PROCESS FOR PREPARING NAPHTHYRIDINE DERIVATIVES

摘要

The antibiotic title compds. (I; R1 = Et, vinyl; R2 = H, lower alkyl) were prepd. by reaction of II(Y = H, lower alkoxy, alkylthio, sulfinyl, sulfonyl) and III(R3 = H, protecting group). Thus, 5.0 g 7-chloro-ethyl-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylic acid in 200 ml acetonitrile was added to a mixt. of 7.69 g anhydrous piperazine and 200 ml acetonitrile reacted to give 5.4 g I(R1 = Et; R2 H).