Investigation of regioselectivity on the reaction of 5-bromo-2,4-dichloro-6-methylpyrimidine with ammonia

Regioselective displacement reaction of ammonia with 5-bromo-2,4-dichloro-6-methylpyrimidine was studied by X-ray crystallography analysis and showed the formation of 5-bromo-2-chloro-6-methylpyrimidin-4-amine as a main product. Reaction of the latter compound with secondary amines in boiling ethanol afforded 4-amino-5-bromo-2-substituted aminopyrimidines. The synthesized compound in this paper crystallized in the monoclinic crystal system space group P21/n. In the title cocrystal, 5-bromo-2-chloro-6-methylpyrimidin-4-amine·3H2O, the asymmetric unit contains one crystallographically independent 5-bromo-2-chloro-6-methylpyrimidin-4-amine and three crystallization of water molecules. The typical intramolecular O−H⋯N as well as O−H⋯O hydrogen bond is observed in the crystalline network of the title compound. It is interesting to point out that the crystal structure is further stabilized by O−H⋯O hydrogen bonds created by (H2O)∞ clusters