First example of the Groebke MCR using hydoxybenzaldehydes and substituted 2-aminopyrimidines

(Chemical Equation Presented) A three component condensation of 2-aminopyrimidines, isocyanides and 4-hydroxybenzaldehydes was studied. 3-Amino-2-(4-hydroxyphenyl)imidazo[1,2-a]pyrimidine derivatives were obtained in moderate yields. Using 4-hydroxy-3,5-dimethoxybenzaldehyde and 2-aminopyrimidine as starting materials in the condensation led to mixtures of isomeric 2- and 3-aminoimidazo[1,2-a]pyrimidines. It was demonstrated, that the regiospecificity of this reaction is mainly defined by the steric hindrance of substituents on the pyrimidine nucleus and the carbonyl activity of the corresponding aldehydes.