Indazoles prepn - by cyclization of o-alkyl anilines with organic nitrites

Prepn. of indazoles of formula: where R1 gps. are the same or diff. and are H, aliphatic, cycloaliphatic, araliphatic or aromatic gp., or halogen; R2 is H or aliphatic gp is by reaction of a cpd. of formula: in presence of acetic acid, an alkali metal alkanoate and an inert solvent with an alkyl nitrile, an ester of glycol or a deriv. with nitrous acid and/or nitrous gases and removing in known manner the acetyl gp. from the 1-acetylindazole. The simple, economica process is applicable to industrial scale and gives high yields of good quality prodt., used as inters. for dyes. drugs and pesticides.