from plant extracts had pleasant aromas) were found to possess chemical properties which were characteristically different from those of the aliphatic group. Many of the aromatic compounds isolated from these sources were recognised as derivatives of benzene ( Q H ^ ) into which they could be converted by suitable reaction sequences; the following are illustrative. C6H5CHO
[O]
Benzaldehyde (from oil of bitter almonds)
-> C6H5CO2H Benzoic acid
^ • Q H a Benzene
C,H4(OH)CO,H-^vC,H50H Salicylic acid (from oil of wintergreen)
Phenol
Benzene
A detailed study of the reactions of benzene and its derivati