Early intermediates in the biosynthesis of ansamycins. III. Isolation and identification of further 8-deoxyansamycins of the rifamycin-type.

A number of minor compounds were isolated from fermentations of the protorifamycin I producing strain Nocardia mediterranei F 1/24(1,2)) and identified by means of chemical and spectroscopic methods. Two types of structures were identified: Type 1: modified protorifamycins (derived from protorifamycin I) Type 2: defective rifamycins (8-deoxyrifamycins).