Abstract

Ali Aminkhani

DOI : http://dx.doi.org/10.13005/ojc/300439

Synthesis of the Guanidium-Meldrum acid zwitterionic salts was developed through a three component reaction of 2, 2-dimethyl-1, 3-dioxane-4, 6-dione (Meldrum acid), aromatic aldehydes and N, N, N', N'-Tetramethyl-guanidine in benzen at room temperature. These reaction conditions allow the preparation of stable zwitterionic salts in good yields. A dynamic NMR effect is observed as a result of restricted rotation around the C-NH bond in the ¹H NMR spectra of these compounds. The free-energy of activation (∆G^#) for this process is 66 ± 2 kJmol^-1 for 4b.

Benzaldehydes; Dynamic NMR; Meldrum acid; Michael addition; N; N; N'; N'-Tetramethyl-guanidine; Zwitterionic salts

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