Publication Date:
2017-02-11
Description:
The syntheses of several polyazaheterocycles are demonstrated. The cyclocondensation reactions between β-enaminodiketones [CCl 3 C(O)C(=CNMe 2 )C(O)-CO 2 Et] 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. Beilstein J. Org. Chem. 2017, 13, 257–266. doi:10.3762/bjoc.13.29
Keywords:
DFT-B3LYPpolyazaheterocyclespyrazinonepyrido[1,2-a]pyrimidinonepyrimido[1,2-a]benzimidazolequinoxalinonethiazolo[3,2-a]pyrimidinone
Electronic ISSN:
1860-5397
Topics:
Chemistry and Pharmacology
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