반응 #1563938

반응 방정식

NaNO2

3-(ethoxycarbonyl)-4-fluoropyrazolo[1,5-a]pyridin-5-aminium 2,2,2-trifluoroacetate

HBr

HBr

→

ethyl 5-bromo-4-fluoropyrazolo[1,5-a]pyridine-3-carboxylate

용매

water

반응 조건

후처리

1. 1
   기타Reaction mixture
2. 2
   기타was quenched with ice water
3. 3
   추출extracted into EtOAc
4. 4
   세척washed it with water
5. 5
   건조dried over anhydrous sodium sulphate
6. 6
   농축concentrated under reduced pressure
7. 7
   기타to afford crude
8. 8
   기타The crude obtained
9. 9
   기타was purified by column purification (using 60-120 silicagel and 5% EtOAc in Hexane as eluant)

실험 절차

NaNO2 (2.26 g, 32.89 mmol) in water (7 mL) was added dropwise at 0° C. to a solution of 3-(ethoxycarbonyl)-4-fluoropyrazolo[1,5-a]pyridin-5-aminium 2,2,2-trifluoroacetate (7 g, 97.5 mmol) in aq.47% HBr (56 mL) and continued stirring at same temperature for 30 min. CuBr (6.29 g, 44 mmol) in aq. 47% HBr (56 mL) was added dropwise to above solution at 0° C. and stirring was continued at 28° C. for 1 hr. Reaction mixture was quenched with ice water, extracted into EtOAc, washed it with water followed by brine, dried over anhydrous sodium sulphate and concentrated under reduced pressure to afford crude. The crude obtained was purified by column purification (using 60-120 silicagel and 5% EtOAc in Hexane as eluant) to afford ethyl 5-bromo-4-fluoropyrazolo[1,5-a]pyridine-3-carboxylate. NMR (300 MHz, DMSO-d6) δ 9.45-9.43 (d, 1H), 8.51 (s, 1H), 8.33-8.30 (d, 1H), 4.35-4.28 (m, 2H), 1.36-1.31 (t, 3H).

출처