Synthesis, antimicrobial, antioxidant, anti-inflammatory, and analgesic activities of some new 3-(2′-thienyl)pyrazole-based heterocycles

Small molecules containing chalcogen elements (S, Se, Te) as new warhead to fight neglected tropical diseases

Neglected tropical diseases (NTDs) encompass a group of infectious diseases with a protozoan etiology, high incidence, and prevalence in developing countries. As a result, economic factors constitute one of the main obstacles to their management. Endemic countries have high levels of poverty, deprivation and marginalization which affect patients and limit their access to proper medical care. As a matter of fact, statistics remain uncollected in some affected areas due to non-reporting cases. World Health Organization and other organizations proposed a plan for the eradication and control of the vector, although many of these plans were halted by the COVID-19 pandemic. Despite of the available drugs to treat these pathologies, it exists a lack of effectiveness against several parasite strains. Treatment protocols for diseases such as American trypanosomiasis (Chagas disease), leishmaniasis, and human African trypanosomiasis (HAT) have not achieved the desired results. Unfortunately, these drugs present limitations such as side effects, toxicity, teratogenicity, renal, and hepatic impairment, as well as high costs that have hindered the control and eradication of these diseases. This review focuses on the analysis of a collection of scientific shreds of evidence with the aim of identifying novel chalcogen-derived molecules with biological activity against Chagas disease, leishmaniasis and HAT. Compounds illustrated in each figure share the distinction of containing at least one chalcogen element. Sulfur (S), selenium (Se), and tellurium (Te) have been grouped and analyzed in accordance with their design strategy, chemical synthesis process and biological activity. After an exhaustive revision of the related literature on S, Se, and Te compounds, 183 compounds presenting excellent biological performance were gathered against the different causative agents of CD, leishmaniasis and HAT.

Expedition of sulfur-containing heterocyclic derivatives as cytotoxic agents in medicinal chemistry: A decade update

This review article proposes a comprehensive report of the design strategies engaged in the development of various sulfur-bearing cytotoxic agents. The outcomes of various studies depict that the sulfur heterocyclic framework is a fundamental structure in diverse synthetic analogs representing a myriad scope of therapeutic activities. A number of five-, six- and seven-membered sulfur-containing heterocyclic scaffolds, such as thiazoles, thiadiazoles, thiazolidinediones, thiophenes, thiopyrans, benzothiazoles, benzothiophenes, thienopyrimidines, simple and modified phenothiazines, and thiazepines have been discussed. The subsequent studies of the derivatives unveiled their cytotoxic effects through multiple mechanisms (viz. inhibition of tyrosine kinases, topoisomerase I and II, tubulin, COX, DNA synthesis, and PI3K/Akt and Raf/MEK/ERK signaling pathways), and several others. Thus, our concise illustration explains the design strategy and anticancer potential of these five- and six-membered sulfur-containing heterocyclic molecules along with a brief outline on seven-membered sulfur heterocycles. The thorough assessment of antiproliferative activities with the reference drug allows a proficient assessment of the structure-activity relationships (SARs) of the diversely synthesized molecules of the series.

Synthesis, antioxidant, antimicrobial and antiviral docking studies of ethyl 2-(2-(arylidene)hydrazinyl)thiazole-4-carboxylates

A series of ethyl 2-(2-(arylidene)hydrazinyl)thiazole-4-carboxylates (2a-r) was synthesized in two steps from thiosemicarbazones (1a-r), which were cyclized with ethyl bromopyruvate to ethyl 2-(2-(arylidene)hydrazinyl)thiazole-4-carboxylates (2a-r). The structures of compounds (2a-r) were established by FT-IR, ¹H- and ¹³C-NMR. The structure of compound 2a was confirmed by HRMS. The compounds (2a-r) were then evaluated for their antimicrobial and antioxidant assays. The antioxidant studies revealed, ethyl 2-(2-(4-hydroxy-3-methoxybenzylidene)hydrazinyl)thiazole-4-carboxylate (2g) and ethyl 2-(2-(1-phenylethylidene)hydrazinyl)thiazole-4-carboxylate (2h) as promising antioxidant agents with %FRSA: 84.46 ± 0.13 and 74.50 ± 0.37, TAC: 269.08 ± 0.92 and 269.11 ± 0.61 and TRP: 272.34 ± 0.87 and 231.11 ± 0.67 μg AAE/mg dry weight of compound. Beside bioactivities, density functional theory (DFT) methods were used to study the electronic structure and properties of synthesized compounds (2a-m). The potential of synthesized compounds for possible antiviral targets is also predicted through molecular docking methods. The compounds 2e and 2h showed good binding affinities and inhibition constants to be considered as therapeutic target for M^pro protein of SARS-CoV-2 (COVID-19). The present in-depth analysis of synthesized compounds will put them under the spot light for practical applications as antioxidants and the modification in structural motif may open the way for COVID-19 drug.

