New rifamycin derivatives.

摘要

Compounds of the general formula: <CHEM> in which R is a lower alkyl group, and R1 is a tri-lower alkylmethylcarbonyl group, the structure elements -A1-A2-, A3-A4- or A5-A6- each represent ethylene or vinylene, or the elements -A1-A2- and -A3-A4- each represent ethylene and -A5-A6- represents vinylene, their optical isomers and their salts exhibit valuable pharmaceutical properties.