Butyryl chloride → N-(6,7-difluoro-1H-indazol-3-yl)butanamide

Participants

Reaction Conditions

Reaction Steps

0.61 cm3 of butyryl chloride is added to 1 g of 6,7-difluoro-1H-indazole-3-amine, described previously, in 15 cm3 of pyridine, after cooling to about 3° C., and the mixture is then left at room temperature for 76 hours. The reaction medium is concentrated under reduced pressure (2 kPa; 40° C.) and the residue is taken up in 25 cm3 of ethyl acetate and 25 cm3 of water. The organic phase is washed with 25 cm3 of distilled water and then with 25 cm3 of saturated aqueous sodium chloride solution. After drying over magnesium sulphate, filtration and concentration under reduced pressure (2 kPa; 40° C.), the residue obtained is purified by chromatography under an argon pressure of 50 kPa, on a column of silica gel (particle size 40-60 μm; diameter 3 cm), eluting with a dichloromethane/methanol mixture (98/2 by volume). The fractions containing the expected product are combined and then evaporated under reduced pressure (2 kPa; 40° C.); after drying (90 Pa; 40° C.), 596 mg of N-(6,7-difluoro-1H-indazol-3-yl)butanamide are obtained in the form of a white solid melting at 191° C.

Provenance & Evidence