The Synthesis and Biosynthesis of Chlorine Containing Metabolites

[摘要] The biosynthesis of cryptosporiopsinol was investigated, in particular the nature of the contraction of the 6-membered ring to the 5-membered ring. The feeding of different labelled acetates to Periconia macrospinosa has been studied. The feeding result of CH313C18O2Na suggests that the ring contraction previously proposed cannot be correct and that the ring contraction must go via an alternative mechanism. The isocoumarin isolated from feeding of CD313CO2Na to Periconia macrospinosa showed in its 13C n. m. r. spectra two different beta-shifts at C-4a arising from the axial and equatorial deuteriums at C-4. A number of deuterium labelled 5-chloro-3,4-dihydro-8-hydroxy-6-methoxy-3-methylisocoumarins were synthesised. The results obtained confirmed that beta-shifts are additive and it was also shown that the equatorial deuterium exerted a greater beta-shift than the axial deuterium. The biosynthesis of microline and dechloromicroline was studied. 3,4-Dihydro-6,8-dihydroxy-3-methylisocoumarin was synthesised with a 14C at C-3. This isocoumarin was also synthesised with deuterium atoms at C-4 and the methyl group. These compounds were fed to Gilmaniella humicola and shown to be incorporated into dechloromicroline intact. A synthetic route was developed which gave the dimethyl ether of perimacol a metabolite of Periconia macrospinosa. It was shown that a trans arrangement exists between the methyl group and methoxyl group at C-3 and C-4 respectively. Previously it was thought that a cis arrangement existed between the substituents at C-3 and C-4.

[发布机构] University:University of Glasgow

[关键词] Organic chemistry