7-(2-chloromethylmorpholino)-1-ethyl-6,8-difluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid 、
二甲胺 以to give 7-[2-(dimethylaminomethyl)morpholino]-1-ethyl-6,8-difluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid, melting at 185°-188° C.的产率得到1-ethyl-6,8-difluoro-1,4-dihydro-7-[2-(dimethylaminomethyl)morpholino]-4-oxoquinoline-3-carboxylic acid