Formic Acid → 7-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonylamino]-4H-furo[2,3-c]chromene-6-carboxylic acid

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Reaction Steps

Methyl 7-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonylamino]-4H-furo[2,3-c]chromene-6-carboxylate (Intermediate 9, 0.129 g) was added to a solution of lithium hydroxide monohydrate (0.42 g) in water (2 mL) and dioxane (8 mL), and the mixture was irradiated in the microwave at 130° C. for 1 hour. After cooling, the mixture was acidified with formic acid, and evaporated to dryness. The residue was triturated with 10% methanol in DCM, filtered and the filtrate was evaporated to dryness. The residue was purified by chromatography on silica, eluting with a mixture of methanol and DCM with a gradient of 0-10%. The isolated product was triturated with ethyl acetate and the solid was collected by filtration and dried in vacuo to give 7-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonylamino]-4H-furo[2,3-c]chromene-6-carboxylic acid (0.056 g) as a white solid.

Provenance & Evidence