methyl 2-(3-oxo-4H-1,4-benzoxazin-2-yl)acetate

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

Procedure: A mixture of 76.4 g of 2-aminophenol and 68.6 g of maleic anhydride in 1 liter of methanol was stirred at room temperature. After addition of 100 ml of triethylamine, the yellow mass dissolved and the solution was heated for 7 hours at reflux temperature. The methanol was then removed by evaporation under reduced pressure, and the remaining oil was added to ice-water. The mixture was extracted with dichloromethane, and the organic extract was dried over sodium sulfate and evaporated. The remaining residue was crystallized from ethanol. In this way, 47.5 g of methyl (3-oxo-2,3-dihydro-4H-1,4-benzoxazin-2-yl)acetate were obtained as white crystals having a melting point of 140° C. the yellow mass dissolved the solution was heated for 7 hours at reflux temperature The methanol was then removed by evaporation under reduced pressure the remaining oil was added to ice-water The mixture was extracted with dichloromethane the organic extract was dried over sodium sulfate evaporated The remaining residue was crystallized from ethanol

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

Procedure: A mixture of 76.4 g of 2-aminophenol and 68.6 g of maleic anhydride in 1 liter of methanol was stirred at room temperature. After addition of 100 ml of triethylamine, the yellow mass dissolved and the solution was heated for 7 hours at reflux temperature. The methanol was then removed by evaporation under reduced pressure, and the remaining oil was added to ice-water. The mixture was extracted with dichloromethane, and the organic extract was dried over sodium sulfate and evaporated. The remaining residue was crystallized from ethanol. In this way, 47.5 g of methyl (3-oxo-2,3-dihydro-4H-1,4-benzoxazin-2-yl)acetate were obtained as white crystals having a melting point of 140° C. the yellow mass dissolved the solution was heated for 7 hours at reflux temperature The methanol was then removed by evaporation under reduced pressure the remaining oil was added to ice-water The mixture was extracted with dichloromethane the organic extract was dried over sodium sulfate evaporated The remaining residue was crystallized from ethanol

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

Procedure: A mixture of 76.4 g of 2-aminophenol and 68.6 g of maleic anhydride in 1 liter of methanol was stirred at room temperature. After addition of 100 ml of triethylamine, the yellow mass dissolved and the solution was heated for 7 hours at reflux temperature. The methanol was then removed by evaporation under reduced pressure, and the remaining oil was added to ice-water. The mixture was extracted with dichloromethane, and the organic extract was dried over sodium sulfate and evaporated. The remaining residue was crystallized from ethanol. In this way, 47.5 g of methyl (3-oxo-2,3-dihydro-4H-1,4-benzoxazin-2-yl)acetate were obtained as white crystals having a melting point of 140° C. the yellow mass dissolved the solution was heated for 7 hours at reflux temperature The methanol was then removed by evaporation under reduced pressure the remaining oil was added to ice-water The mixture was extracted with dichloromethane the organic extract was dried over sodium sulfate evaporated The remaining residue was crystallized from ethanol