Synthesis of 4,4-Disubstituted 3,4-Dihydropyrimidin-2(1H)-ones and -thiones, the Corresponding Products of Biginelli Reaction Using Ketone, and Their Antiproliferative Effect on HL-60 Cells.

An efficient synthetic method for novel 4,4-disubstituted 3,4-dihydropyrimidin-2(1H)-ones 5 and -thiones 6 was developed. The cyclocondensation reaction of O-methylisourea hemisulfate salt 11 with 8 gives a tautomeric mixture of dihydropyrimidines 12 and 13 following acidic hydrolysis of the cyclized products to produce 5 in high yields. Thionation reaction of 5 at the 2-position smoothly proceeds to give 2-thioxo derivatives 6. These compounds 5 and 6, corresponding to the products of a Biginelli-type reaction using urea or thiourea, a ketone and a 1,3-dicarbonyl compound, have long been inaccessible and hitherto unavailable for medicinal chemistry. These methods are invaluable for the synthesis of 5 and 6, which have been inaccessible by conventional methods. Therefore, the synthetic methods established in this study will expand the molecular diversity of their related derivatives. These compounds were also assessed for their antiproliferative effect on a human promyelocytic leukemia cell line, HL-60. Treatment of 10 µM 6b and 6d showed high inhibitory activity similarly to 1 µM all-trans retinoic acid (ATRA), indicating that the 2-thioxo group and length of two alkyl substituents at the 4-position are strongly related to activity.

1,2,4-Triazole-3-thione compounds with a 4-ethyl alkyl/aryl sulfide substituent are broad-spectrum metallo-ß-lactamase inhibitors with re-sensitization activity.

Metallo-ß-lactamases (MBLs) are important contributors of Gram-negative bacteria resistance to ß-lactam antibiotics. MBLs are highly worrying because of their carbapenemase activity, their rapid spread in major human opportunistic pathogens while no clinically useful inhibitor is available yet. In this context, we are exploring the potential of compounds based on the 1,2,4-triazole-3-thione scaffold as an original ligand of the di-zinc active sites of MBLs, and diversely substituted at its positions 4 and 5. Here, we present a new series of compounds substituted at the 4-position by a thioether-containing alkyl chain with a carboxylic and/or an aryl group at its extremity. Several compounds showed broad-spectrum inhibition with Ki values in the µM to sub-µM range against VIM-type enzymes, NDM-1 and IMP-1. The presence of the sulfur and of the aryl group was important for the inhibitory activity and the binding mode of a few compounds in VIM-2 was revealed by X-ray crystallography. Importantly, in vitro antibacterial susceptibility assays showed that several inhibitors were able to potentiate the activity of meropenem on Klebsiella pneumoniae clinical isolates producing VIM-1 or VIM-4, with a potentiation effect of up to 16-fold. Finally, a selected compound was found to only moderately inhibit the di-zinc human glyoxalase II, and several showed no or only moderate toxicity toward several human cells, thus favourably completing a promising behaviour.

Thiocysteine lyases as polyketide synthase domains installing hydropersulfide into natural products and a hydropersulfide methyltransferase.

Nature forms S-S bonds by oxidizing two sulfhydryl groups, and no enzyme installing an intact hydropersulfide (-SSH) group into a natural product has been identified to date. The leinamycin (LNM) family of natural products features intact S-S bonds, and previously we reported an SH domain (LnmJ-SH) within the LNM hybrid nonribosomal peptide synthetase (NRPS)-polyketide synthase (PKS) assembly line as a cysteine lyase that plays a role in sulfur incorporation. Here we report the characterization of an S-adenosyl methionine (SAM)-dependent hydropersulfide methyltransferase (GnmP) for guangnanmycin (GNM) biosynthesis, discovery of hydropersulfides as the nascent products of the GNM and LNM hybrid NRPS-PKS assembly lines, and revelation of three SH domains (GnmT-SH, LnmJ-SH, and WsmR-SH) within the GNM, LNM, and weishanmycin (WSM) hybrid NRPS-PKS assembly lines as thiocysteine lyases. Based on these findings, we propose a biosynthetic model for the LNM family of natural products, featuring thiocysteine lyases as PKS domains that directly install a -SSH group into the GNM, LNM, or WSM polyketide scaffold. Genome mining reveals that SH domains are widespread in Nature, extending beyond the LNM family of natural products. The SH domains could also be leveraged as biocatalysts to install an -SSH group into other biologically relevant scaffolds.

