Synthesis of antimicrobial agents. III. Synthesis and antimicrobial activities of thiazolo[5,4-b]naphthyridine derivatives.
作者:NORIO SUZUKI、RENZO DOHMORI
DOI:10.1248/cpb.27.410
日期:——
In order to search for new antimicrobial agents, a number of 2-substituted 8-ethyl-5, 8-dihydro-5-oxothiazolo [5, 4-b] naphthyridine-6-carboxylic acid and their related compounds which consist of a new ring system were prepared. Reactions of the 6-amino-1-ethyl-7-mercapto-1, 4-dihydro-4-oxonaphthyridine-3-carboxylic acid (2) with acid, acid anhydride, acid chloride and ethylxanthate afforded several thiazolo [5, 4-b] naphthyridine derivatives. Refluxing ethyl 7-chloro-1-ethyl-6-nitro-1, 4-dihydro-4-oxonaphthyridine-3-carboxylate (16) with KSCN in acetic acid gave directly the thiazole cyclization product 19. Reaction of 8-ethyl-2-methylthio-5, 8-dihydro-5-oxothiazolo [5, 4-b] naphthyridine-6-carboxylic acid (11) with dimethyl sulfate gave various products (13b, 25 and 26) depending upon its reaction conditions. Some compounds obtained in this work exhibited high activities against gram-negative and gram-positive bacteria in vitro.
为了寻找新型抗菌剂,合成了一系列含有新环体系的化合物,即2-取代的8-乙基-5,8-二氢-5-氧代噻唑并[5,4-b]萘啶-6-羧酸及其相关衍生物。6-氨基-1-乙基-7-巯基-1,4-二氢-4-氧代萘啶-3-羧酸(2)与酸、酸酐、酰氯和乙基黄原酸酯反应,得到了多种噻唑并[5,4-b]萘啶衍生物。在乙酸中回流乙基7-氯-1-乙基-6-硝基-1,4-二氢-4-氧代萘啶-3-羧酸酯(16)与KSCN,直接得到了噻唑环化产物19。8-乙基-2-甲硫基-5,8-二氢-5-氧代噻唑并[5,4-b]萘啶-6-羧酸(11)与二甲基硫酸反应,根据反应条件的不同,得到了不同的产物(13b、25和26)。本工作中合成的一些化合物在体外对革兰氏阴性和革兰氏阳性细菌显示出高活性。