Addition reactions of 2-chloronicotinoyl isothiocyanate with primary and secondary amines and subsequent cyclization of intermediate thioureas represent new synthesis of pyrido[3,2-e]thiouracil and pyrido[3,2-e]-thiazine derivatives. 2-Amino-4-oxopyrido[3,2-e]-1,3-thiazines are formed upon heating the reaction components in ethanol, whereas 1-alkyl(aryl)pyrido[3,2-e]-2-thiouracils are products of alkali-catalyzed reaction. In reaction with primary amines the corresponding thioureas were isolated as intermediates, whereas secondary amines reacted directly to give the pyridothiazine derivatives. Structure of the synthesized compounds was confirmed by their 13C NMR and mass spectra; also the IR and 1H NMR spectra are in accord with the suggested formulae.
2-
氯烟酰异
硫氰酸酯与一级和二级胺的加成反应,以及中间
硫脲的环化代表了新的
吡啶并[3,2-e]
嘧啶和
吡啶并[3,2-e]-
噻嗪衍
生物的合成。在
乙醇中加热反应组分会形成2-
氨基-4-氧代
吡啶[3,2-e]-
1,3-噻嗪,而1-烷基(芳基)
吡啶[3,2-e]-2-
硫脲是碱催化反应的产物。与一级胺反应时,相应的
硫脲被分离出来作为中间体,而二级胺直接反应形成
吡啶噻嗪衍
生物。通过它们的13C NMR和质谱,已确认合成化合物的结构;同时,IR和1H NMR谱与所提出的
化学式相符。