Discovery of a rhodanine class of compounds as inhibitors of Plasmodium falciparum enoyl-acyl carrier protein reductase

Selective Construction of 2,4-Bisthioquinolines via Copper-Catalyzed Tandem Cyclization from o-Alkynylphenyl Isothiocyanates

The selective synthesis of polysubstituted quinoline has been recognized as an important but highly challenging transformation. In this study, a highly efficient method for the synthesis of 2,4-bisthioquinolines has been developed through a copper(II)-promoted tandem cycloaddition of o-alkynylphenyl isothiocyanates, utilizing inexpensive and readily available sodium sulfide (Na2S) as the sulfur source. This transformation enables the direct synthesis of 2,4-bis(thioquinoline) heterocycles via the formation of C-C and C-S bonds in a one-pot reaction, demonstrating excellent tolerance for various functional groups.

Development of Mycobacterium tuberculosis Enoyl Acyl Reductase (InhA) Inhibitors: A Mini-Review

This review article delves into the critical role of Enoyl acyl carrier protein reductase (InhA; ENR), a vital enzyme in the NADH-dependent acyl carrier protein reductase family, emphasizing its significance in fatty acid synthesis and, more specifically, the biosynthesis of mycolic acid. The primary objective of this literature review is to elucidate diverse scaffolds and their developmental progression targeting InhA inhibition, thereby disrupting mycolic acid biosynthesis. Various scaffolds, including thiourea, piperazine, thiadiazole, triazole, quinazoline, benzamide, rhodanine, benzoxazole, and pyridine, have been systematically explored for their potential as InhA inhibitors. Noteworthy findings highlight thiadiazole and triazole derivatives, demonstrating promising IC50 values within the nanomolar concentration range. The review offers comprehensive insights into InhA's structure, structure-activity relationships, and a detailed overview of distinct scaffolds as effective inhibitors of InhA.

A Review on Synthetic Thiazole Derivatives as an Antimalarial Agent

BACKGROUND

Thiazole is a widely studied core structure in heterocyclic chemistry and has proven to be a valuable scaffold in medicinal chemistry. The presence of thiazole in both naturally occurring and synthetic pharmacologically active compounds demonstrates the adaptability of these derivatives.

METHODS

The current study attempted to review and compile the contributions of numerous researchers over the last 20 years to the medicinal importance of these scaffolds, with a primary focus on antimalarial activity. The review is based on an extensive search of PubMed, Google Scholar, Elsevier, and other renowned journal sites for a thorough literature survey involving various research and review articles.

RESULTS

A comprehensive review of the antimalarial activity of the thiazole scaffold revealed potential therapeutic targets in Plasmodium species. Furthermore, the correlation of structure-activity-relationship (SAR) studies from various articles suggests that the thiazole ring has therapeutic potential.

CONCLUSION

This article intends to point researchers in the right direction for developing potential thiazole-based compounds as antimalarial agents in the future.

Design, Synthesis, Computational Investigations, and Antitumor Evaluation of N-Rhodanine Glycosides Derivatives as Potent DNA Intercalation and Topo II Inhibition against Cancer Cells

Nitrogen and sulfur glycosylation was carried out via the reaction of rhodanine (1) with α-acetobromoglucose 3 under basic conditions. Deacetylation of the protected nitrogen nucleoside 4 was performed with CH₃ONa in CH₃OH without cleavage of the rhodanine ring to afford the deprotected nitrogen nucleoside 6. Further, deacetylation of the protected sulfur nucleoside 5 was performed with CH₃ONa in CH₃OH with the cleavage of the rhodanine ring to give the hydrolysis product 7. The protected nitrogen nucleosides 11a-f were produced by condensing the protected nitrogen nucleoside 4 with the aromatic aldehydes 10a-f in C₂H₅OH while using morpholine as a secondary amine catalyst. Deacetylation of the protected nitrogen nucleosides 11a-f was performed with NaOCH₃/CH₃OH without cleavage of the rhodanine ring to afford the deprotected nitrogen nucleosides 12a-f. NMR spectroscopy was used to designate the anomers' configurations. To examine the electrical and geometric properties derived from the stable structure of the examined compounds, molecular modeling and DFT calculations using the B3LYP/6-31+G (d,p) level were carried out. The quantum chemical descriptors and experimental findings showed a strong connection. The IC₅₀ values for most compounds were very encouraging when evaluated against MCF-7, HepG2, and A549 cancer cells. Interestingly, IC₅₀ values for 11a, 12b, and 12f were much lower than those for Doxorubicin (7.67, 8.28, 6.62 μM): (3.7, 8.2, 9.8 μM), (3.1, 13.7, 21.8 μM), and (7.17, 2.2, 4.5 μM), respectively. Against Topo II inhibition and DNA intercalation, when compared to Dox (IC₅₀ = 9.65 and 31.27 μM), compound 12f showed IC₅₀ values of 7.3 and 18.2 μM, respectively. In addition, compound 12f induced a 65.6-fold increase in the rate of apoptotic cell death in HepG2 cells, with the cell cycle being arrested in the G2/M phase as a result. Additionally, it upregulated the apoptosis-mediated genes of P53, Bax, and caspase-3,8,9 by 9.53, 8.9, 4.16, 1.13, and 8.4-fold change, while it downregulated the Bcl-2 expression by 0.13-fold. Therefore, glucosylated Rhodanines may be useful as potential therapeutic candidates against cancer because of their topoisomerase II and DNA intercalation activity.

