TY - JOUR A1 - Campos, Patrick T. A1 - Rodrigues, Leticia V. A1 - Belladona, Andrei L. A1 - Bender, Caroline R. A1 - Bitencurt, Juliana S. A1 - Rosa, Fernanda A. A1 - Back, Davi F. A1 - Bonacorso, Helio G. A1 - Zanatta, Nilo A1 - Frizzo, Clarissa P. A1 - Martins, Marcos A. P. T1 - Regiochemistry of cyclocondensation reactions in the synthesis of polyazaheterocycles JF - Beilstein Journal of Organic Chemistry PY - 2017/// VL - 13 SP - 257 EP - 266 SN - 1860-5397 DO - 10.3762/bjoc.13.29 PB - Beilstein-Institut JA - Beilstein J. Org. Chem. UR - https://doi.org/10.3762/bjoc.13.29 KW - DFT-B3LYP KW - polyazaheterocycles KW - pyrazinone KW - pyrido[1,2-a]pyrimidinone KW - pyrimido[1,2-a]benzimidazole KW - quinoxalinone KW - thiazolo[3,2-a]pyrimidinone N2 - The syntheses of several polyazaheterocycles are demonstrated. The cyclocondensation reactions between β-enaminodiketones [CCl3C(O)C(=CNMe2)C(O)-CO2Et] and aromatic amidines resulted in glyoxalate-substituted pyrido[1,2-a]pyrimidinone, thiazolo[3,2-a]pyrimidinone and pyrimido[1,2-a]benzimidazole. Pyrazinones and quinoxalinones were obtained through the reaction of these glyoxalates with ethylenediamine and 1,2-phenylenediamine derivatives. On the other hand, the reaction of glyoxalates with amidines did not lead to the formation of imidazolones, but rather N-acylated products were obtained. All the products were isolated in good yields. DFT-B3LYP calculations provided HOMO/LUMO coefficients, charge densities, and the stability energies of the intermediates, and from these data it was possible to explain the regiochemistry of the products obtained. Additionally, the data were a useful tool for elucidating the reaction mechanisms. ER -