Novel acridine derivatives have been synthesized from dimedone and different aromatic aldehydes by following the classical Hantzsch's procedure. The particular substitution pattern of these compounds is responsible for the observed strong push‐pull effect. Quantum chemical calculations were carried out on these molecules by using the AM1 method with complete geometry optimization. The calculated heats of formation reveal two equally favoured conformations. The parameter of planarity and the charge density calculations are in agreement with the 13C nmr spectroscopic data.

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The Brandi reaction is the transformation of spiro[cyclopropane-1,5Ј-isoxazolidines] into tetrahydropyridones under thermal conditions. According to calculations performed by the restricted and unrestricted density functional theory and post-Hartree−Fock single-and multireference methods of ab initio quantum chemistry, the reaction proceeds through two biradical intermediates. These intermediates result from the homolytic cleavage of the N−O bond of the isoxazolidine ring in the first step, and the homolytic cleavage of one of the C−C bonds of the spiro-fused cyclopropane in the second. The activation energy of the rate-determining first step of the parent reaction amounts to about 40 kcal mol −1 at the RDFT/ UDFT level of theory. This energy is not much higher than

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The title compounds 6 have been prepared in a one‐step procedure from the corresponding 4‐aryl substituted 5‐alkoxycarbonyl‐6‐methyl‐3,4‐dihydropyridones 4 in good yields. Quantum chemical calculations reveal a non‐planar molecule with a distorted dihydropyridone ring and two favoured conformations. The 13C nmr data and theoretical calculations support a strong push‐pull effect on the olefinic moiety.