133698-17-6 3'-Hydroxy-5'(S)-(4-sec-butylpiperazinyl)benzoxazinorifamycin AIDS-008666 AIDS008666 KRM 1687 KRM-1687 Rifamycin VIII, 1',4-didehydro-1-deoxy-1,4-dihydro-3'-hydroxy-5'-[4-(1-methylpropyl)-1-piperazinyl]-1-oxo-, [5'(S)]-