Methanol → (2S, 4R)-4-hydroxy-N-(4-nitrobenzyloxycarbonyl)proline methyl ester

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Reaction Steps

To a mixture of methanol (94.5 ml) and dichloromethane (945 ml) under ice cooling are dropwise added thionyl chloride (18.7 ml) and after 5 minutes stirring N-p-nitrobenzyloxycarbonyl-L-hydroxyproline (1: 72.4 g), and the mixture is stirred overnight at room temperature. The reaction mixture is concentrated in vacuum to give crude (2S,4R)-4-hydroxy-2-methoxycarbonyl-1-p-nitrobenzyloxycarbonylpyrrolidine (86.5 g) as pale yellow oil. This product can be used in the next step without further purification. IR ν (CHCl3) cm-1 : 3450, 1742, 1703, 1605. 1HNMR δ (CDCl3) ppm: 1.77(1H, s), 2.05 to 2.45(2H, m), 3.55 to 3.8(2H, m), 3.66, 3.76(3H, 2s), 4.49 to 4.62(2H, m), 5.06 to 5.35(2H, m), 7.43 to 7.56(2H, m), 8.22(2H, d, J=8.2 Hz).

Provenance & Evidence