Synthesis of new pyrazolone and pyrazole-based adamantyl chalcones and antimicrobial activity

Chalcones and their derivatives are becoming increasingly popular due to their various pharmacological effects. Chalcone molecules may be extracted from natural resources, entirely synthesised, or biosynthesised by modifying the natural ones. In the present study, five pyrazole-based adamantyl heterocyclic compounds were synthesised by condensation of 1-adamantyl chalcone with substituted phenylhydrazine. The products were characterised by using ¹H NMR, ¹³C NMR and FT-IR spectroscopy. The microbiological activity of these compounds was investigated against bacteria and fungi. The new compounds showed good to moderate activity against the microbial species used for screening. All developed molecules showed antibacterial activity against Gram-negative and Gram-positive. These molecules showed antifungal activities against Fusarium oxysporum fungus and in a dose-dependent manner, apart from RS-1 molecules which showed compromised antifungal activity and even at a high dose.

The crystal structure of 4-(4-bromophenyl)-2-(3-(4-bromophenyl)-5-(4-fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl)thiazole, C24H16Br2FN3S

C24H16Br2FN3S, monoclinic, P21/n (no. 14), a = 14.9517(9) Å, b = 5.4857(3) Å, c = 27.9582(17) Å, β = 102.434(6)°, V = 2239.4(2) Å3, Z = 4, Rgt (F) = 0.0444, wRref (F 2) = 0.1237, T = 296 K.

Recent advances of thiazole hybrids in biological applications

Thiazoles have attracted much synthetic interest due to their wide variety of biological properties and are important members of heterocyclic compounds. In recent years, studies on the synthesis of thiazole compounds have been increasing because of the properties of this core. In particular, the hybrid structures in which the thiazole ring and the other nuclei are linked have gained popularity. Hybrid structures are formed by the combination of different groups of chemical reactivity and biological activity characteristics. In this review, we highlight recent developments related to hybrid structures containing a thiazole core, recently developed as anticancer, antibacterial, anti-inflammatory, analgesic, anti-tubercular, antialzheimer and antidiabetic compounds.

Design and Synthesis of New Benzophenone Derivatives with In Vivo Anti-Inflammatory Activity through Dual Inhibition of Edema and Neutrophil Recruitment

A series of novel benzophenone derivatives containing a thiazole heterocyclic nucleus were designed by molecular hybridization. Molecular docking studies have demonstrated the inhibitory potential of the designed compounds against cyclooxygenase (COX) isoenzymes. These compounds were synthesized, characterized, and evaluated for their anti-inflammatory properties by the croton oil-induced ear edema assay to examine their effect on both prostaglandin (PG) production and neutrophils recruitment. The thiazole derivatives displayed a potent effect in terms of reducing ear edema. The analysis suggested that the presence of 4-phenyl-2-hydrazinothiazole and the absence of C4'-OCH₃ on the benzophenone derivative structure are strongly related to the inhibition of PG production. In addition, the derivatives 2e, 3a and 3c concomitantly inhibit PG production and neutrophil recruitment, which may be a mechanism of action better than of common NSAIDs due to their inability to inhibit the neutrophil recruitment. Thus, these compounds can be considered as potential lead compounds toward the development of new anti-inflammatory drugs with an innovating mechanism of action.

(E)-2-Benzoyl-3-[1-phenyl-3-(thiophen-2-yl)-1H-pyrazol-4-yl]acrylonitrile

The asymmetric unit of the title compound, C23H15N3OS, consists of two crystallographically independent molecules, which are related by a pseudo-inversion centre. In one molecule, the pyrazolyl ring makes dihedral angles of 35.7 (4), 19.1 (1) and 47.3 (1)°, respectively, with the thiophenyl ring, the attached phenyl ring and the phenyl ring of the benzoyl group. In the second molecule, the corresponding values are 37.4 (1), 16.1 (1) and 48.2 (1)°, respectively. In the crystal, the two independent molecules are linked to each otherviaa π–π interaction between the pyrazolyl rings [centroid–centroid distance = 3.578 (12) Å]. Weak intermolecular C—H...O interactions are also observed. The thiophenyl ring of one molecule is disordered over two orientations, with a refined occupancy ratio of 0.768 (3):0.232 (3).

A review on antioxidant potential of bioactive heterocycle benzofuran: Natural and synthetic derivatives

The majority of heterocycle compounds and typically common heterocycle fragments present in most pharmaceuticals currently marketed, alongside with their intrinsic versatility and unique physicochemical properties, have poised them as true cornerstones of medicinal chemistry. In this context, oxygen heterocycles exhibit diverse biological and pharmacological activities due in part to the similarities with many natural and synthetic molecules with known biological activity. Among oxygen containing heterocycles, benzofuran (synthetic and natural isolated) and its derivatives have attracted medicinal chemists and pharmacologists due to their pronounced biological activities and their potential applications as pharmacological agents such as antioxidant, antitumor, antiplatelet, antimalarial, antiinflammatory, antidepressant and anticonvulsant properties. There are also an amazing number of approved benzofuran-containing drugs in the market as well as compounds currently going through different clinical phases or registration statuses. Due to the wide range of biological activities of benzofurans, their structure activity relationships have generated interest among medicinal chemists, and this has culminated in the discovery of several lead molecules in numerous disease conditions. Recently, this scaffold has emerged as a pharmacophore of choice for designing antioxidant drug development as their derivatives have shown excellent results through different mechanism of action. This review focused on the recent development of benzofuran derivatives as antioxidant agents (including natural products) and their antioxidant activities; summarize the structure property, hoping to inspire new and even more creative approaches. Also, this study systematically provides a comprehensive report on current developments in benzofuran-based compounds as antioxidant agents and is also helpful for the researchers working on a substitution pattern around the nucleus, with an aim to help medicinal chemists to develop structure activity relationships (SAR) on these derivatives as antioxidant drugs.

