Synthesis, Spectroscopic Analysis, and in Vitro/in Silico Biological Studies of Novel Piperidine Derivatives Heterocyclic Schiff-Mannich Base Compounds.

In the present study, 3-substitued-4-(4-hydroxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (S1-8) were synthesized by treating 4-hydroxybenzaldehyde (B) with eight different 3-substitued-4-amino-4,5-dihydro-1H-1,2,4-triazole-5-ones (T1-8) in acetic acid medium, separately. The synthesized Schiff bases (S) were reacted with formaldehyde and secondary amine such as 4-piperidinecarboxyamide to afford novel heterocyclic bases. 3-Substitued-4-(4-hydroxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (T) were treated with 4-piperidinecarboxyamide in the presence of formaldehyde to synthesize eight new 1-(4-piperidinecarboxyamide-1-yl-methyl)-3-substitued-4-(4-hydroxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (M1-8). The structure characterization of compounds was carried out using 1 H-NMR, IR, HR-MS, and 13 C-NMR spectroscopic methods. The inhibitory properties of the newly synthesized compounds were calculated against the acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and glutathione S-transferase (GST) enzymes. Ki values were calculated in the range of 20.06±3.11-36.86±6.17 µM for GST, 17.87±2.91-30.53±4.25 µM for AChE, 9.08±0.69-20.02±2.88 µM for BChE, respectively, Besides, IC50 values were also calculated. Best binding scores of -inhibitors against used enzymes were calculated as -12.095 kcal/mol, -12.775 kcal/mol, and -9.336 kcal/mol, respectively. While 5-oxo-triazole piperidine-4-carboxamide moieties have a critical role in the inhibition of AChE and GST enzymes, hydroxy benzyl moiety is important for BChE enzyme inhibition.

Synthesis, design, and assessment of novel morpholine-derived Mannich bases as multifunctional agents for the potential enzyme inhibitory properties including docking study.

The synthesized Schiff Bases were reacted with formaldehyde and secondary amine such as 2,6-dimethylmorpholine to afford N-Mannich bases through the Mannich reaction. 3-Substitued-4-(4-hydroxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (4) were treated with 2,6-dimethylmorpholine in the presence of formaldehyde to synthesize eight new 1-(2,6-dimethylmorpholino-4-yl-methyl)-3-substitued-4-(4-hydroxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (4a-h). The structures of the synthesized eight new compounds were characterized using IR, 1H NMR, 13C NMR, and HR-MS spectroscopic methods. Synthesized compounds inhibitory activity determined against the acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and glutathione S-transferase (GST) enzymes with Ki values in the range 25.23-42.19 µM for AChE, 19.37-34.22 µM for BChE, and 21.84-41.14 µM for GST, respectively. Binding scores of most active inhibitors against AChE, BChE, and GST enzymes were detected as -10.294 kcal/mol, -9.562 kcal/mol, and -7.112 kcal/mol, respectively. The hydroxybenzylidene moiety of the most active inhibitors caused to inhibition of the enzymes through hydrophobic interaction and hydrogen bond.