Biophysical Survey of Small-Molecule β-Catenin Inhibitors: A Cautionary Tale

The canonical Wingless-related integration site signaling pathway plays a critical role in human physiology, and its dysregulation can lead to an array of diseases. β-Catenin is a multifunctional protein within this pathway and an attractive yet challenging therapeutic target, most notably in oncology. This has stimulated the search for potent small-molecule inhibitors binding directly to the β-catenin surface to inhibit its protein–protein interactions and downstream signaling. Here, we provide an account of the claimed (and some putative) small-molecule ligands of β-catenin from the literature. Through in silico analysis, we show that most of these molecules contain promiscuous chemical substructures notorious for interfering with screening assays. Finally, and in line with this analysis, we demonstrate using orthogonal biophysical techniques that none of the examined small molecules bind at the surface of β-catenin. While shedding doubts on their reported mode of action, this study also reaffirms β-catenin as a prominent target in drug discovery.

Catalyst-free aerobic radical cascade reactions of o-vinylphenylisocyanides with thiols to access 2-thio-substituted quinolines

We herein report an efficient and green aerobic radical cascade reaction of o-vinylphenylisocyanides with thiols to access a broad range of 2-thio-substituted quinolines without the need for additional catalysts or oxidants.

A Comparative Review on Current and Future Drug Targets Against Bacteria & Malaria

Long before the discovery of drugs like 'antibiotic and anti-parasitic drugs', the infectious diseases caused by pathogenic bacteria and parasites remain as one of the major causes of morbidity and mortality in developing and underdeveloped countries. The phenomenon by which the organism exerts resistance against two or more structurally unrelated drugs is called multidrug resistance (MDR) and its emergence has further complicated the treatment scenario of infectious diseases. Resistance towards the available set of treatment options and poor pipeline of novel drug development puts an alarming situation. A universal goal in the post-genomic era is to identify novel targets/drugs for various life-threatening diseases caused by such pathogens. This review is conceptualized in the backdrop of drug resistance in two major pathogens i.e. "Pseudomonas aeruginosa" and "Plasmodium falciparum". In this review, the available targets and key mechanisms of resistance of these pathogens have been discussed in detail. An attempt has also been made to analyze the common drug targets of bacteria and malaria parasite to overcome the current drug resistance scenario. The solution is also hypothesized in terms of a present pipeline of drugs and efforts made by scientific community.

Structure-based molecular modeling in SAR analysis and lead optimization

In silico methods like molecular docking and pharmacophore modeling are established strategies in lead identification. Their successful application for finding new active molecules for a target is reported by a plethora of studies. However, once a potential lead is identified, lead optimization, with the focus on improving potency, selectivity, or pharmacokinetic parameters of a parent compound, is a much more complex task. Even though in silico molecular modeling methods could contribute a lot of time and cost-saving by rationally filtering synthetic optimization options, they are employed less widely in this stage of research. In this review, we highlight studies that have successfully used computer-aided SAR analysis in lead optimization and want to showcase sound methodology and easily accessible in silico tools for this purpose.