Tripodal scaffolds with three appended imidazole thiones for Cu(I) chelation and protection from Cu-mediated oxidative stress.

Imidazole thiones appear as interesting building blocks for Cu(I) chelation and protection against Cu-mediated oxidative stress. Therefore, a series of tripodal molecules derived from nitrilotriacetic acid appended with three imidazole thiones belonging either to histamine-like or histidine-like moieties were synthesized. These tripods demonstrate intermediate affinity between that previously measured for tripodal analogues bearing three thiol moieties such as cysteine and those grafted with three thioethers, like methionines, consistently with the thione group in the imidazole thione moiety existing as a tautomer between a thiol and a thione. The two non-alkylated tripods derived from thioimidazole, TH and TH* demonstrated three orders of magnitude larger affinity for Cu(I) (logKpH 7.4 = 14.3) than their analogues derived from N,N'-dialkylated thioimidazole TMe and TEt (logKpH 7.4 = 11-11.6). Their efficiency to inhibit Cu-mediated oxidative stress is demonstrated by several assays involving ascorbate consumption or biomolecule damages and correlates with their ability to chelate Cu(I), related to their conditional complexation constants at pH 7.4. The two non-alkylated tripods derived from thioimidazole, TH and TH* are significantly more powerful in reducing Cu-mediated oxidative stress than their analogues derived from N,N'-dialkylated thioimidazole TMe and TEt.

5-Aryl-1-Arylideneamino-1H-Imidazole-2(3H)-Thiones: Synthesis and In Vitro Anticancer Evaluation.

A novel series of N-1 arylidene amino imidazole-2-thiones were synthesized, identified using IR, 1H-NMR, and 13C-NMR spectral data. Cytotoxic effect of the prepared compounds was carried out utilizing three cancer cell lines; MCF-7 breast cancer, HepG2 liver cancer, and HCT-116 colon cancer cell lines. Imidazole derivative 5 was the most potent of all against three cell lines. DNA flow cytometric analysis showed that, imidazoles 4d and 5 exhibit pre-G1 apoptosis and cell cycle arrest at G2/M phase. The results of the VEGFR-2 and B-Raf kinase inhibition assay revealed that compounds 4d and 5 displayed good inhibitory activity compared with reference drug erlotinib.

Hydroxypyridinethione Inhibitors of Human Insulin-Degrading Enzyme.

Insulin-degrading enzyme (IDE) is a human mononuclear Zn2+ -dependent metalloenzyme that is widely regarded as the primary peptidase responsible for insulin degradation. Despite its name, IDE is also critically involved in the hydrolysis of several other disparate peptide hormones, including glucagon, amylin, and the amyloid ß-protein. As such, the study of IDE inhibition is highly relevant to deciphering the role of IDE in conditions such as type-2 diabetes mellitus and Alzheimer disease. There have been few reported IDE inhibitors, and of these, inhibitors that directly target the active-site Zn2+ ion have yet to be fully explored. In an effort to discover new, zinc-targeting inhibitors of IDE, a library of ∼350 metal-binding pharmacophores was screened against IDE, resulting in the identification of 1-hydroxypyridine-2-thione (1,2-HOPTO) as an effective Zn2+ -binding scaffold. Screening a focused library of HOPTO compounds identified 3-sulfonamide derivatives of 1,2-HOPTO as inhibitors of IDE (Ki values of ∼50 µM). Further structure-activity relationship studies yielded several thiophene-sulfonamide HOPTO derivatives with good, broad-spectrum activity against IDE that have the potential to be useful pharmacological tools for future studies of IDE.

Synthesis of 5-[(1H-indol-3-yl)methyl]-1,3,4-oxadiazole-2(3H)-thiones and their protective activity against oxidative stress.

