Sodium hydride → methyl 7-[(2-bromo-4-fluorobenzenesulfonyl)-(2-trimethylsilanyl-ethoxymethyl)-amino]-4H-furo[2,3-c]chromene-6-carboxylate

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Reaction Steps

Sodium hydride (60% dispersion in oil, 0.304 g) was added to a stirred solution of methyl 7-(2-bromo-4-fluorobenzenesulfonylamino)-4H-furo[2,3-c]chromene-6-carboxylate (Intermediate 7, 2.93 g) in THF (30 mL). The resultant mixture was stirred at room temperature for 5 minutes until effervescence had ceased. 2-(trimethylsilyl)ethoxymethyl chloride (1.27 g) was added and the solution was stirred at room temperature for one hour. The mixture was concentrated in vacuo and the residue was dissolved in ethyl acetate, washed with water, dried (Na2SO4) and filtered. The filtrate was evaporated to dryness and the residue was purified by chromatography on silica, eluting with a mixture of ethyl acetate and cyclohexane, with a gradient of 0-20% to give methyl 7-[(2-bromo-4-fluorobenzenesulfonyl)-(2-trimethylsilanyl-ethoxymethyl)-amino]-4H-furo[2,3-c]chromene-6-carboxylate (3.51 g) as a white foam.

Provenance & Evidence