Synthesis and Structure-Activity Relationship of Some New Thiophene-Based Heterocycles as Potential Antimicrobial Agents

Several new pyrazole, pyridine, [1,2,4]triazolo[1,5-α]pyrimidine, benzimidazo[1,2-a]pyrimidine and 1,2,4-triazolo[3,4-c][1,2,4]triazine derivatives incorporating a thiophene moiety were synthesized from (E)-ethyl 5-(3-(dimethylamino)acryloyl)-4-phenyl-2-(phenylamino)thiophene-3-carboxylate (1). The structures of the newly synthesized compounds were confirmed by IR, ¹H-, ¹³C-NMR, mass spectral data and elemental analysis. The antibacterial and antifungal activities of all the synthesized compounds were evaluated. The results indicated that compounds 9, 12, and 19 were found to be more potent than the standard drug Amphotericin B against Aspergillus fumigates. Additionally, compound 12 exhibited higher activity than the standard drug Amphotericin B against Syncephalastrum racemosum.

Synthetic approaches, structure activity relationship and biological applications for pharmacologically attractive pyrazole/pyrazoline-thiazolidine-based hybrids

The features of the chemistry of 4-thiazolidinone and pyrazole/pyrazolines as pharmacologically attractive scaffolds were described in a number of reviews in which the main approaches to the synthesis of mentioned heterocycles and their biological activity were analyzed. However, the pyrazole/pyrazoline–thiazolidine-based hybrids as biologically active compounds is poorly discussed in the context of pharmacophore hybrid approach. Therefore, the purpose of this review is to summarize the data about the synthesis and modification of heterocyclic systems with thiazolidine and pyrazoline or pyrazole fragments in molecules as promising objects of modern bioorganic and medicinal chemistry. The description of biological activity was focused on SAR analysis and mechanistic insights of mentioned hybrids.

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Synthesis and chemistry of pyrazole/pyrazoline–thiazolidine-based hybrids.

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A diverse spectrum of pyrazole/pyrazoline–thiazolidine-based hybrids biological activities has been presented.

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Structure activity relationship of pyrazole/pyrazoline–thiazolidine-based hybrids for different activities has been discussed.

Design, synthesis, computational calculation and biological evaluation of some novel 2-thiazolyl hydrazones

In the present study a novel series of 1-(1-(4-isobutylphenyl)ethylidene)-2-(4-phenylthiazol-2-yl)hydrazine 2a and its derivatives 2b-2f have been synthesized by the cyclization of 1-(1-(4-isobutylphenyl)ethylidene)thiosemicarbazide with 2-bromoacetophenone/ 4-substituted 2-bromoacetophenones. The structures of the synthesized thiazolyl hydrazones 2a-2f were characterized by FT-IR, (1)H, (13)C NMR, 2D NMR and mass spectral techniques. The molecular geometries were also investigated theoretically using B3LYP functional with 6-311G(d,p) basis set. To explain the molecular properties energy gap (Eg), electronegativity (χ), hardness (g), electrophilicity (ω) and softness (S) were computed, natural bonding orbital (NBO) analysis and molecular electrostatic potential (MEP) were also performed at the same level of theory. All the synthesized thiazolyl hydrazones 2a-2f were screened for their in vitro antimicrobial activity against selected bacterial and fungal strains. The results showed that the heterocyclic thiazolyl hydrazone derivatives exhibit a promising selective inhibitory activity against various bacterial and fungal strains.

Synthesis and anticancer activity of di(3-thienyl)methanol and di(3-thienyl)methane

Di(3-thienyl)methanol (2) and di(3-thienyl)methane (3) have been synthesized and screened against the T98G (brain cancer) cell line. Treatment induced cell death (MTT and macro-colony assay), growth inhibition, cytogenetic damage (micronuclei formation), were studied as cellular response parameters. Treatment with the compounds enhanced growth inhibition and cell death in a concentration dependent manner in both T98G and HEK (normal) cell lines. At higher concentrations (>20 µg/mL) the cytotoxic effects of the compounds were highly significant. The effect on clonogenic capacity and micronuclei formation observed after treatment of cells. Amongst the compounds, compound 2 exhibited potent activity against T98G brain cancer cells. Despite potent in vitro activity, both compounds exhibited less cytotoxicity against normal human HEK cells at all effective concentrations.