Lamellicolic Anhydride and Other Polyketides of Verticillium lamellicola and Aspergillus nidulans

McRitchie, Allan Campbell (1973) Lamellicolic Anhydride and Other Polyketides of Verticillium lamellicola and Aspergillus nidulans. PhD thesis, University of Glasgow.

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Abstract

A number of novel, phenolic 1,8-naphthalic anhydrides have been isolated from a strain of VerticiIlium lamellicola and the major metabolite, lamellicolic anhydride, shown to be 2,4,7-trihydroxy-5-methyl-1,8-naphthalic anhydride. Amongst a number of unusual and characteristic reactions exhibited by this compound was a remarkably facile aminolysis of ether groups in its O,O,O-trimethyl derivative with the formation of amino derivatives. Routes from lamellicolic anhydride have been studied in order to provide an entry into the dimeric scries of compounds typified by duclauxin. Minor metabolites of Y. lamellicola include 2,7-dihydrexy-5-methyl-1,4-naphthaquinone - the in vitro synthesis of this compound from, lamellioolio anhydride has been accomplished - and the monomethyl ester of 3-chlorolameilicolic acid. 4-O-Carbomethoxylamellicolic anhydride-the first natural product reported which contains a methyl carbonate group - co-occurs with lamellicolic anhydride and has been prepared, from it. The biosynthesis of these compounds and the results of some preliminary feeding experiments are discussed. Two phenolic, yellow pigments - arugoxanthones A and B - have been isolated from the spores of the yellow mutant of Aspergillus nidulans and identified as the first reported prenylated fungal xanthones. Model studies have confirmed the feasibility of the unusual chroman-4-ol unit found in arugoxanthone A being derived bdogenetically via a novel intramolecular cyclisation of an O-3,3-dimethylallyl unit and a formyl group. Arugoxanthones A and B have also been isolated from mycelial extract of the yellow mutant along with the closely related compounds isoarugo-xanthone A and arugoxanthones C and D. The two latter compounds contain a substituent previously unrecorded in a natural product - namely the O-3,3-dimethyl-3-hydroxy-l-prcpyl ether group. The known mould metabolite arugosin co-occurs with these xanthones and routes to the latter compounds from it have been explored. In particular, the acid catalysed rearrangement of arugosin has been studied and the products of a novel intramolecular cyclisation reaction identified. The close relationship between arugosin and the xanthones has been demonstrated by the conversion of arugoxanthone B into anhydroarugosin and deisopentenyl-anhydroarugosin, reported as transformation products of arugosin. The methyl ester of isocanadensic acid - a metabolite of Penicillium canadense and possible biogenetic precursor of the antibiotic canadensolide - has been synthesised by a five step route.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Organic chemistry
Date of Award: 1973
Depositing User: Enlighten Team
Unique ID: glathesis:1973-78634
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 28 Feb 2020 12:09
Last Modified: 28 Feb 2020 12:09
URI: http://theses.gla.ac.uk/id/eprint/78634

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