Cardioprotective Activity of Some 2-Arylimino-1,3-Thiazole Derivatives

Discovery of novel thiazole-pleuromutilin derivatives with potent antibacterial activity

A series of novel thiazole-pleuromutilin derivatives were designed and synthesized, and their antibacterial activities were evaluated. Most of the synthesized derivatives showed good activity against Gram-positive bacteria, among which compound h19 was more prominent and had the strongest antibacterial activity against MRSA. Compound h19 was selected for further evaluation of bacterial time-kill kinetics, and the results demonstrated its highly promising efficacy in inhibiting MRSA growth. Moreover, h19 exhibited a superior post-antibiotic effect (PAE) value and a lower possibility for bacterial resistance development compared to tiamulin. Docking studies demonstrated the strong affinity of h19 for the 50S ribosomal subunit with a binding free energy of -10.6 kcal/mol. The cytotoxic assay indicated that h19 had low cytotoxicity on both HEK293T and HepG2 cells (IC50 > 200 μM). In MRSA systemic-infected mouse model, h19 improved survival rates, reduced the bacterial load, and alleviated pathological changes in the lungs of the infected mice, which exhibited a more potent antibacterial efficacy compared to tiamulin. Compound h19 also displayed low oral toxicity with an LD50 value more than 2000 mg/kg.

From Bench to Bedside: What Do We Know about Imidazothiazole Derivatives So Far?

Imidazothiazole derivatives are becoming increasingly important in therapeutic use due to their outstanding physiological activities. Recently, applying imidazothiazole as the core, researchers have synthesized a series of derivatives with biological effects such as antitumor, anti-infection, anti-inflammatory and antioxidant effects. In this review, we summarize the main pharmacological effects and pharmacological mechanisms of imidazothiazole derivates; the contents summarized herein are intended to advance the research and rational development of imidazothiazole-based drugs in the future.

Horbachevsky Ternopil National Medical University, 1, Maidan Voli, Ternopil, Ukraine, Lviv Polytechnic National University, 12, S. Bandery St., Lviv, Ukraine, National University of Life and Environmental Sciences of Ukraine, Kyiv, Ukraine, Danylo Halytsky Lviv National Medical University, 69, Pekarska St., Lviv, Ukraine, Danylo Halytsky Lviv National Medical University, 69, Pekarska St., Lviv, Ukraine, Institute of Pharmacology and Toxicology, National Academy of Medical Sciences, 14, Anton Tsedik St., Kyiv, Ukraine. Synthesis of New 3-Morpholyl-Substituted 4-Aryl-2-Arylimino-2,3-Dihydrothiazole Derivatives and Their Anti-Inflammatory and Analgesic Activity

New 4-aryl-3-(morpholin-4-yl)-2-arylimino-2,3-dihydrothiazole derivatives 1.1-1.16 were obtained using the Hantzsch reaction by condensation of N-(morpholin-4-yl)-N'-arylthioureas with the corresponding α bromoacetophenones in alcohols. Synthesized hydrobromides 1.1-1.8 were formed as crystalline precipitates during the boiling of the reaction mixture. Bases 1.9-1.16 were obtained by neutralizing the corresponding hydrobromides with NH4OH solution. It has been proposed a possible mechanism of the reaction that is based on the study of the structure of the synthesized compounds. The structures of the synthesized compounds were confirmed by 1H NMR spectroscopy with its special techniques (NOESY and ROESY experiments). It has been shown the formation of the isomer 4-(4'-chlorophenyl)-3-(morpholin-4-yl)-2-(4'-chlorophenylamino)-2.3-dihydrothiazole on the basis of compound 1.14. Pharmacological screening of synthesized derivatives of 4-aryl-2-arylimino-2,3-dihydrothiazole compounds revealed the analgesic effect in the model of visceral pain caused by the introduction of acetic acid to white mice. The anti-inflammatory effect of the synthesized compounds was evaluated in vivo by reducing limb edema in rats with carrageenan-induced inflammation. Thus, the synthesized compounds have analgesic and anti-inflammatory activity.

Thiazole: A Versatile Standalone Moiety Contributing to the Development of Various Drugs and Biologically Active Agents

For many decades, the thiazole moiety has been an important heterocycle in the world of chemistry. The thiazole ring consists of sulfur and nitrogen in such a fashion that the pi (π) electrons are free to move from one bond to other bonds rendering aromatic ring properties. On account of its aromaticity, the ring has many reactive positions where donor–acceptor, nucleophilic, oxidation reactions, etc., may take place. Molecules containing a thiazole ring, when entering physiological systems, behave unpredictably and reset the system differently. These molecules may activate/stop the biochemical pathways and enzymes or stimulate/block the receptors in the biological systems. Therefore, medicinal chemists have been focusing their efforts on thiazole-bearing compounds in order to develop novel therapeutic agents for a variety of pathological conditions. This review attempts to inform the readers on three major classes of thiazole-bearing molecules: Thiazoles as treatment drugs, thiazoles in clinical trials, and thiazoles in preclinical and developmental stages. A compilation of preclinical and developmental thiazole-bearing molecules is presented, focusing on their brief synthetic description and preclinical studies relating to structure-based activity analysis. The authors expect that the current review may succeed in drawing the attention of medicinal chemists to finding new leads, which may later be translated into new drugs.

