ALDECALMYCIN, A NEW ANTIMICROBIAL ANTIBIOTIC FROM STREPTOMYCES .3. DETERMINATION OF ABSOLUTE-CONFIGURATION

The planar structure of aldecalmycin (1) had been determined in the pr evious paper, together with the conformations of the substituted Irans decalin ring having one double bond and the sugar; beta-glucopyranosi de type. The absolute configuration of 1 was a following problem to be solved. X-Ray crystallographic analysis of crystalline 4',6'-O-benzyl idenedihydroaldecalmycin (4) revealed the relative configuration. On t he other hand, the stereoisomerism of the sugar was determined to be D by the optical rotation value of tetra-O-acetyl-alpha-methylglucopyra noside derived from 1. These results established the absolute configur ation of 1.