Methanol → methyl L-prolinate hydrochloride

반응식

S(Cl)([Cl:3])=O.[NH:5]1[CH2:12][CH2:11][CH2:10][C@H:6]1[C:7]([OH:9])=[O:8].[CH3:13]O>>[ClH:3].[NH:5]1[CH2:12][CH2:11][CH2:10][C@H:6]1[C:7]([O:9][CH3:13])=[O:8]

참가 물질

반응물 3

HCID 887Methanol

HCID 24386Thionyl Chloride

HCID 145742L-Proline

생성물 1

HCID 2733200methyl L-prolinate hydrochloride수율 99.6%

실험 절차

Thionyl chloride (65 ml, 0.89 mol) was added dropwise at ice-cooling for 45 min to a solution of L-proline (57.6 g, 0.50 mol) in 500 ml MeOH. The temperature was raised to reflux. After 4 h at reflux the mixture was cooled and the solvent evaporated in vacuo. MeOH was added to the residue and then evaporated repeatedly three times to give 86 g crude methyl (S)-2-pyrrolidinecarboxylate hydrochloride (99.6% purity by GLC) as a thick syrup. The ester (1.65 g, 0.01 mol) was transferred to a flask containing acetaldehyde (2.21 g, 0.05 mol) 10% Pd/C (0.15 g) and 15 ml MeOH. The mixture was shaken in a Parr apparatus at 55 psi hydrogen pressure for 4 h at room temperature, filtered and evaporated to give 2.1 g crude hydrochloride of the title ester. (91% purity by GLC). This material was subjected to aminolysis in Example 7D.