A small library of 2-[(1H-indol-3-yl)methyl]-5-(alkylthio)-1,3,4-oxadiazoles was prepared, starting from indole-3-acetic acid methyl ester and its 5-methyl-substituted derivative. The synthetic route involved the formation of intermediate hydrazides, their condensation with carbon disulfide, and intramolecular cyclization to corresponding 5-[(1H-indol-3-yl)methyl]-1,3,4-oxadiazole-2(3H)-thiones. The latter were then S-alkylated, and in case of ester derivatives, they were further hydrolyzed into corresponding carboxylic acids. All 5-[(1H-indol-3-yl)methyl]-1,3,4-oxadiazole-2(3H)-thiones and their S-alkylated derivatives were then screened for their protective effects in vitro and in vivo. Methyl substitution on the indole ring and propyl, butyl, or benzyl substitution on sulfhydryl group-possessing compounds were revealed to protect Friedreich's ataxia fibroblasts against the effects of glutathione depletion induced by the γ-glutamylcysteine synthetase inhibitor, buthionine sulfoximine. Two of the active compounds also reproducibly increased the survival of Caenorhabditis elegans exposed to juglone-induced oxidative stress.

Molecular Design toward Heavy-Atom-free Photosensitizers Based on the C═S Bond and their Dual Functions in Hypoxia Photodynamic Cancer Therapy and ClO- Detection.

In this article, we designed and synthesized the thionated NpImidazole derivatives BS and NS, new heavy-atom-free photosensitizers, which efficiently generate a triplet excited state with high singlet oxygen quantum yield. The introduction of the C═S bond to the NpImidazole core is essential for increasing spin-orbit coupling (SOC). The fluorescence emission of BS and NS was quenched at standard ambient temperature, accompanied with the increase in the ISC process from the singlet states to triplet excited states via thionation. BS and NS showed negligible dark cytotoxicity against HeLa cells in working concentration. In contrast, BS and NS rapidly induced cell death under blue light irradiation both under normoxia and hypoxia conditions. Our current study demonstrates that the C═S group can play an important role in type I ROS generation of PSs, which are unprecedented in the previous reports. Finally, the photophysical changes were assigned to the oxidative desulfurization of the C═S group of BS and NS to the C═O group of the corresponding BO and NO via hypochlorite. The combined results demonstrated the dual function of BS and NS as a fluorescent imaging agent for ClO- and an anti-cancer therapeutic by PDT that showed the potential strategy for "one-for-all" and multifunctional agents.

Design and Synthesis of New CDK2 Inhibitors Containing Thiazolone and Thiazolthione Scafold with Apoptotic Activity.

Cyclin dependent kinase 2 (CDK2) inhibition is a well-established strategy for treating cancer. Different series of novel thiazolone (1, 7-9) together with fused thiazolthione (2-6, and 10) derivatives were designed, then synthesized and evaluated for their biological inhibitory activity against CDK2. Additionally, the cytotoxicity of the new compounds was explored against breast and colon cancer cell lines. The novel thiazolone and the fused thiazolthione derivatives exhibited potent CDK2/cyclin A2 inhibitory effect of an IC50 values ranging 105.39-742.78 nM. Amongst them compounds 4 and 6 revealed highest IC50 of 105.39 and 139.27 nM, respectively. Most compounds showed significant inhibition on both breast cancer and colon cancer cell lines with IC50 range 0.54-5.26 and 0.83-278 µM, respectively. Further investigations involved flow cytometry analysis on MCF-7 cancer cell line for compounds 5 and 7 which resulted in arrest cell-cycle at two phases Pre G1/G2-M and re-enforced apoptosis via activation of caspase-7. Molecular modeling simulation of the designed compounds revealed that they were well fitted into CDK2 active site and their complexes were stabilized through the essential hydrogen bonding. Three dimensional quantitative structure activity relationship (3D QSAR) pharmacophore, and absorption, distribution, metabolism, excretion, and toxicity (ADMET) studies were also carried out showing proper pharmacokinetic and drug-likeness which aided in the prediction of the structure requirements responsible for the observed antitumor activity.

