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[摘要]：A new divergent and efficient synthesis of substituted 2-aminoimidazoles and has been developed starting from readily available 2-aminopyrimidines and a-bromocarbonyl compds., using conventional heating or microwave irradn. Thus, the cleavage of 1,2,3-substituted imidazo[1,2-a]pyrimidin-1-ium salts, e.g., I, with hydrazine or secondary amines led to 1,4,5-trisubstituted 2-aminoimidazoles, e.g., II, while the hydrazinolysis of 2-hydroxy-2,3-dihydro-1H-imidazo[1,2-a]pyrimidin-4-ium salts, e.g., III, followed by a novel Dimroth-type rearrangement, resulted in formation of 2-amino-1H-imidazoles, e.g., IV. The likely pathway of the transformations was identified by characterization of the intermediates. |
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