Abstract
Leucomycin A3 (I) was oxidized with active manganese dioxide to dehydroleucomycin A3 (II) which was identical with magnamycin B. Acid treatment of I yielded demycarosylleucomycin A3 (VII), which was converted to a triacetate showing mass spectrum M+ (m/e 725), and this observation confirmed the structure of I. The diene system of I was assumed to have a trans-trans configuration on the basis of its NMR spectrum, and a full structure of I was proposed with stereochemistry.
