Architecture of the rings of 5-arylidenerhodanine derivatives versus P-gp inhibition

5-Arylidene derivatives of rhodanine show various biological activities. The new crystal structures of five derivatives investigated towards ABCB1 efflux pump modulation are reported, namely, 2-[5-([1,1'-biphenyl]-4-ylmethylidene]-4-oxo-2-thioxothiazolidin-3-yl)acetic acid dimethyl sulfoxide monosolvate, C18H13NO3S2·C2H6OS (1), 4-[5-([1,1'-biphenyl]-4-ylmethylidene]-4-oxo-2-thioxothiazolidin-3-yl)butanoic acid, C20H17NO3S2 (2), 5-[4-(benzyloxy)benzylidene]-2-thioxothiazolidin-4-one, C17H13NO2S2 (3), 4-{5-[4-(benzyloxy)benzylidene]-4-oxo-2-thioxothiazolidin-3-yl}butanoic acid, C21H19NO4S2 (4), and 5-[4-(diphenylamino)benzylidene]-2-thioxothiazolidin-4-one, C22H16N2OS2 (5). Compounds 1 and 3-5 crystallize in the triclinic space group P-1, while 2 crystallizes in the monoclinic space group P21/n, where the biphenyl moiety is observed in two positions (A and B). Two molecules are present in the asymmetric unit of 5 and, for the other four compounds, there is only one molecule; moreover, 1 crystallizes with one dimethyl sulfoxide molecule. The packing of the molecules containing a carboxyl group (1, 2 and 4) is determined by O-H...O hydrogen bonds, while in the other two compounds (3 and 5), the packing is determined by N-H...O hydrogen bonds. Additionally, induced-fit docking studies have been performed for the active compounds to investigate their putative binding mode inside the human glycoprotein P (P-gp) binding pocket.

Design, Synthesis, and Antiproliferative Activity of Novel Neocryptolepine-Rhodanine Hybrids

A series of novel neocryptolepine-rhodanine hybrids (9a,b, 11a-d, 14, and 16a,b) have been synthesized by combining neocryptolepine core 5 modified at the C-11 position with rhodanine condensed with the appropriate aryl/hetero aryl aldehydes. Based on these findings, the structures of the hybrids were confirmed by spectral analyses. By employing the MTT assay, all hybrids were tested for their in vitro antiproliferative activity against two cancer cell lines, including MDA-MB-231 (human breast) and HepG-2 (hepatocellular carcinoma). Interestingly, the IC50 values of all hybrids except 9b and 11c showed activity comparable to the standard anticancer drug, 5-fluorouracil, against HepG-2 cancer cells. Furthermore, the cytotoxicity of all the synthesized hybrids was investigated on a normal skin human cell line (BJ-1), and the results showed that these compounds had no significant cytotoxicity toward these healthy cells at the highest concentration used in this study. This study also indicated that the active hybrids exert their cytotoxic activity via the induction of apoptosis. A molecular docking study was used to shed light on the molecular mechanism of their anticancer activity. The docking results revealed that the hybrids exert their mode of action through DNA intercalation. Furthermore, in silico assessment for pharmacokinetic properties was performed on the most potent compounds, which revealed candidates with good bioavailability, high tolerability with cell membranes, and positive drug-likeness values.

Sulfonamide-Derived Dithiocarbamate Gold(I) Complexes Induce the Apoptosis of Colon Cancer Cells by the Activation of Caspase 3 and Redox Imbalance

Two new families of dithiocarbamate gold(I) complexes derived from benzenesulfonamide with phosphine or carbene as ancillary ligands have been synthesized and characterized. In the screening of their in vitro activity on human colon carcinoma cells (Caco-2), we found that the more lipophilic complexes—those with the phosphine PPh₃—exhibited the highest anticancer activity whilst also displaying significant cancer cell selectivity. [Au(S₂CNHSO₂C₆H₅)(PPh₃)] (1) and [Au(S₂CNHSO₂-p-Me-C₆H₄)(IMePropargyl)] (8) produce cell death, probably by intrinsic apoptosis (mitochondrial membrane potential modification) and caspase 3 activation, causing cell cycle arrest in the G1 phase with p53 activation. Besides this, both complexes might act as multi-target anticancer drugs, as they inhibit the activity of the enzymes thioredoxin reductase (TrxR) and carbonic anhydrase (CA IX) with the alteration of the redox balance, and show a pro-oxidant effect.

