反应详情

To a solution of methyl 2-(6-chloro-2-methoxypyridin-3-yl)propanoate (100 g, 435 mmol) in THF (1.5 L) was added LiHMDS (609 mL, 609 mmol) dropwise over a period of 60 min at −60° C. while maintaining reaction temperature below −50° C. After the addition, the reaction mixture was stirred below −50° C. for 30 min. Then a solution of 3-bromopropanenitrile (92 g, 697 mmol) in THF (0.4 L) was added dropwise to above solution below −50° C. over a period of 90 min. The resulting mixture was stirred at r.t. for 16 hours. The reaction mixture was quenched with saturated aqueous NH4Cl (500 mL) below 25° C. The 22 batches were combined for workup together. The mixture was diluted with H2O (15 L), and extracted with EtOAc (15 L). The combined organic layers were washed with water (15 L) and brine (15 L), dried over Na2SO4 and concentrated to dryness. The crude residue was purified by column chromatography (petroleum ether/EtOAc=100:0˜80:20) to give methyl 2-(6-chloro-2-methoxypyridin-3-yl)-4-cyano-2-methylbutanoate (1100 g, 41%) as a colorless oil. 1H NMR (400 MHz, CDCl3) δ 1.56 (s, 3H), 2.16-2.33 (m, 3H), 2.35-2.47 (m, 1H), 3.65 (s, 3H), 3.93 (s, 3H), 6.96 (d, 1H), 7.44 (d, 1H).

1. temperaturewhile maintaining
2. customreaction temperature below −50° C
3. additionAfter the addition
4. stirringThe resulting mixture was stirred at r.t. for 16 hours
5. customThe reaction mixture was quenched with saturated aqueous NH4Cl (500 mL) below 25° C
6. additionThe mixture was diluted with H2O (15 L)
7. extractionextracted with EtOAc (15 L)
8. washThe combined organic layers were washed with water (15 L) and brine (15 L)
9. dry with materialdried over Na2SO4
10. concentrationconcentrated to dryness
11. customThe crude residue was purified by column chromatography (petroleum ether/EtOAc=100:0˜80:20)