An improved process for the preparation of 7- substituted amino-1-cyclopropyl-6, 8-difluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acids of formula
and pharmaceutically acceptable acid addition or base salts thereof, wherein A is a substituted amino group, X is hydrogen or fluorine, and R2 is alkyl of one to three carbon atoms or cycloalkyl of three to six carbon atoms, is described. An alkyl ester precursor is converted via an anhydrous preparation to an alkali metal salt which in a separate step or in situ is displaced and hydrolyzed to the desired product.
一种制备式 7-取代
氨基-1-环丙基-6, 8-二
氟-1,4-二氢-4-氧代-
3-喹啉羧酸及其药物可接受的酸加成盐或碱盐的改进工艺
及其药学上可接受的酸加成盐或碱盐,其中 A 是取代的
氨基,X 是氢或
氟,R2 是 1 至 3 个碳原子的烷基或 3 至 6 个碳原子的环烷基。烷基酯前体通过无
水制备转化为碱
金属盐,碱
金属盐在单独步骤中或原位置换并
水解为所需产物。