The general procedure for the synthesis of 2,4-dimethylpyrimidine-5-carboxylic acid from ethyl 2,4-dimethylpyrimidine-5-carboxylate was as follows: potassium hydroxide (67 g, 1.0 mol) was dissolved in 95% ethanol (300 mL), and this solution was then added to a 95% ethanol (100 mL) solution of ethyl 2,4-dimethyl-5-pyrimidinecarboxylate (73 g, 0.40 mol) to the solution. The mixture was heated under reflux conditions for 5 hours. Upon completion of the reaction, the ethanol was removed by evaporation under reduced pressure, the residue was dissolved in water and the aqueous solution was acidified with concentrated hydrochloric acid. The precipitated solid was collected by filtration, washed with water and dried to give 2,4-dimethylpyrimidine-5-carboxylic acid (36 g, 58% yield). The product was characterized by 1H-NMR (CDCl3), δ: 2.63 (3H, s), 2.69 (3H, s), 8.97 (1H, s).
