Hermann Fuhrer

A genetic approach to the biosynthesis of the rifamycin-chromophore in Nocardia mediterranei. III. Isolation and identification of an early aromatic ansamycin-precursor containing the seven-carbon amino starter-unit and three initial acetate/propionate-units of the ansa chain.

A number of rifamycin non-producing UV-mutants derived from Nocardia mediterranei strains N813 (rifamycin B producer) and A10 (aro--mutant excreting shikimate derived from strain N813) were found to accumulate an identical complex of aromatic components instead of rifamycin B. The main component of this aromatic complex, product P8/1-OG, was isolated from six of these P--mutant strains and identified spectroscopically as a very early precursor in the biosynthesis of rifamycins.

Revised structures of pipoxide and pipoxide chlorohydrin

The structures assigned earlier to pipoxide and pipoxide chlorohydrin have been revised on the basis of 360 MHz PMR spectral evidence and decoupling experiments.