Pyrazole → methyl 2-[3-cyano-4-(1H-pyrazol-1-yl)phenyl]isonicotinate

Participants

Reaction Steps

212 mg of methyl 2-(3-cyano-4-fluorophenyl)isonicotinate and 68 mg of pyrazole were dissolved in 4 ml of DMSO, and 102 mg of potassium tert-butoxide was added, followed by stirring at room temperature for 30 minutes. The reaction mixture was diluted with water, and extracted with ethyl acetate. The organic layer was washed with brine, dried and concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (hexane:ethyl acetate=67:33) to obtain 251 mg of methyl 2-[3-cyano-4-(1H-pyrazol-1-yl)phenyl]isonicotinate. (2) 236 mg of this compound was dissolved in a mixture liquid of 10 ml of methanol and 5 ml of THF, and 1.16 ml of aqueous 1 M sodium hydroxide solution was added, followed by heating at 80° C. for 40 minutes. The reaction liquid was cooled to room temperature, washed with water, and the organic solvent was evaporated away under reduced pressure. The reaction liquid was washed with diethyl ether to obtain an aqueous layer. The aqueous layer was neutralized with 1 M hydrochloric acid, followed by extraction with ethyl acetate. The organic layer was washed with brine, dried and concentrated under reduced pressure, and the resulting residue was recrystallized from a mixture of ethanol and water to obtain 103 mg of 2-[3-cyano-4-(1H-pyrazol-1-yl)phenyl]isonicotinic acid. (3) 92 mg of this compound was dissolved in ethanol, and 0.317 ml of aqueous 1 M sodium hydroxide solution was added thereto, followed by stirring at room temperature for 15 minutes. The reaction liquid was concentrated, the residue was suspended in 2-propanol, and the precipitate was collected by filtration to obtain 93 mg of sodium 2-[3-cyano-4-(1H-pyrazol-1-yl)phenyl]isonicotinate.

Provenance & Evidence