Meerwein reactions of arenediazonium bromides with methyl and ethyl acrylates gave 3-aryl-2-bromopropionic acid esters which were subjected to cyclocondensation with N-(2-pyridyl)- and N-(6-methyl-2-pyridyl) thioureas to obtain 5-R1-benzyl-2-(R2-2-pyridylimino)thiazolidin-4-ones. The latter were shown to exist in solution as E isomers of the imino form.
芳烷基
溴化铵与
丙烯酸甲酯和
丙烯酸乙酯的 Meerwein 反应得到 3-芳基-
2-溴丙酸酯,再与 N-(2-
吡啶基)- 和 N-(6-甲基-2-
吡啶基)
硫脲进行环缩合反应,得到 5-R1-苄基-2-(R2-2-
吡啶亚
氨基)
噻唑烷-4-酮。研究表明,后者在溶液中以亚
氨基形式的 E 异构体存在。