Photochimie d''heterocycles azotes—VI : Synthese par voie photochimique d''amino et d''alkoxy indazoles

The preparation of different aminoindazoles by nucleophilic aromatic photosubstitution of nitroindazoles by amines is described. In this manner, the amino, methylamino, dimethylamino and dimethylamino substituents are introduced in 3,4,5 or 7-position. The irradiation in the presence of ethanol gives ethoxyindazoles in only four cases. Two demethylation reactions have been observed: the first one concerns the formation of methylamino derivatives starting from dimethylamine; the second one, the formation of N(H)1-indazoles by irradiation in presence of diethylamine.