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.

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.

No abstract

Satisfactory yields have been obtained in a one pot synthesis of hexahydroquinoleines and unsymmetrical 1,4-dihydropyridines using acidic or basic alumina respectively using catalytic DMF under microwave activation. Results were compared with those obtained following the classical method. The advantages obtained by the use of microwave irradiation were demonstrated. Introduction :

New substituted pyrido[2,3‐d]pyrimidines 5 and 6 have been prepared in one‐step from the readily available 6‐amino‐2,4‐dioxotetrahydropyrimidine (1) or 6‐amino‐4‐oxo‐2‐thioxotetrahydropyrimidine (2) and the arylidene substituted Meldrum's acid. The substitution pattern of the ethylene moiety in compounds 5 and 6 results in a strong push‐pull electronic effect. The semiempirical calculations using the AM1 method reveal two equally favoured conformations showing a distorted geometry. The calculated charge density values confirm the observed 13C nmr chemical shifts.