Advanced Practical Organic Chemistry

Transcription

1 Advanced Practical Organic Chemistry

2 Dedicated to Professor Gi/bert Stork In recognition ofthe skills and enthusiasmfor chemistry gained in his laboratories

3 ADV ANCED PRACTICAL ORGANIC CHEMISTRY M.CASEY J.LEONARD B. LYGO Department of Chemistry and Applied Chemistry University of Salford G. PROCTER George Ramage Professor of Chemistry University of Salford Springer Science+Business Media, LLC

4 1990 Springer Science+Business Media New York First Published 1990 Originally published by Blackie and Son Ltd in All rights reserved. No part 01 this book may be reproduced, stored in a retrieval system, or transmitted, in any lorm or by any means, electronic, mechanical, recording or otherwise without prior permission 01 the Publishers British Library Cataloguing in Publication Data Advanced practical organie chemistry. 1. Organie chemistry. Laboratory techniques I. Casey, M. 547' ISBN ISBN (ebook) DOI / For the USA, International Standard Book Number is

5 Preface The preparation of organic compounds is central to many areas of scientific research, from the most applied to the most academic, and is not limited to ehemists. Any research which uses new organic chemicals, or those which are not available commercially, will at some time require the synthesis of such compounds. This highly practical book, covering the most up-to-date techniques commonly used in organic synthesis, is based on our experience of establishing research groups in synthetic organic chemistry and our association with some of the leading laboratories in the field. It is not claimed to be a eomprehensive compilation of information to meet all possible needs and circumstances; rather, the intention has been to provide sufficient guidance to allow the researcher to carry out reactions under conditions which offer the highest ehance of success. The book is written for postgraduate and advanced level undergraduate organie chemists and for chemists in industry, particularly those involved in pharmaeeutical, agrochemical and other fine chemicals research. Biologists, biochemists, genetie engineers, material scientists and polymer researchers in university and industry will find the book a useful source of reference.

6 Contents 1 General Introduction 1 2 Keeping records of laboratory work Introduction The laboratory notebook Why keep a lab book? How to write a lab book Suggested notebook format Keeping records of data What type of data should be collected Formats for data records 9 3 Equipping the laboratory and the bench Introduction Setting up the laboratory Generallaboratory equipment The individual bench Routine glassware Personal items Specialized personal items 21 4 Purification and drying of solvents Introduction Purification of solvents Drying agents Drying of solvents Solvent stills 39

7 viii Contents 5 Reagents: purification and handling Introduction Classification of reagents for handling Techniques for obtaining pure and dry reagents Purification and drying ofliquids Purifying and drying solid reagents Techniques for handling and measuring reagents Storing liquid reagents or solvents under inert atmosphere Bulk transfer of a liquid under inert atmosphere (cannulation) Using cannulation techniques to transfer measured volumes of liquid under inert atmosphere Use of syringes for the transfer of reagents or solvents Handling and weighing solids under inert atmosphere Preparationof~omethane Safety measures Preparation of ~omethane (a dilute ethereal solution) General procedure for esterification of carboxylic acids Titration of diazomethane solutions 73 6 Gases Introduction Use of gas cylinders Handling gases Measurement of gases Inert gases Reagent gases 84 7 Vacuum pumps Introduction Low vacuum pumps Water aspirators House vacuum systems Electric diaphragm pumps High vacuum pumps 90

8 Contents ix Rotary oil pumps Vapour diffusion pumps Pressure measurement and regulation Units ofpressure (vacuum) measurement 93 8 Carrying out the reaction Introduction Reactions with air sensitive reagents Introduction Preparing to carry out areaction under inert conditions Drying and assembling glassware Typical reaction set-ups using a double manifold Basic procedure for inert atrnosphere reactions Modifications to basic procedure Use of bauoons for holding an inert atrnosphere The use of a 'spaghetti' tubing manifold Reaction monitoring Thin layer chromatography High performance liquid chromatography Gas-liquid chromatography Reactions at other than room temperature Low temperature reactions Reactions above room temperature Driving equilibria Dean and Stark traps High pressure reactions Agitation Magnetic stirring Mechanical stirrers Mechanical shakers Sonication Working up the re action Introduction 141

9 X Contents 9.2 Quenching the reaction General comments Strongly basic non-aqueous reactions Neutral non-aqueous reactions Strongly acidie non-aqueous reactions Acidie or basic aqueous reactions Liquid ammonia reactions Isolation of the crude product General comments Very polar aprotic solvents Purification Crystallization Distillation Sublimation Chromatographie purification of reaction product Flash chromatography Dry-column flash chromatography Preparative tlc Medium pressure liquid chromatography Preparative hplc Small scale reactions Introduction Reactions at or below room temperature Reactions above room temperature Reactions in nmr tubes Purification of materials Distillation Crystallization Chromatography Large scale reactions Introduction Carrying out the reaction 198

10 Contents xi 11.3 Purification of the products Characterization Introduction Nmr Ir Uv Mass spectra M.p. and b.p Optical rotation Microanalysis Keeping the data The chemical literature The structure of the chemical information Introduction The structure of the literature Some important sources of chemical information Chemical Abstracts Beilstein Science Citation Index Computer databases How to fmd chemical information How to do searches How to find information on specific compounds How to find information on classes of compounds How to fmd information on synthetic methods Current awareness Special procedures Introduction Catalytic hydrogenation Photolysis Ozonolysis 223

11 xü Contents 14.5 Flash vacuum pyrolysis 14.6 Liquid ammonia reactions 'Trouble shooting'; 227 what to do when things don 't work 16 Example reactions 16.1 Preparation of n-butyllithium 16.2 Titration of n-butyllithium 16.3 Aldol reaction 16.4 Preparation of ethyl(triphenyl-phosphoranylidene)acetate 16.5 Claisen rearrangement 16.6 Hydrogenation of maleie acid Safety Safety is your primary responsibility Safe working practice Common hazards Accident and emergency procedures Bibliography Appendices 243 Appendix 1. Properties of common solvents 243 Appendix 2. Properties of common gases 244 Appendix 3. Approximate pka values for some common deprotonations 245 compared to some common bases Appendix 4. Lewis acids 246 Appendix 5. Common reducing reagents 247 Appendix 6. Common oxidizing reagents 252 Index 257