2-Amino-4-methoxybenzonitrile → 6-methoxy-1H-indazol-3-amine

Reaction equation

[NH2:1][C:2]1[CH:9]=[C:8]([O:10][CH3:11])[CH:7]=[CH:6][C:3]=1[C:4]#[N:5].[N:12]([O-])=O.[Na+]>Cl.O>[CH3:11][O:10][C:8]1[CH:9]=[C:2]2[C:3]([C:4]([NH2:12])=[N:5][NH:1]2)=[CH:6][CH:7]=1

Participants

Procedure

To an ice-cooled suspension of 66.35 g (0.448 mol) of 2-amino-4-methoxybenzonitrile in 530 ml of concentrated HCl, a solution of 37.07 g (0.537 mol) of sodium nitrite in 55 ml of water was added dropwise. After 1.5 hours the cold suspension was added dropwise to a preformed solution of 679.25 g (3.58 mol) of stannous chloride in 530 ml of concentrated hydrochloric acid (HCl), at SOC. After 3 hours the cold suspension was filtered and the moist solid was treated with 1.7 l of boiling water for 30 min. The hot cloudy solution was clarified by filtration through a cloth filter. The liquors were ice-cooled and treated dropwise with 0.8 l of 17% NaOH. The solid was filtered off and dried under vacuum at 50° C.: 67.2 g of product were obtained as light brown solid. Yield=91.9%. mp=195-197° C. dec. HPLC r.t. 1.9 [M+H]+=164