[Na].Cl.[Cl:3][C:4]1[CH:5]=[C:6]([CH:10]=[CH:11][CH:12]=1)[C:7]([NH2:9])=[NH:8].[C:13](OCC)(=[O:20])[CH2:14][C:15](OCC)=[O:16]>C(O)C>[Cl:3][C:4]1[CH:5]=[C:6]([C:7]2[NH:9][C:13](=[O:20])[CH2:14][C:15](=[O:16])[N:8]=2)[CH:10]=[CH:11][CH:12]=1To a stirred solution of 56.4 g. of sodium metal in one liter of absolute ethanol there is added 156 g. of m-chlorobenzamidine hydrochloride followed by the dropwise addition of 144 g. of diethyl malonate over a fifteen minutes period. The reaction mixture is heated under reflux for three hours. The solution is filtered and the filter cake dissolved in water. The ethanol filtrate is evaporated to dryness and the solid residue added to the water solution. Upon acidification of the aqueous solution to pH2 with concentrated hydrochloric acid, a solid separates which is removed by filtration. After washing this material several times with water the product (123 g., m.p. 254°-256°C.) is recrystallized from aqueous N,N-dimethylformamide to yield 2-(3-chlorophenyl)-4,6-(1H,5H)-pyrimidinedione, m.p. 256°-257°C.
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