4,5-Dimethyl-2-Furoic Acid

Abstract

Methyl 4,5-Dimethyl-2-furoate. A mixture of 37.8 g (0.2 mole) of methyl 4-(chloromethyl)-5-methyl-2-furoate (see p. 42), b.p. 120–121°/3 mm, and 120 ml of 90% acetic acid was prepared in a 250-ml round-bottomed flask having a side neck and fitted with stirrer and reflux condenser. The mixture was stirred while 39.2 g (0.6 g-atom) of zinc dust was added in small portions, and with continued stirring it was heated in a water bath for four hours. It was then cooled and poured into a beaker containing 300 ml of cold water. The oily substance that formed on the bottom was extracted with four 100-ml portions of ether. The combined ether extract was washed with water, with 5% sodium bicarbonate solution until the acetic acid was completely neutralized, and again with water; it was dried with sodium sulfate. Solvent was distilled off, and the residue was vacuum-distilled. The product came over at 78–80°/1 mm; yield 16.4–17.0 g (53.2–55.1%).