Hydrochloric Acid → (2S,4R)-4-benzamido-1-(2-((tert-butoxycarbonyl)amino)acetyl)pyrrolidine-2-carboxylic acid

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Reaction Conditions

Reaction Steps

To a solution of (2S,4R)-methyl 4-benzamido-1-(2-(tert-butoxycarbonyl-amino)acetyl)pyrrolidine-2-carboxylate (23.33 g, 0.0575 mol) in methanol (450 mL) NaOH (0.2875 mol, 144 mL of 2N aqueous solution) was added at −1 to 1° C. over 15 min. The mixture was stirred at −5 to 1° C. for 2.5 h. HCl (0.2875 mol, 144 mL of 2N aqueous solution) was added at −3 to 1° C. over 25 min. MeOH was distilled off in vacuum. 500 mL of EtOAc were added. Aqueous phase was saturated with NaCl. Phases were separated. Aqueous phase was extracted with 2×250 mL of EtOAc. Combined EtOAc solution was dried over MgSO4, and concentrated to afford 22.54 g of the title product as a white foamy solid (contains 6.6 wt % EtOAc; 94% yield adjusted to residual EtOAc). 1H NMR (CD3OD, δ, ppm): 7.87-7.79 (m, 2H), 7.58-7.42 (m, 3H), 4.81-4.7 (m 1H), 4.69-4.56 (m, 1H), 4.05-3.72 (m, 3H), 3.67-3.49 (m, 1H), 2.64-2.28 (m, 2H), 1.43 (s, 9H). MS (m/z, positive ESI) for M+H: 392; for M+Na: 414.

Provenance & Evidence