New and efficient synthesis of bi- and trisubstituted indazoles

Abstract In this paper, the synthesis of bi- and trisubstituted indazoles was described. 4-Alkoxy-7-aminoprotected-indazole or 7-aminoprotected-indazole derivatives were prepared selectively using SnCl 2 in alcohol or SnCl 2 in ethyl acetate, respectively. The effects of the halogen atom in position 3 and of the N -alkylation in N -1 position of 7-nitroindazoles were investigated.