129791-92-0 188910-97-6 3'-Hydroxy-5'-(4-isobutylpiperazinyl)benzoxazinorifamycin ABI 1648 KRM-1648 Krm 1648 Rifalazil Rifamycin viii, 1',4-didehydro-1-deoxy-1,4-dihydro-3'-hydroxy-5'-(4-(2-methylpropyl)-1-piperazinyl)-1-oxo-