A series of 3-substituted-5-(4-carboxycyclohexylmethyl)-tetrahydro-2H-1,3,5thiadiazine-2-thione derivatives was prepared and examined for antifibrinolytic and antimicrobial activities. Their structures were elucidated by spectral methods. Antifibrinolytic activities of these compounds, were investigated in vitro and compared to tranexamic acid (CAS 1197-18-8). Among the synthesized compounds, 3-methyl-5-(4-carboxycyclohexylmethyl)-tetrahydro-2H-1,3,5-thiadiazine-2-thione (Ia) was the most prominent one (104%) when compared to tranexamic acid. Besides, 3-ethyl-5-(4-carboxycyclohexyl-methyl)-tetrahydro-2H-1,3,5-thiadiazine-2-thione (Ib), 3-iso-propyl-5-(4-carboxycyclohexylmethyl)-tetrahydro-2H-1,3,5-thiadiazine-2-thione (Id) and 3-isobutyl-5-(4-carboxycyclohexyl-methyl)-tetrahydro-2H-1,3,5-thiadiazine-2-thione (Ig) showed antifibrinolytic activity similar to tranexamic acid. Antibacterial activities of these compounds against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis), Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa) and yeast-like fungi (Candida albicans, Candida tropicalis) were investigated by the micro-dilution method and compared with the activity of tranexamic acid, ofloxacin and fluconazole. By this way their minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and minimal fungicidal concentration (MFC) values were determined. Compound Ia exhibited almost equally potent activity against B. subtilis (MIC and MBC: 6.25 microg/mL). Compounds Ib-Id, If-Ig and In exhibited similar bactericidal activity against B. subtilis (MBC: 12.5 microg/mL). Compounds Ik and Im showed bacteriostatic activity against S. aureus. None of the compounds exhibited activity against Gram-negative bacteria. On the other hand, all compounds had potent antifungal activities against the yeast utilized. Among the synthesized compounds, 3-methyl-5-(4-carboxycyclohexylmethyl)-tetrahydro-2H-1,3,5-thiadiazine-2-thione (Ia) seems to be the most effective compound with antifibrinolytic and antimicrobial activity.

No abstract

In the current study, some novel ethyl 6- [(substituted-phenylpiperazine]-3(2H)-pyridazinone-2-yl propionate III and 6-[(substituted-phenylpiperazine]-3(2H)-pyridazinone-2-yl propionohydrazide IV derivatives were synthesized as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors. The structures of these new pyridazinone derivatives were confirmed by their IR, 1H-NMR spectra and elementary analysis. 6-Substituted-3(2H)-pyridazinone-2-yl propionate IIIa-e derivatives showed significant inhibitory activity against AChE and BChE. 6-[4-(3-Trifluoromethylphenyl)piperazine]-3(2H)-pyridazinone-2-yl propionate IIIe has been found to be the most active compound in terms of inhibition of either AChE or BChE. Compound IIIe exhibited inhibitory activity close to that of galantamine (CAS 357-70-0) and did not show any selectivity between the two enzymes. Also the antimicrobial activities of III and IV derivatives have been evaluated. All III and IV derivatives exhibited poor antibacterial activities but moderate antifungal activities.

Background: Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are known to be serine hydrolase enzymes responsible for the hydrolysis of acetylcholine (ACh), which is a significant neurotransmitter for regulation of cognition in animals. Inhibition of cholinesterases is an effective method to curb Alzheimer’s disease, a progressive and fatal neurological disorder. Objective: In this study, 30 new hydrazone derivatives were synthesized. Then we evaluated their anticholinesterase activity of compounds. We also tried to get insights into binding interactions of the synthesized compounds in the active site of both enzymes by using molecular docking approach. Methods: The compounds were synthesized by the reaction of various substituted/nonsubstituted benzaldehydes with 6-(substitute/nonsubstituephenyl)-3(2H)-pyridazinone-2-yl propiyohydrazide. Anticholinesterase activity of the compounds was determined using Ellman’s method. Molecular docking studies were done by using the ADT package version 1.5.6rc3 and showed by Maestro. RMSD values were obtained using Lamarckian Genetic Algorithm and scoring function of AutoDock 4.2 release 4.2.5.1 software. Results: The activities of the compounds were compared with galantamine as cholinesterase enzyme inhibitor, where some of the compounds showed higher BChE inhibitory activity than galantamine. Compound F111 was shown to be the best BChE inhibitor effective in 50 μM dose, providing 89.43% inhibition of BChE (IC50=4.27±0.36 μM). Conclusion: This study supports that novel hydrazone derivates may be used for the development of new BChE inhibitory agents.

In this study, a series of N‐substituted‐(p‐tolyl)pyridazin‐3(2H)‐one derivatives were synthesized and evaluated for their AChE inhibitory activity. The chemical structures of novel compounds 5(a–m) were confirmed by 1H‐NMR, 13C‐NMR, IR and HRMS analysis. In order to eliminate the symptomatic effects of Alzheimer's disease, the proposed compounds were evaluated by acetylcholinesterase inhibition activity study in accordance with the cholinergic hypothesis. The results revealed that the N‐substituted‐(p‐tolyl)pyridazin‐3(2H)‐one derivatives inhibited the enzymes significantly. Ki values for acetylcholinesterase in the range of 0.56±0.15–4.12±1.42 μM. Compound 5 h demonstrated the greatest in AChE activity compared with tacrine (0.56±0.15 μM). Molecular docking studies were performed for all compounds that compared tacrine in AChE activity in‐vitro. As a result of molecular docking studies (ΔGBind, docking score, XP Gscore, Glide energy, Glide emodel), 5 f, 5 g and 5 h compounds showed good inhibitory properties in the AChE active site as in silico.