Synthesis of antimicrobial agents. V. Synthesis and antimicrobial activities of some heterocyclic condensed 1,8-naphtyridine derivatives.
作者:NORIO SUZUKI
DOI:10.1248/cpb.28.761
日期:——
In order to search for compounds with higher activity than thiazolo [5, 4-b], imidazo-[4, 5-b] and triazolo [4, 5-b] [1, 8] naphthyridine derivatives against Ps. aeruginosa, we synthesized some heterocyclic condensed 1, 8-naphthyridine derivatives by using bifunctional 6, 7-disubstituted 1, 8-naphthyridine as a starting material. Thiadiazolo [5, 4-b] and oxazolo [5, 4-b] [1, 8] naphthyridine derivatives (3) and (5) were prepared by hydrolysis of the 6-amino-7-chloro-3-ester (1) with sodium hydroxide or sodium hydrosulfide, followed by cyclization with acetic anhydride or sodium nitrite. Pyrazolo [3, 4-b] and isothiazolo [5, 4-b] [1, 8] naphthyridine derivatives (12) and (14) were synthesized by ring cyclization of the 7-chloro-6-formyl-3-ester (10) with methyl hydrazine or ethanolic ammonia in the presence of sulfur, followed by hydrolysis. Thieno and furo [2, 3-b] [1, 8] naphthyridine derivatives (20) and (31) were prepared through a series of reaction steps, e.g. diazotization, reduction of the nitrile ester (7) or (24), ring cyclization by means of ethyl mercaptoacetate or ethyl bromomalonate, hydrolysis and decarboxylation. The compounds obtained were tested for antimicrobial activities in vitro. 8-Ethyl-5, 8-dihydro-5-oxothieno [2, 3-b] [1, 8] naphthyridine-6-carboxylic acid (20) exhibited the highest activities among these compounds against many gram-negative bacteria, including Ps. aeruginosa, and against gram-positive bacteria.
为了寻找比噻唑并[5,4-b]、咪唑并[4,5-b]和三唑并[4,5-b][1,8]萘啶衍生物对绿脓杆菌具有更高活性的化合物,我们以双官能团 6,7-二取代 1,8-萘啶为起始原料,合成了一些杂环缩合 1,8-萘啶衍生物。噻二唑并[5,4-b]和噁唑并[5,4-b] [1,8]萘啶衍生物(3)和(5)是通过氢氧化钠或硫氢化钠水解 6-氨基-7-氯-3-酯(1),然后用乙酸酐或亚硝酸钠环化而制备的。吡唑并[3,4-b]和异噻唑并[5,4-b][1,8]萘啶衍生物(12)和(14)是在有硫存在的情况下,通过 7-氯-6-甲酰基-3-酯(10)与甲基肼或乙醇氨进行环化,然后水解而合成的。噻吩和呋喃 [2, 3-b] [1, 8] 萘啶衍生物 (20) 和 (31) 是通过一系列反应步骤制备的,例如重氮化、腈酯 (7) 或 (24) 还原、巯基乙酸乙酯或溴丙二酸乙酯环化、水解和脱羧。得到的化合物在体外进行了抗菌活性测试。在这些化合物中,8-乙基-5,8-二氢-5-氧代噻吩并[2,3-b] [1,8] 萘-6-羧酸(20)对包括绿脓杆菌在内的多种革兰氏阴性菌和革兰氏阳性菌的活性最高。