[H-].[Na+].[NH:3]1[CH:7]=[CH:6][N:5]=[CH:4]1.[Cl:8][C:9]1[CH:14]=[C:13](Cl)[N:12]=[CH:11][N:10]=1.O>CN(C=O)C>[Cl:8][C:9]1[CH:14]=[C:13]([N:3]2[CH:7]=[CH:6][N:5]=[CH:4]2)[N:12]=[CH:11][N:10]=1To a stirred suspension of sodium hydride (0.65 g, 55% dispersion in oil, pre-washed with petrol) in dry DMF (5 ml) at 10°-15° C. under nitrogen, was added a solution of imidazole (1.02 g, 15 mmol) over five minutes. The reaction mixture effervesced and an exotherm took place. After stirring for 11/2 hours at room temperature, the cloudy solution was added drop-wise over one hour to a solution of 4,6-dichloropyrimidine in dry DMF (10 ml) at 0° C. for one hour, added to water and then extracted with ether (×3). The combined ether extracts were washed with dilute sodium hydroxide solution and water (×3) and then dried. Concentration under reduced pressure gave 4-chloro-6-(imidazol-1-yl)pyrimidine as a pale yellow solid (1.00 g); m.p. 122°-4° C., which was used without further purification.
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