ALKYL-SUBSTITUTED BENZOXAZINORIFAMYCIN DERIVATIVE, PROCESS FOR PREPARING THE SAME AND ANTIBACTERIAL AGENT CONTAINING THE SAME

摘要

A novel rifamycin derivative having the formula (I): (I) wherein X1 is an alkyl group with 1 to 6 carbon atoms or a cycloalkyl group with 3 to 8 carbon atoms; X2 is a hydrogen atom or an alkyl group with 1 to 4 carbon atoms; R1 is hydrogen atom or acetyl group; A is a group represented by the formula: , wherein R2 is an alkyl group with 1 to 4 carbon atoms or an alkoxyalkyl group with 2 to 6 carbon atoms and R3 is an alkyl group with 1 to 6 carbon atoms or an alkoxyalkyl group with 2 to 6 carbon atoms, or a group represented by the formula: wherein is a 3 to 9 membered cyclic amino group with 2 to 8 carbon atoms, R4 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, or salts thereof, a process for preparing the same and antibacterial agents containing the same as an effective ingredient. The rifamycin derivative of the present invention having the formula (I) shows a strong antibacterial activity against the Gram-positive bacteria and the acid-fast bacteria.