Vanillic Mannich bases were catalytically synthesized, and their cytotoxic and antioxidative activities examined.

Diethanolammonium hydrogensulfate (DHS), as a liquid salt, and glycolic acid (GA) were used for the synthesis of highly functionalized tetrahydropyridines (THPs). Due to the simplicity of the reaction procedure, excellent diastereoselectivity, and catalyst regeneration, these green protocols may be considered as an attractive approach for the preparation of THPs. Unlike numerous reported reactions for the synthesis of THPs that last for hours and with heating, GA‐promoted reactions finished mostly within an hour and at room temperature. As improvement to other organocatalysed reactions for the synthesis of THPs with moderate yields, this protocol provided good to excellent yields. Application of these procedures produced three vanillic compounds reported here for the first time. Their structure was elucidated based on experimental and theoretical data (IR, 1H NMR, 13C NMR, NOESY, UV‐Vis, and DFT). Experimental and theoretical antioxidant evaluation of these compounds has been carried out. DFT thermodynamical parameters supported experimental results that newly synthesized THPs deserve considerable attention as potent radical scavengers.

ARTICLE This journal isThe four trans chelate N, O-palladium(II) complexes were synthetized starting from salicylaldehyde anil Schiff bases, as ligands. Their structure was elucidated using experimental and theoretical tools. The structures of the theoretically possible cis isomers are examined using DFT method. The biological activity, in vitro cytotoxic and prooxidative effects against human breast carcinoma MDA-MB-231, human colon carcinoma HCT-116, and human fibroblast healthy MRC-5 cell lines of investigated compounds were determined. Schiff bases show moderate or weak cytotoxic effect. On the other hand, complexes Pd-1 and Pd-6 show significant cytotoxic effect on all three cell lines, with IC 50 values in range of 0.6 to 17.1 µM on HCT-116 cells, 7.2 to 55.6 µM on MDA-MB-231 cells and 34.5 to 48.1 µM on MRC-5 cells. Also, Pd-1 and Pd-6 induce extreme oxidative stress in the all treated cell lines. At this stage of investigations, Pd-1 and Pd-6 showed no selectivity towards cancer cells, i.e. they were also cytotoxic to MRC-5 cells in the similar extent. Taking into account these facts, it could be further investigated how the most active substances impact on the type of the cell death (apoptotic and/or necrotic pathways).

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