Hydrochloric Acid → 5-Iodo-1H-indazole-3-carbaldehyde

Participants

Reaction Steps

1 g of sodium nitrite (27.6 g, 400 mmol) is added portionwise, under argon, to a suspension of 5-iodoindole (9.722 g, 40 mmol) in water, followed dropwise by a 6N HCl solution (59 ml). The temperature of the reaction mixture is maintained below 15° C. and the reaction mixture is then left at ambient temperature overnight, with vigorous stirring. The nitrous vapours are expelled under a stream of argon, and the reaction mixture is then filtered. Washing the solid with H2O followed by purification on silica gel (600 g), elution being carried out according to an elution gradient from CH2Cl2 to a CH2Cl2/EtOAc (9/1) mixture, makes it possible to isolate 1.37 g of product in the form of a brown solid.

Provenance & Evidence