A novel antiplasmodial compound: integration of in silico and in vitro assays

Malaria is a disease caused by Plasmodium genus. which P. falciparum is responsible for the most severe form of the disease, cerebral malaria. In 2018, 405,000 people died of malaria. Antimalarial drugs have serious adverse effects and limited efficacy due to multidrug-resistant strains. One way to overcome these limitations is the use of computational approaches for prioritizing candidates to phenotypic assays and/or in vitro assays against validated targets. Plasmodium falciparum Enoyl-ACP reductase (PfENR) is noteworthy because it catalyzes the rate-limiting step of the biosynthetic pathway of fatty acid. Thus, the study aimed to identify potential PfENR inhibitors by ligand (2D molecular similarity and pharmacophore models) and structure-based virtual screening (molecular docking). 2D similarity-based virtual screening using Tanimoto Index (> 0.45) selected 29,236 molecules from natural products subset available in ZINC database (n = 181,603). Next, 10 pharmacophore models for PfENR inhibitors were generated and evaluated based on the internal statistical parameters from GALAHAD™ and ROC/AUC curve. These parameters selected a suitable pharmacophore model with one hydrophobic center and two hydrogen bond acceptors. The alignment of the filtered molecules on best pharmacophore model resulted in the selection of 10,977 molecules. These molecules were directed to the docking-based virtual screening by AutoDock Vina 1.1.2 program. These strategies selected one compound to phenotypic assays against parasite. ZINC630259 showed EC₅₀ = 0.12 ± 0.018 µM in antiplasmodial assays and selective index similar to other antimalarial drugs. Finally, MM/PBSA method showed stability of molecule within PfENR binding site (ΔG_binding=-57.337 kJ/mol).Communicated by Ramaswamy H. Sarma.

Mediterranean Diet: Lipids, Inflammation, and Malaria Infection

The Mediterranean diet (MedDiet) consists of consumption of vegetables and healthy oils and have beneficial effects on metabolic and inflammatory diseases. Our goal here is to discuss the role of fatty acid content in MedDiet, mostly omega-3, omega-6, and omega-9 on malaria. Malaria affects millions of people around the globe. The parasite Plasmodium causes the disease. The metabolic and inflammatory alterations in the severe forms have damaging consequences to the host. The lipid content in the MedDiet holds anti-inflammatory and pro-resolutive features in the host and have detrimental effects on the Plasmodium. The lipids from the diet impact the balance of pro- and anti-inflammation, thus, lipids intake from the diet is critical to parasite elimination and host tissue damage caused by an immune response. Herein, we go into the cellular and molecular mechanisms and targets of the MedDiet fatty acids in the host and the parasite, reviewing potential benefits of the MedDiet, on inflammation, malaria infection progression, and clinical outcome.

A Concise Approach to N-Substituted Rhodanines through a Base-Assisted One-Pot Coupling and Cyclization Process

An efficient approach to obtain functionalized rhodanines was developed through a base-assisted one-pot coupling and continuous cyclization of a primary amine, carbon disulfide, and methyl (2-chloroacetyl)carbamate. This conversion tolerates a broad range of functional groups and can be used to scale the preparation of N-substituted rhodanines in excellent yields.

Synthesis, in-Vitro Cytotoxicity and Antimicrobial Evaluations of Some Novel Thiazole Based Heterocycles

Condensation of rhodanine (1) with pyrazol-3(2H)-one derivatives (2a-f) gave 5-substituted-2-thioxo-1,3-thiazolidin-4-one derivatives (3a-f). Reaction of compound (1) with 2-arylmethylidene-malononitrile (4a-d) yielded the unexpected derivatives (5a-d). The latter compounds were subjected to cyclization reactions with malononitrile under different basic conditions, hydroxylamine hydrochloride and/or thiourea to furnish the fused thiazole derivatives (6a-d) and (8-10a-d). Coupling of (1) with diazotized aromatic amines (11a-c) in pyridine afforded the arylhydrazones (12a-c). Fusion of latter compounds with malononitrile afforded the thiazolopyridazine derivatives (13a-c). The structures of the newly synthesized compounds were elucidated via spectral data and elemental analyses. The in-vitro cytotoxic activity of compounds (3a-f) against the cell line MCF-7 was evaluated. Also, the synthesized products were investigated for their antibacterial and antifungal activities against six standard organisms including the G⁺ bacteria, Staphylococcus aureus and Bacillus subtilis, G^- bacteria, Escherichia coli and Proteus vulgaris in addition to fungi, Candida albicans and Aspergillus flavus.

