MECHANISM FOR ANNELATION ([2+4] CYCLOCONDENSATION) OF SCHIFF BASES BY β-DICARBONYL AND β,β'-TRICARBONYL COMPOUNDS IN AMPHIPROTIC MEDIA
DOI:
https://doi.org/10.1007/6997Keywords:
azangular heterocycles, 8-azasteroids, azomethines, 2-acyl-1, 3-cyclanediones, β-dicarbonyl compounds, β, β'-tricarbonyl compounds, pyrido[2, 1-a]isoquinolines, Schiff bases, annelation, keto-enol tautomerism, reaction mechanism, [2 4] cyclocondensationAbstract
The mechanism was established for annelation ([2+4] cyclocondensation) of Schiff bases or azomethines by β-dicarbonyl and β,β'-tricarbonyl compounds in amphiprotic media. The condensation was found to be a self-catalyzed pericyclic process achieved through six-membered transition states. The key reaction intermediates are dipoles of quaternized azomethine ions and enol-anions of the β-dicarbonyl and β,β'-tricarbonyl compounds, which display 1,4-dipolarophilicity.
How to Cite
Gulyakevich, O. V.; Mikhal'chuk, A. L. Chem. Heterocycl. Compd. 2008, 44, 253. [Khim. Geterotsikl. Soedin. 2008, 335.]
For this article in the English edition see DOI 10.1007/s10593-008-0041-5
