3-Cyclobutene-1,2-dione, 3,4-dimethoxy- → HCID 89533687, compound

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Reaction Steps

1.80 g (0.01 mol; 2.0 eq) of 3,4-dimethoxy-3-cyclobutene-1,2-dione were added to a solution of 1.87 g (0.08 mol; 1.0 eq) of isopropyl (S)-1-(3-amino-2-fluorobenzoyl)pyrrolidine-2-carboxylate in 45 ml of methanol. The reaction medium was stirred at ambient temperature for 24 hours. The solvent was evaporated off and the residue was chromatographed on silica gel (200 g prepacked column, eluent 20/80 then 0/100 heptane/ethyl acetate). 1.32 g of isopropyl (S)-1-[2-fluoro-3-(2-methoxy-3,4-dioxocyclobut-1-enylamino)benzoyl]pyrrolidine-2-carboxylate were obtained in the form of a light yellow amorphous solid. Yield=51%.

Provenance & Evidence