The absolute structures of rubeomycins A and A1 (carminomycins II and III) and rubeomycins B and B1 (4-hydroxybaumycinols A1 and A2).

Abstract
The absolute configurations of rubeomycins A and A1 (corresponding to carminomycins II and III) and rubeomycins B and B1 (corresponding to 4-hydroxybaumycinols A1 and A2), except at the C-1" position, were determined by comparison of the optical rotations and other spectral data of rubeomycin derivatives with those of daunomycin and L-(+)-lactic acid.