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2 20 o C, H +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.

POLYAKOV, A. I.; ERYOMINA, V. A.; MEDVEDEVA, L. A.; TIHONOVA, N. I.; LISTRATOVA, A. V.; VOSKRESSENSKY*, L. G.; Tetrahedron Lett. 50 (2009) 30, 4389-4393; Org. Chem. Dep., Russ. Peoples' Friendship Univ., Moscow 117198, Russia; Eng.) -Mais 45-148

Fused pyrimidine derivatives R 0515First Example of the Groebke MCR Using Hydroxybenzaldehydes and Substituted 2-Aminopyrimidines. -Groebke multicomponent reaction of aminopyrimidines (I) with isocyanides (II) and hydroxybenzaldehydes (III) leads to the imidazo[1,2-a]pyrimidines (IV). The regiospecifity of the reaction is mainly defined by the steric hindrance of the pyrimidine substituents and the carbonyl activity of the aldehydes. -(POLYAKOV, A. I.; ERYOMINA, V. A.; MEDVEDEVA, L. A.; TIHONOVA, N. I.; VOSKRESSENSKY*, L. G.; J. Heterocycl. Chem. 45 (2008) 6, 1589-1596; Org. Chem. Dep., Russ. Peoples' Friendship Univ., Moscow 117198, Russia; Eng.) -R. Staver 15-161

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