Syntheses, in vitro, and in silico studies of rhodanine-based schiff bases as potential α-amylase inhibitors and radicals (DPPH and ABTS) scavengers

A two-step reaction method was used to synthesize a series of rhodanine-based Schiff bases (2-33) that were characterized using spectroscopic techniques. All compounds were assessed for α-amylase inhibitory and radical scavenging (DPPH and ABTS) activities. In comparison to the standard acarbose (IC₅₀ = 9.08 ± 0.07 µM), all compounds demonstrated good to moderate α-amylase inhibitory activity (IC₅₀ = 10.91 ± 0.08-61.89 ± 0.102 µM). Compounds also demonstrated significantly higher DPPH (IC₅₀ = 10.33 ± 0.02-96.65 ± 0.03 µM) and ABTS (IC₅₀ = 12.01 ± 0.12-97.47 ± 0.13 µM) radical scavenging activities than ascorbic acid (DPPH, IC₅₀ = 15.08 ± 0.03 µM; ABTS, IC₅₀ = 16.09 ± 0.17 µM). The limited structure-activity relationship (SAR) suggests that the position and nature of the substituted groups on the phenyl ring have a vital role in varying inhibitory potential. Among the series, compounds with an electron-withdrawing group at the para position showed the highest potency. Kinetic studies revealed that the compounds followed a competitive mode of inhibition. Molecular docking results are found to agree with experimental findings, showing that compounds reside in the active pocket due to the main rhodanine moiety.

Discovery of Cinnamylidene Derivative of Rhodanine with High Anthelmintic Activity against Rhabditis sp

The treatment of parasitic infections requires the application of chemotherapy. In view of increasing resistance to currently in-use drugs, there is a constant need to search for new compounds with anthelmintic activity. A series of 16 cinnamylidene derivatives of rhodanine, including newly synthesized methoxy derivatives (1-11) and previously obtained chloro, nitro, and diethylamine derivatives (12-16), was investigated towards anthelmintic activity. Compounds (1-16) were evaluated against free-living nematodes of the genus Rhabditis sp. In the tested group of rhodanine derivatives, only compound 2 shows very high biological activity (LC50 = 0.93 µg/µL), which is higher than the reference drug albendazole (LC50 = 19.24 µg/µL). Crystal structures of two compounds, active 2 and inactive 4, were determined by the X-ray diffraction method to compare molecular geometry and search for differences responsible for observed biological activity/inactivity. Molecular modelling and selected physicochemical properties prediction were performed to assess the potential mechanism of action and applied in the search for an explanation as to why amongst all similar compounds only one is active. We can conclude that the tested compound 2 can be further investigated as a potential anthelmintic drug.

The Importance of Rhodanine Scaffold in Medicinal Chemistry: A Comprehensive Overview

After the clinical use of epalrestat that contains a rhodanine ring, in type II diabetes mellitus and diabetic complications, rhodanin-based compounds have become an important class of heterocyclic in the field of medicinal chemistry. Various modifications to the rhodanine ring have led to a broad spectrum of biological activity of these compounds. Synthesis of rhodanine derivatives, depended on advenced throughput scanning hits, frequently causes potent and selective modulators of targeted enzymes or receptors, which apply their pharmacological activities through different mechanisms of action. Rhodanine-based compounds will likely stay a privileged scaffold in drug discovery because of different probability of chemical modifications of the rhodanine ring. We have, therefore reviewed their biological activities and structure activity relationship.