4-Amino-1,2,4-triazole-3-thione-derived Schiff bases as metallo-ß-lactamase inhibitors.

Resistance to ß-lactam antibiotics in Gram-negatives producing metallo-ß-lactamases (MBLs) represents a major medical threat and there is an extremely urgent need to develop clinically useful inhibitors. We previously reported the original binding mode of 5-substituted-4-amino/H-1,2,4-triazole-3-thione compounds in the catalytic site of an MBL. Moreover, we showed that, although moderately potent, they represented a promising basis for the development of broad-spectrum MBL inhibitors. Here, we synthesized and characterized a large number of 4-amino-1,2,4-triazole-3-thione-derived Schiff bases. Compared to the previous series, the presence of an aryl moiety at position 4 afforded an average 10-fold increase in potency. Among 90 synthetic compounds, more than half inhibited at least one of the six tested MBLs (L1, VIM-4, VIM-2, NDM-1, IMP-1, CphA) with Ki values in the µM to sub-µM range. Several were broad-spectrum inhibitors, also inhibiting the most clinically relevant VIM-2 and NDM-1. Active compounds generally contained halogenated, bicyclic aryl or phenolic moieties at position 5, and one substituent among o-benzoic, 2,4-dihydroxyphenyl, p-benzyloxyphenyl or 3-(m-benzoyl)-phenyl at position 4. The crystallographic structure of VIM-2 in complex with an inhibitor showed the expected binding between the triazole-thione moiety and the dinuclear centre and also revealed a network of interactions involving Phe61, Tyr67, Trp87 and the conserved Asn233. Microbiological analysis suggested that the potentiation activity of the compounds was limited by poor outer membrane penetration or efflux. This was supported by the ability of one compound to restore the susceptibility of an NDM-1-producing E. coli clinical strain toward several ß-lactams in the presence only of a sub-inhibitory concentration of colistin, a permeabilizing agent. Finally, some compounds were tested against the structurally similar di-zinc human glyoxalase II and found weaker inhibitors of the latter enzyme, thus showing a promising selectivity towards MBLs.

Synthesis of New Planar-Chiral Linked [2.2]Paracyclophanes-N-([2.2]-Paracyclophanylcarbamoyl)-4-([2.2]Paracyclophanylcarboxamide, [2.2]Paracyclophanyl-Substituted Triazolthiones and -Substituted Oxadiazoles.

The manuscript describes the synthesis of new racemic and chiral linked paracyclophane assigned as N-5-(1,4(1,4)-dibenzenacyclohexaphane-12-yl)carbamoyl)-5'-(1,4(1,4)-dibenzenacyclohexaphane-12-yl)carboxamide. The procedure depends upon the reaction of 5-(1,4(1,4)-dibenzenacyclohexaphane-12-yl)hydrazide with 5-(1,4(1,4)-dibenzenacyclohexaphane-12-yl)isocyanate. To prepare the homochiral linked paracyclophane of a compound, the enantioselectivity of 5-(1,4(1,4)-dibenzenacyclohexaphane-12-yl)carbaldehyde (enantiomeric purity 60% ee), was oxidized to the corresponding acid, which on chlorination, gave the corresponding acid chloride of [2.2]paracyclophane. Following up on the same procedure applied for the preparation of racemic-carbamoyl and purified by HPLC purification, we succeeded to obtain the target Sp-Sp-N-5-(1,4(1,4)-dibenzenacyclohexaphane-12-yl)carbamoyl)-5'-(1,4(1,4)-dibenzenacyclohexaphane-12-yl)carboxamide. Subjecting N-5-(1,4(1,4)-dibenzenacyclohexaphane-12-yl)hydrazide to various isothiocyanates, the corresponding paracyclophanyl-acylthiosemicarbazides were obtained. The latter compounds were then cyclized to a new series of 5-(1,4(1,4)-dibenzenacyclohexaphane-12-yl)-2,4-dihydro-3H-1,2,4-triazol-3-thiones. 5-(1,4(1,4)-Dibenzenacyclohexaphane-12-yl)-1,3,4-oxadiazol-2-amines were also synthesized in good yields via internal cyclization of the same paracyclophanyl-acylthiosemicarbazides. NMR, IR, and mass spectra (HRMS) were used to elucidate the structure of the obtained products. The X-ray structure analysis was also used as an unambiguous tool to elucidate the structure of the products.

