Efficient preparation of derivatives of resibufogenin using microbial catalytic technique.

Microbial catalysis is a useful biotechnology in studies on natural products, by which a diversity of novel or active compounds can be obtained. Structural modifications of resibufogenin (1) by hydroxylases, isomerase and glucosyltransferase in Mucor subtilissimus AS 3.2454 were investigated. Eleven products were obtained, and, on the basis of their spectral data, their structures were identified as 12beta-hydroxyresibufogenin (2), 11beta-hydroxyresibufogenin (3), 16alpha-hydroxyresibufogenin (4), 12beta-hydroxy-3-epi-resibufogenin (5), 12alpha-hydroxyresibufogenin (6), 1beta,11beta-dihydroxyresibufogenin (7), 12beta,16alpha-dihydroxyresibufogenin (8), 12alpha,16alpha-dihydroxyresibufogenin (9), 7alpha-hydroxyresibufogenin (10), 1beta,12beta-dihydroxyresibufogenin (11) and resibufogenin 12-O-beta-D-glucoside (12), respectively, of which 3, 5, 7, 11 and 12 are new compounds. This microbial catalytic process was efficient for the production of derivatives of resibufogenin giving 11 products and an overall yield of 93.60%.