Introducing Broadened Antibacterial Activity to Rhodanine Derivatives Targeting Enoyl-Acyl Carrier Protein Reductase

Broadened antibacterial activity was introduced to rhodanine derivatives targeting Mycobacterial tuberculosis enoyl-acyl carrier protein reductase (Mtb InhA) by recruiting feature of xacins to bring DNA Gyrase B inhibitory capability. This is significant for preventing further bacterial injections in the tuberculosis treatment. The most potent compound Cy14 suggested comparable bioactivity (IC₅₀ = 3.18 µM for Mtb InhA; IC₅₀ = 10 nM for DNA Gyrase B) with positive controls. Structure-activity relationship discussion and molecular docking model revealed the significance of rhodanine moiety and derived methoxyl on meta-position, pointing out orientations for future modification.

Convenient and Template-Free Route to One-Pot Green Synthesis of Polyrhodanine Core-Shell Nanoparticles

In this publication, a copper acetate-mediated rhodanine polymerization reaction is examined. It is demonstrated that at room temperature, Cu(II) acetate complexes with rhodanine generate solid nanospheres, which, upon heating in a microwave, results in polyrhodanine core-shell nano- and microsphere particles. The structural analysis of the polyrhodanine nanosphere produced by this efficient microwave-initiated method was conducted by Fourier transform infrared spectroscopy, UV-vis spectroscopy, scanning electron microscopy, and transmission electron microscopy. In addition, it is verified that this template-free, efficient, and versatile synthesis of polyrhodanine nanospheres can also be accomplished by introducing a strong oxidant KMnO₄ as a cocatalyst with copper acetate without compromising the morphology of the resulting core-shell nanospheres. It is also demonstrated that the polyrhodanine nanospheres can be used to adsorb methyl orange dye, a known contaminant in industrial wastewater.

Drug targets for resistant malaria: Historic to future perspectives

New antimalarial targets are the prime need for the discovery of potent drug candidates. In order to fulfill this objective, antimalarial drug researches are focusing on promising targets in order to develop new drug candidates. Basic metabolism and biochemical process in the malaria parasite, i.e. Plasmodium falciparum can play an indispensable role in the identification of these targets. But, the emergence of resistance to antimalarial drugs is an escalating comprehensive problem with the progress of antimalarial drug development. The development of resistance has highlighted the need for the search of novel antimalarial molecules. The pharmaceutical industries are committed to new drug development due to the global recognition of this life threatening resistance to the currently available antimalarial therapy. The recent developments in the understanding of parasite biology are exhilarating this resistance issue which is further being ignited by malaria genome project. With this background of information, this review was aimed to highlights and provides useful information on various present and promising treatment approaches for resistant malaria, new progresses, pursued by some innovative targets that have been explored till date. This review also discusses modern and futuristic multiple approaches to antimalarial drug discovery and development with pictorial presentations highlighting the various targets, that could be exploited for generating promising new drugs in the future for drug resistant malaria.

Atropisomerism in 3-arylthiazolidine-2-thiones. A combined dynamic NMR and dynamic HPLC study

Sterically hindered 3-arylthiazolidine-2-thiones were prepared by a solvent-free reaction with arylisothiocyanates and 1,4-dithiane-2,5-diol. Atropisomerism was observed in two compounds (3 and 4, aryl = 1-naphthyl and 2-methylnaphth-1-yl), whose rotational energy barriers were measured using dynamic NMR and dynamic HPLC. The experimental analyses were supported by DFT calculations. Thermally stable atropisomers were obtained by dehydration of compounds 3 and 4 and the absolute configuration of the atropisomers of compound 6 was determined by theoretical simulation of the ECD and VCD spectra.

Gold- and silver-catalyzed intramolecular annulation and rearrangement of aniline-linked 1,6-enynes containing methylenecyclopropanes

A new synthetic approach for the construction of 1,2-dihydroquinolines having a methylenecyclopropane moiety or a cyclobutene moiety has been developed from gold- and silver-catalyzed annulation of N-tethered 1,6-enynes containing methylenecyclopropanes.

Base-catalyzed thio-lactamization of 2-(1-arylvinyl)anilines with CS2 for the synthesis of quinoline-2-thiones

Quinoline-2-thiones were prepared through a base-catalyzed thio-lactamization of 2-(1-arylvinyl)anilines with CS₂.

Base-controlled chemoselectivity reaction of vinylanilines with isothiocyanates for synthesis of quinolino-2-thione and 2-aminoquinoline derivatives

Quinolino-2-thione and 2-aminoquinoline derivatives were obtained by a base-controlled chemo-selective reaction of vinylanilines with alkyl/aryl isothiocyanates.

