133697-12-8 3'-Hydroxy-5'(R)-(4-sec-butylpiperazinyl)benzoxazinorifamycin AIDS-008665 AIDS008665 KRM 1686 KRM-1686 Rifamycin VIII, 1',4-didehydro-1-deoxy-1,4-dihydro-3'-hydroxy-5'-[4-(1-methylpropyl)-1-piperazinyl]-1-oxo-, [5'(R)]-