An efficient one-pot synthesis of 2-aminobenzothiazoles from substituted anilines using benzyltrimethylammonium dichloroiodate and ammonium thiocyanate in DMSO:H2O
作者:Reuben Dass、Matt A. Peterson
DOI:10.1016/j.tetlet.2021.153388
日期:2021.10
and ammonium thiocyanate (1.0 equiv) in DMSO:H2O (9:1) at 70 °C gave the corresponding 2-aminobenzothiazoles in excellent isolated yields (75–97%; ave. yield for all substrates = 90%). The reaction worked well for 2(4)-mono-, 2,4-di-, or 3,4,5-tri-substituted anilines, and a wide range of both electron donating groups (MeO, HO, CF3O, Me) and electron withdrawing groups (NO2, CN, CO2Et, CO2H, Cl, F)
在 DMSO:H 2 O (9:1) 中,在 70 °C 下用苄基三甲基二氯碘酸铵(1.2 当量)和硫氰酸铵(1.0 当量)处理各种取代苯胺,得到相应的 2-氨基苯并噻唑,分离产率高(75-97 %;所有底物的平均产率 = 90%)。该反应适用于 2(4)-单-、2,4-二-或 3,4,5-三-取代的苯胺,以及范围广泛的两种给电子基团(MeO、H2O、CF 3 O、 Me)和吸电子基团(NO 2、CN、CO 2 Et、CO 2 H、Cl、F)耐受性良好。这种方法为其他方法提供了一种有用的替代方法,这些方法要么效率较低(需要 3-7 倍当量的试剂),要么使用剧毒和腐蚀性液体溴2作为氧化剂。