Design, synthesis, biological evaluation and molecular dynamics simulation studies of imidazolidine-2,4-dione derivatives as novel PTP1B inhibitors.

Protein tyrosine phosphatase 1B (PTP1B) is a member of the phosphotyrosine phosphatase family and plays an important role in the signal transduction of diabetes. Inhibition of PTP1B activity can increase insulin sensitivity and reduce blood sugar levels. Therefore, it is urgent to find compounds with novel structures that can inhibit PTP1B. This study designed imidazolidine-2,4-dione derivatives through the computer-aided drug design (CADD) strategy, and the Comp#10 showed outstanding inhibitory ability. (IC50 = 2.07 µM) and selectivity. The inhibitory mechanism at molecular level of Comp#10 on PTP1B was studied by molecular dynamics simulation. The results show that the catalytic region of PTP1B protein is more stable, which makes the catalytic sites unsuitable for exposure. Interestingly, the most obvious changes in the interaction between residues in the P-loop region (such as: His214, Cys215, and Ser216). In short, this study reported for the first time that imidazolidine-2,4-dione derivatives as novel PTP1B inhibitors had good inhibitory activity and selectivity, providing new ideas for the development of small molecule PTP1B inhibitors.

Inhibition of the NorA efflux pump of S. aureus by (Z)-5-(4-Fluorobenzylidene)-Imidazolidines.

Searching for new alternatives to antibiotic treatments is crucial to surmount the multidrug-resistant bacteria. In this work, the antimicrobial activity of synthetic imidazolidines was evaluated as well as their modulating effect on the resistance to fluoroquinolones in a S. aureus strain (SA-1199B), which overexpresses the norA gene that encodes the NorA efflux pump. Results showed weak antimicrobial activity (512 µg mL-1) for two fluorobenzylidene derivatives against this bacterial strain, while the other benzylidene derivatives were inactive. Despite this fact, both fluorinated compounds were able to enhance the activity of norfloxacin and ciprofloxacin against SA-1199B up to 6.4- and 3.2-fold, respectively. In addition, both derivatives potentiated the action of ethidium bromide against this strain, suggesting that the modulating effect probably involves the inhibition of the NorA efflux pump, which is in concordance with the fluorimetic assays and molecular docking analyses performed in this work.

An insight into the structure of 5-spiro aromatic derivatives of imidazolidine-2,4-dione, a new group of very potent inhibitors of tumor multidrug resistance in T-lymphoma cells.

A series of 17 arylpiperazine derivatives of the 5-spiroimidazolidine-2,4-diones (6-22) has been explored, including variations in (i) the number of aromatic rings at position 5, (ii) the length of the linker, as well as (iii) the kind and position of the linked arylpiperazine terminal fragment. Synthesis (6-16) and X-ray crystallographic studies for representative compounds (8, 10, 14 and 18) have been performed. The ability to inhibit the tumor multidrug resistance (MDR) efflux pump P-glycoprotein (P-gp, ABCB1) overexpressed in mouse T-lymphoma cells was investigated. The cytotoxic and antiproliferative actions of the compounds on both the reference and the ABCB1-overproducing cells were also examined. The pharmacophore-based molecular modeling studies have been performed. ADMET properties in vitro of selected most active derivatives (6, 11 and 12) have been determined. All compounds, excluding 18, inhibited the cancer P-gp efflux pump with higher potency than that of reference verapamil. The spirofluorene derivatives with amine alkyl substituents at position 1, and the methyl group at position 3 (6-16), occurred the most potent P-gp inhibitors in the MDR T-lymphoma cell line. In particular, compounds 7 and 12 were 100-fold more potent than verapamil. Crystallography-supported pharmacophore-based SAR analysis has postulated specific structural properties that could explain this excellent cancer MDR-inhibitory action.

The Highly Regioselective Synthesis of Novel Imidazolidin-2-Ones via the Intramolecular Cyclization/Electrophilic Substitution of Urea Derivatives and the Evaluation of Their Anticancer Activity.

A series of novel 4-(het)arylimidazoldin-2-ones were obtained by the acid-catalyzed reaction of (2,2-diethoxyethyl)ureas with aromatic and heterocyclic C-nucleophiles. The proposed approach to substituted imidazolidinones benefits from excellent regioselectivity, readily available starting materials and a simple procedure. The regioselectivity of the reaction was rationalized by quantum chemistry calculations and control experiments. The anti-cancer activity of the obtained compounds was tested in vitro.

Design, synthesis and biological evaluation of imidazolidine-2,4-dione and 2-thioxothiazolidin-4-one derivatives as lymphoid-specific tyrosine phosphatase inhibitors.

