Hydrochloric Acid → 1-((Tert-butoxy)carbonyl)-4,4-difluoropyrrolidine-2-carboxylic acid

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Reaction Steps

To a stirred solution of methyl 1-(tert-butoxycarbonyl)-4,4-difluoropyrrolidine-2-carboxylate (885 mg, 3.34 mmol) in THF (25 ml) was added 0.25 N NaOH (26.7 ml, 6.67 mmol) and the stirring was continued for 1 h. The mixture was poured into 1 N HCl (100 ml) and extracted with CHCl3 (2×200 ml). The combined extracts were washed with brine (100 ml), dried over MgSO4, and evaporated to give 1-(tert-butoxycarbonyl)-4,4-difluoropyrrolidine-2-carboxylic acid (775 mg, 92%) as a yellow crystalline solid. mp 113–117° C.; 1H-NMR (CDCl3) δ 1.44 and 1.49 (s, each, total 9 H), 2.53–2.80 (m, 2 H), 3.71–3.90 (m, 2 H), 4.20–4.61 (m, 1 H); MS (FAB) m/z, 252 (M++1); Anal. Calcd for C10H15F2O4: C, 47.81; H, 6.02; N, 5.58. Found: C, 48.06; H, 6.05; N, 5.45.

Provenance & Evidence