Synthesis and conformational study of a new class of highly bioactive compounds

Several conformers of the bioactive Morita–Baylis–Hillman adducts (MBHA) 1–4 were studied. Relaxed potential energy surfaces scan (RPESS) have been performed. The principal structures obtained from RPESS approach were then fully optimized at B3LYP/6-311++G∗∗ level and with PCM model simulating water media at B3LYP/6-31+G∗ level. The relative stabilities obtained for conformers 1, 2 and 4 in gas and water media are different. Six and seven member intramolecular hydrogen bonds (IHBs) have been characterized for adducts 1 and 4, respectively, through atoms in molecules (AIM) calculations. The occurrence of such type of IHBs was also supported by IR and 1H NMR spectroscopic data.