[C:1]([CH2:4][C:5](=O)[CH3:6])(=O)[CH3:2].[CH2:8]([NH:10][C:11]([NH2:13])=[O:12])[CH3:9].C(O)C.S(=O)(=O)(O)O>CCOCC>[CH2:8]([N:10]1[C:1]([CH3:2])=[CH:4][C:5]([CH3:6])=[N:13][C:11]1=[O:12])[CH3:9]Acetylacetone (9.0 g., 0.09 moles) and ethylurea (7.13 g., 0.081 moles) are dissolved in 30 ml. ethanol. The solution is cooled in an ice-water bath while 30 g. of cold concentrated sulfuric acid is added. The resulting yellow solution is stored at room temperature for 10 days and diluted with a large volume of ether. The ether-ethanol mixture is decanted from the thick syrupy residue which is washed with additional fresh ether. The residue is made basic with 2.5 N sodium hydroxide and extracted throughly with methylene chloride. The organic extracts are dried over sodium sulfate, treated with charcoal, filtered, and evaporated under vacuum affording 1-ethyl-4,6-dimethyl-2(1H)-pyrimidinone as a tan solid (7.6 g., 62%).
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