Diolmycins, new anticoccidial agents produced by Streptomyces sp. II. Structure elucidation of diolmycins A1, A2, B1 and B2, and synthesis of diolmycin A1

The structures of diolmycins A1, A2, B1 and B2, novel anticoccidial agents, were determined by spectroscopic analyses. Diolmycins A1 and A2 are stereoisomers with the structure of 1-(3-indolyl)-4-(p-hydroxyphenyl)-2,3-butanediol. From the chemical synthesis of the erythro-isomer, the relative configurations of diolmycins A1 and A2 were determined to be the erythro- and threo-isomers, respectively. The stereoisomers, diolmycins B1 and B2, were also deduced to be erythro- and threo-1,4-di-(p-hydroxyphenyl)-2,3-butanediol, respectively.