Sulfuric Acid → Methyl 2-bromo-4-(3,4-dichlorophenyl)-7-oxo-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-5-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a mixture of sulfuric acid (5.01 mL, 94.0 mmol) and chloroform (49.6 mL, 6.20E2 mmol) was added methyl 2-bromo-4-(3,4-dichlorophenyl)-6-oxo-5,6-dihydro-4H-cyclopenta[b]thiophene-5-carboxylate (5.01 g, 11.9 mmol) followed by sodium azide (3.72 g, 57.2 mmol) in small portions over 3 h with vigorous stirring at 15° C. After addition, the mixture was stirred at rt overnight. The reaction was quenched by ice, basified with sodium bicarbonate, and extracted with DCM. The DCM layer was washed with brine, followed by sodium bicarbonate solution and brine. Dried and evaporated to afford crude product which was purified by silica gel chromatography to afford product as off-white solid (2.50 g, 48.2%). LCMS: (AA) ES+: 435, 437, 1H NMR (400 MHz, CDCl3) δ 7.43-7.38 (m, 1H), 7.28 (d, J=2.2 Hz, 1H), 7.00 (dd, J=8.3, 2.2 Hz, 1H), 6.77 (s, 1H), 5.92 (t, J=9.3 Hz, 1H), 4.67 (d, J=3.3 Hz, 1H), 4.28 (t, J=3.6 Hz, 1H), 3.76 (s, 3H).

Provenance & Evidence