Dialkyl acylphosphonate worked as an acylating agent on 2-methylthiazolium and thiazolinium salts in the presence of base, to give 2-acylidenethiazoline and thiazolidine derivatives, respectively. Dialkyl [1-aryl (alkyl)-1-dialkylphosphatomethyl] phosphonate was also isolated as a by-product in the same reaction. Dialkyl acylphosphonate afforded 2-acylidenethiazolines in better yield compared with acyl chlorides and showed on apparent affinity for carbanions. Application of diethyl benzoylphosphonate to 1, 2, 3-trimethylbenzimidazolium iodide, however, formed a dimeric salt, 1, 1', 3, 3'-tetramethyl-2, 2'-(2-phenyltrimethylene) di (benzimidazolium) diiodide in addition to 2-(1, 3-dimethylbenzimidazolin-2-ylidene) acetophenone. On the basis of the reactivity difference between the 2-methylthiazolium and 2-methylimidazolium salts and the kinetic experiments, the mechanism of the acylating reaction was proposed.
二烷基酰基
膦酸酯作为酰基化试剂,在碱存在下与
2-甲基噻唑盐和
噻唑啉盐反应,分别生成2-酰亚
氨基
噻唑啉和
噻唑烷衍
生物。同时,反应中还分离得到了副产物:二烷基[1-芳基(烷基)-1-二烷基膦甲基]
膦酸酯。与酰
氯相比,二烷基酰基
膦酸酯在生成2-酰亚
氨基
噻唑啉时产率更高,并显示出对碳负离子的明显亲和性。然而,将二
乙基苯甲酰
膦酸酯应用于1,2,3-三甲基
苯并咪唑盐
碘时,除了生成2-(1,3-二甲基
苯并咪唑啉-2-亚基)
苯乙酮外,还形成了二聚盐:1,1',3,3'-四甲基-2,2'-(2-苯基亚丙基)二(
苯并咪唑盐)二
碘化物。基于
2-甲基噻唑盐和
2-甲基咪唑盐之间的反应活性差异及动力学实验,提出了酰基化反应的机理。