Fluorocinnoline derivatives. II. Synthesis and antibacterial activity of fluorinated 1-alkyl-1,4-dihydro-4-oxocinnoline-3-carboxylic acids.
作者:Teruyuki MIYAMOTO、Jun-ichi MATSUMOTO
DOI:10.1248/cpb.37.93
日期:——
Chemical modification of cinoxacin was studied with the aim of improving its antibacterial activity and spectrum. Alkylation of ethyl 6, 7, 8-trifluoro- and 6, 7-difluoro-4-hydroxycinnoline-3-carboxylates (1 and 7) with alkyl iodide or dialkyl sulfate gave ethyl 1-alkyl-6, 7, 8-trifluoro- and 6, 7-difluoro-1, 4-dihydro-4-oxocinoline-3-carboxylates (2 and 8), together with the isomeric anhydro-bases 3 and 9 of 2-alkyl-3-ethoxycarbonyl-6, 7, 8-trifluoro- and 6, 7-difluoro-4-hydroxycinnolinium hydroxides, respectively. Acid-catalyzed hydrolysis of the 1-alkyl derivatives 2 and 8 gave the corresponding carboxylic acids 4 and 10. The same treatment of 3 and 9, accompanied with decarboxylation of the inner salts 5 and 11, afforded the anhydro-bases 6 and 12 of 2-alkyl-4-hydroxycinnolinium hydroxides, respectively. Displacement reactions of 4 and 10 with nucleophiles such as amine, alkoxide and thiolate gave 7-substituted 1-alkyl-6, 8-difluoro- and 6-fluoro-1, 4-dihydro-4-oxocinnoline-3-carboxylic acids (13 and 17-35). Antibacterial activities of these compounds were evaluated and compared with those of cinoxacin and norfloxacin. Some compounds showed a broader spectrum and more potent activity than cinoxacin, but were considerably inferior in activity to norfloxacin.
对 cinoxacin 进行化学修饰的研究旨在提高其抗菌活性和谱系。将乙基 6, 7, 8-三氟和 6, 7-二氟-4-羟基肉桂啉-3-羧酸酯(1 和 7)与烷基碘或二烷基硫酸盐发生烷基化反应,得到乙基 1-烷基-6, 7, 8-三氟和 6, 7-二氟-1, 4-二氢-4-氧肉桂啉-3-羧酸酯(2 和 8),同时得到等位异构体 2-烷基-3-乙氧羰基-6, 7, 8-三氟和 6, 7-二氟-4-羟基肉桂铵氢氧化物的无水鹼(3 和 9)。用酸催化水解 1-烷基衍生物 2 和 8 得到相应的羧酸 4 和 10。对 3 和 9 进行相同的处理,伴随内盐 5 和 11 的脱羧反应,分别得到 2-烷基-4-羟基肉桂铵的无水鹼(6 和 12)。将羧酸 4 和 10 与亲核试剂如胺、醇盐和硫醇发生取代反应,得到 7-取代的 1-烷基-6, 8-二氟和 6-氟-1, 4-二氢-4-氧肉桂酸(13 和 17-35)。对这些化合物的抗菌活性进行了评估,并与 cinoxacin 和 norfloxacin 进行比较。一些化合物显示出比 cinoxacin 更广泛的谱系和更强的活性,但其活性远低于 norfloxacin。