Syntheses and spectral studies of novel ciprofloxacin derivatives

Reaction of 1-cyclopropyl-6-fluoro-4-oxo-7-(piperazin-1-yl)-1,4-dihydroquinoline-3-carboxylic acid (ciprofloxacin) with thiazole/benzothiazole diazonium chloride afforded piperazine substituted ciprofloxacin derivative. The acid part of these derivatives was further condensed with various β-diketones to get 1-cyclopropyl-6-fluoro-4-oxo-7-(4-(thiazol-2-yldiazenyl)piperazin-1-yl)-1,4-dihydroquinoline-3-carboxylic acid derivatives (5a-e) and 7-(4-(benzo[d]thiazol-2-yldiazenyl)piperazin-1-yl)-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid derivatives (5f-j). Structures of these compounds were established on the basis of spectral studies.