Antibacterial properties of 5-substituted derivatives of rhodanine-3-carboxyalkyl acids

A series of rhodanine 3-carboxyalkanoic acid derivatives possessing 4′-(N,N-dialkyl-amino or diphenylamino)-benzylidene moiety as a substituent at the C-5 position were synthesised and their antibacterial activity was screened. All the rhodanine derivatives showed bacteriostatic or bactericidal activity to the reference gram-positive bacterial strains, but lack of activity to the reference Gram-negative bacterial strains and yeast strains was observed.

The apicoplast genomes of two taxonomic units of Babesia from sheep

The apicoplast (ap) is a unique, non-photosynthetic organelle found in most apicomplexan parasites. Due to the essential roles that this organelle has, it has been widely considered as target for drugs against diseases caused by apicomplexans. Exploring the ap genomes of such parasites would provide a better understanding of their systematics and their basic molecular biology for therapeutics. However, there is limited information available on the ap genomes of apicomplexan parasites. In the present study, the ap genomes of two operational taxonomic units of Babesia (known as Babesia sp. Lintan [Bl] and Babesia sp. Xinjiang [Bx]) from sheep were sequenced, assembled and annotated using a massive parallel sequencing-based approach. Then, the gene content and gene order in these ap genomes (∼30.7kb in size) were defined and compared, and the genetic differences were assessed. In addition, a phylogenetic analysis of ap genomic data sets was carried out to assess the relationships of these taxonomic units with other apicomplexan parasites for which complete ap genomic data sets were publicly available. The results showed that the ap genomes of Bl and Bx encode 59 and 57 genes, respectively, including 2 ribosomal RNA genes, 25 transfer RNA genes and 30-32 protein-encoding genes, being similar in content to those of Babesia bovis and B. orientalis. Ap gene regions that might serve as markers for future epidemiological and population genetic studies of Babesia species were identified. Using sequence data for a subset of six protein-encoding genes, a close relationship of Bl and Bx with Babesia bovis from cattle and B. orientalis from water buffalo was inferred. Although the focus of the present study was on Babesia, we propose that the present sequencing-bioinformatic approach should be applicable to organellar genomes of a wide range of apicomplexans of veterinary importance.

Fungal naphtho-γ-pyrones: Potent antibiotics for drug-resistant microbial pathogens

Four naphtho-γ-pyrones (fonsecinones A and C and aurasperones A and E) were identified as potential antibacterial agents against Escherichia coli, extended-spectrum β-lactamase (ESBL)-producing E. coli, Pseudomonas aeruginosa, Enterococcus faecalis, and methicillin-resistant Staphylococcus aureus (MRSA) in an in vitro antibacterial screen of 218 fungal metabolites. Fonsecinone A (2) exhibited the most potent antibacterial activity, with minimum inhibitory concentrations (MICs) of 4.26, 17.04, and 4.26 μg/mL against ESBL-producing E. coli, P. aeruginosa, and E. faecalis, respectively. The inhibitory effects of fonsecinones A (2) and C (3) against E. coli and ESBL-producing E. coli were comparable to those of amikacin. Molecular docking-based target identification of naphtho-γ-pyrones 1–8 revealed bacterial enoyl-acyl carrier protein reductase (FabI) as an antibacterial target, which was further validated by FabI affinity and inhibition assays. Fonsecinones A (2) and C (3) and aurasperones A (6) and E (7) bound FabI specifically and produced concentration-dependent inhibition effects. This work is the first report of anti-drug-resistant bacterial activities of naphtho-γ-pyrones 1–8 and their possible antibacterial mechanism of action and provides an example of the successful application of in silico methods for drug target identification and validation and the identification of new lead antibiotic compounds against drug-resistant pathogens.

Prioritization of active antimalarials using structural interaction profile of Plasmodium falciparum enoyl-acyl carrier protein reductase (PfENR)-triclosan derivatives

An empirical relationship between the experimental inhibitory activities of triclosan derivatives and its computationally predicted Plasmodium falciparum enoyl-acyl carrier protein (ACP) reductase (PfENR) dock poses was developed to model activities of known antimalarials. A statistical model was developed using 57 triclosan derivatives with significant measures (r = 0.849, q(2) = 0.619, s = 0.481) and applied on structurally related and structurally diverse external datasets. A substructure-based search on ChEMBL malaria dataset (280 compounds) yielded only two molecules with significant docking energy, whereas eight active antimalarials (EC(50) < 100 nM, tested on 3D7 strain) with better predicted activities (pIC(50) ~ 7) from Open Access Malaria Box (400 compounds) were prioritized. Further, calculations on the structurally diverse rhodanine molecules (known PfENR inhibitors) distinguished actives (experimental IC(50) = 0.035 μM; predicted pIC(50) = 6.568) and inactives (experimental IC(50) = 50 μM; predicted pIC50 = -4.078), which showed that antimalarials possessing dock poses similar to experimental interaction profiles can be used as leads to test experimentally on enzyme assays.

