A Novel Synthesis of Iminodipyrimidines

The reaction of 4-amino-6-hydroxy-2-methylpyrimidine with phosphorus oxychloride at 220-230° gave 6, 6'-dichloro-2, 2'-dimethyl-4, 4'-iminodipyrimidine (I) in good yield. I was also obtained from 4-amino-6-chloro-2-methylpyrimidine under these conditions. The reaction was extended successfully to some other 4-aminopyrimidine derivatives to form the corresponding iminodipyrimidines. Reaction of either 4-amino-6-methoxy (or ethoxy)-2-methylpyrimidine or 6, 6'-dimethoxy (or diethoxy)-2, 2'-dimethyl-4, 4'-iminodipyrimidine with phosphorus oxychloride at 220-230° proceeds anomalously to give I in quantitative yields. Replacement of the chlorine atoms in I by nucleophiles was carried out. Direct synthesis of 4, 4'-dichloro-6, 6'-dimethyl-2, 2'-iminodipyrimidine was realized in the reaction of 2-amino-4-hydroxy-6-methylpyrimidine or 2-amino-4-chloro-6-methylpyrimidine with phosphorus oxychloride.