An insight into medicinal attributes of dithiocarbamates: Bird's eye view

Dithiocarbamates are considered as an important motif owing to its extensive biological applications in medicinal chemistry. The synthesis of this framework can easily be achieved via a one-pot reaction of primary/secondary amines, CS₂, and alkyl halides under catalyst-free conditions or sometimes in the presence of a base. By virtue of its colossal pharmacological scope, it has been an evolving subject of interest for many researchers around the world. The present review aims to highlight various synthetic approaches for dithiocarbamates with the major emphasis on medicinal attributes of these architectures as leads in the drug discovery of small molecules such as HDAC inhibitor, lysine-specific demethylase 1 (LSD1) down-regulator, kinase inhibitor (focal adhesion kinase, pyruvate kinase, Bruton's tyrosine kinase), carbonic anhydrase inhibitor, DNA intercalators, and apoptosis-inducing agents. Moreover, recent medicinal advancements in the synthesis of dithiocarbamate derivatives as anticancer, antifungal, antibacterial, anti-Alzheimer, antitubercular, anti-glaucoma, anti-cholinergic, antihyperglycemic, anti-inflammatory activities have been elaborated with notable examples.

Recent advances in the catalytic asymmetric reactions of thiazolone derivatives

Thiazolones as a class of five-membered heterocyclic compounds containing both nitrogen and sulfur, have been proved to possess important biological activities. Because thiazolone molecules have many reaction sites, they can carry out a series of modification reactions, which makes them good reaction substrates for various molecular syntheses. In recent years, research on the use of asymmetric organocatalysis to construct thiazolone derivatives has attracted a lot of attention. Among these, some breakthrough results have been achieved in the asymmetric synthesis of thiazolone derivatives. This review highlights recent developments in thiazolone derivatives in asymmetric reactions, including Michael additions, Mannich reactions as well as various cascade reactions.

Design and synthesis of new drugs inhibitors of Candida albicans hyphae and biofilm formation by upregulating the expression of TUP1 transcription repressor gene

Candida albicans is a common human fungal pathogen that causes disease ranging from superficial to lethal infections. C. albicans grows as budding yeast which can transform into hyphae in response to various environmental or biological stimuli. Although both forms have been associated with virulence, the hyphae form is responsible for the formation of multi-drug resistance biofilm. Here, new compounds were designed to selectively inhibit C. albicans hyphae formation without affecting human cells to afford sufficient safety. The newly designed 5-[3-substitued-4-(4-substituedbenzyloxy)-benzylidene]-2-thioxo-thiazolidin-4-one derivatives, named SR, showed very specific and effective inhibition activity against C. albicans hyphae formation. SR compounds caused hyphae inhibition activity at concentrations 10-40 fold lower than the concentration required to inhibit Candida yeast and bacterial growths. The anti-hyphae inhibition activities of SR compounds were via activation of the hyphae transcription repressor gene, TUP1. Correlation studies between the expression of TUP1 gene and the activity of SR compounds confirmed that the anti-C. albicans activities of SR compounds were via inhibition of hyphae formation. The newly designed SR compounds showed 10-40% haemolytic activity on human erythrocytes when compared to 100% haemolysis by 0.1% triton employed as positive control. Furthermore, theoretical prediction of absorption, distribution, metabolism, excretion, and toxicity (ADMET) of SR compounds confirmed their safety, efficient metabolism and possible oral bioavailability. With the minimal toxicity and significant activity of the newly-designed SR compounds, a future optimization of pharmaceutical formulation may develop a promising inhibitor of hyphal formation not only for C. albicans but also for other TUP1- dependent dimorphic fungal infections.

Green Synthesis, Biological Activity Evaluation, and Molecular Docking Studies of Aryl Alkylidene 2, 4-thiazolidinedione and Rhodanine Derivatives as Antimicrobial Agents

AIMS AND OBJECTIVE

The magic scaffolds rhodanine and thiazolidine are very important heterocyclic compounds in drug design and discovery. Those are important heterocyclic compounds that have attracted a great deal of attention due to the fact that they exhibit a variety of bioactivities including antibacterial, antifungal, antiviral, antimalarial, and anti-inflammatory activities. These agents often exhibit selective toxicity. The goal of this study was molecular docking, green and solvent-free efficient synthesis of a new series of hetero/aromatic substituted rhodanine and thiazolidine analogues and then investigation of their antimicrobial activity.

