Dimethyl Carbonate → HCID 71060952, compound

Participants

Reaction Steps

To a solution of 7-bromo-3,4-dihydrobenzo[b]oxepin-5(2H)-one from step H2 (5.41 g, 22.4 mmol) in dimethyl carbonate (28.3 ml, 337 mmol) was slowly added a sodium hydride dispersion in mineral oil (2.69 g, 112 mmol). The mixture was stirred at rt for 15 min, then at 80° C. for 2 h. The mixture was then cooled to rt and stirred for 16 h. The mixture was concentrated in vacuo and diethyl ether (150 mL) of was added. The organic layer was washed with of 1 N HCl (100 mL) followed by water, and dried over sodium sulfate. The solvent was removed in vacuo. The crude product was purified by silica-gel column chromatography (10-40% EtOAc/hexanes, linear gradient) to afford methyl 7-bromo-5-oxo-2,3,4,5-tetrahydrobenzo[b]oxepine-4-carboxylate (3.32 g, 11.1 mmol, 50% yield) as a white solid. LCMS (M+H)+=300.95. 1H NMR (500 MHz, chloroform-d) δ 7.91 (d, J=2.4 Hz, 1H), 7.61-7.48 (m, 1H), 7.03-6.89 (m, 1H), 4.49 (ddd, J=12.4, 6.7, 3.9 Hz, 1H), 4.15-4.03 (m, 2H), 3.77 (s, 3H), 2.68-2.47 (m, 2H).

Provenance & Evidence