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 alkylhalide, acid halides, and sulfornyl chloride in high yields.
Efficient one-pot synthesis of substituted 2-amino-1,3,4-oxadiazoles
作者:Eugene L. Piatnitski Chekler、Hassan M. Elokdah、John Butera
DOI:10.1016/j.tetlet.2008.09.057
日期:2008.11
A convenient one-pot method for the preparation of substituted 2-amino-1,3,4-oxadiazoles has been developed. The method is a significant improvement over previously reported syntheses. Reaction of carboxylic acids with thiosemicarbazides afforded the corresponding oxadiazoles in moderate to good yields. In general, the products precipitated from the reaction mixture, and were collected by filtration. In most of the cases, no chromatographic separations were required. To explore the scope and limitations of this reaction, various aliphatic, aromatic, and heteroaromatic carboxylic acids were reacted with different substituted thiosemicarbazides. The influence of R-1 and R-2 substituents on the reaction yield and additional results demonstrating the versatility of this method are presented. (c) 2008 Elsevier Ltd. All rights reserved.
Froeyen, Paul, Phosphorus, Sulfur and Silicon and the Related Elements, 1991, vol. 57, # 1/2, p. 11 - 15
作者:Froeyen, Paul
DOI:——
日期:——
Huisgen,R. et al., Chemische Berichte, 1961, vol. 94, p. 1555 - 1562