Regioselective synthesis and S-derivatization reactions of 4- and 6-trifluoromethyl-3-cyano-2(1H)-pyridinethiones
作者:Victor P. Kislyi、Kirill G. Nikishin、Elena Ya. Kruglova、Alexandr M. Shestopalov、Victor V. Semenov、Andrei A. Gakh、A.C. Buchanan
DOI:10.1016/0040-4020(96)00632-1
日期:1996.8
The regioselective synthesis of the title compounds was developed on the basis of condensation reactions of trifluoroacetylacetone and its methyl enacetal with cyanothioacetamide in the presence of bases. Thus, the condensation of trifluoroacetyl-acetone with cyanothioacetamide yields predominantly 4-trifluoromethyl-6-methyl-3-cyano-2(1H)-pyridinethiones, whereas the methyl enacetal of trifluoroacetylacetone
在三氟乙酰丙酮及其甲基烯醇缩醛与氰基硫代乙酰胺在碱存在下的缩合反应的基础上,开发了标题化合物的区域选择性合成方法。因此,三氟乙酰丙酮与氰基硫代乙酰胺的缩合主要产生4-三氟甲基-6-甲基-3-氰基-2(1H)-吡啶硫酮,而三氟乙酰丙酮的甲基乙缩醛仅产生6-三氟甲基-4-甲基异构体。三氟甲基-吡啶硫酮盐的S-烷基化可通过在DMF水中使用甲基碘或溴苯乙酮来实现。在过量的KOH存在下,可以将溴苯乙酮衍生物进一步转化为3-氨基噻吩-[2,3-b]吡啶。