Triethylamine → (2S)-4-Oxo-2-(3-thiazolidinylcarbonyl)-1-pyrrolidinecarboxylic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

(2S, 4R)-4-Hydroxy-2-(thiazolidine-3-carbonyl)-pyrrolidine-1-carboxylic acid tert-butyl ester (3.34 g, 0.0111 mol, Example 17A) was dissolved in DMSO and cooled to 0° C. To the cold solution, triethylamine (7.37 g, 0.0729 mol) and sulfur trioxide pyridine complex (8.44 g, 0.0530 mol) were added. The mixture was stirred at 0° C. for 2 hours, brought to room temperature and quenched with water. The mixture was extracted with ethyl acetate and washed with 1 M HCl (60 mL), saturated NaHCO3 (2×40 mL) and brine (1×30 mL). The organic layer was dried with Na2SO4, filtered, concentrated, and purified by column chromatography (ethyl acetate/hexane, 1/1) to give the titled compound 2.05 g. MS (ESI APCI) m/e 299 (M−H)+; 1H NMR (300 MHz, methanol-d4): δ ppm 5.07 (d, 1 H), 4.80 (m, 1 H), 4.57-4.68 (m, 2 H), 4.45 (m, 1 H), 3.85 (d, 2 H), 3.78 (m, 2 H), 3.17 (t, 1 H), 3.05 (m, 2 H), 2.44-2.49 (d, 1 H), 1.47 (s, 9 H).

Provenance & Evidence