Preparation of Carbamoyl Derivatives of Indole and of Derivatives of 1,2,4-Triazol-3-one from Semicarbazides

A simple and one-step method for the preparation of the title compounds is described. Semicarbazides 2 react easily with levulinic acid in the presence of HCl to give 4 , whereas in a alkaline medium they cyclize to form the triazole derivatives 3 .