Bromine → 2-Bromo-5,6-dihydro-6-hydroxy-5,5-dimethyl-7-(2-oxopyrrolidin-1-yl)-7H-thieno [3,2-b]pyran

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Reaction Steps

A solution of bromine (0.20 mL, 3.92 mmol) in dichloromethane (5 mL) was slowly added to a solution of 5,6-dihydro-6-hydroxy-5,5-dimethyl-7-(2-oxopyrrolidin-1-yl)-7H-thieno[3,2-b]pyran (1.0 g, 3.74 mmol) at -5° C. The resultant mixture was stirred at rt for 2 h. The resulting precipitate was collected by filtration and purified by medium pressure chromatography using 5% methanol in dichloromethane as the eluant to give the product as a colorless solid, 0.28 g (22%): mp 162°-165° C.; IR(KBr): 3287, 1666 and 1570 cm-1 ; MS: m/z 346 (MH+); 1H NMR (CDCl3): δ 1.30 (s, 3H), 1.47 (s, 3H), 2.06 (m, 2H), 7.50 (m, 2H), 3.23 (bs, 1H, exchanges with D2O), 3.34 (m, 2H), 3.76 (d, J=9.1 Hz, 1H) 5.16 (d, J=9.1 Hz, 1H) and 6.56 (s, 1H). Anal. Calcd. for C13H16BrNO3S: C, 45.10; H, 4.66; N, 4.05. Found: C, 45.10; H, 4.40; N, 3.97.

Provenance & Evidence