Studies on pyridonecarboxylic acids.<b>V</b>. A practical synthesis of ethyl 6,7-difluoro- 1-methyl-4-oxo-4<i>H</i>-[1,3]thiazeto[3,2-<i>a</i>]quinoline-3-carboxylate, a key intermediate for the new tricyclic quinolone, prulifloxacin (NM441) and versatile new syntheses of the 2-thioquinoline skeleton
作者:Masato Matsuoka、Jun Segawa、Yoshihiko Makita、Sbinji Ohmachi、Tatsuhiko Kashima、Ken-Ichi Nakamura、Masayuki Hattori、Masahiko Kitano、Masahiro Kise
DOI:10.1002/jhet.5570340622
日期:1997.11
A practical synthesis of ethyl 6,7-difluoro-1-methyl-4-oxo-4H-[1,3]trüazeto[3,2-a]quinoline-3-carboxylate (9), the key intermediate for 6-fluoro-1-methyl-7-[4-(5-methyl-2-oxo-1,3-dioxol-4-yl)methyl-1-piperazinyl]-4-oxo-4H-[1,3]thiazeto[3,2-a]quinoline-3-carboxylic acid (2), NM441, was developed. The crucial points of this synthetic route are the chlorination of ethyl 4-acetoxy-2-(ethylthio)-6,7-di
6,7-二氟-1-甲基-4-氧代-4 H- [1,3]Trüazeto[3,2 - a ]喹啉-3-羧酸乙酯的实用合成方法(9),是6-的关键中间体氟-1-甲基-7- [4-(5-甲基-2-氧代-1,3-二氧杂-4-基)甲基-1-哌嗪基] -4-氧代-4 H- [1,3]噻嗪酮开发了[3,2 - a ]喹啉-3-羧酸(2),NM441。该合成路线的关键点是氯化4-乙酰氧基-2-(乙硫基)-6,7-二氟喹啉-3-羧酸乙酯(12)和随后的生成的2-(1-氯乙基)硫代化合物脱乙酰化13然后进行分子内环化反应。还开发了2-硫喹啉骨架的多功能新合成物。第一条途径包括N,S-乙缩醛22的分子内环化,其由三步法由2,4,5-三氟苯甲酸制备。第二个化合物包含乙酸乙酯的乙硫醇锂对4-位新的2-(甲硫基)-4 H- [3,l]苯并噻嗪-4-酮29的区域选择性攻击,然后将所得β进行分子内环化-酮酸酯30。