Syntheses of 2-(trifluoromethyl)-1,3-dicarbonyl compounds through direct trifluoromethylation with CF3I and their application to fluorinated pyrazoles syntheses
作者:Yuhki Ohtsuka、Daisuke Uraguchi、Kyoko Yamamoto、Kenji Tokuhisa、Tetsu Yamakawa
DOI:10.1016/j.tet.2012.01.075
日期:2012.3
Direct trifluoromethylation of 1,3-dicarbonyl compounds with CF3I in the presence of a Fenton reagent in dimethylsulfoxide was investigated. 1,3-Diketones, 3-oxocarboxylates and 3-oxocarboxamides were readily trifluoromethylated at the methylene carbon between two oxo groups. Cycloaddition of hydrazine derivatives to the obtained 2-(trifluoromethyl)-1,3-dicarbonyl compounds provided fluorinated pyrazoles
研究了在Fenton试剂存在下于二甲基亚砜中用CF 3 I对1,3-二羰基化合物进行的直接三氟甲基化。1,3-二酮,3-氧代羧酸酯和3-氧代羧酰胺很容易在两个氧代基之间的亚甲基碳上被三氟甲基化。肼衍生物与所获得的2-(三氟甲基)-1,3-二羰基化合物的环加成反应提供了氟化吡唑。由2-(三氟甲基)-1,3-二酮形成4-(三氟甲基)吡唑衍生物,而3-氧代-2-(三氟甲基)羧酸盐或羧酰胺分别通过3生成5-氟吡唑-4-羧酸盐或羧酰胺。 -肼基-2-(三氟甲基)羧酸酯或羧酰胺为中间体。