Novel Chemoselective Annulationof Imidazole and 1,2,4-Thiadiazine Rings on Azoles Involving AcidLabile Methanesulfinyl Group
作者:Lal Dhar Yadav、Ritu Kapoor
DOI:10.1055/s-2003-39179
日期:——
la-d are chemoselectively annulated with sulfuric acid, acetic acid, and thionyl chloride to yield imidazo[2,1-b]-1,3,4-oxa(thia)diazoles 3a-d. Their 5-methylsulfenyl analogues 4a-d and 1,3,4-oxa(thia)diazolo[3,2-b]-1,2,4-thiadiazines 5a-d, respectively, 3-5 are formed via demethylsulfinylation, the Pummerer rearrangement, and deoxygenative demethylation, in a one-pot procedure.
氧杂(噻)二唑加合物 2a-d、DMSO 和唑席夫碱 la-d 与硫酸、乙酸和亚硫酰氯化学选择性环化生成咪唑并[2,1-b]-1,3,4-oxa(噻)二唑 3a-d. 它们的 5-甲基亚硫基类似物 4a-d 和 1,3,4-oxa(thia)diazolo[3,2-b]-1,2,4-thiadiazines 5a-d 分别通过脱甲基亚磺酰化形成 3-5,在一锅程序中进行 Pummerer 重排和脱氧去甲基化。