27957-91-1

497-19-8

147-85-3

27957-91-1

1. L-proline (46 kg), paraformaldehyde (13.2 kg), palladium carbon (5%, 350 g) and methanol (158 kg) were added to a hydrogenation reactor. The hydrogenation reaction was carried out at 40 psi hydrogen pressure for 6 hours. 2. upon completion of the reaction, the reaction mixture was filtered and the filtrate was returned to the reaction vessel. 3. trimethyl orthoformate (170 kg) and thionyl chloride (171 kg) were added to the reaction vessel and the mixture was heated to reflux for 2 hours. 4. At the end of the reaction, the volatiles were removed by vacuum distillation. 5. The residue was dissolved in dichloromethane (215 kg), 10% aqueous sodium carbonate solution (360 kg) was added, vigorously mixed and the dichloromethane layer was separated. 6. The aqueous layer was extracted with dichloromethane (215kg) and the organic extracts were combined. 7. The organic phase was dried with anhydrous sodium sulfate (40 kg) and filtered. 8. The solvent was removed by vacuum distillation and the residue was distilled under high vacuum (10 mmHg) to afford methyl (S)-1-methylpyrrolidine-2-carboxylate (34.5 kg, 60% yield).