21,23-DIACETYL-27,28-DIDEHYDRO-12-DEHYDROXY-27-DEMETHOXY-12,19-DIDEOXY-11,28,29-TRIHYDRO-29-DIMETHOXYRIFAMYCIN S
21,23-diacetyl-27,28-didehydro-12-dehydroxy-27-demethoxy-12,19-dideoxy-11,28,29-trihydro-29-dimethoxyrifamycin s