反应详情

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).

1. extractionextracted with dichloromethane
2. stirringstirred for 15 minutes
3. customThe solvents were evaporated
4. extractionthe remaining solid was extracted with 20% methanol in ethyl acetate
5. filtrationfiltered
6. customto remove the insoluble
7. concentrationThe filtrate was concentrated to dryness by rotary evaporation