2,4-Dioxathiazolidine derivatives (7) have been obtained in synthetically useful yields by the condensations of easily available 1-substituted-4,4,6-trimethyl-1,4-dihydropyrimidine-2(3H) thione derivatives (4) and α-halogenated carboxylic acids in aqueous medium. The condensations of 4 with α-haloketones in ethanol containing cone HCl furnish 2-oxa-4-thiazolines (8). The condensations of N,N-dialkyl-N'-aryl
2,4- Dioxathiazolidine衍
生物(7)已在合成有用的产率通过的缩合获得容易获得的1-取代-4,4,6-三
甲基-1,4-二
氢嘧啶-2(3H)
硫酮衍
生物(4)和在
水性介质中的α-卤代
羧酸。在含有浓HCl的
乙醇中,4与α-卤代
酮的缩合反应提供了2-oxa-4-thiazolines(8)。在浓HCl存在下,N,N-二烷基-N'-芳基
硫脲或芳基
硫代
氨基甲酸酯与α-
氯代
羧酸和α-卤代
酮的缩合分别得到7和8。