Potassium Carbonate → 3-(Heptyloxy)benzoic acid

In a 2-liter three-necked flask were placed 100 g of methyl 3-hydroxybenzonate, 143 g of 1-bromoheptane, 140 g of potassium carbonate and 300 of N,N-dimethylacetamide (DMAc), and were vigorously stirred for 2 hours with a mechanical stirrer while the flask was heated in oil bath under reflux. After the obtained reaction mixture was cooled, it was poured into 1 l of water, and was extracted with ethyl acetate. Subsequently, the extract was dried under anhydrous sodium sulfate. After the extract was concentrated by removing the solvent in vacuo, the resultant residue was dissolved in 200 ml of methanol. Then, an aqueous solution (40 ml) containing potassium hydroxide of 8.4 g was dropwise added gradually to the ethanol solution and refluxed under heating for 1 hour. After the resultant reaction mixture was cooled, the precipitated crystals were filtered, and the resultant crystals were dissolved in 1.5 l of water. To the solution, 60 ml of concentrated hydrochloric acid was added. Then, the precipitated crystals were filtered in vacuo, washed with ice water and dried to obtain the above compound (2-4a) of 130 g (yield: 84%).