反应详情

温度

70 °C

A solution of 2-(1-ethyl-propyl)-6-methoxy-isonicotinic acid methyl ester (50 g, 0.211 mol) in ethanol (250 mL), water (50 mL) and 32% aq. NaOH (50 mL) is stirred at 80° C. for 1 h. The mixture is concentrated and the residue is dissolved in water (200 mL) and extracted with TBME. The org. phase is separated and washed once with water (200 mL). The TBME phase is discarded. The combined aq. phases are acidified by adding 25% aq. HCl and then extracted with EA (400+200 mL). The combined org. extracts are concentrated. Water (550 mL) is added to the remaining residue. The mixture is heated to 70° C., cooled to rt and the precipitate that forms is collected and dried to give the title compound (40.2 g) as a white solid; LC-MS: tR=0.95 min, [M+1]+=224.04; 1H NMR (D6-DMSO): δ 0.73 (t, J=7.3 Hz, 6H), 1.59-1.72 (m, 4H), 2.52-2.58 (m, 1H), 3.88 (s, 3H), 7.00 (d, J=1.0 Hz, 1H), 7.20 (d, J=1.0 Hz, 1H).

1. concentrationThe mixture is concentrated
2. dissolutionthe residue is dissolved in water (200 mL)
3. extractionextracted with TBME
4. customphase is separated
5. washwashed once with water (200 mL)
6. additionby adding 25% aq. HCl
7. extractionextracted with EA (400+200 mL)
8. concentrationextracts are concentrated
9. additionWater (550 mL) is added to the remaining residue
10. temperaturecooled to rt
11. customthe precipitate that forms is collected
12. customdried