Lymphoid-specific tyrosine phosphatase (LYP), which exclusively exists in immune cells and down-regulates T cell receptor signaling (TCR), has becoming a potent target for various autoimmune diseases. Herein, we designed and synthesized imidazolidine-2,4-dione and 2-thioxothiazolidin-4-one derivatives as new LYP inhibitors. Among them, the cinnamic acids-based inhibitors (9p and 9r) displayed good LYP inhibitory activities (IC50 = 2.85-6.95 µM). Especially, the most potent inhibitor 9r was identified as competitive inhibitor (Ki = 1.09 µM) and bind LYP reversibly. Meanwhile, 9r exhibited better selectivity over other phosphatases than known LYP inhibitor A15. Furthermore, compound 9r could regulate TCR associated signaling pathway in Jurkat T cell.

Design, synthesis and biological evaluation of novel 5-((substituted quinolin-3-yl/1-naphthyl) methylene)-3-substituted imidazolidin-2,4-dione as HIV-1 fusion inhibitors.

A series of novel 5-(substituted quinolin-3-yl or 1-naphthyl)methylene)-3-substituted imidazolidin-2,4-dione 9-26 was designed and synthesized. The prepared compounds were identified using 1H NMR, 13C NMR as well as elemental analyses. The inhibitory activity of 9-26 on HIV-1IIIB replication in MT-2 cells was evaluated. Some derivatives showed good to excellent anti-HIV activities as compounds 13, 18, 19, 20, 22 and 23. They showed EC50 of 0.148, 0.460, 0.332, 0.50, 0.271 and 0.420 µM respectively being more potent than compound I (EC50 = 0.70 µM) and II ( EC50 = 2.40 µM) as standards. The inhibitory activity of 9-26 on infected primary HIV-1 domain, 92US657 (clade B, R5) was investigated. All the tested compounds consistently inhibited infection of this virus with EC50 from 0.520 to 11.857 µM. Results from SAR studies showed that substitution on ring A with 6/7/8-methyl group resulted in significant increase in the inhibitory activity against HIV-1IIIB infection (5- >300 times) compared to the unsubstituted analog 9. The cytotoxicity of these compounds on MT-2 cells was tested and their CC50 values ranged from 11 to 85 µM with selectivity indexes ranged from 0.53 to 166. The docking study revealed nice fitting of the new compounds into the hydrophobic pocket of HIV-1 gp41 and higher affinity than NB-64. Compound 13, the most active in preventing HIV-1IIIB infection, adopted a similar orientation to compound IV. Molecular docking analysis of the new compounds revealed hydrogen bonding interactions between the imidazolidine-2,4-dione ring and LYS574 which were missed in the weakly active derivatives.

Synthesis of imidazolidine-2,4-dione and 2-thioxoimidazolidin-4-one derivatives as inhibitors of virulence factors production in Pseudomonas aeruginosa.

In an attempt to counteract bacterial pathogenicity, a set of novel imidazolidine-2,4-dione and 2-thioxoimidazolidin-4-one derivatives was synthesized and evaluated as inhibitors of bacterial virulence. The new compounds were characterized and screened for their effects on the expression of virulence factors of Pseudomonas aeruginosa, including protease, hemolysin, and pyocyanin. Imidazolidine-2,4-diones 4c, 4j, and 12a showed complete inhibition of the protease enzyme, and they almost completely inhibited the production of hemolysin at 1/4 MIC (1/4 minimum inhibitory concentration; 1, 0.5, and 0.5 mg/ml, respectively). 2-Thioxoimidazolidin-4-one derivative 7a exhibited the best inhibitory activity (96.4%) against pyocyanin production at 1 mg/ml (1/4 MIC). A docking study was preformed to explore the potential binding interactions with quorum-sensing receptors (LasR and RhlR), which are responsible for the expression of virulence genes.

Polyhalonitrobutadienes as Versatile Building Blocks for the Biotargeted Synthesis of Substituted N-Heterocyclic Compounds.

Substituted nitrogen heterocycles are structural key units in many important pharmaceuticals. A new synthetic approach towards heterocyclic compounds displaying antibacterial activity against Staphylococcus aureus or cytotoxic activity has been developed. The selective synthesis of a series of 64 new N-heterocycles from the three nitrobutadienes 2-nitroperchloro-1,3-butadiene, 4-bromotetrachloro-2-nitro-1,3-butadiene and (Z)-1,1,4-trichloro-2,4-dinitrobuta-1,3-diene proved feasible. Their reactions with N-, O- and S-nucleophiles provide rapid access to push-pull substituted benzoxazolines, benzimidazolines, imidazolidines, thiazolidinones, pyrazoles, pyrimidines, pyridopyrimidines, benzoquinolines, isothiazoles, dihydroisoxazoles, and thiophenes with unique substitution patterns. Antibacterial activities of 64 synthesized compounds were examined. Additionally, seven compounds (thiazolidinone, nitropyrimidine, indole, pyridopyrimidine, and thiophene derivatives) exhibited a significant cytotoxicity with IC50-values from 1.05 to 20.1 µM. In conclusion, it was demonstrated that polyhalonitrobutadienes have an interesting potential as structural backbones for a variety of highly functionalized, pharmaceutically active heterocycles.