MATERIALS AND METHODS

To a mixture of TZD or rhodanine (1 mmol) in the presence of ionic liquid ChCl/urea, various aldehyde (1 mmol) was added. After completion of the reaction, obtained crude compound was collected by filtration and products were recrystallized from ethanol. The binding-free energy between all synthesized compounds with 3EEJ protein (C. glabrata enzyme) were obtained by molecular docking studies. These compounds were evaluated using microdilution method against (ATCC 6538) and (ATCC 12228) Gram-negative, (ATCC 8739) and (ATCC 9027) as Gram-positive and (ATCC 1012), (ATCC 339), C. (ATCC 1057), (ATCC 503), (ATCC 340) and (ATCC 194) as fungi.

RESULTS

All of the acceptable products were determined by 1H NMR, 13C NMR, Mas and FT-IR spectroscopy. The binding-free energy between compounds 10a and 10b with 3EEJ protein were found to be -8.08 kcal/mol and -8.15 kcal/mol, respectively. These compounds having a heteroaromatic ring attached to the TZD or rhodanine core showed excellent antimicrobial activity with MIC values of 0.25-8 μg/mL (compound 10a) and 0.5-16 μg/mL (compound 10b) against the most tested fungi strains, Gram-positive and Gram-negative bacteria.

CONCLUSION

A convenient and rapid method has been developed for the synthesis of rhodanine and thiazolidine-2,4-dione (TZD) derivatives as efficient antimicrobial agents using a Deep Eutectic Ionic Liquids (DEILs) choline chloride urea under solvent-free condition. Among the newly synthesized compounds, (Z)-5-((quinoxalin-3-yl) methylene) thiazolidine-2, 4-dione (10a) and (Z)- 5- ((quinoxalin-3-yl) methylene)-2-thioxothiazolidin-one (10b) exerted the promising effect and these compounds can be considered to be further probed as inhibitors of cgDHFR enzyme.

Synthesis and antimicrobial activity of novel thienopyrimidine linked rhodanine derivatives

This work presents the preparation of a new series of N-(substituted phenyl)-2-(4-oxo-5-(4-(thieno[2,3-d]-pyrimidin-4-yloxy)benzylidene)-2-thioxothiazolidin-3-yl)acetamide derivatives (8a–8l). A condensation reaction of thienopyrimidin-2-thioxothiazolidin-4-one derivative (5) with various 2-chloro-N-phenylacetamides (7a–7l) was employed to afford the new thienopyrimidine tagged rhodanine derivatives under acetone solvent in the presence of potassium carbonate (K2CO3). All of the novel target molecules were characterized by IR, 1H NMR, 13C NMR, and LC–MS spectral analyses and were screened for their in vitro antimicrobial activity by using the broth dilution method. Compounds 8c, 8g, and 8h found to have antibacterial potency against E. coli, B. subtilis, B. cereus, and K. pneumonia with minimum inhibitory concentrations (MICs) of 3.25–6.25 μg/mL compared with the standard Gentamicin. Compounds 8c and 8f demonstrated better antifungal potency (MIC = 3.25–6.25 μg/mL) against A. flavus, A. niger, P. marneffei, and C. albicans when compared with Fluconazole.

Synthesis and antibacterial activity of new (2,4-dioxothiazolidin-5-yl/ylidene)acetic acid derivatives with thiazolidine-2,4-dione, rhodanine and 2-thiohydantoin moieties

A series of new (2,4-dioxothiazolidin-5-yl/ylidene)acetic acid derivatives with thiazolidine-2,4-dione, rhodanine and 2-thiohydantoin moiety (28–65) were synthesized by the reaction of (2,4-dioxothiazolidin-5-yl/ylidene)acetic acid chlorides with 5-(hydroxybenzylidene) thiazolidine-2,4-dione, rhodanine and 2-thiohydantoin derivatives. Obtained compounds (28–65) were tested on reference strains of Gram-positive bacteria and ones of the Gram-negative bacteria. The antibacterial activity of target compounds was determined by broth microdilution method. These derivatives showed antibacterial activity generally against Gram-positive bacterial strains. Most active compounds possess MIC = 3.91 mg/L. Our results suggest that presence of electron-withdrawing substituent at phenyl ring is favorable while geometry of molecule does not play important role in antibacterial response. It was confirmed the lack of direct influence of substitution pattern at phenyl ring on antibacterial activity of closely related compounds of series 1–3. The antibacterial activity of some compounds was similar or higher than the activity of commonly used reference drugs such as oxacillin and cefuroxime.

