1-环丙基-6,7-二氟-1,4-二氢-8-羟基-4-氧代喹啉-3-羧酸乙酯的合成

Synthesis of Ethyl 1-Cyclopropyl-6,7-difluoro-1,4-dihydro-8-hydroxy-4-oxo-3-quinolinecarboxylate

1-环丙基-6,7-二氟-1,4-二氢-8-甲氧基-4-氧代喹啉-3-羧酸乙酯(2)经40%氢溴酸水解得到1-环丙基-6,7-二氟-1,4-二氢-8-羟基-4-氧代喹啉-3-羧酸(4),再在三甲基氯硅烷存在下经乙醇酯化得1-环丙基-6,7-二氟-1,4-二氢-8-羟基-4-氧代喹啉-3-羧酸乙酯(1),总收率为52.1%。也可用2在无水三氯化铝作用下水解直接得到1,收率66.9%。

Ethyl 1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-hydroxy-4-oxo-3-quinolinecarboxylate（1） was synthesized from ethyl 1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxo-3-quinolinecarboxylate（2） by hydrolysis with 40% hydrobromic acid to give 1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-hydroxy-4-oxo-3-quinolinecarboxylic acid（4）,followed by esterification with ethanol in the presence of trimethyl chlorosilane with an overall yield of about 52.1%. Also compound 1 was hydrolyzed directly from 2 in the presence of anhydrous aluminum chloride in 1,2-dichloroethane with a yield of 66.9%.