A One-Step Fusion of 1,3-Thiazine and Pyrimidine Cycles

The chlorotrimethylsilane-promoted Biginelli type reactions of aldehydes, thiourea, and cyanoketones led to a diverse set of tetrahydropyrimidine-2(1H)-thiones. Under similar conditions, thioureas, benzaldehyde, and cyanoacetamide reacted to give first representatives of hexahydro-5H-pyrimido[5,4-e][1,3]thiazin-5-ones in high preparative yield.

以三甲基氯硅烷（chlorotrimethylsilane）为促进剂，醛类、硫脲类与氰基酮类发生Biginelli类反应（Biginelli type reactions），可得到一系列结构多样的四氢嘧啶-2(1H)-硫酮（tetrahydropyrimidine-2(1H)-thiones）。在相似反应条件下，硫脲类、苯甲醛与氰乙酰胺发生反应，首次得到六氢-5H-嘧啶并[5,4-e][1,3]噻嗪-5-酮（hexahydro-5H-pyrimido[5,4-e][1,3]thiazin-5-ones）的首批代表性产物，且制备收率较高。