Simple,Novel Synthesis for 1-Carbamoyl-lH-benzotriazole and Some of Its Analogs

1-Carbamoyl-1H-benzotriazole (benzotriazole-1-carboxamide, 2a), an effective carbamoyl chloride substitute, and a range of its analogs can be synthesized in good yields in two very simple steps from 1,2-diaminobenzene. The facile preparation of the intermediate o-aminophenylurea is key to this process. A preliminary study of the reactivity of 2a has shown that once in solution in tetrahydrofuran (THF), the 1-carbamoyl isomer equilibrates to give a mixture of both 1- and 2-isomers. If the solvent is ethanol or water, equilibration occurs rapidly compared to the ultimate formation of solvolysis products.