Ascorbic Acid: An Efficient Organocatalyst for the Synthesis of 2‐Amino‐1,3,4‐oxadiazoles and Thiadiazoles via C−X Bond Formation

A new protocol for the synthesis of 2‐amino‐substituted 1,3,4‐oxadiazoles and 1,3,4‐thiadiazoles, were developed using semicarbazide or thiosemicarbazide along with the various aldehydes, followed by C−X (X=O, S) bond formation using ascorbic acid as a catalyst. This rapid, efficient, accessible, and robust/scalable sequential synthesis works with aromatic, aliphatic, and cinnamic aldehydes to provide a wide range of diazole derivatives with a 2‐amino substituent without the use of any transition metals. The synthesised molecules were characterised by 1H and 13C NMR analysis. Ascorbic acid is an effective and easily accessible organocatalyst for the synthesis of 2‐Amino‐1,3,4‐oxadiazoles and thiadiazoles from semicarbazide/thiosemicarbazide and different aldehydes. This one‐pot solvent free approach is ecofriendly, straightforward and produces good to exceptional yields.