Rapid, microwave-assisted synthesis of N1-substituted 3-amino-1,2,4-triazoles

A robust, regioselective synthesis of 3-amino-1,2,4-triazoles is described. This reaction employs a key intermediate 2, which is coupled to carboxylic acids in good yields to afford intermediates 3a–d. These entities, in turn, react with a variety of hydrazines or hydrazine hydrochlorides to provide proposed intermediates 4a–j, which under microwave conditions cyclize to the desired 3-amino-1,2,4-triazoles (compounds 5a–j). This approach permits the rapid synthesis of regioselective N1-substituted 3-amino-1,2,4-triazoles, and is shown to afford a variety of such compounds in 34–70% isolated yields.