Design, synthesis ADMET and molecular docking of new imidazo[4,5-b]pyridine-5-thione derivatives as potential tyrosyl-tRNA synthetase inhibitors.

In our effort of discovering new antimicrobial agents, a novel series of imidazo[4,5-b]pyridine-5-thione scaffolds were designed and synthesized and their chemical structures were characterized by physicochemical and spectral analysis. The synthesized compounds were assessed for their in vitro antimicrobial activities against pathogenic microorganisms. Results revealed that out the tested compounds, 3 exhibited the potent inhibitory effect (MIC = 0.49 µg/mL) as compared to the positive control, chloramphenicol (0.98 µg/mL) which predicted also to have the best pharmacokinetic and druglikness properties as well as lower toxicity profiles. Preliminary structure-activity relationships (SARs) study has been also investigated. Moreover, to understand the binding patterns of the tested compounds in the Staphylococcus aureus tyrosyl-tRNA synthetase active site, molecular docking study using the most active compound 3 was carried out. The obtained results indicate that analog 3 can potentially bound to the target enzyme with the highest docking score (-9.37 kcal/mol). Overall, our results showed that antimicrobial activity as well as ADMET and toxicity predictions were in consensus with the docking results.

Synthesis and biological evaluation of ß-lapachone-monastrol hybrids as potential anticancer agents.

A series of novel ß-lapachone analogs was designed and synthesized by replacing pyran ring of ß-lapachone with tetrahydropyrimidinethione moiety of monastrol. These hybrids had potent antiproliferative activity against NQO1-rich cell lines (HepG2 and A549), while NQO1-defficient cell lines (H596 and LO2) were less sensitive to these hybrids. Dicoumarol partially inhibited the activity of these compounds against A549 cell lines, indicating that the activation of biological reduction mediated by NQO1 might partly affect the antiproliferative effects. NQO1 assay and docking study demonstrated 4j was a good substrate of NQO1. Furthermore, as suggested by cellular mechanistic research concerning antitumor activity, the representative compound 4j resulted in ROS production depending on NQO1, then oxidative stress triggered apoptotic cell death. Importantly, 4j significantly suppressed cancer growth in HepG2 xenograft models without obvious toxicity, suggesting that 4j deserve further research as potent antitumor agents for cancer therapy.

N-Substituted pyrimidinethione and acetophenone derivatives as a new therapeutic approach in diabetes.

In this study, compounds with 4-hydroxybutyl, 4-phenyl, 5-carboxylate, and pyrimidine moieties were determined as α-glycosidase inhibitors. N-Substituted pyrimidinethione and acetophenone derivatives (A1-A5, B1-B11, and C1-C11) were good inhibitors of the α-glycosidase enzyme, with Ki values in the range of 104.27 ± 15.75 to 1,004.25 ± 100.43 nM. Among them, compound B7 was recorded as the best inhibitor, with a Ki of 104.27 ± 15.75 nM against α-glycosidase. In silico studies were carried out to clarify the binding affinity and interaction mode of the compounds with the best inhibition score against α-glycosidase from Saccharomyces cerevisiae. Compounds B7 (S) and B11 (R) exhibited a good binding affinity with docking scores of -8.608 and 8.582 kcal/mol, respectively. The docking results also showed that the 4-hydroxybutyl and pyrimidinethione moieties play a key role in S. cerevisiae and human α-glycosidase inhibition.

Design, synthesis, and molecular docking study of new monastrol analogues as kinesin spindle protein inhibitors.

