Methyl chloroformate → methyl 7-{N-[2-bromo-4-fluorobenzenesulfonyl]-N-(methoxycarbonyl)amino}-4H-furo[2,3-c]chromene-6-carboxylate

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Reaction Steps

To a suspension of sodium hydride (60% dispersion in oil, 0.043 g) in THF (10 mL) was added methyl 7-(2-bromo-4-fluorobenzenesulfonylamino)-4H-furo[2,3-c]chromene-6-carboxylate (Intermediate 7, 0.40 g). Once gas evolution had ceased, methyl chloroformate (0.102 mL) was added and the resultant mixture was stirred at room temperature for 2.5 hours. Saturated aqueous sodium bicarbonate solution was added and the mixture was extracted with ethyl acetate. The combined organic layers were dried (MgSO4), filtered and the filtrate was concentrated in vacuo. The residue was triturated with ether to give methyl 7-{N[2-bromo-4-fluorobenzenesulfonyl]-N-(methoxycarbonyl)amino}-4H-furo[2,3-c]chromene-6-carboxylate (0.230 g) as a white powder.

Provenance & Evidence