Methanol → Methyl (2R,4R)-4-hydroxypyrrolidine-2-carboxylate hydrochloride

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Reaction Steps

To a suspension of cis-4-hydroxy-D-proline (16.46 g: 125.5 mmole) in methanol (66 ml), thionylchloride (9.16 ml: 125.5 mmole) is added in a nitrogen atmosphere under ice cooling, and the mixture is stirred at room temperature for 30 minutes. The mixture is further stirred to react at 40° C. for 4 hours to give (2R,4R)-4-hydroxy-2-methoxycarbonylpyrrolidine hydrochloride as crude crystals (25.74 g). Yield: 113%. Colorless crystals. NMR δ(D2O) ppm: 2.3 to 2.6(m, 2H), 3.33(s, 1H), 3.4 to 3.5(m, 2H), 3.84(s, 3H), 4.6 to 4.7(m, 2H). IR ν (KBr) cm-1 : 3320, 2980, 1728.

Provenance & Evidence