Lung, colorectal, and breast cancers are the top three types of cancer by incidence and are responsible for one-third of the cancer incidence and mortality. A series of 18 3,4-dihydropyrimidine analogues bearing a 1,2-methylenedioxybenzene component at position 4 with diverse side chains at positions 5 and 6 was designed and synthesized as inhibitors of the Eg5 kinesin enzyme. Target compounds were screened for their anticancer activity according to the NCI-USA protocol toward a panel of 60 cancer cell lines. Compounds 12a and 12b displayed the best antiproliferation activity against many cell lines. Interestingly, compound 12a displayed lethal effects against non-small-cell lung cancer NCI-H522 cells (-42.26%) and MDA-MB-468 breast cancer cells (-1.10%) at a single-dose assay concentration of 10-5 M. Compounds 11c, 11d, 11g, 12a-d, 13, 15, and 18a were assayed against the kinesin enzyme, with IC50 values ranging from 1.2 to 18.71 µM, which were more potent compared with monastrol (IC50 = 20 µM). Cell cycle analysis of NCI-H522 cells treated with compound 12a showed cell cycle arrest at the G2/M phase. Furthermore, the expression levels of active caspase-3 and -9 were measured. A molecular docking study was performed for some demonstrative compounds as well as monastrol docked into the allosteric binding site of the kinesin spindle protein.

Synthesis, anti-inflammatory activity, and molecular docking studies of some novel Mannich bases of the 1,3,4-oxadiazole-2(3H)-thione scaffold.

A series of novel ibuprofen and salicylic acid-based 3,5-disubstituted-1,3,4-oxadiazole-2(3H)-thione derivatives was synthesized, and they were evaluated as potential anti-inflammatory agents. Following the structure identification studies employing IR, 1 H nuclear magnetic resonance (NMR), 13 C NMR, and elemental analysis, the title compounds were tested by cyclooxygenase (COX)-1 and COX-2 inhibition assays concomitant to lipopolysaccharide (LPS)-induced nitric oxide and prostaglandin production prevention experiments. The results indicated that the majority of the compounds displayed either a superior or comparable activity in preventing both LPS-induced NO production and COX-1 activity in comparison to the activities of the reference molecules. Furthermore, docking studies were also performed to reveal possible interactions with the COX enzymes.

The In Vitro Anticancer Activity and Potential Mechanism of Action of 1-[(1R,2S)-2-fluorocyclopropyl]Ciprofloxacin-(4-methyl/phenyl/benzyl-3- aryl)-1,2,4-triazole-5(4H)-thione Hybrids.

AIM: Development of 1-[(1R, 2S)-2-fluorocyclopropyl]ciprofloxacin-1,2,4-triazole-5(4H)- thione hybrids as potential dual-acting mechanism anticancer agent to overcome the drug resistance. BACKGROUND: Chemotherapy is an essential tool for the treatment of lung and female breast cancers, and numerous anticancer agents have been launched for this purpose. However, the clinical outcomes of chemotherapy are usually far from satisfactory due to the side effects and resistance to chemotherapeutic drugs. Thus, it is urgent to develop novel anti-lung and anti-breast cancer agents. OBJECTIVE: The primary objective of this study was to evaluate the potential of bis-isatin scaffolds with alkyl/ether linkers between the two isatin moieties against different human breast cancer cell lines including A549, MCF-7 and their drug-resistant counterparts A549/CDDP, MCF-7/ADM cells. METHODS: The 1-[(1R, 2S)-2-fluorocyclopropyl]ciprofloxacin-(4-methyl/phenyl/benzyl-3-aryl)-1,2,4- triazole-5(4H)-thione hybrids were screened for their in vitro activity against drug-sensitive lung (A549), breast (MCF-7) and their drug-resistant counterparts A549/CDDP (cisplatin-resistant), MCF- 7/ADM (doxorubicin-resistant) cancer cell lines by MTT assay. The inhibitory activity of these hybrids against topoisomerase II and EGFR was also evaluated to investigate the potential mechanism of action of these hybrids. RESULTS: The most prominent hybrid 7k (IC50: 37.28-49.05 µM) was comparable to Vorinostat against A549 and A549/CDDP lung cancer cells, and was 2.79-2.94 times more active than Vorinostat against MCF-7 and MCF-7/ADM breast cancer cell lines. Moreover, hybrid 7k (IC50: 8.6 and 16.4 µM) also demonstrated dual inhibition against topoisomerase II and EGFR. CONCLUSION: The 1-[(1R, 2S)-2-fluorocyclopropyl]ciprofloxacin-1,2,4-triazole-5(4H)-thione hybrids possess equally activity against both drug-sensitive cancer cells and their drug-resistant counterparts, and the majority of them were no inferior to the reference Vorinostat. The mechanistic study revealed that these hybrids could inhibit both topoisomerase II and EGFR, so these hybrids can be developed as dual-acting mechanism anticancer agents.

