The Biosynthesis of Cryptosporiopsinol

[摘要] Cryptosporiopsinol is a cyclopentene polyketide metabolite isolated from the fungus Periconia macrospinosa. Cryptosporiopsinol is believed to arise via a ring contraction of an isocoumarin precursor. This study is concerned with further details of the biosynthetic pathway to cryptosporiopsinol. [3,4,9-2H3]-5,7-dichloro-3,4-dihydro-6,8-dihydroxy-3-methylisocoumarin and [4,9,9,9-2H4]-5,7-dichloro-3,4-dihydro-6,8-dihydroxy-3-methylisocoumarin were synthesised. On feeding these compounds to Periconia macrospinosa it was found that the cryptosporiopsinol was labelled with deuterium. The results indicated that the 4-proS proton of the isocoumarin is cleaved whereas the 4-proR proton is retained. This supports the proposal that stereospecific hydroxylation may occur at the 4-position of an isocoumarin similar to that in perimacol, a 4-hydroxylated isocoumarin co-metabolite. To further investigate the ring contraction in the biosynthesis of cryptosporiopsinol 5,7-dichloro-3,4-dihydro-6-hydroxy-8-methoxy-3-methylisocoumarin and 2-methoxy-6-prop-l-enyl-1,4-benzoquinone are required. Routes to these compounds were investigated and synthetic strategies to their syntheses were developed. During the studies of the synthesis of the 1,4-benzoquinone, the successful coupling of heptyne with iodovanillin was achieved using bis(triphenylphosphine)-dichloropalladium and cuprous iodide as a catalyst. In another route to the 1,4-benzoquinone the condensation of 2,3,5-trimethoxy bromobenzene with propanal using n-butyllithium was achieved.

[发布机构] University:University of Glasgow

[关键词] Organic chemistry