Synthesis, evaluation of biological activity and SAR of new thioalkyl derivatives of pyridine.

BACKGROUND: Pyridine and its derivatives play a vital role in medicinal chemistry, serving as key scaffolds for drugs. The ability to bind to biological targets makes pyridine compounds significant, sparking interest in creating new pyridine-based drugs. Thus, the purpose of the research is to synthesize new thioalkyl derivatives of pyridine, predict their biological spectrum, study their psychotropic properties, and based on these findings, perform structure-activity relationships to assess pharmacophore functional groups. METHODS: Classical organic methods were employed for synthesizing new thioalkyl derivatives of pyridine, with a multifaceted pharmacological profiles. Various software packages and methods were employed to evaluate the biological spectrum of the newly synthesized compounds. For the evaluation of neurotropic activity of new synthesized compounds, some biological methods were used according to indicators characterizing anticonvulsant, sedative and antianxiety activity as well as side effects. RESULTS: Effective synthetic methods for 6-amino-4-phenyl-2-thio-2H-thiopyran-5-carboxylic acid ethyl ester, 2-amino substituted thiopyridine derivatives and 6-cycloamino-2-thioalkyl-4-phenylnicotinate derivatives were obtained in high yield. Predicted biological spectra and pharmacokinetic data indicated high gastrointestinal absorption and low blood-brain barrier passage for most compounds and demonstrated potential various biological effects, particularly psychotropic properties. Studied compounds demonstrated high anticonvulsant activity through antagonism with pentylenetetrazole. They exhibited low toxicity without inducing muscle relaxation in the studied doses. In psychotropic studies, the compounds displayed activating, sedative, and anxiolytic effects. Notably, the 6-amino-2-thioalkyl-4-phenylnicotinate derivatives demonstrated significant anxiolytic activity (about four times more compared to diazepam). They also exhibited pronounced sedative effects. Ethyl 2-({2-[(diphenylmethyl)amino]-2-oxoethyl}thio)-4-phenyl-6-pyrrolidin-1-ylnicotinate exhibited anxiolytic activity even two times greater than diazepam. Moreover, all studied compounds showed statistically significant antidepressant effects. Noteworthy ethyl 2-({2-oxo-2-[(tetrahydrofuran-2-ylmethyl)amino]ethyl}thio)-4-phenyl-6-pyrrolidin-1-ylnicotinate showcasing its unique psychotropic effect. CONCLUSIONS: The selected compounds demonstrate anticonvulsant properties, activating behavior, and anxiolytic effects, while simultaneously exhibiting antidepressant effects and these compounds as promising candidates for further exploration in the development of therapeutics with a broad spectrum of neuropsychiatric applications.

Synthesis and Psychotropic Properties of Novel Condensed Triazines for Drug Discovery.

The exploration of heterocyclic compounds and their fused analogs, featuring key pharmacophore fragments like pyridine, thiophene, pyrimidine, and triazine rings, is pivotal in medicinal chemistry. These compounds possess a wide array of biological activities, making them an intriguing area of study. The quest for new neurotropic drugs among derivatives of these heterocycles with pharmacophore groups remains a significant research challenge. The aim of this research work was to develop a synthesis method for new heterocyclic compounds, evaluate their neurotropic and neuroprotective activities, study histological changes, and perform docking analysis. Classical organic synthesis methods were used in the creation of novel heterocyclic systems containing pharmacophore rings. To evaluate the neurotropic activity of these synthesized compounds, a range of biological assays were employed. Docking analysis was conducted using various software packages and methodologies. The neuroprotective activity of compound 13 was tested in seizures with and without pentylenetetrazole (PTZ) administration. Histopathological examinations were performed in different experimental groups in the hippocampus and the entorhinal cortex. As a result of chemical reactions, 16 new, tetra- and pentacyclic heterocyclic compounds were obtained. The biologically studied compounds exhibited protection against PTZ seizures as well as some psychotropic effects. The biological assays evidenced that 13 of the 16 studied compounds showed a high anticonvulsant activity by antagonism with PTZ. The toxicity of the compounds was low. According to the results of the study of psychotropic activity, it was found that the selected compounds have a sedative effect, except compound 13, which exhibited activating behavior and antianxiety effects (especially compound 13). The studied compounds exhibited antidepressant effects, especially compound 13, which is similar to diazepam. Histopathological examination showed that compound 13 produced moderate changes in the brain and exhibited neuroprotective effects in the entorhinal cortex against PTZ-induced damage, reducing gliosis and neuronal loss. Docking studies revealed that out of 16 compounds, 3 compounds bound to the γ-aminobutyric acid type A (GABAA) receptor. Thus, the selected compounds demonstrated anticonvulsant, sedative, and activating behavior, and at the same time exhibited antianxiety and antidepressant effects. Compound 13 bound to the GABAA receptor and exhibited antianxiety, antidepressant, and neuroprotective effects in the entorhinal cortex against PTZ-induced changes.