Development, synthesis and biological investigation of a novel class of potent PC-PLC inhibitors.

Phospholipases are enzymes that are involved in the hydrolysis of acyl and phosphate esters of phospholipids, generating secondary messengers that have implications in various cellular processes including proliferation, differentiation and motility. As such inhibitors of phospholipases have been widely studied for their use as anti-cancer therapeutics. Phosphatidylcholine-specific phospholipase C (PC-PLC) is implicated in the progression of a number of cancer cell lines including aggressing triple-negative breast cancers. Most current studies on PC-PLC have utilised D609 as the standard inhibitor however it is known to have multiple failings, including poor stability in aqueous media. 2-Morpholinobenzoic acids were recently identified using vHTS as a potential class of lead compounds, with improvements over D609. In this work 129 analogues in this class were prepared and their PC-PLC inhibitory activity was assessed. It was found that the majority of these novel compounds had improved activity when compared to D609 with the most potent inhibitors completely inhibiting enzyme activity. It was determined that the best compound/s contained a morpholino and 2-substituted N-benzyl moieties with these findings explained using molecular modelling. The compounds reported here will allow for improved study of PC-PLC activity.

A One-pot Synthesis of Novel Derivatives of Oxadiazine-4-thione, and its Antibacterial Activity, and Molecular Modeling Studies.

BACKGROUND: The synthesis of a novel series of oxadiazine-4-thione biological molecules was executed through the incorporation of the ortho-, meta-, and para-benzoyl isocyanates to the tetrabromophthalimide nucleus. OBJECTIVES: A one-pot multicomponent methodology in a solvent-free microwave irradiation environment was employed to afford this series of oxadiazine-4-thione, deriving a comparison with the conventional method. Subsequently, the yielded derivatives were subjected to further biological assessment. MATERIALS AND METHODS: The acquired results denoted that the one-pot procedure, which delivered products in a 2-4 min. interval, was more efficient in evaluation against the classical method, which consumed a 1-2:30 hr. interval. RESULTS: The application of the antibacterial analyses was subjected to all the compounds, resulting in molecules 6a and 6c demonstrating the highest activity regarding Aspergillus Favus; molecules 5b and 5c exhibiting an equivalent level of activity towards E-coli and Fusarium Moniliform; and molecules 4b, 4c, 5b, and 5c presenting an identical level of activity to the aforementioned derivatives involving Staphylococcus. Concluison: Molecular modeling studies by the MOE, the preceding antibacterial behavior was conducted to advocate the newly prepared compounds. Moreover, the spectroscopic approaches were exploited to verify and establish the structures and mechanisms of the synthesized derivatives' reactions.

Synthesis, Modification, and Biological Evaluation of a Library of Novel Water-Soluble Thiopyridone-Based Organometallic Complexes and Their Unexpected (Biological) Behavior.

A series of 16 dinuclear thiopyridone-based organometallics with excellent water solubility, increased stability and remarkable cytotoxicity were synthesized and characterized. The complexes of this work formed dimeric species featuring a double positive charge in polar protic solvents, accounting for their outstanding solubility in aqueous solution. Most of them displayed higher antiproliferative activity than their parental thiomaltol complex, with unexpected cytotoxicity trends depending on the employed metal center, ligand modification, and cell line. Insights into their behavior in biological systems were gathered by means of amino-acid interaction studies, cytotoxicity tests in 3D spheroid models, laser ablation, cellular accumulation measurements, as well as cell cycle experiments.