Synthesis and Antimicrobial Activity of New Derivatives of 1,3,4-Thiadiazoles and 1,2,4-Triazoles with 5-Nitroindazole as Support

Synthesis and anthelmintic activity of novel thiosemicarbazide and 1,2,4-triazole derivatives: In vitro, in vivo, and in silico study

INTRODUCTION

Intestinal parasitic infections are neglected diseases and, due to the increasing resistance of parasites to available drugs, they pose an increasing therapeutic challenge. Therefore, there is a great need for finding new compounds with antiparasitic activity.

OBJECTIVES

In this work, new thiosemicarbazide and 1,2,4-triazole derivatives were synthesized and tested for their anthelmintic activity.

METHODS

The synthesis was carried out by classical methods of organic chemistry. Anthelmintic activity tests were carried out in vitro (Rhabditis sp., Haemonchus contortus, Strongylidae sp.) in vivo (Heligmosomoides polygyrus/bakeri), and in silico analysis was performed.

RESULTS

Quinoline-6-carboxylic acid derivative compounds were designed and synthesized. The highest activity in the screening tests in the Rhabditis model was demonstrated by compound II-1 with a methoxyphenyl substituent LC50 = 0.3 mg/mL. In the next stage of the research, compound II-1 was analyzed in the H. contortus model. The results showed that compound II-1 was active and had ovicidal (percentage of dead eggs > 45 %) and larvicidal (percentage of dead larvae > 75 %) properties. Studies in the Strongylidae sp. model confirmed the ovicidal activity of compound II-1 (percentage of dead eggs ≥ 55 %). In vivo studies conducted in the H. polygyrus/bakeri nematode model showed that the number of nematodes decreased by an average of 30 % under the influence of compound II-1. In silico studies have shown two possible modes of action of compound II-1, i.e. inhibition of tubulin polymerization and SDH. The test compound did not show any systemic toxic effects. Its influence on drug metabolism related to the activity of cytochrome CYP450 enzymes was also investigated.

CONCLUSION

The results obtained in the in vitro, in vivo, and in silico studies indicate that the test compound can be described as a HIT, which in the future may be used in the treatment of parasitic diseases in humans and animals.

New Semisynthetic Penicillins Obtained by Coupling of the 6-Aminopenicillanic Acid with 5-Mercapto-1,2,4-triazoles-3,4-disubstituted

In a basic medium, 5-Mercapto-1,2,4-triazoles pass into the thiol form, allowing their transformation into sodium salts, which, in reaction with sodium monochloroacetate, lead to sodium 5-thioacetates of 1,2,4-triazoles-3,4-disubstituted. Sulfur derivatives converted to pivalic mixed anhydrides were used as active forms in the acylation of 6-amino penicillanic acid (6-AP) to obtain new semisynthetic penicillins. They contain in the molecule, together with the β-lactam ring, the nucleus 3-[(5-nitroindazol-1'-yl-methyl)]-4-aryl-5-mercapto-1,2,4-triazole, both contributing to an important antibacterial effect. The structure of the new antibiotics was confirmed by the results of elemental and spectral analysis (FT-IR, ¹H- and ¹³C-NMR). The synthetic penicillins were tested for toxicological action and antibacterial activity and the obtained results were close to those for amoxicillin, the reference drug.

Optimized Synthesis of New Thiosemicarbazide Derivatives with Tuberculostatic Activity

Original results are presented in the field of research that addresses the extension of the reaction of residue of acyl-thiosemicarbazide fixation on the structure of 5-nitrobenzimidazole by a sulphonic group. The aim of the study is the increase of new thiosemicarbazide derivatives’ applicative potential in the field of biochemistry, with a wide range of medical applications. The newly obtained compounds were characterized by using elemental analysis and spectral analysis (FT-IR and ¹H NMR). A study regarding the optimization of the chemical reactions was made. The performed in vitro biological tests confirmed the tuberculostatic activity of three newly obtained compounds against Mycobacterium tuberculosis.

