Condensation of aromatic (heteroaromatic) aldehydes with 1,3-dicarbonyl compounds under the 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) ionic liquid-piperidinium acetate catalytic system (0.2 equiv. of each component) in the absence of a solvent affords, depending on the structures of the reagents, 2-arylidene derivatives of methyl acetoacetate and acetylacetone, diethyl 2,4-bis(trifluoroacetyl)-3-phenylpentanedioate, or dimethyl 2-aryl-4-hydroxy-6-oxocyclohexane-1,3-dicarboxylates. The reactions of the resulting 2-arylidene derivatives with O-methylisourea in the [Bmim][BF4] ionic liquid produced methyl 2-methoxy-4-methyl-6-aryldihydropyrimidine-5-carboxylates and 1-(2-methoxy-4-methyl-6-phenyldihydropyrimidin-5-yl)ethanone (mixtures of 3,6- and 1,6-dihydro isomers), which were transformed into the corresponding 3,4-dihydropyrimidin-2(1H)-one derivatives.
在无溶剂条件下,通过1-丁基-3-甲基
咪唑四
氟硼酸盐([Bmim][BF4])
离子液体-
哌啶醇
醋酸盐催化体系(每种组分等摩尔量0.2 equiv.),将芳香(杂芳香)醛与1,3-二羰基化合物缩合,根据反应物的结构,可以得到甲基
乙酰乙酸乙酯和
乙酰丙酮的2-芳亚甲基衍
生物,
二乙基2,4-双(三
氟乙酰基)-
3-苯基戊二酸酯,或二甲基2-芳基-
4-羟基-6-氧代
环己烷-1,3-二
羧酸酯。将所得到的2-芳亚甲基衍
生物与[Bmim][BF4]
离子液体中的O-甲基异
脲反应,生成甲基2-甲氧基-4-甲基-6-芳基二氢
嘧啶-5-
羧酸酯和1-(2-甲氧基-4-甲基-6-苯基二氢
嘧啶-5-基)乙酮(3,6-和1,6-二氢异构体混合物),这些化合物被转化为相应的3,4-二氢
嘧啶-2(1H)-酮衍
生物。