2-Oxime 2,3-butanedione → HCID 23076475, compound

Participants

Reaction Steps

A mixture of ethyl 5-formyl-2-furancarboxylate (5.33 g), 2,3-butanedione-2-oxime (3.21 g) and 4N hydrogenchloride-ethyl acetate solution (100 mL) was stirred at room temperature for 3 days. After concentration of the reaction mixture, diethyl ether was added to the residue and the precipitated crystals were collected by filtration. A mixture of the obtained crystal, tetrahydrofuran (100 mL) and thionyl chloride (5.66 g) was heated under reflux for 3 hrs. The reaction mixture was concentrated and ethyl acetate was added to the residue. The ethyl acetate layer was washed successively with saturated aqueous sodium hydrogen carbonate solution and saturated brine, dried over anhydrous magnesium sulfate and concentrated. The residue was subjected to silica gel column chromatography to give ethyl 5-(4-chloromethyl-5-methyl-1,3-oxazol-2-yl)-2-furancarboxylate as colorless crystals (2.60 g, yield 30%) from a fraction eluted with ethyl acetate-hexane (1:4, v/v). Recrystallization from ethyl acetate-hexane gave colorless prism crystals. melting point: 117-118° C.

Provenance & Evidence