反应详情

SOCl2 (6.4 g, 54 mmol) was added dropwise to methanol (40 mL) followed by addition of 1-(2,4-dimethoxybenzyl)-5-oxopyrrolidine-3-carboxylic acid (5.0 g, 18 mmol) at 0° C. The reaction mixture was stirred at ambient temperature for 1 h and then heated under reflux for 7 h. The mixture was cooled to ambient temperature and concentrated. The residue was purified by flash column chromatography on silica gel (petroleum ether/EtOAc=6:1 to 2:1) to afford methyl 1-(2,4-dimethoxybenzyl)-5-oxopyrrolidine-3-carboxylate (a mixture of two enantiomers, 4.3 g, 81% yield) as a colorless oil. The two enantiomers were separated by chiral prep-HPLC.

1. temperatureheated
2. temperatureunder reflux for 7 h
3. temperatureThe mixture was cooled to ambient temperature
4. concentrationconcentrated
5. customThe residue was purified by flash column chromatography on silica gel (petroleum ether/EtOAc=6:1 to 2:1)