Abstract: 2-Alkyl-6-oxo-8-fluoro-9-(4-methylpiperazin-1-yl)-6H-imidazo(4,5,1-ij)-quino-line-5-carboxylic acids (2Ab~2Ae) were prepared by condensation of ethyl 6-fluoro-7-(4-meth-ylpiperazin-1-yl)-8-amino-1,4-dihydro-4-oxo-3-quinolinecarboxylate (5A) with the aliphatic acids in PPA. Other target compounds 2Af~2Ah, 2Bc, 2Cc, 2Aa~2Da, 2Bi and 2Ci were prepared by the condensation of 6-fluoro-7-nitrogen-containing heterocycle-8-amino-1,4-dihydro-4-oxo-3-quinoline-carboxylic acids (9A~9D) with the corresponding acids in PPA or with ethyl ortho-formate or by the diazotisation of 9B and 9C, respectively. Only 2Ab and 2Ac showed moderate antibacterial activity in in vitro test.

Key words: Fluoroquinolones, Imidazoquinolines, Antibacterials