Chryscandin, a novel peptidyl nucleoside antibiotic. II. Structure determination and synthesis

The structure of chryscandin, a novel antifungal antibiotic, produced by Chrysosporium pannorum No. 4629 was deduced to be 1 from spectroscopic and chemical evidences. In order to confirm the structure and to determine the absolute configuration, the total synthesis of chryscandin was performed. D-Xylose was transformed into 10 in ten steps. After beta-glycosidation of silylated benzoyl adenine with 10, the resulting 11 was converted into 4, which was identical with the product obtained from chryscandin by alkaline hydrolysis. From the key intermediate 13, chryscandin was synthesized via peptide formation followed by removal of the protecting groups. Chryscandin (1) is the first naturally occurring nucleoside antibiotic possessing a 3-aminoribofuranuronic acid in the molecule.