PROCESS FOR PRODUCING NEW NAPHTRIDINE DERIVATIVES

摘要

The present invention provides a 1,8-naphthyridine compound of the formula wherein R is hydrogen, methyl, ethyl or propyl, and a nontoxic pharmaceutically acceptable salt thereof, and a process for preparing a 1,8-naphthyridine compound of the above formula which comprises (A) reacting a compound of the formula wherein Y is halogen, lower alkoxy, lower alkylthio, lower alkylsulfinyl, lower alkylsulfonyl, lower alkylsulfonyloxy or arylsulfonyloxy, and R1 is hydrogen or lower alkyl, with a compound of the formula wherein R2 is hydrogen or a protective group for the amino group, and R is as defined above, and when a reaction product in which R1 is lower alkyl and/or R2 is the amino protective group is obtained, treating it with an acid or base, and/or reductively cleaving it, (B) decomposing a compound of the formula wherein A (-) is a fluorine-containing anion, and R1 and R2 are as defined above, and when a reaction product in which R1 is lower alkyl and/or R2 is the amino protective group is obtained, treating it with an acid or base, and/or reductively cleaving it, (C) treating a compound of the formula wherein R'1 is hydrogen or lower alkyl, R'2 is hydrogen or a protective group for the amino group, provided that R'1 and R'2 are not hydrogen atoms at the same time, and R is as defined above, with an acid or base, and/or reductively cleaving it, and optionally converting the resulting compound to a nontoxic pharmaceutically acceptable salt thereof. The 1,8-naphthyridine compound is useful as an antibacterial agent.