Ethyl Acetate → 2-butyl-7-methoxycarbonyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazine

Beteiligte Stoffe

Reaktionsschritte

To a solution of 2-amino-5-methoxycarbonylphenol [Tetrahedron, 4.6 (15), 5177-5186 (1990)] (8.0 g) in a mixed solvent of ethyl acetate (200 ml) and water (200 ml) were added sodium hydrogen carbonate (11.18 g) and 2-bromohexanoyl bromide (12.73 g) and the mixture was stirred at room temperature for 10 minutes. The organic layer was separated and the solvent was distilled off under reduced pressure. The resulting residue was dissolved in dimethylformamide (300 ml), to the solution was added potassium carbonate (6.0 g) and the mixture was stirred at room temperature for 1 hour. Water was added to the reaction solution and extraction with ethyl acetate was conducted. The solvent was distilled off under reduced pressure and the resulting crystals were recrystallized from ether to give 2-butyl-7-methoxycarbonyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazine (10.3 g).

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