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Title: 2:3-Dihydro-3-oxobenz-1:4-oxazines (A) ; A note on lycorine (B)
Author: Ogg, James
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 1954
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Abstract:
Part I. The chemistry of the 2:3-dihydro-3-oxo-benz-1:4-oxazines is reviewed, and a general method for their N-methylation developed. The possession of a feebly reactive methylene group is demonstrated in the formation of a benzylidene derivative by 2:3-dihydro-3-oxobenz-1:4-oxazine and its N-methyl derivative. Reduction of 2:3-dihydro-4-methyl-3-oxobenz-l:4-oxazine with lithium aluminium hydride is shown to give 2:3-dihydro-4-methyl-benz-1:4-oxazine. The reaction with aluminium chloride whereby chloroacetyl-N-methyl-o-anisidide yields 2:3-dihydro-4-methyl-3-oxobenz-l:4-oxazine and, hence, a mixture of hydroxy-l-methyloxindoles is investigated and a search made for other examples of analogous rearrangements. The formation of benzoxazine derivatives from chloroacetyl-o-anisidides appears to be general, and proceeds through demethylation to chloroacetyl-o-amido phenols, which are isolable only when the nitrogen atom does not carry a methyl substituent, and which yield the corresponding benzoxazines on dissolution in alkali. The rearrangement of these oxazines to oxindoles appears to depend on two factors (a) the presence of an N-methyl substituent (b) the stability of the compound at the high reaction temperatures used. Hence, no oxindoles could be obtained from benz-1:4-oxazines which did not carry an N-methyl group. 2:3-Dihydro-2:4-dimethyl-3-oxobenz-1:4-oxazine rearranges to a single product, 7-hydroxy-1:3-dimethyloxindole, which is identified by conversion to, and independent synthesis of, 7-methoxy-1:3-dimethylindole. No oxindoles could be obtained, either, from 2:3-dihydro-6-hydroxy-4-methyl-3-oxobenz-1:4-oxazine, 2:3-dihydro- 7-hydroxy-4-methyl-3-oxobenz-1:4-oxazine (or the corresponding N-methylanilides), or 5:6-benz-2:3-dihydro-4-methyl-3-oxobenz-1:4-oxazine owing to their instability in the high temperature melt. Incidentally to the preparative work entailed in this study, a convenient preparation of 2:4-dimethoxynitrobenzene is evolved. The action of aluminium chloride on beta-chloropropionyl-o-anisidide and -N-methyl-o-anisidide, leading to 3:4-dihydrocarbostyrils is examined. In each case a single product is obtained and is identified as 3:4-dihydro-8-hydroxycarbostyril and its N-methyl derivative respectively. Part II. Lycorine is obtained from the bulbs of Narcissus pseudonarcissus. The products of fusing the alkaloid with potassium hydroxide are examined, but although the formation of indole, or a simple indole derivative, is indicated by colour reactions, conclusive proof is still lacking. Attempts to dehydrate lycorine under mild conditions failed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.803053  DOI: Not available
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