3709-98-6

3599-89-1

105-53-3

3709-98-6

The general procedure for synthesizing 2-ethyl-4,6-dihydroxypyrimidine from propionamidine hydrochloride and diethyl malonate was as follows: referring to the method for the preparation of 2-ethylpyrimidine-4,6-diol in Example 29, to a solution of methanol (20 mL) of the compound obtained by reference to Example 28 (11 g, 99 mmol) a methanol solution of sodium methanolate 28% (57 g, 296 mmol) was added , and stirred for 10 minutes at room temperature. Subsequently, diethyl malonate (15 mL, 99 mmol) was slowly added dropwise and the reaction continued to be stirred at room temperature for 16 hours. Upon completion of the reaction, the reaction mixture was concentrated under reduced pressure and the residue was dissolved in water and acidified with concentrated hydrochloric acid. The precipitated solid was collected by filtration, washed sequentially with water and ether, and dried to give white crystals of 2-ethyl-4,6-dihydroxypyrimidine (9.3 g, 67% yield). The product was characterized by 1H NMR (300 MHz, DMSO-d6): δ 1.16 (3H, t, J=7.6 Hz), 2.36-2.60 (2H, m), 5.03 (1H, s), 11.62 (2H, br s).