Water → 6-Bromo-9-(2-trimethylsilanyl-ethoxymethyl)-9H-dipyrido[2,3-b;4',3'-d]pyrrole-1,7-dioxide

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Reaction Steps

To a suspension of hydrogen peroxide-urea adduct (4.2 g, 45 mmol) in chloroform (37 mL) was added trifluoroacetic anhydride (6.3 mL, 44.4 mmol) dropwise over 10 minutes. The reaction mixture was stirred at ambient temperature for 5 minutes and then to this was added 6-bromo-9-(2-trimethylsilanyl-ethoxymethyl)-9H-dipyrido[2,3-b;4′,3′-d]pyrrole (2.1 g, 5.6 mmol) as a solution in chloroform (15 mL). Note: an exotherm is observed upon addition of the substrate. The reaction mixture was stirred at ambient temperature for 10 minutes and then at 50° C. for 30 minutes. The reaction mixture was cooled to ambient temperature, treated with saturated sodium thiosulfate solution (20 mL), and diluted with water (50 mL) and methanol (10 mL). The layers were separated and the organic layer was washed with 0.5N hydrochloric acid (50 mL), dried over sodium sulfate, filtered, concentrated in vacuo, and purified by flash chromatography (silica, 80 g, ISCO, 0-10% methanol in dichloromethane) to afford the title compound as a pale yellow solid, which was used in the next step without any further purification (1 g, 44%).

Provenance & Evidence