A one-pot method for obtaining novel thieno[3,2-c][1,7]naphthyridine derivatives based on the reaction of 3-amino-4-(thien-2-yl)pyridin-2(1H)-one with aromatic aldehydes in 80% ­phosphoric acid at 130 °C has been developed. The formation of the thieno[3,2-c][1,7]naphthyridine ring was due to the intermediate generation of the corresponding azomethine, which underwent intra­molecular cyclization with electrophilic attack of the β-carbon atom of the thiophene core under Pictet–Spengler conditions. The isolated 5,7-dihydrothieno[3,2-c][1,7]naphthyridin-4(3H)-ones underwent oxidative aromatization in air to give thieno[3,2-c][1,7]naphthyridin-6(7H)-ones. A two-step synthesis of thieno[3,2-c][1,7]naphthyridines involving the isolation of the intermediate imine did not lead to a significant increase in the product yield.

中文翻译：

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基于3-Amino-6-methyl-4-(2-thienyl)pyridin-2(1H)-one的噻吩并[3,2-c][1,7]萘啶衍生物的第一代表合成

基于 3-amino-4-(thien-2-yl)pyridin-2(1H)-one 与 3-amino-4-(thien-2-yl)pyridin-2(1H)-one 反应获得新型噻吩并[3,2-c][1,7]萘啶衍生物的一锅法已开发出 80% 磷酸中 130 °C 的芳香醛。噻吩并[3,2-c][1,7]萘啶环的形成是由于相应的偶氮甲碱的中间生成，其在Pictet-下噻吩核的β-碳原子的亲电攻击下经历了分子内环化-斯宾格勒条件。分离的 5,7-dihydrothieno[3,2-c][1,7]naphthyridin-4(3H)-ones 在空气中进行氧化芳构化得到 thieno[3,2-c][1,7]naphthyridin-6 (7H)-一个。涉及分离中间体亚胺的噻吩并 [3,2-c][1,7] 萘啶的两步合成不会导致产品产量的显着增加。