Synthesis and evaluation of the antileishmanial activity of silver compounds containing imidazolidine-2-thione.

A new series of silver compounds could be of interest on designing new drugs for the treatment of leishmaniasis. The compounds [Ag(phen)(imzt)]NO3(1), [Ag(phen)(imzt)]CF3SO3(2), [Ag(phen)2](BF4)·H2O (3), [Ag2(imzt)6](NO3)2(4), and imzt have been synthesized and evaluated in vitro for antileishmanial activity against Leishmania. (L.) amazonensis (La) and L. (L.) chagasi (Lc), and two of them were selected for in vivo studies. In addition to investigating the action on Leishmania, their effects on the hydrogen peroxide production and cysteine protease inhibition have also been investigated. As for antileishmanial activity, compound (4) was the most potent against promastigote and amastigote forms of La (IC50 = 4.67 and 1.88 µM, respectively) and Lc (IC50 = 9.35 and 8.05 µM, respectively); and comparable to that of amphotericin B, reference drug. Beside showing excellent activity, it also showed a low toxicity. In the in vivo context, compound (4) reduced the number of amastigotes in the liver and spleen when compared to the untreated group. In evaluating the effect of the compounds on Leishmania, the level of hydrogen peroxide production was maintained between the lag and log phases; however, in the treatment with compound (4) it was possible to observe a reduction of 25.44 and 49.13%, respectively, in the hydrogen peroxide rates when compared to the lag and log phases. It was noticed that the presence of a nitrate ion and imzt in compound (4) was important for the modulation of the antileishmanial activity. Thus, this compound can represent a potentially new drug for the treatment of leishmaniasis.

Synthesis and pharmacological evaluation of novel N-Mannich bases derived from 5,5-diphenyl and 5,5-di(propan-2-yl)imidazolidine-2,4-dione core.

The aim of this study was to design and synthesize two series of N-Mannich bases with imidazolidine-2,4-dione core as a potential anticonvulsant with reduced toxicity and broad antiseizure activity. Preliminary screening revealed that the majority of synthesized compounds were effective in the maximal electroshock seizure (MES) and/or subcutaneous pentylenetetrazole (scPTZ) test. The most active in vivo compound, 18 (3-((4-methylpiperazin-1-yl)methyl)-5,5-diphenylimidazolidine-2,4-dione), exhibited an ED50 value comparable to that of phenytoin in the MES test (38.5 mg/kg vs 28.1 mg/kg), and more importantly, it showed four times higher potency than phenytoin in the 6 Hz test (12.2 mg/kg vs > 60 mg/kg). Additionally, 18 exhibited antiallodynic properties in the von Frey test in neuropathic (oxaliplatin-treated) mice. Compound 18 also demonstrated a broader spectrum of anticonvulsant activity than phenytoin and showed statistically significant antinociceptive properties in selected models of chronic pain.

5-Thioxoimidazolidine-2-one derivatives: Synthesis, anti-inflammatory activity, analgesic activity, COX inhibition assay and molecular modelling study.

A series of 5-imino-4-thioxo-2-imidazolidinone derivatives with different substituents at N1 and N3 was synthesized with high yield and excellent purity by the reaction of different N-arylcyanothioformamide derivatives with isocyanate derivatives. Treatment 5-imino-4-thioxo-2-imidazolidinone derivatives with acidic medium afforded 4-thioxoimidazolidin-2,5-dione derivatives. The structures of the obtained products were established based on spectroscopic IR, 1H NMR, 13C NMR, 1H, 1H-COSY, HSQC and elemental analyses. The anti-inflammatory activity of the synthesized compounds through the carrageenan-paw edema model as well as in vitro COX-1 and COX-2 inhibition assay were evaluated where most of the synthesized compounds showed significant anti-inflammatory activity. Mostly, all of our synthesized compounds have greater activity more than celecoxib toward both cyclooxygenase enzymes. All of the tested compounds (except one compound) exhibited IC50 valves for COX-2 ranged from 0.001 × 10-3 to 0.827 × 10-3 µM while the reference drug has IC50 40.0 × 10-3 µM. Furthermore, the analgesic activity of such compounds was also determined. Molecular modeling study was also conducted to rationalize the potential as anti-inflammatory agents of our synthesized compounds by predicting their binding modes, binding affinities and optimal orientation at the active site of the COX enzymes.

