反应详情

To a solution of methyl-α-butyl-N-(diphenylmethylene)phenylalaninate (0.31 g, 0.78 mmol) from step A in 10 mL MeOH was added 3.33M hydrochloric acid (0.69 mL, 2.3 mmol). After 1.5 h at rt, the reaction was concentrated in vacuo to remove volatiles, then redissolved in saturated aqueous NaHCO3. The aqueous layer was extracted with EtOAc (2×), the combined organics were washed with water, brine, dried over Na2SO4, filtered and concentrated. Purification by silica gel chromatography (20 g silica, 0->30% EtOAc/hexanes) afforded methyl-α-butylphenylalaninate as a viscous oil. 1H NMR (400 MHz, d4-MeOH) δ 7.30-7.23 (m, 3H), 7.14-7.12 (m, 2H), 3.68 (d, J=13.1, 1H), 3.18 (d, J=13.1, 1H), 1.92 (m, 1H), 1.61 (m, 1H), 1.51-1.32 (m, 3H), 1.12 (m, 1H) M+H=236.

1. concentrationthe reaction was concentrated in vacuo
2. customto remove volatiles
3. dissolutionredissolved in saturated aqueous NaHCO3
4. extractionThe aqueous layer was extracted with EtOAc (2×)
5. washthe combined organics were washed with water, brine
6. dry with materialdried over Na2SO4
7. filtrationfiltered
8. concentrationconcentrated
9. customPurification by silica gel chromatography (20 g silica, 0->30% EtOAc/hexanes)