A process for the preparation of a 1,8-bridged 4-quinolone-3-carboxylic acid of the formula ##STR1## comprising in a first reaction step reacting an enamine of the formula ##STR2## in an anhydrous, aprotic solvent with one equivalent of a base, at a temperature from 80.degree. C. to 180.degree. C., to give a 4-quinolone-3-carboxylic acid derivative of the formula ##STR3## and, in a second reaction step, reacting that with another equivalent of a base, to give the 1,8-bridged 4-quinolone-3-carboxylic acid derivative of the formula (I) and optionally converting the group Y into a carboxyl group or salt thereof. Both steps may be effected simultaneously in a one-pot process without intermediate isolation of the compound II. Some of the compounds are new. The old and new compounds are antibacterials and promote animal growth.
一种制备式为##STR1##的1,8-桥联4-
喹啉-3-羧酸的方法,包括在第一反应步骤中,在无
水、无质子溶剂中,用一当量的碱与式为##STR2##的恩酰胺反应,反应温度为80℃至180℃,以得到式为##STR3##的4-
喹啉-3-羧酸衍
生物;在第二反应步骤中,用另一当量的碱反应,以得到式为(I)的1,8-桥联4-
喹啉-3-羧酸衍
生物,并可将基团Y转化为羧基或其盐。两个步骤可以在一个反应釜中同时进行,无需中间分离化合物II。其中一些化合物是新的。旧的和新的化合物都是抗菌剂并促进动物生长。