Br[CH:2]([C:11]1[CH:16]=[CH:15][N:14]=[C:13]([S:17][CH3:18])[N:12]=1)[C:3]([C:5]1[CH:10]=[CH:9][CH:8]=[CH:7][CH:6]=1)=O.[NH2:19][C:20]([NH2:22])=[S:21]>C(O)C>[NH2:22][C:20]1[S:21][C:2]([C:11]2[CH:16]=[CH:15][N:14]=[C:13]([S:17][CH3:18])[N:12]=2)=[C:3]([C:5]2[CH:10]=[CH:9][CH:8]=[CH:7][CH:6]=2)[N:19]=1A solution of 2-bromo-2-(2-methylthio-pyrimidin-4-yl)-1-phenyl-ethanone (45 g, 0.14 mol) and thiourea (21.2 g, 0.28 mol) in ethanol (300 ml) is heated at reflux for 4 hours. On cooling the product starts to crystallize as salt. It is filtered with suction and washed with ether. The free amine is obtained by partitioning of the product between an aqueous solution of sodium bicarbonate and a 1:1 mixture of ethyl acetate and tetrahydrofuran, followed by drying of the organic phase over magnesium sulfate, filtering and evaporation of the solvents. The 4-(2-amino-4-phenyl-thiazol-5-yl)-2-methylthio-pyrimidine is obtained in crystalline form, m.p. 208–209° C.
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