Regioselective Synthesis of 2-Amino-Substituted 1,3,4-Oxadiazole and 1,3,4-Thiadiazole Derivatives via Reagent-Based Cyclization of Thiosemicarbazide Intermediate
作者:Seung-Ju Yang、Seok-Hyeong Lee、Hyun-Jung Kwak、Young-Dae Gong
DOI:10.1021/jo302324r
日期:2013.1.18
is shown in select sets of thiosemicarbazide 3 with R1(benzyl) and R2(phenyl). 2-Amino-1,3,4-oxadiazole 4 was also shown in the reaction of p-TsCl mediated cyclization. The resulting 2-amino-1,3,4-oxadiazole and 2-amino-1,3,4-thiadiazole core skeleton are functionalized with various electrophiles such as alkyl halide, acid halides, and sulfornyl chloride in high yields.
描述了一种基于区域选择性的基于试剂的2-氨基-1,3,4-恶二唑与2-氨基-1,3,4-噻二唑核心骨架环化反应的方法。使硫代氨基脲中间体3与DMSO中的EDC·HCl或p- TsCl,N-甲基-2-吡咯烷酮中的三乙胺反应,得到相应的2-氨基-1,3,4-恶二唑4和2-氨基-1,3 ,4-噻二唑5通过区域选择环化过程。区域选择性是受两个R 1和R 2在p -TsCl介导的环化。在具有R 1(苄基)和R 2的硫代氨基脲3的精选集中显示(苯基)。在对-TsCl介导的环化反应中还显示了2-氨基-1,3,4-恶二唑4。所得的2-氨基-1,3,4-恶二唑和2-氨基-1,3,4-噻二唑核心骨架被各种亲电试剂如烷基卤,酰卤和磺酰氯高官能度地官能化。