Sulfuric acid magnesium salt (1:1) → 4-(2-{2-[(2R)-2-methyl-5-oxo-1-pyrrolidinyl]ethyl}-1-benzofuran-5-yl)benzonitrile

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Reaction Steps

The mono-(L)-tartaric acid salt of the product of Example 1D (96 mg, 0.20 mmol) was suspended in acetone (10 mL) and treated with a solution of KMnO4 (158 mg, 1.0 mmol) and MgSO4 (120 mg, 1.0 mmol) in water (5 mL) over 30 minutes. After the purple color had disappeared, the solids were filtered off. The filtrate was diluted with EtOAc, washed with aqueous potassium dihydrogen phosphate, concentrated, and purified by HPLC [Waters Nova-Pak HR C18 column (25 mm×100 mm, 6 μm particle size) using a gradient of 10% to 100% MeCN/0.1% aqueous TFA over 8 min (10 min run time) at a flow rate of 40 mL/min.] to provide the title compound (2% yield). MS (ESI APCI) m/z 345 (M+H)+; 1HNMR (300 MHz, CD3OD) δ 1.22 (d, 3H), 1.55-1.64 (m, 1H), 2.15-2.32 (m, 2H), 2.34-2.42 (m, 1H), 2.99-3.13 (m, 2H), 3.39-3.46 (m, 1H), 3.68-3.76 (m, 1H), 3.89-3.97 (m, 1H), 6.65 (s, 1H), 7.51-7.56 (m, 2H), 7.76-7.84 (m, 5H).

Provenance & Evidence