Substd. piperazinyl quinolone carboxylic acid deriv. prepn. - involves conversion of 3-chloro-4-fluoro:aniline to acetanilide, redn. conversion to formanilide, ring closure with ethoxy-malonyl chloride, etc.

摘要

1-ethyl 6-fluoro 1,4-dihydro 4-oxo 7-(4-methyl 1-piperazinyl) quinoline 3-carboxylic acid is made by (1) reacting acetic anhydride with 3-chloro-4-fluoro aniline; (2) reducing the acetanilide with diborane to give N-ethyl 3-chloro 4-fluoro aniline; (3 reacting with formic acid to give the formanilide; (4) reacting with POCl3 and ethoxy-malonyl chloride and basifying to give 1-ethyl 7-chloro 6-fluoro 1,4-dihydro 4-oxo quinoline 3-carboxylic acid; and (5) reacting with 1-methyl piperazine to give the required prod.