By using a strain ofStreptomyces willmorii, daunorubicin (daunomycin) was stereoselectively Converted intoN-acetyl-13(S)-dihydrodaunomycin and bisanhydro-13-dihydrodaunomycinone. The absolute stereochemistry of the new chiral center inN-acetyl-13(S)-dihydrodaunomycin was established by means of nuclear Overhauser effect measured in the 9, 13-O-isopropylidene derivative.