Design, Synthesis and Antifungal Activity Evaluation of New Thiazolin-4-ones as Potential Lanosterol 14α-Demethylase Inhibitors

Twenty-three thiazolin-4-ones were synthesized starting from phenylthioamide or thiourea derivatives by condensation with α-monochloroacetic acid or ethyl α-bromoacetate, followed by substitution in position 5 with various arylidene moieties. All the synthesized compounds were physico-chemically characterized and the IR (infrared spectra), ¹H NMR (proton nuclear magnetic resonance), ¹³C NMR (carbon nuclear magnetic resonance) and MS (mass spectrometry) data were consistent with the assigned structures. The synthesized thiazolin-4-one derivatives were tested for antifungal properties against several strains of Candida and all compounds exhibited efficient anti-Candida activity, two of them (9b and 10) being over 500-fold more active than fluconazole. Furthermore, the compounds' lipophilicity was assessed and the compounds were subjected to in silico screening for prediction of their ADME-Tox properties (absorbtion, distribution, metabolism, excretion and toxicity). Molecular docking studies were performed to investigate the mode of action towards the fungal lanosterol 14α-demethylase, a cytochrome P450-dependent enzyme. The results of the in vitro antifungal activity screening, docking study and ADME-Tox prediction revealed that the synthesized compounds are potential anti-Candida agents that might act by inhibiting the fungal lanosterol 14α-demethylase and can be further optimized and developed as lead compounds.

Synthesis and Antifungal Screening of 2-{[1-(5-Alkyl/arylalkylpyrazin-2-yl)ethylidene]hydrazono}-1,3-thiazolidin-4-ones

Two novel thiosemicarbazones and eight novel 2-{[1-(5-alkyl/arylalkylpyrazin-2-yl)ethylidene]hydrazono}-1,3-thiazolidin-4-ones were prepared and tested against a panel of eight fungal strains–Candida albicans ATCC 44859, Candida tropicalis 156, Candida krusei E 28, Candida glabrata 20/I, Trichosporon asahii 1188, Aspergillus fumigatus 231, Lichtheimia corymbifera 272, and Trichophyton interdigitale 445. 1,3-Thiazolidin-4-ones exhibited activity against all strains, the most potent derivative was 2-{[1-(5-butylpyrazin-2-yl)ethylidene]hydrazono}e-1,3-thiazolidin-4-one. Susceptibility of C. glabrata to the studied 1,3-thiazolidin-4-ones (minimum inhibitory concentrations (MICs) were in the range 0.57 to 2.78 mg/L) is of great interest as this opportunistic pathogen is poorly susceptible to azoles and becomes resistant to echinocandins. Antifungal potency of thiosemicarbazones was slightly lower than that of 1,3-thiazolidin-4-ones.

Novel tetrazoloquinoline-rhodanine conjugates: Highly efficient synthesis and biological evaluation

In search of new active molecules against Mycobacterium tuberculosis (MTB) H37Ra and Mycobacterium bovis BCG, a small focused library of rhodanine incorporated tetrazoloquinoline has been efficiently synthesized by using [HDBU][HSO4] acidic ionic liquid. The compound 3c found to be promising inhibitor of MTB H37Ra and M. bovis BCG characterized by lower MIC values 4.5 and 2.0 μg/mL, respectively. The active compounds were further tested for cytotoxicity against HeLa, THP-1, A549 and PANC-1 cell lines using MTT assay and showed no significant cytotoxic activity at the maximum concentration evaluated. Again, the synthesized compounds were found to have potential antifungal activity. Furthermore, to rationalize the observed biological activity data, the molecular docking study also been carried out against a potential target Zmp1 enzyme of MTB H37Ra, which revealed a significant correlation between the binding score and biological activity for these compounds. The results of in vitro and in silico study suggest that these compounds possess ideal structural requirement for the further development of novel therapeutic agents.

