Acetic Anhydride → HCID 53298866, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of the compound obtained in the above step (1) (13.6 g) in methylene chloride (200 mL) is added piperidine (18.9 g) and thereto is added dropwise a solution of ethyl chlorooxoacetate (16.3 g) in methylene chlorode (200 mL) under ice-cooling. The mixture is stirred at 0° C. for 1.5 hours. The reaction mixture is diluted with chloroform (100 mL) and thereto is added water (300 mL). After stirring, the organic layer is separated and the aqueous layer is extracted with chloroform. The organic layers are combined and washed with saturated brine, dried over anhydrous sodium sulfate, and filtered. The filtrate is concentrated and the residue is purified by column chromatography on silica gel (Solvent; chloroform:ethyl acetate=9:1) to give ethyl [(3-cyano-4,5-dimethylfuran-2-yl)amino](oxo)acetate (17 g, yield; 72%) as a colorless powder. A mixture of formic acid (30 mL) and acetic anhydride (30 mL) is stirred at 60° C. under argon gas atmosphere for 2 hours and thereto is added ethyl [(3-cyano-4,5-dimethylfuran-2-yl)amino](oxo)acetate (7.07 g). The mixture is refluxed for 14 hours. The reaction mixture is concentrated and the residue is purified by column chromatography on silica gel (Solvent; chloroform:ethyl acetate=9:1→chloroform:methanol=19:1) to give ethyl 5,6-dimethyl-4-oxo-3,4-dihydrofuro[2,3-d]pyrimidine-2-carboxylate (4.30 g, yield; 61%) as a colorless powder. M.p. 180-182° C.

Provenance & Evidence