ethyl 5-oxo-3,4-dihydro-2H-1-benzoxepine-4-carboxylate

Conditions: temp:82.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of ethyl 4-(2-ethoxycarbonylphenyloxy)-butyrate (13.0 g, 46.4 mmol), 60% sodium hydride (5.56 g, 139 mmol), ethanol (2.5 ml) and toluene (250 ml) was stirred at 80-85° C. for 2 hours. The reaction mixture was poured into cold 1N hydrochloric acid and extracted twice with ethyl acetate, and the extract solution was washed with a 5% aqueous sodium chloride solution and dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure and the resulting residue was purified by a silica gel column chromatography (eluent; ethyl acetate:n-hexane=3:97) to obtain 9.05 g of ethyl 1,2,3,4-tetrahydro-5-oxo-benz[b]oxepine-4-carboxylate. extracted twice with ethyl acetate the extract solution was washed with a 5% aqueous sodium chloride solution dried over anhydrous magnesium sulfate The solvent was distilled off under reduced pressure the resulting residue was purified by a silica gel column chromatography (eluent; ethyl acetate:n-hexane=3:97)

Conditions: temp:82.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of ethyl 4-(2-ethoxycarbonylphenyloxy)-butyrate (13.0 g, 46.4 mmol), 60% sodium hydride (5.56 g, 139 mmol), ethanol (2.5 ml) and toluene (250 ml) was stirred at 80-85° C. for 2 hours. The reaction mixture was poured into cold 1N hydrochloric acid and extracted twice with ethyl acetate, and the extract solution was washed with a 5% aqueous sodium chloride solution and dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure and the resulting residue was purified by a silica gel column chromatography (eluent; ethyl acetate:n-hexane=3:97) to obtain 9.05 g of ethyl 1,2,3,4-tetrahydro-5-oxo-benz[b]oxepine-4-carboxylate. extracted twice with ethyl acetate the extract solution was washed with a 5% aqueous sodium chloride solution dried over anhydrous magnesium sulfate The solvent was distilled off under reduced pressure the resulting residue was purified by a silica gel column chromatography (eluent; ethyl acetate:n-hexane=3:97)