New quinolone antibacterial agents. Synthesis and biological activity of 7-(3,3- or 3,4-disubstituted-1-pyrrolidinyl)quinoline-3-carboxylic acids.

A series of 7-(3-amino- or 3-aminomethyl-1-pyrrolidinyl)-1-cyclopropyl-6,8-difluoro-1,4-dihydro-4-o xo-3-quinolinecarboxylic acids was synthesized and tested for antibacterial activity. Unique to these quinolones was the presence of a methyl or phenyl group in the pyrrolidine ring. Although the in vitro activity of these agents was usually equal to or less than that of their unsubstituted counterparts, one quinolone, 7-[3-(aminomethyl)-3-methyl-1-pyrrolidinyl]-1-cyclopropyl-6,8-difluoro-1 ,4-dihydro-4-oxo-3-quinolinecarboxylic acid, displayed exceptional potency both in vitro and in vivo, particularly against Gram-positive organisms.