Natural acetylenes. Part XXI. The biosynthesis and transformation of some polyacetylenic metabolites of Merulius lacrymans Fr. and Clitocybe rhizophora velen

Abstract

The triacetylenic acid (II; RH), the major polyacetylenic metabolite of the fungus Merulius lacrymans, has been biosynthesised on a medium containing either [¹⁴C]-acetate or [¹⁴C]-malonate. Degradation of the radioactive metabolite by selective copper-catalysed decarboxylation has revealed that the αβ-acetylenic carboxylic acid group is derived from an acetate-methyl group. The acid (II; RH) is probably an intermediate in the catabolism of some C₁₀ to C₉ polyacetylenic metabolites.

The two diacetylenic metabolites (VII and VIII) of Clitocybe rhizophora have been obtained in a radioactive form by addition of [¹⁴C]-acetate to the culture medium. Degradation of the triol (VII) revealed that the terminal hydroxylated carbon atom was generated from an acetate-methyl group. By adding the radioactive metabolites separately to cultures of Clitocybe rhizophora it was possible to demonstrate that the diacetylenic ketone (VIII) is very probably the precursor of the triol (VII).