Facile synthesis of some new functionalized 2-selenoxopyrimidines

Some new functionalized 2-selenoxodihydropyrimidines 1-6 were synthesized in good yields via a simple one-pot reaction. The simple method depended on the reaction of selenourea with some nitrile active methylene compounds under basic-catalyzed conditions. Also, treatment of selenourea with each of malononitrile and ethyl cyanoacetate in the presence of benzaldehyde under the same basic reaction conditions afforded the 2-selenoxopyrimidine-5-carbonitriles 7 and 8, respectively. Furthermore, selenourea reacted with benzaldehyde and different beta-dicarbonyl compounds under Biginelli reaction conditions to afford the 2-selenoxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates 10, 11 and 13. Using acetylacetone as a substrate in Biginelli reaction yielded the unexpected 5-benzylidene-4,6-dimethyl-pyrimidine-2(5H)-selenone (14). The structures of the synthesized compounds were established on the basis of elemental analysis, IR, H-1- and C-13-NMR and mass spectral data.