The synthesis of N-(4-aryl-thiazol-2-yl)-N1-(4,5,6,7-tetrahydro-3H-azepin-2-yl)-hydrazine hydrobromides and the cardioprotective activity of (41-methoxyphenyl-thiazol-2-yl) derivative

A novel series of N-(4-aryl-thiazol-2-yl)-N1-(4,5,6,7-tetrahydro-3Н-azepin-2-yl)-hydrazine derivatives were synthesized by interaction of equimolar quantities of substituted α-bromacetophenones with thiosemicarbazide and characterized on the basis of their elemental analyses and spectral data. Study of cardioprotective activity of the all new products in comparison to levocarnitine and its synthetic analogue mildronate were carried out. Thus, specified results indicate, N-[(41-methoxyphenyl)-thiazol-2-yl)]-N1-(4,5,6,7-tetrahydro-3Н-azepin-2-yl)-hydrazine hydrobromide was influenced deceleration of contractive response of smooth muscles to hypoxia 13.2% more effective than levocarnitine and 6.85% more effective than mildronate and were shown pronounced cardioprotective properties. Obtained data justifies further study of N-(4-aryl-thiazol-2-yl)-N1-(4,5,6,7-tetrahydro-3Н-azepin-yl)-hydrazine derivatives as new potential cardioprotective drugs for treatment of various cardiac diseases.

QSAR-ANALYSIS OF POLYSUBSTITUTED FUNCTIONALIZED AMINOTHIAZOLES WITH ANTIHYPERTENSIVE ACTIVITY

Background. QSAR analysis is an important tool for the identification of pharmacophore fragments in biologically active substances and helps optimize the search for new effective drugs. Objective. The aim of the study was to determine the molecular descriptors for QSAR analysis of polysubstituted functionalized aminothiazoles as a theoretical basis for purposeful search de novo of potential antihypertensive drugs among the investigated compounds. Methods. Calculation of molecular descriptors and QSAR-models creation was carried out using the Hyper-Chem 7.5 and BuildQSAR packages. Results. The calculation of a number of molecular descriptors (electronic, steric, geometric, energy) was performed for 15 new polysubstituted functionalized aminothiazoles, with established in vivo antihypertensive activity. According to the calculated molecular descriptors and antihypertensive activity parameter, the QSAR models were derived НА = a + b ∙ X1 + c ∙ X2 + d ∙ X3 , where the activity parameter НА is antihypertensive activity and X1, X2, X3 are molecular descriptors. Conclusion. The study of ‘the structure - antihypertensive activity’ relationship for polysubstituted functionalized aminothiazoles was carried out. QSAR analysis revealed that volume, area, lipophilicity, dipole moment, refractivity, polarization of the molecule and energy of the lowest unoccupied molecular orbital have the most significant effect on antihypertensive activity. It was suggested that the attained QSAR-models may have antihypertensive activity within abovementioned row of compounds and can be considered as theoretical basis for de novo design of new potential antihypertensive drugs.

Search for angiotensin II receptor antagonists among 4-aryl-n-(aryl)-3-(prop-2-en-1-yl)-2,3-dihydro-1,3-thiazol-2-imine derivatives

The aim of study was to find potential antihypertensive and cardiotropic drugs among new 4-aryl-N-(aryl)-3-(prop-2-en-1-yl)-2,3-dihydro-1,3-thiazol-2-imines.

Materials and methods: The target compounds were synthesized by condensation asymmetrical substituted thioureas with α-bromo-4-R1-acetophenones in ethanol medium. The structure and purity of the compounds synthesized were confirmed by 1H, 13C NMR-spectroscopy and elemental analysis. Docking studies of synthesized compounds to the active site of angiotensin receptor ІІ (PDB ID: 3R8A) were performed in order to find its potential inhibitors and to select promising compounds for experimental screening. Pharmacological studies of the influence on the cardiovascular system were performed.

Results: The results of docking studies indicate a high affinity of all tested substances to the selected biotarget. The thermodynamic probability of binding of synthesized substances to protein 3R8A was confirmed by negative values of scoring functions. Hydrobromide of 4-(4-methoxyphenyl)-N-phenyl-3-(prop-2-en-1-yl)-2,3-dihydro-1,3-thiazol-2-imine 3(1) and hydrobrmide of 4-(4-methoxyphenyl)-N-(4-bromphenyl)-3-(prop-2-en-1-yl)-2,3-dihydro-1,3-thiazol-2-imine 3(3), which have the highest negative values of scoring functions, are recommended for in vivo pharmacological studies. Based on a complete analysis of the geometric location of the synthesized compounds (ligands) in the active site of the angiotensin II receptor, it was found that the complexes are formed with the involvement of Nitrogen atom of imino group, the 1,3-thiazole ring, the phenyl and alkyl moieties of the molecule form hydrogen bonds, intermolecular electrostatic and donor-acceptor interactions. The conducted pharmacological studies of the influence on the cardiovascular system have allowed to confirm the presence of antihypertensive effect inherent in compounds of this series (except for compound 3(2)). The most effective antihypertensive effect, which is similar in duration and strength of the effect of valsartan, was the effect of compound 3(5).

Conclusions: In order to expand the arsenal of biologically active substances of cardiotropic action a systematic series of new 4-aryl-N-(aryl)-3-(prop-2-en-1-yl)-2,3-dihydro-1,3-thiazol-2-imine derivatives were synthesized. The structure and purity of the compounds synthesized were confirmed by 1H, 13C NMR-spectroscopy and elemental analysis. Based on the results of docking studies using Autodock 4.2.6 software, selected compounds with the best affinity for protein biomes (PDB codes: 3R8A) are promising for experimental studies of hypotensive and cardiotropic activity. The most effective antihypertensive effect, which is similar in duration and strength of the effect of valsartan, was the effect of compound 3(5). A comparative analysis of the results of molecular docking and in vivo results suggests that there is a positive correlation between scoring protein inhibition and experimental data.