Ethyl 3-[(Ethylthio)carbonyl]-4,4,5,5,5-pentafluoropentanoate: A Building Block towards Trifluoromethyl Pyrazoles and Pyrimidin-4-ones
作者:Jean-Philippe Bouillon、Charles Portella、Cédric Brulé
DOI:10.1055/s-0030-1260976
日期:2011.8
Reaction of the title substrate with methylhydrazine yields, via a domino process, HF elimination-β-addition/elimination-cyclocondensation, to 3-hydroxy-5-trifluoromethylpyrazol-4-ylacetic acid derivatives. In a similar domino process, reaction with benzamidine led mainly to ethyl 4-oxo-2-phenyl-6-trifluoromethylpyrimidin-4-yl acetate. While pyrazole was obtained in high yield via a totally chemo- and regioselective process, reaction with amidine led to a mixture of regioisomers.
通过多米诺反应,标题底物与甲基肼反应,生成3-羟基-5-三氟甲基吡唑-4-基乙酸衍生物,该反应通过氟化氢消除-β-加成/消除-环缩合进行。在类似的多米诺反应中,与苯甲脒反应主要生成4-氧代-2-苯基-6-三氟甲基嘧啶-4-基乙酸乙酯。虽然通过完全化学和区域选择性过程可以高收率地获得吡唑,但与脒反应会产生区域异构体的混合物。