Proton-deuterium exchange of acetone catalyzed in imidazolium-based ionic liquid-D2O mixtures.

The reaction of the proton-deuterium exchange of acetone in imidazolium-based ionic liquid (IL)-deuterium oxide mixtures was studied in detail via NMR spectroscopy. Certain ILs exhibit considerable catalytic properties and contribute to the course of reaction up to the complete deuteration. The efficiency of deuterium exchange crucially depends on the features of ILs; the type of anion and chain length of cation. The linear secondary isotope effects on the NMR chemical shifts of the 13C atoms in acetone were observed depending on the deuteration level of the molecule.

Derivatives of a new heterocyclic system - pyrano[3,4-c][1,2,4]triazolo[4,3-a]pyridines: synthesis, docking analysis and neurotropic activity.

8-Hydrazino derivatives of pyrano[3,4-c]pyridines and derivatives of the new heterocyclic system 3-thioxopyrano[3,4-c][1,2,4]triazolo[4,3-a]pyridines on the basis of methanesulfonates of pyrano[3,4-c]pyridinium were synthesized by optimization of a previously used method. Derivatives of alkylsulfonyl pyrano[3,4-c][1,2,4]triazolo[4,3-a]pyridines were also synthesized. All compounds were evaluated for their neurotropic activity. Among all the compounds tested for anticonvulsant activity by pentylenetetrazole and maximal electric shock seizure (MES) tests, six compounds (5a, 5b, 5e, 5g, 5j, and 5p) appeared to be active. These compounds were also evaluated for their anxiolytic as well as antidepressant activities using "open field", "elevated plus maze" (EPM), and "forced swimming" tests, respectively. It should be mentioned that compounds tested by the "rotating rod" method did not affect neuromuscular coordination. The most active compound appeared to be 5g in all tests. Docking studies of the most active compounds were performed on the GABAA receptor, SERT and 5-HT1A receptor.

Novel amphiphilic cationic porphyrin and its Ag(II) complex as potential anticancer agents.

In the present study we have synthesized a novel amphiphilic porphyrin and its Ag(II) complex through modification of water-soluble porphyrinic structure in order to increase its lipophilicity and in turn pharmacological potency. New cationic non-symmetrical meso-substituted porphyrins were characterized by UV-visible, electrospray ionization mass spectrometry (ESI-MS), (1)H NMR techniques, lipophilicity (thin-layer chromatographic retention factor, Rf), and elemental analysis. The key toxicological profile (i.e. cytotoxicity and cell line- (cancer type-) specificity; genotoxicity; cell cycle effects) of amphiphilic Ag porphyrin was studied in human normal and cancer cell lines of various tissue origins and compared with its water-soluble analog. Structural modification of the molecule from water-soluble to amphiphilic resulted in a certain increase in the cytotoxicity and a decrease in cell line-specificity. Importantly, Ag(II) porphyrin showed less toxicity to normal cells and greater toxicity to their cancerous counterparts as compared to cisplatin. The amphiphilic complex was also not genotoxic and demonstrated a slight cytostatic effect via the cell cycle delay due to the prolongation of S-phase. As expected, the performed structural modification affected also the photocytotoxic activity of metal-free amphiphilic porphyrin. The ligand tested on cancer cell line revealed a dramatic (more than 70-fold) amplification of its phototoxic activity as compared to its water-soluble tetracationic metal-free analog. The compound combines low dark cytotoxicity with 5 fold stronger phototoxicity relative to Chlorin e6 and could be considered as a potential photosensitizer for further development in photodynamic therapy.