A solvent- and catalyst-free domino reaction for the efficient synthesis of 3-arylthiazolidine-2-thiones under microwave irradiation

A facile synthesis of 4-hydroxy-3-arylthiazolidine-2-thiones through novel domino reactions of aryl isothiocyanates and 1,4-dithiane-2,5-diol under solvent- and catalyst-free microwave irradiation is reported.

Celastrol inhibits Plasmodium falciparum enoyl-acyl carrier protein reductase

Enoyl-acyl carrier protein reductase (ENR), a critical enzyme in type II fatty acid biosynthesis, is a promising target for drug discovery against hepatocyte-stage Plasmodium falciparum. In order to identify PfENR-specific inhibitors, we docked 70 FDA-approved, bioactive, and/or natural product small molecules known to inhibit the growth of whole-cell blood-stage P. falciparum into several PfENR crystallographic structures. Subsequent in vitro activity assays identified a noncompetitive low-micromolar PfENR inhibitor, celastrol, from this set of compounds.

In silico screening for Plasmodium falciparum enoyl-ACP reductase inhibitors

The need for novel therapeutics against Plasmodium falciparum is urgent due to recent emergence of multi-drug resistant malaria parasites. Since fatty acids are essential for both the liver and blood stages of the malarial parasite, targeting fatty acid biosynthesis is a promising strategy for combatting P. falciparum. We present a combined computational and experimental study to identify novel inhibitors of enoyl-acyl carrier protein reductase (PfENR) in the fatty acid biosynthesis pathway. A small-molecule database from ChemBridge was docked into three distinct PfENR crystal structures that provide multiple receptor conformations. Two different docking algorithms were used to generate a consensus score in order to rank possible small molecule hits. Our studies led to the identification of five low-micromolar pyrimidine dione inhibitors of PfENR.

Synthesis and biological evaluation of new rhodanine analogues bearing 2-chloroquinoline and benzo[h]quinoline scaffolds as anticancer agents

Several rhodanine derivatives (9-39) were synthesized for evaluation of their potential as anticancer agents. Villsmeier cyclization to synthesize aza-aromatic aldehydes, rhodanine derivatives preparation and Knoevenagel type of condensation between the rhodanines and aza-aromatic aldehydes are key steps used for the synthesis of 31 compounds. In vitro antiproliferative activity of the synthesized rhodanine derivatives (9-39) was studied on a panel of six human tumor cell lines viz. HGC, MNK-74, MCF-7, MDAMB-231, DU-145 and PC-3 cell lines. Some of the compounds were capable of inhibiting the proliferation of cancer cell lines at a micromolar concentration. Six compounds are found to be potent against HGC cell lines; compound 15 is found to be active against HGC - Gastric, MCF7 - Breast Cancer and DU145 - Prostate Cancer cell lines; compound 39 is potent against MNK-74; four compounds are found to be potent against MCF-7 cell lines; three compounds are active against MDAMB-231; nine compounds are found to be potent against DU-145; three compounds are active against PC-3 cell lines. These compounds constitute a promising starting point for the development of novel and more potent anticancer agents in future.

New 5-ylidene rhodanine derivatives based on the dispacamide A model

A practical approach for the preparation of (5Z) 5-ylidene rhodanine derivatives bearing the (4,5-dihalogeno-pyrrol-2-yl)carbamoyl fragment of dispacamide A is reported. The new compounds were obtained in good yields (19-88 %) by Knoevenagel condensation according to a solution-phase microwave dielectric heating protocol in the presence of organic bases (piperidine, TEA, and AcONa) from a set of N-substituted rhodanines 2(a-i). The ten synthetic products 3(a-j) have been synthesized with a Z-geometry about their exocyclic double bond and the structure of one of these compounds (3) was confirmed by a single X-ray diffraction analysis. The new (5Z) 5-ylidene rhodanine derivatives 3(a-j) were tested against eight protein kinases.