129791-94-2 3'-Hydroxy-5'-(4-sec-butylpiperazinyl)benzoxazinorifamycin AIDS-008519 AIDS008519 KRM 1668 KRM-1668 Rifamycin VIII, 1',4-didehydro-1-deoxy-1,4-dihydro-3'-hydroxy-5'-(4-(1-methylpropyl)-1-piperazinyl)-1-oxo-, [5'(RS)]-