Pyridone-carboxylic acids as antibacterial agents. I. Synthesis and antibacterial activity of 1-alkyl-1,4-dihydro-4-oxo-1,8- and 1,6-naphthyridine-3-carboxylic acids.
作者:TOHRU HIROSE、SHINSAKU MISHIO、JUNICHI MATSUMOTO、SHINSAKU MINAMI
DOI:10.1248/cpb.30.2399
日期:——
Condensation of 2-amino-6-chloropyridine (1) with diethyl ethoxymethylenemalonate gave the aminomethylenemalonate 2, which upon thermal cyclization (Gould-Jacobs reaction) afforded ethyl 7-chloro-1, 4-dihydro-4-oxo-1, 8-naphthyridine-3-carboxylate (3). Alkylation of 3 produced the 1-alkyl derivative 4. Substitution of 4 with a cyclic amine gave ethyl 7-substituted 1-alkyl-1, 4-dihydro-4-oxo-1, 8-naphthyridine-3-carboxylate (5). The ester 5 was hydrolyzed to the corresponding carboxylic acid 6. 7-Substituted 1-alkyl-1, 4-dihydro-4-oxo-1, 6-naphthyridine-3-carboxylic acids (20) were also synthesized from 4-amino-2-chloropyridine (13) in a similar manner. The in vitro antibacterial activity was enhanced by the presence of a cyclic amine at position 7 on 6 and 20. In general, the 1, 8-naphthyridine 6 was more active than the 1, 6-naphthyrdine counterpart 20. 1-Ethyl-1, 4-dihydro-4-oxo-7-(1-piperazinyl)-1, 8-naphthyridine-3-carboxylic acid (6e) (an analog of both pipemidic acid and nalidixic acid) was comparable to pipemidic acid but superior to nalidixic acid in terms of activity in vitro against Pseudomonas aeruginosa.
2-氨基-6-氯吡啶(1)与乙二醇乙氧基亚甲基丙二酸酯反应生成胺亚甲基丙二酸盐(2),进一步热环化(Gould-Jacobs反应)得到乙基7-氯-1,4-二氢-4-氧-1,8-萘啶-3-羧酸酯(3)。对3进行烷基化反应生成1-烷基衍生物(4)。用环胺取代4得到乙基7-取代的1-烷基-1,4-二氢-4-氧-1,8-萘啶-3-羧酸酯(5)。酯5水解得到相应的羧酸(6)。7-取代的1-烷基-1,4-二氢-4-氧-1,6-萘啶-3-羧酸(20)也以类似方式从4-氨基-2-氯吡啶(13)中合成。在6和20的7位引入环胺可增强其体外抗菌活性。通常情况下,1,8-萘啶(6)的活性优于1,6-萘啶(20)。1-乙基-1,4-二氢-4-氧-7-(1-哌嗪基)-1,8-萘啶-3-羧酸(6e)(是一种匹匹酸和那吡酸的类药物)在体外对铜绿假单胞菌的活性与匹匹酸相当,但优于那吡酸。