Methylparaben → methyl 4-[(2S,4S)-4-acetoxy-1-tert-butoxycarbonyl-2-pyrrolidinyl]methoxybenzoate

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Reaction Steps

To a stirred mixture of (2S,4S)-4-acetoxy-1tert-butoxycarbonyl-2-pyrrolidinemethanol (9.70 g, 37.4 mmol), p-hydroxybenzoic acid methyl ester (5.69 g, 37.4 mmol) and PPh3 (10.8 g, 41.1 mmol) in THF (200 ml) was added DIAD (8.10 ml, 41.1 mmol) at room temperature. After 1.5 h stirring, the mixture was concentrated in vacuo. The resulting residue was chromatographed on silica gel [700 g, CHCl3/EtOAc (10/1)], to give methyl 4-[(2S,4S)-4-acetoxy-1-tert-butoxycarbonyl-2-pyrrolidinyl]methoxybenzoate (11.8 g, 81%) as a pale yellow oil. 1H-NMR (CDCl3) δ1.48 (s, 9H), 2.03 (s, 3H), 2.27 (m, 2H), 3.46 (m, 1H), 3.72 (m, 1H), 3.88 (s, 3H), 3.98 (t, J=9.0 Hz, 1H), 4.21-4.47 (m, 2H), 5.31 (br, 1H), 6.96 (br, 2H), 7.98 (d, J=8.8 Hz, 2H).

Provenance & Evidence