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Title: Studies in the alkyl-oxygen fission of carboxylic esters
Author: Dabby, Ruben Ephraim
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 1949
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Abstract:
Investigations of p-methoxybenzhydrol (Balfe, Doughty, Kenyon and Poplett: J. G. S. 1942,605) showed that asters of this carbinol undergo hydrolysis mainly by the alkyl-oxygen fission mechanism. This led to the belief that the thio-methyl group would have a similar effect to that of the methoxyl group in modifying the reactivity of the benzhydryl molecule. This expectation has been fully realised in thioanisylphnyl carbinol and its esters. Accordingly, thioanisylphenyl carbinol has been prepared and resolved through its hydrogen phthalic ester by means of quinine. Reactions of this carbinol and its esters appear to be parallel with those of p-methoxy-benzhydrol. Acid hydrolysis of the (-)-hydrogen phthalic ester of this carninol proceeds by the alkyl-oxygen fission mechanism with production of the optically inactive carbinol; a mechanism for this type of acid hydrolysis is postulated, (-)-thioantsylphenylcarbinol and its (-)-hydrogen phthalic ester undergo smooth oxidation with hydrogen peroxide to yield the (+)-p-methyl-sulphonylbenzhydrol and its (+)-hydrogen phthalic ester respectively. The electromeric displacement in the p-methylsulphonyl group is expected to take place in a direction opposite to that in the thionanisyl group, thus, [chemical formulas], and, therefore, hydrolysis of esters of p-methylsulphonylbenzhydrol would be expected to proceed by the acyl-oxygen fission mechanism. That this is actually the case, is borne out by the experimental evidence recorded in this thesis. Investigations by Kenyon et al on the esters of anisyl-a-naphthylcarbinol, showed that these behave in a manner very much similar to that of esters of p-mathoxybenzhydrol; a fact undoubtedly attributed to the presence of the anisyl group. In the case of phanyl-a-naphthylcarbinol, we found the esters of this carbinol undergo various reactions mainly by the acyl-oxygen fission mechanism in a manner similar to that undergone by the esters of benzhydrol. Therefore , the presence of the methoxyl group appears to modify the reactivity, to a great extent, of the benzhydryl or the phenyl-a-naphthylcarbinyl groups.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.751446  DOI: Not available
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