Poly[μ2-aqua-aqua-[μ3-N-butyl-N-(2-hy-droxy-ethyl)di-thio-carbamato-κ(3) O,O':S]sodium]

In the title compound, [Na(C7H14NOS2)(H2O)2] n , the Na(I) cation is coordinated by five O atoms [Na-O = 2.3142 (11)-2.4677 (10) Å] from three aqua and two N-butyl-N-(2-hy-droxy-eth-yl)di-thio-carbamate (L) ligands and one S atom [Na-S = 3.0074 (6) Å] from a third L ligand in a highly distorted octa-hedral geometry. Two aqua ligands related by an inversion center bridge two Na(I) cations, and each L ligand coordinates three Na(I) cations, leading to a layered arrangement aligned parallel to the bc plane. Inter-molecular O-H⋯S hydrogen bonds are observed in the inner part of each polymeric layer; these are packed along the a axis and held together by weak van der Waals forces.

A magnetically recyclable iron oxide-supported copper oxide nanocatalyst (Fe3O4–CuO) for one-pot synthesis of S-aryl dithiocarbamates under solvent-free conditions

A convenient preparation of S-aryl dithiocarbamates from amine, carbon disulfide and aryl iodide was developed by using the Fe₃O₄–CuO nanocatalyst under solvent free conditions.

New class of methyl tetrazole based hybrid of (Z)-5-benzylidene-2-(piperazin-1-yl)thiazol-4(%H)-one as potent antitubercular agents

In search of potential therapeutics for tuberculosis, we describe here the synthesis and in vitro antitubercular activity of a novel series of thiazolone piperazine tetrazole derivatives. Among all the synthesized derivatives, four compounds (10, 14, 20 and 33) exhibited more potent activity (MIC=3.08, 3.01, 2.62 and 2.51 μM) than ethambutol (MIC=9.78 μM) and pyrazinamide (MIC=101.53 μM) against Mycobacterium tuberculosis. Furthermore, they displayed no toxicity against Vero cells (C1008) and mouse bone marrow derived macrophages (MBMDMϕ). These investigated analogues have emerged as possible lead molecule to enlarge the scope of the study.

Investigation of Ugi-4CC derived 1H-tetrazol-5-yl-(aryl) methyl piperazinyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid: synthesis, biology and 3D-QSAR analysis

Novel series of 7-piperazinylquinolones with tetrazole derivatives were synthesized and evaluated for their antibacterial activity against various strains of Staphylococcus aureus. All the synthesized compounds showed significant in vitro antibacterial activity against Gram-positive bacteria whereas some compounds displayed moderate activity against Gram-negative bacteria. Among all the synthesized compounds, compounds (6a-c, 6e-g, 6i-k, 6m, 6'f and 6'm) were found to be more effective with MIC ranging from (0.78-3.12 μg/mL) against S. aureus (ATCC-29213) than the control; ciprofloxacin (MIC = 25 μg/mL). Moreover, these analogues displayed no toxicity up to MIC = 0.39 μg/mL against mammalian cell line L-929. Furthermore, to correlate the biological activities of synthesized compounds with their 3D conformation, we attempted 3D-QSAR study.

A unique dithiocarbamate chemistry during design & synthesis of novel sperm-immobilizing agents

Unusual loss of CS₂ observed in benzyl substituted dithiocarbamates during synthesis of double edged spermicides which acted through sulfhydryl binding.

Discovery of triazine mimetics as potent antileishmanial agents

The World Health Organization has classified the leishmaniasis as a major tropical disease. The discovery of new compounds for leishmaniasis is therefore a pressing concern for the anti-infective research program. We have synthesized 19 compounds of triazine dimers as novel antileishmanial agents. Most of the synthesized derivatives exhibited better activity against intracellular amastigotes (IC50 ranging from 0.77 to 10.32 μM) than the control, pentamidine (IC50 = 13.68 μM), and are not toxic to Vero cells. Compounds 14 and 15 showed significant in vivo inhibition of 74.41% and 62.64%, respectively, in L. donovani/hamster model. Moreover, expansion of Th1-type and suppression of Th2-type immune responses proved that compound 14 stimulates mouse macrophages to prevent the progression of leishmania parasite. The molecular docking studies involving PTR1 protein PDB further validated the concepts involved in the design of these compounds. Among the investigated analogues, compound 14 has emerged as the potential one to enlarge the scope of the study.