Microwave assisted one pot synthesis of 2-alkyl amino benzimidazoles, 2-alkyl amino benzoxazoles and 2-alkyl amino benzthiazoles by using various carbodiimides

A library of bioisosteres namely 2-amino substituted benzimidazole, 2-amino substituted benzoxazole, 2-amino substituted benzthiazole derivatives has been synthesized by an efficient ligand free, zinc catalysed one-pot cascade microwave irradiation technique has been developed. The procedure starts with coupling of various carbodiimides with appropriately substituted o-phenylendiamine, o-aminophenol, o-aminothiols to give the corresponding derivatives in excellent yields.