反应详情

A mixture of 2,4-dimethoxy-benzaldehyde (50 g, 0.30 mole), glycine ethyl ester hydrochloride (44 g, 0.32 mole) and triethylamine (43.9 mL, 0.32 mole) in dichloroethane was stirred for one hour before sodium triacetoxyborohydride (100 g, 0.47 mole) was added in four portions. The mixture was stirred for three days before it was quenched with saturated sodium bicarbonate. The organic layer was extracted with 3N HCl (2×400 mL, 2.4 mole). The aqueous layers were combined, adjusted with solid sodium hydroxide (97.68 g, 2.4 mole) to pH=8 and extracted with ethyl acetate (500 mL). The ethyl acetate extract was washed with brine, dried over sodium sulfate, and concentrated. The residue was purified by flash column chromatography with a gradient of methanol and dichloromethane on silica gel (120 g) to give the title compound as a yellow oil (42.77 g) 1H NMR (CDCl3, 200 MHz): δ=7.11 (m, 1H), 6.41 (m, 2H), 4.15 (q, J=7.2 Hz, 2H), 3.81 (s, 3H), 3.80 (s, 3H), 3.74 (s, 2H), 3.37 (s, 2H), 1.27 (t, J=7.2 Hz, 3H).

1. additionwas added in four portions
2. customwas quenched with saturated sodium bicarbonate
3. extractionextracted with ethyl acetate (500 mL)
4. extractionThe ethyl acetate extract
5. washwas washed with brine
6. dry with materialdried over sodium sulfate
7. concentrationconcentrated
8. customThe residue was purified by flash column chromatography with a gradient of methanol and dichloromethane on silica gel (120 g)