Trifluoroacetic acid → 2-(2',3-Difluoro-2,4'-bipyridin-5-yl)acetic acid

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Reaction Steps

A mixture of tert-butyl 2-(2′,3-difluoro-2,4′-bipyridin-5-yl)acetate 205-5 (248 mg, 0.81 mmol) and TFA (0.8 mL) in DCM (0.8 mL) was stirred at room temperature for 3 hours. The solution was adjusted to pH around 12 by Na2CO3 and extracted with dichloromethane. The aqueous phase was acidified to pH 3 by 1N HCl aqueous solution and stirred for 15 minutes. The solvents were evaporated and the remaining solid was extracted with 20% methanol in ethyl acetate and filtered to remove the insoluble. The filtrate was concentrated to dryness by rotary evaporation to give 2-(2′,3-difluoro-2,4′-bipyridin-5-yl)acetic acid 205-6, which was used directly for next step. MS m/z 251.1 (M+1).

Provenance & Evidence