Conversion of enamines, enamides and triazoles by trithiazyl trichloride into 1,2,5-thiadiazoles
作者:Charles W. Rees、Tai-Yuen Yue
DOI:10.1039/b010140k
日期:——
Trithiazyl trichloride 1 converts primary and secondary enamines, enamides and 1,2,3-triazoles into 1,2,5-thiadiazoles. These mild reactions provide one-pot routes to various alkyl, aryl, functional and quaternary 1,2,5-thiadiazoles, in moderate to good yields. The trimer 1 reacts as a 1,2-bis-electrophile adding an N–S unit across CC–N. For primary enamines 15N-labelling reveals an additional, minor pathway in which N–S–N is added across CC, with elimination of the enamine nitrogen. With N-alkylated enamines the alkyl group is retained in a quaternised thiadiazole, but this can be dealkylated insitu. Enamides react similarly but with spontaneous N-deacylation. 1,2,3-Triazoles with electron withdrawing groups to stabilise their acyclic diazoimine tautomers also give 1,2,5-thiadiazoles, with loss of dinitrogen. Mechanisms are proposed for these new reactions.
三噻唑三氯化物 1 可将伯胺和仲胺、烯胺和 1,2,3- 三唑转化为 1,2,5- 噻二唑。这些温和的反应为各种烷基、芳基、官能基和季铵盐基 1,2,5-噻二唑的制备提供了一锅式途径,产率从中等到较高不等。三聚体 1 作为 1,2-双亲电体在 CC-N 上添加一个 N-S 单元进行反应。对于原烯胺,15N 标记揭示了另一个次要途径,即在 CC-N 上添加 N-S-N,并消除烯胺氮。对于 N-烷基化的烯胺,烷基保留在季铵化的噻二唑中,但也可以在原位脱烷基。烯酰胺也会发生类似的反应,但会自发发生 N-脱烷基反应。1,2,3-三唑的无环重氮亚胺同系物中含有取电子基团以稳定其无环重氮亚胺同系物,在失去二氮的情况下也会生成 1,2,5-噻二唑。提出了这些新反应的机理。