4-Toluenesulfonyl chloride → tert-butyl 2-oxo-4-(tosyloxy)-2,5-dihydro-1H-pyrrole-1-carboxylate

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Reaction Steps

To tert-butyl 4-hydroxy-2-oxo-2,5-dihydro-1H-pyrrole-1-carboxylate (680 mg, 3.41 mmol) in DCM (12 mL) was added DIEA (1.192 mL, 6.83 mmol) and tosyl chloride (651 mg, 3.41 mmol). The reaction mixture was stirred at room temperature for 6 h. The reaction mixture was diluted with DCM and washed with saturated sodium bicarbonate. The organic layer was separated, washed with brine, dried over sodium sulfate, filtered and evaporated. The crude product was purified by flash chromatography (0 to 50% EtOAc/heptane). Pure fractions were combined, evaporated and dried to give desired product as a white solid (0.98 g, 81%). LCMS (m/z): 354.1 (MH+), 0.97 min; 1H NMR (400 MHz, DMSO-d6) δ ppm 7.99 (d, J=8.22 Hz, 2H) 7.54 (d, J=7.83 Hz, 2H) 5.77 (s, 1H) 4.33 (s, 2H) 2.43 (s, 3H) 1.41 (s, 9H).

Provenance & Evidence