Pyridine → HCID 21929893, compound

Participants

Reaction Conditions

Reaction Steps

0.845 cm3 of pyridine and 0.74 cm3 of trifluoroacetic anhydride are successively added dropwise to a solution, cooled to a temperature in the region of 5° C., of 1.1 g of 6,6-diphenyl-6,7-dihydro-1H-indazole-3-carboxamide in 100 cm3 of dioxane. After warming to a temperature in the region of 20° C., the reaction mixture is stirred for about 20 hours at this temperature. 2 cm3 of pyridine and 2 cm3 of trifluoroacetic anhydride are added to the solution and the reaction mixture is refluxed for about 4 hours. After cooling to a temperature in the region of 20° C., the mixture is concentrated to dryness under reduced pressure (13 kPa). The residue is taken up in 50 cm3 of water and 150 cm3 of ethyl acetate; the pH of the mixture is brought to the region of 8 by addition of sodium bicarbonate. After separation of the phases by settling, the aqueous phase is extracted with three times 50 cm3 of ethyl acetate, and the combined organic phases are washed with three times 50 cm3 of water and then dried over magnesium sulphate, filtered and concentrated to dryness under reduced pressure (13 kPa). The residue is purified by flash chromatography on a column of silica [eluent: dichloromethane/ethyl acetate (90/10 by volume)]. 0.8 g of 6,6-diphenyl-6,7-dihydro-1H-indazole-3-carbonitrile is thus obtained in the form of a white powder, the characteristics of which are as follows:

Provenance & Evidence