A divergent synthesis of substituted 2-aminoimidazoles from 2-aminopyrimidines.
A new divergent and efficient synthesis of substituted 2-aminoimidazoles 5 and 6 has been developed starting from the readily available 2-aminopyrimidines 1 and alpha-bromocarbonyl compounds 2, using conventional heating or microwave irradiation. Thus, the cleavage of 1,2,3-substituted imidazo[1,2-a]pyrimidin-1-ium salts 4 with hydrazine or secondary amines led to 1,4,5-trisubstituted 2-aminoimidazoles 5, when the hydrazinolysis of 2-hydroxy-2,3-dihydro-1H-imidazo[1,2-a]pyrimidin-4-ium salts 3, followed by a novel Dimroth-type rearrangement, resulted in formation of 2-amino-1H-imidazoles 6. The relevant pathway of transformations was identified by characterization of the intermediates.
Ermolat'ev
Denis S
DS
Laboratory for Organic & Microwave-Assisted Chemistry, Department of Chemistry, University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
Van der Eycken
Erik V
EV
D000588:Amines / Q000737:chemistry*; D020650:Combinatorial Chemistry Techniques / Q000379:methods*; D006834:Hydrazines / Q000737:chemistry; D007093:Imidazoles / Q000138:chemical synthesis*; D008872:Microwaves; D008956:Models, Chemical; D011743:Pyrimidines / Q000737:chemistry*; D013237:Stereoisomerism
D000588:Amines; D006834:Hydrazines; D007093:Imidazoles; D011743:Pyrimidines; C014973:2-aminoimidazole; C030986:pyrimidine