The biosynthesis of chlorine-containing metabolites of Periconia macrospinosa

Abstract

The biosynthesis of cryptosporiopsinol (methyl 2-prop-1-enyl-3,5-dichloro-1,4-dihydroxycyclopent-2-enoate (1) and 5-chloro-3,4-dihydro-8-hydroxy-6-methoxy-3-methylisocoumarin (2), metabolites of the fungus Periconia macrospinosa, have been studied using dihydro[3-¹⁴C]isocoumarins. 3,4-Dihydro-6,8-dihydroxy-3-methylisocoumarin (9), 5-chloro-3,4-dihydro-6,8-dihydroxy-3-methylisocoumarin (10), 7-chloro-3,4-dihydro-6,8-dihydroxy-3-methylisocoumarin (11), and 5,7-dichloro-3,4-dihydro-6,8-dihydroxy-3-methylisocoumarin (12) were the most efficient precursors of cryptosporiopsinol, thus establishing that a ring contraction is involved in the biosynthetic route. The results of the incorporations of the dihydro[3-¹⁴C]isocoumarins into (1) and (2) suggest that chlorination occurs early in the biosynthetic pathways of these metabolites.