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): <CHEM> wherein X<1> is an alkyl group with l to 6 carbon atoms or a cycloalkyl group with 3 to 8 carbon atoms; X<2> is a hydrogen atom or an alkyl group with l to 4 carbon atoms; R<1> is hydrogen atom or acetyl group; A is a group represented by the formula: <CHEM> wherein R<2> is an alkyl group with l to 4 carbon atoms or an alkoxyalkyl group with 2 to 6 carbon atoms and R<3> is an alkyl group with l to 6 carbon atoms or an alkoxyalkyl group with 2 to 6 carbon atoms, or a group represented by the formula: <CHEM> wherein <CHEM> is a 3 to 9 membered cyclic amino group with 2 to 8 carbon atoms, R<4> is a hydrogen atom or an alkyl group having l 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.