1,3-Dipolar cycloaddition of imidazoline 3-oxides 1 with methylisothiocyanate proceeds regio- and diastereoselectively to give tetrahydroimidazo[1,5- b ][1,2,4]oxadiazol-2(1 H )-thiones 3 in high yields. The cis configuration of the adducts were proved by our double cis elimination test as well as by NOESY experiments. The imidazooxadiazol-2-thiones 3a-e were treated with concentrated HCl in ethanol
咪唑啉 3-氧化物 1 与甲基异
硫氰酸酯的 1,3-偶极环加成反应区域选择性和非对映选择性地进行,以高产率得到四氢
咪唑并[1,5-b][1,2,4]恶二唑-2(1 H)-
硫酮 3。我们的双顺式消除试验以及 NOESY 实验证明了加合物的顺式构型。
咪唑并恶二唑-2-
硫酮 3a-e 在 50°C 下用浓 HCl
乙醇溶液处理得到相应的 4 H -[1,2,4]恶二唑-5-
硫酮,仅在 C- 6是芳基。