Design and evaluation of non-carboxylate 5-arylidene-2-thioxo-4-imidazolidinones as novel non-competitive inhibitors of protein tyrosine phosphatase 1B.

Protein tyrosine phosphatase 1B (PTP1B) acts as a negative regulator of insulin and leptin signalling and is crucially involved in the development of type 2 diabetes mellitus, obesity, cancer and neurodegenerative diseases. Pursuing our efforts to identify PTP1B inhibitors endowed with drug-like properties, we designed and evaluated 3-aryl-5-arylidene-2-thioxo-4-imidazolidinones (7) as a novel class of non-carboxylate PTP1B inhibitors. In agreement with our design, kinetic studies demonstrated that selected compounds 7 act as reversible, non-competitive inhibitors of the target enzyme at low micromolar concentrations. Accordingly, molecular docking experiments suggested that these inhibitors can fit an allosteric site of PTP1B that we previously individuated. Moreover, cellular assays demonstrated that compound 7e acts as a potent insulin-sensitizing agent in human liver HepG2 cells. Taken together, our results showed that these non-competitive PTP1B inhibitors can be considered promising lead compounds aimed to enhance druggability of the target enzyme and identify novel antidiabetic drugs.

New 2-Oxoimidazolidine Derivatives: Design, Synthesis and Evaluation of Anti-BK Virus Activities in Vitro.

A series of novel 2-oxoimidazolidine derivatives were synthesized and their antiviral activities against BK human polyomavirus type 1 (BKPyV) were evaluated in vitro. Bioassays showed that the synthesized compounds 1-{[(4E)-5-(dichloromethylidene)-2-oxoimidazolidin-4-ylidene]sulfamoyl}piperidine-4-carboxylic acid (5) and N-Cyclobutyl-N'-[(4E)-5-(dichloromethylidene)-2-oxoimidazolidin-4-ylidene]sulfuric diamide (4) exhibited moderate activities against BKPyV (EC50 =5.4 and 5.5 µm, respectively) that are comparable to the standard drug Cidofovir. Compound 5 exhibited the same cytotoxicity in HFF cells and selectivity index (SI50 ) as Cidofovir. The selectivity index of compound 4 is three times less than that of Cidofovir due to the higher toxicity of this compound. Hence, these compounds may be taken as lead compound for further development of novel ant-BKPyV agents.

Design and synthesis of imidazolidinone derivatives as potent anti-leishmanial agents by bioisosterism.

Bioisosterism is a useful strategy in rational drug design to improve pharmacodynamic and pharmacokinetic properties of lead compounds. Imidazolidinones have been reported as potent kinase inhibitors and antileishmanial agents. In this study, bioisosteres of imidazolidinones (compounds 1-3) were evaluated for their antileishmanial properties. The modified imidazolidinones exhibited potent antileishmanial activity against extracellular as well as intracellular Leishmania donovani parasites in nanomolar concentrations. The selectivity index of these compounds on host cells was found to be more than 1000, emphasizing their specificity toward the parasite. Using SwissTargetPrediction software, we assessed the potential targets of these compounds and found MAPK as the most probable target. To in vitro validate, we developed a novel in vitro kinase assay that mimics the in vivo nature of the functional kinome. Compounds 1-3 displayed specific inhibition of parasite kinase activity accompanied by an increase in intracellular sodium levels in the parasites. This might be the effect of kinase inhibition that regulates sodium homeostasis through Na-ATPases. Finally, the compound-treated parasites underwent apoptosis-like death. This study represents bioisoterism as a novel approach for drug design to establish the structure-activity relationship, which in turn helps to improve the therapeutic activity of lead compounds.

Synthesis of 1,2,3-Triazolium Ionic Liquid-Supported Chiral Imidazolidinones and Their Application in Asymmetric Alkylation Reaction.

New 1,2,3-triazolium ionic liquid-supported chiral imidazolidinones were developed. The feasibility of the ionic liquid-supported imidazolidinones as chiral auxiliaries was demonstrated in sequential propionylation-alkylation-cleavage reactions, which provided the chiral product with good to excellent chemical yields (up to 90%) and high selectivities (up to 94% ee). The progress of the reactions could be monitored by TLC and NMR, and the ionic liquid-supported chiral auxiliaries could be recovered by simple extraction.