Immobilization and Release Studies of Triazole Derivatives from Grafted Copolymer Based on Gellan-Carrying Betaine Units

New polymer-bioactive compound systems were obtained by immobilization of triazole derivatives onto grafted copolymers and grafted copolymers carrying betaine units based on gellan and N-vinylimidazole. For preparation of bioactive compound, two new types of heterocyclic thio-derivatives with different substituents were combined in a single molecule to increase the selectivity of the biological action. The 5-aryl-amino-1,3,4 thiadiazole and 5-mercapto-1,2,4-triazole derivatives, each containing 2-mercapto-benzoxazole nucleus, were prepared by an intramolecular cyclization of thiosemicarbazides-1,4 disubstituted in acidic and basic medium. The structures of the new bioactive compounds were confirmed by elemental and spectral analysis (FT-IR and 1H-NMR). The antimicrobial activity of 1,3,4 thiadiazoles and 1,2,4 triazoles was tested on gram-positive and gram-negative bacteria. The triazole compound was chosen to be immobilized onto polymeric particles by adsorption. The Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherm were used to describe the adsorption equilibrium. Also, the pseudo-first and pseudo-second models were used to elucidate the adsorption mechanism of triazole onto grafted copolymer based on N-vinylimidazole and gellan (PG copolymer) and grafted copolymers carrying betaine units (PGB1 copolymer). In vitro release studies have shown that the release mechanism of triazole from PG and PGB1 copolymers is characteristic of an anomalous transport mechanism.

New Quinoline-Based Heterocycles as Anticancer Agents Targeting Bcl-2

The Bcl-2 protein has been studied as an anticancer drug target in recent years, due to its gatekeeper role in resisting programmed cancer cell death (apoptosis), and the design of BH3 domain mimetics has led to the clinical approval of Venetoclax (ABT-199) for the treatment of chronic lymphocytic leukaemia. In this work we extend our previous studies on the discovery of indole-based heterocycles as Bcl-2 inhibitors, to the identification of quinolin-4-yl based oxadiazole and triazole analogues. Target compounds were readily synthesized via a common aryl-substituted quinolin-4-carbonyl-N-arylhydrazine-1-carbothioamide (5a–b) intermediate, through simple variation of the basic cyclisation conditions. Some of the quinoline-based oxadiazole analogues (e.g. compound 6i) were found to exhibit sub-micromolar anti-proliferative activity in Bcl-2-expressing cancer cell lines, and sub-micromolar IC₅₀ activity within a Bcl2-Bim peptide ELISA assay. The Bcl-2 targeted anticancer activity of 6i was further rationalised via computational molecular modelling, offering possibilities to extend this work into the design of further potent and selective Bcl-2 inhibitory heteroaromatics with therapeutic potential.

Synthesis and antibacterial activity of novel 4-bromo-1H-indazole derivatives as FtsZ inhibitors

A series of novel 4-bromo-1H-indazole derivatives as filamentous temperature-sensitive protein Z (FtsZ) inhibitors were designed, synthesized, and assayed for their in vitro antibacterial activity against various phenotypes of Gram-positive and Gram-negative bacteria and their cell division inhibitory activity. The results indicated that this series showed better antibacterial activity against Staphylococcus epidermidis and penicillin-susceptible Streptococcus pyogenes than the other tested strains. Among them, compounds 12 and 18 exhibited 256-fold and 256-fold more potent activity than 3-methoxybenzamide (3-MBA) against penicillin-resistant Staphylococcus aureus, and compound 18 showed 64-fold better activity than 3-MBA but 4-fold weaker activity than ciprofloxacin in the inhibition of S. aureus ATCC29213. Particularly, compound 9 presented the best activity (4 µg/mL) against S. pyogenes PS, being 32-fold, 32-fold, and 2-fold more active than 3-MBA, curcumin, and ciprofloxacin, respectively, but it was four times less active than oxacillin sodium. In addition, some synthesized compounds displayed moderate inhibition of cell division against S. aureus ATCC25923, Escherichia coli ATCC25922, and Pseudomonas aeruginosa ATCC27853, sharing a minimum cell division concentration of 128 µg/mL.

The effect of 5-nitroindazole as an inhibitor for the corrosion of copper in a 3.0% NaCl solution

A new environment-friendly inhibitor which can prevent the chloride corrosion of copper significantly.