Abstract The synthesis of two new derivatives of 3H [1, 2] diazepino [5, 6-b] indole, 5 and 11, and one new derivative of 3H [1, 2] diazepino [4, 5-b] indole, 16, are described. Compound 5 was obtained by the reaction of methyl 2-(3-methoxycarbonyl-1-methylindole) acetate 2, with hydrazine. Compound 11 was obtained in two ways from ethyl 2-(1-methylindole) acetate (8) by formylation and reaction with hydrazine. Compound 16 was obtained treating 3-(2- ...