Total Synthesis of (+)-Guadinomic Acid via Hydroxyl-Directed Guanidylation.

Protecting-group-free total synthesis of (+)-guadinomic acid is reported using δ-valerolactone as a readily available starting material. The protocol utilizes the recent hydroxyl-directed guanidylation of unactivated alkenes as an approach for direct stereoselective incorporation of the guanidine unit furnishing the natural product in 7 steps.

Identification of 2-thioxoimidazolidin-4-one derivatives as novel noncovalent proteasome and immunoproteasome inhibitors.

This paper describes the design, synthesis, and biological evaluation of 2-thioxoimidazolidin-4-one derivatives as inhibitors of proteasome and immunoproteasome, potential targets for the treatment of hematological malignancies. In particular, we focused our efforts on the design of noncovalent inhibitors, which might be a promising therapeutic option potentially devoid of drawbacks and side-effects related to irreversible inhibition. Among all the synthesized compounds, we identified a panel of active inhibitors with Ki values towards one or two chymotrypsin-like activities of proteasome (ß5c) and immunoproteasome (ß5i and ß1i subunits) in the low micromolar range. Docking studies suggested a unique binding mode of the molecules in the catalytic site of immunoproteasome proteolytic subunits.

Diastereoselective synthesis and profiling of bicyclic imidazolidinone derivatives bearing a difluoromethylated catechol unit as potent phosphodiesterase 4 inhibitors.

Metal-mediated C-H functionalization of cyclic N-oxides was exploited to access a series of new difluoromethylated analogs of imidazolidinone-based PDE4 inhibitor CMPI in a diastereoselective manner. Among the products synthesized, compounds with fine-tuned activity/selectivity profiles compared to both CMPI and the clinically applied apremilast were identified. From these studies, an unusual fused 1,2-oxazinoimidazolidinone heterocyclic system was suggested as a novel scaffold for the design of potent and selective PDE4 inhibitors. Computational studies suggest that the oxygen atom in the imidazolidinone unit can bind to the metal ion center (most likely Mg2+). DFT calculations of the relative interaction energies of inhibitors with Mg2+ and Zn2+ ions were performed on a model of the bimetal active site of PDE4.

Synthesis of N-H Bearing Imidazolidinones and Dihydroimidazolones Using Aza-Heck Cyclizations.

The synthesis of unsaturated, unprotected imidazolidinones via an aza-Heck reaction is described. This palladium-catalyzed process allows for the cyclization of N-phenoxy ureas onto pendant alkenes. The reaction has broad functional group tolerance, can be applied to complex ring topologies, and can be used to directly prepare mono- and bis-unprotected imidazolidinones. By addition of Bu4 NI, dihydroimidazolones can be accessed from the same starting materials. Improved conditions for preparing unsaturated, unprotected lactams are also reported.

Reversible Hydride Transfer to N,N'-Diarylimidazolinium Cations from Hydrogen Catalyzed by Transition Metal Complexes Mimicking the Reaction of [Fe]-Hydrogenase.

[Fe]-hydrogenase is a key enzyme involved in methanogenesis and facilitates reversible hydride transfer from H2 to N5,N10-methenyltetrahydromethanopterin (CH-H4MPT+). In this study, a reaction system was developed to model the enzymatic function of [Fe]-hydrogenase by using N,N'-diphenylimidazolinium cation (1+) as a structurally related alternative to CH-H4MPT+. In connection with the enzymatic mechanism via heterolytic cleavage of H2 at the single metal active site, several transition metal complex catalysts capable of such activation were utilized in the model system. Reduction of 1[BF4] to N,N'-diphenylimidazolidine (2) was achieved under 1 atm H2 at ambient temperature in the presence of an equimolar amount of NEt3 as a proton acceptor. The proposed catalytic pathways involved the generation of active hydride complexes and subsequent intermolecular hydride transfer to 1+. The reverse reaction was accomplished by treatment of 2 with HNMe2Ph+ as the proton source, where [(η5-C5Me5)Ir{(p-MeC6H4SO2)NCHPhCHPhNH}] was found to catalyze the formation of 1+ and H2 with high efficiency. These results are consistent with the fact that use of 2,6-lutidine in the forward reaction or 2,6-lutidinium in the reverse reaction resulted in incomplete conversion. By combining these reactions using the above Ir amido catalyst, the reversible hydride transfer interconverting 1+/H2 and 2/H+ was performed successfully. This system demonstrated the hydride-accepting and hydride-donating modes of biologically relevant N-heterocycles coupled with proton concentration. The influence of substituents on the forward and reverse reactivities was examined for the derivatives of 1+ and 2 bearing one para-substituted N-phenyl group.