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An Investigation Into the Synthesis of an Optically Active Trityl System

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An Investigation Into the Synthesis of an Optically Active Trityl System University of Windsor Scholarship at UWindsor Electronic Theses and Dissertations Theses, Dissertations, and Major Papers 1-1-1966 An investigation into the synthesis of an optically active trityl system. Paul L. Fitzgerald University of Windsor Follow this and additional works at: https://scholar.uwindsor.ca/etd Recommended Citation Fitzgerald, Paul L., "An investigation into the synthesis of an optically active trityl system." (1966). Electronic Theses and Dissertations. 6424. https://scholar.uwindsor.ca/etd/6424 This online database contains the full-text of PhD dissertations and Masters’ theses of University of Windsor students from 1954 forward. These documents are made available for personal study and research purposes only, in accordance with the Canadian Copyright Act and the Creative Commons license—CC BY-NC-ND (Attribution, Non-Commercial, No Derivative Works). Under this license, works must always be attributed to the copyright holder (original author), cannot be used for any commercial purposes, and may not be altered. Any other use would require the permission of the copyright holder. Students may inquire about withdrawing their dissertation and/or thesis from this database. For additional inquiries, please contact the repository administrator via email ([email protected]) or by telephone at 519-253-3000ext. 3208. AN INVESTIGATION INTO THE SYNTHESIS OF AN OPTICALLY ACTIVE TRITYL SYSTEM PY PAUL L. FITZGERALD A Thesis {Submitted to the Faculty of Graduate Studies through the Department of Chemistry in Partial Fulfillment of the Requirements for the Degree of Master of Science at the University of Windsor Windsor, Ontario 1966 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI Number: EC52605 INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. UMI® UMI Microform EC52605 Copyright 2008 by ProQuest LLC. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC 789 E. Eisenhower Parkway PO Box 1346 Ann Arbor, Ml 48106-1346 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Approved Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ABSTRACT Several possible routes to obtain an optically active trityl system have been studied. Model systems, using triphenylcarbinol and 4-bromo-^1-chlorotriphenylcarbinol, were employed. Several routes to break down the glycolic acid derivatives of these alcohols were studied. These involve the preparation of the silver salt of the acid and its reaction with bromine; the reaction of the acid with mercuric oxide and bromine and the thermal decomposition of the silver salts of the acids. ii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. I ACKNOWLEDGEMENTS The author would like to express his most sincere gratitude to Dr. K. G. Rutherford for his patience and guidance during the course of this work. Appreciation is also shown to the University of Windsor for a Graduate Teaching Assistantship which was held for each of the years during which these studies were undertaken. iii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS Page ABSTRACT............................................. il ACKNOWLEDGEMENTS..................................... iii LIST OF FIGURES...................................... v Chapter I. INTRODUCTION............................... 1 Resolution of Alcohols................. 2 Resolution of Triarylcarbinols............ 6 Summary.......... 1^ II. DISCUSSION OF EXPERIMENTAL RESULTS............. 16 Conclusions............................... 18 III. EXPERIMENTAL PROCEDURE......................... 19 BIBLIOGRAPHY......................................... 38 VITA AUCTORIS........................................ kO iv Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LIST OF FIGURES Figure Page 1 Preparation and Use of Diazomethane .......... 26 v Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CHAPTER I Introduction Optically active systems arise from the fact that molecules which have the same constitution may still differ, as isomers, in the way in which their atoms are arranged in space. The one main condition for this type of isomerism to take place is met when a molecule is not superimposable on its mirror image. Such a molecule is called dissymmetric and the simplest way a molecule can attain dissymmetry is to contain a carbon atom to which are attached four different atoms or groups. There are other ways in which dissymmetry can be attained but this work only concerns itself with this type of molecule. Compounds of the general formula RR^RgC-X are of this type. These compounds, in general exist as a racemic mixture of optical antipodes which can be separated by mechanical means. Each optical antipode is identical to the other as regards chemical properties but rotates the plane of polarized light in opposite directions. The separation of optical isomers usually involves the formation of a dlastereomeric pair by reaction with an optically active compound. The diastereomers usually differ in physical properties to the extent that they can be separated by fractional crystallization. Regeneration of the optically active antipode is usually effected easily with mineral acid or base. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Resolution of Alcohols Satisfactory methods of resolution have been reported for all types of alkyl and arylalkyl secondary alcohols.* These methods of resolution, however, do not apply to all cases and it is left up to the individual researcher to determine the best method for the resolution of the compound in question. Of the three methods that are outlined by Ingersoll it will be found that only one of them has any practical importance. The first method involves the separation of the enant- lomers by means of crystallization. This method must necessarily involve a solid racemic mixture which upon crystallization deposits crystals of each of the active components. These crystals may then be separated by sorting them out mechanically or by partial crystallization. Separating the enantiomers by this means has proved practical only in a few cases and for that reason is not generally used. The formation of diastereomers and the subsequent fractional crystallization of the diastereomeric derivatives is the second method of resolution mentioned by Ingersoll. It has been shown to be the most useful and practical of all the methods. The first step involves the formation of a semi-permanent linkage between the optically active 1 A.W. Ingersoll, Organic Reactions. Vol. II, John Wiley and Sons, Inc., New York, N.Y., 1 9 ^ , P«3?6 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. resolving agent sand the two enantiomers of the substance to be resolved. This linkage must be strong enough to remain Intact during the fractional crystallization but also must be capable of being readily broken so that the desired optically active substance may be regenerated. Esterification of an alcohol (or phenol) with an acid or acid derivative usually provides the linkage that meets these requirements. The alcohol can be esterified with an optically active acid and separated with the recovery of the alcohol and the resolving agent by alkaline hydrolysis. This method is limited in that the esters formed must be crystalline. Phthalic acid or succinic acid are two of the most common substances with which derivatives of alcohols have been formed. Resolution of the alcohol is effected through the salt of the acid ester. The ester is resolved through the acid portion using an alkaloid, usually brucine or strychnine, as the resolving agent. When the optically active salts have been purified they are hydrolysed and the acid ester is saponified or reduced (in the case where racemization of the alcohol might take place with base) to regenerate the optically active alcohol. The procedure for the use of the hydrogen phthalate derivatives is out­ lined in the following scheme. This scheme has been applied to alcohols of nearly all types except tertiary. Tertiary alcohols were found generally to dehydrate or not form derivatives by this method. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. (±) E-OH + fyridlne „ (±) B-O-O-0 Brucine I V 0=C'OH 0 R-O-C-/ \ Brucine*H+ (D fractionation > (2) HC1 o=c.0- fractionation (active) NaOH LiAlHi NaOOC^^v. R-OH + T I] R-OH + (actiye) (active) Ingersoll's third method involves the reaction of the racemic substance with an optically active agent under different conditions. The enantiomers might be found to react with the reagent at different rates and thus partial resolution may
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