Potassium Carbonate → Ethyl 3-(7-bromo-4-oxo-4,5-dihydroimidazo[1,5-a]quinoxalin-1-yl)propanoate

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Reaction Conditions

Reaction Steps

A mixture of 4-bromo-1-fluoro-2-nitrobenzene 324 mg, ethyl 3-(1H-imidazol-2-yl)propanoate 248 mg, potassium carbonate 407 mg and N,N-dimethylacetamide 10 mL was heated at 100° C. for 12 hours in nitrogen atmosphere. The reaction liquid was diluted with ethyl acetate and water was added thereto to induce phase separation. The organic layer was washed with saturated brine and dried over sodium sulfate, from which then the solvent was distilled off. Thus obtained oily substance was dissolved in a liquid mixture of 10 mL of acetic acid and 10 mL of water, and to the solution 1.51 g of 85% sodium hydrosulfite was added, followed by 2 hours' heating under reflux. The reaction liquid was cooled with ice and neutralized with saturated aqueous sodium hydrogencarbonate solution. Extracting the same with ethyl acetate, the extract was washed with saturated brine, dried over sodium sulfate, and from which the solvent was distilled off. To the resulting oily substance, 358 mg of 1,1′-carbonyldiimidazole and 20 mL of 1,2-dichlorobenzene were added, followed by 5 hours' heating under reflux in nitrogen atmosphere. The solvent was distilled off, and to the residue methanol was added and stirred overnight. Thus precipitated crystals were recovered by filtration, washed with methanol and dried in flowing air to provide 112 mg of the title compound.

Provenance & Evidence