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Title: Some studies into the synthesis of furaneol
Author: Briggs, M. A.
ISNI:       0000 0001 3479 8477
Awarding Body: University of East Anglia
Current Institution: University of East Anglia
Date of Award: 1984
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The purpose of this research was to develop simple routes for furanones from readily available carbohydrate sources. Of particular interest was the synthesis of 4-hydroxy-2,5-dimethyl- 3(2H)-furanone, more commonly known as furaneol, a widely occurring flavour principle. The preparation of furaneol has been the subject of considerable study in recent years in view of possible applications as a flavouring agent in convenience foods. Our primary approach to the synthesis of furaneol uses as a final step, the known cyclization of 3,4-dihydroxyhexane-2,5-dione to furaneol under basic conditions, and the present research for the most part is concerned with the development of an alternative synthesis of the dione. A suitably cheap and readily available starting material for such a synthesis appeared to be L-(+)-tartaric acid. In this case the required synthetic transformation involves the conversion of the two carboxyl groups of the acid into acetyl functions. An extensive investigation was undertaken into the preparation of suitable L-(+)-tartaric acid derivatives and their reaction with organometallic reagents, principally Grignard reagents, in order to accomplish the required conversion. (R, R)-4,5-dicyano-2,2-dimethyl-1,3-dioxolan (2,3-0-isopropylidene-Ltartaronitrile) and (4R, 5R)-(+)-2,2, N, N, N', N'-hexamethyl-l, 3- dioxolan-4,5-dicarboxyamide, (2,3-0-isopropylidene-N, N, N', N'- tetramethyl-L-tartramide), were found to react with Grignard reagents to afford 2,3-dihydroxy-l, 4-diones in which the hydroxyl groups at the 2, and 3 positions are protected as isopropylidene acetals. Treatment of (4R, 5R)-4,5-diacetyl-2,2 =dimethyl-1,3-dioxolan, (3,4-0- isopropylidene (3R, 4R)-3,4-dihydroxyhexane-2,5-dione, prepared by either of the above procedures, with trifluoroacetic acid-water (9: 1 v/v) gave a crude sample of (3R, 4R)-3,4-dihydroxyhexane-2,5-dione, which on reaction with aqueous piperidinium acetate afforded furaneol. The overall yield of furaneol obtained in this way from L-(+)-tartaric acid was 19%. An alternative approach to the synthesis of furaneol which was investigated briefly, involved the preparation of 1-deoxy-D-fructose by a literature procedure. Treatment of 1-deoxy-D-fructose with piperidinium acetate in absolute ethanol however, failed to give either furaneol or 2-ethyl-3-hydroxy-4(2H)-furanone.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Organic chemistry