VIRIPLANIN A, A NEW ANTHRACYCLINE ANTIBIOTIC OF THE NOGALAMYCIN GROUP

II. THE STRUCTURE OF A NOVEL HYDROXYAMINO SUGAR FROM REDUCED VIRIPLANIN A

Abstract

Methyl 2, 3, 6-trideoxy-3-hydroxyamino-3-C-methyl-α-D-ribo-hexopyranoside (2) and the corresponding amino sugar (4) were isolated from reduced viriplanin A by acidic methanolysis and esterified to the di-p-bromobenzoates (3 and 5), respectively. The absolute configuration of crystalline 3 was determined by X-ray analysis to be α-D. This result could be confirmed by oxidation of 2 to methyl α-D-decilonitroside (6) and from the CD spectra of 3 and 5. Thus, the nitrogen-containing sugars of viriplanin A and probably those of decilorubicin and arugomycin belong to the D-series.