Formaldehyde → (S)-Methyl 1-methylpyrrolidine-2-carboxylate

A 10.42 g (62.92 mmol) sample of L-proline methyl ester hydrochloride (Aldrich Chemical Co.) was reductively methylated over 2.5 g of 10% Pd/C under 4 Atm of hydrogen in a solution containing 20 g of sodium acetate and 49.5 mL of 37% aqueous formaldehyde for 48 hours. Upon completion of the reaction, the methanolic solution was concentrated and the residue was dissolved in 10% aq. HCl (60 mL) and washed with ether (3×100 mL), then the aqueous layer was adjusted to pH ~12 with K2CO3 (solid) and extracted with methylene chloride (3×75 mL). The combined methylene chloride layers were dried (MgSO4) and concentrated to afford the crude product as a clear oil (16.6 g, 77% yield).

1. customUpon completion of the reaction
2. concentrationthe methanolic solution was concentrated
3. dissolutionthe residue was dissolved in 10% aq. HCl (60 mL)
4. washwashed with ether (3×100 mL)
5. extractionextracted with methylene chloride (3×75 mL)
6. dry with materialThe combined methylene chloride layers were dried (MgSO4)
7. concentrationconcentrated

ORD-Eintrag

ord-f2e5dc8bddec4c22b2776b5f49d6f5af

Quelldatensatz

uspto-grants-1995_06

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05424444