STRUCTURE AND C-13 NUCLEAR MAGNETIC-RESONANCE ASSIGNMENTS OF VERSICONAL ACETATE, VERSICONOL ACETATE, AND VERSICONOL, METABOLITES FROM CULTURES OF ASPERGILLUS-PARASITICUS TREATED WITH DICHLORVOS

The structure of versiconal acetate, a metabolite elaborated by cultures of Aspergillus parasiticus treated with dichlorvos was investigated. 1H and 13C n.m.r. studies of versiconal acetate and its 3,6-OO-dimethyl derivative indicated that versiconal acetate exists in polar solvents such as (CD3)2SO as an equilibrium mixture of the isomers (6a-c). In (CD3)2CO solution the angular hemiacetal form (6c) was absent. Similarly, 3,6-OO-dimethyl-versiconal acetate exists in (CD 3)2SO solution as the angular hemiacetal (7b) whereas in CDCl3 solution the compound is present as the branched benzylic aldehyde (7a). Two minor metabolites were identified as versiconol acetate (11) and versiconol (12).