The Antibacterial Compound Aspergillic Acid

Dunn, George (1949) The Antibacterial Compound Aspergillic Acid. PhD thesis, University of Glasgow.

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Aspergillic acid the antibacterial compound isolated by White in 1940 from culture filtrates of Aspergillus flavus was investigated by Dutcher and Wintersteiner who formulated it as (I) and its primary reduction product deoxyaspergillic acid as (II). Deoxyaspergillic acid has been totally racemised by treatment with alkali at elevated temperature and the racemate is different from racemic 3-hydroxy-2:5-di-seci-butylpyrazine (II). By oxidation of aspergillic acid or deoxyaspergillic acid acetone is produced. Bromination of aspergillic acid followed by zinc and acetic acid reduction gives a 2:5-diketopiperazine. Hydrolysis of this diketopiperazine by hydrobromic acid gives a mixture of alpha-amino-acids which has been resolved and the components identified as leucine and isoleucine (and alloisoleucine). These reactions do not accord with the structure of aspergillic acid proposed by Dutcher and Wintersteiner and it is now formulated as (III) or (IV). Growth of A. flavus on a casein hydrolysate medium produces in addition to aspergillic acid another metabolite which was named flavacol, C12H20ON2. It was identified by synthesis as 3-hydroxy-2:5-di-isobutylpyrazine. Kojic acid has been produced by growth of A. flavus on a casein hydrolysate medium to which brown sugar was added. Synthetic approaches to compounds related to aspergillic acid and deoxyaspergillic acid have been examined.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Organic chemistry, Pharmacology
Date of Award: 1949
Depositing User: Enlighten Team
Unique ID: glathesis:1949-79813
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 03 Mar 2020 10:33
Last Modified: 03 Mar 2020 10:33

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