Reaction Steps
To a mixture of the (S)-methyl 1-(6-carbamoyl-2-(4-(4-fluorophenoxy)phenyl)pyrimidin-4-yl)pyrrolidine-2-carboxylate (0.439 g, 1.01 mmol) in 5:1 THF/water (10 mL) was added LiOH.H2O (0.084 g, 2.00 mmol). After stirring 3 days the reaction was quenched with 1N aqueous HCl (2.00 mL). The mixture was evaporated in vacuo then chromatographed using reverse-phase HPCL with a 40-100% acetonitrile in water (+0.1% TFA) gradient. The first product to elute was the (S)-6-(2-carboxypyrrolidin-1-yl)-2-(4-(4-fluorophenoxy)phenyl)pyrimidine-4-carboxylic acid (A) followed by the (S)-1-(6-carbamoyl-2-(4-(4-fluorophenoxy)phenyl)pyrimidin-4-yl)pyrrolidine-2-carboxylic acid (B). Separately, product fractions for each product were pooled and concentrated to give solid suspensions. The solid precipitates were filtered, rinsed with water, and dried under vacuum at 50° C. to give (S)-6-(2-carboxypyrrolidin-1-yl)-2-(4-(4-fluorophenoxy)phenyl)pyrimidine-4-carboxylic acid (A) as a light tan powder (0.170 g, 0.402 mmol, 40% yield) and (S)-1-(6-carbamoyl-2-(4-(4-fluorophenoxy)phenyl)pyrimidin-4-yl)pyrrolidine-2-carboxylic acid (B) as an off-white powder (0.125 g, 0.296 g, 29% yield). (S)-6-(2-carboxypyrrolidin-1-yl)-2-(4-(4-fluorophenoxy)phenyl)pyrimidine-4-carboxylic acid (A): 1H NMR (400 MHz, DMSO-d6): Exists as a ˜80:20 ratio of rotamers: 13.71-12.30 (2H, br m), 8.43 (0.4H, d, J=8.8 Hz), 8.37 (1.6H, d, J=8.8 Hz), 7.32-7.24 (2H, m), 7.20-7.13 (2H, m), 7.09-6.99 (2.8H, m), 6.79 (0.2H, s), 4.62-4.55 (1H, m), 3.87-3.48 (2H, m), 2.38-2.29 (1H, m), 2.24-1.98 (3H, m). LC/MS: m/z=424.1 [M+H]+. (S)-1-(6-carbamoyl-2-(4-(4-fluorophenoxy)phenyl)pyrimidin-4-yl)pyrrolidine-2-carboxylic acid (B): 1H NMR (400 MHz, DMSO-d6): Exists as a 80:20 ratio of rotamers: 13.05 (0.2H, br s), 12.60 (0.8H, br s), 8.57 (0.4H, d, J=8.8 Hz), 8.51 (1.6H, d, J=8.8 Hz), 8.35 (1H, s), 7.81 (1H, s), 7.32-7.24 (2H, m), 7.20-7.13 (2H, m), 7.08-6.97 (2.8H, m), 6.79 (0.2H, s), 4.62-4.52 (1H, m), 3.86-3.72 (0.4H, m), 3.66-3.55 (1.6H, m), 2.40-2.28 (1H, m), 2.22-1.95 (3H, m). LC/MS: m/z=423.1 [M+H]+.
