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Title: Stereochemical studies of heterocyclic analogues of decalins
Author: Wilcox, G.
ISNI:       0000 0001 3568 0921
Awarding Body: Keele University
Current Institution: Keele University
Date of Award: 1984
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This dissertation is concerned with the synthesis of the octahydro-1-benzopyran and octahydro-1,4-benzoxazine systems and the application of 1H and 13C n.m.r. spectroscopy to determine the stereochemistry and major conformation adopted by the isomers of these systems. A synthetic route has been developed for the synthesis of isomerically pure samples of both the cis and trans isomers of the heterocyclic analogue of decalin, octahydro-1-benzopyran. The position of the conformational equilibrium in the cis isomer has been established by low temperature 13C n.m.r. spectroscopy and the result is compared with that previously reported for the analogous nitrogen system, decahydroquinoline. High field n.m.r. spectroscopy has enabled vicinal coupling data to be obtained for the C2-C3 bond in both the ci£ and trans isomers. This is used to assess the degree of distortion in the pyran portion of the ring system. A route for the production of octahydro-1,4-benzoxazine has been developed together with a chromatographic procedure for obtaining samples of the pure cis and trans isomers. This synthetic route has also been extended to produce pure samples of many of the isomers of the 2,3,6 and 7 methyl-substituted derivatives. The stereochemistry of these isomers has been determined from their 1H and 13C n.m.r. spectra. The proton-proton vicinal coupling constants for the C2-C3 bond in these isomers is used to assess the degree of distortion in the oxazine portion of the ring system. The position of the conformational equilibria in the cis isomers of these systems has been assessed by low temperature n.m.r. spectroscopy and is interpreted in terms of the interactions present in the major conformations.
Supervisor: Griffiths, D. V. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QD Chemistry