Tailored quinoline hybrids as promising COX-2/15-LOX dual inhibitors endowed with diverse safety profile: Design, synthesis, SAR, and histopathological study.

Complications of the worldwide use of non-steroidal anti-inflammatory drugs (NSAIDs) sparked scientists to design novel harmless alternatives as an urgent need. So, a unique hybridization tactic of quinoline/pyrazole/thioamide (4a-c) has been rationalized and synthesized as potential COX-2/15-LOX dual inhibitors, utilizing relevant reported studies on these pharmacophores. Moreover, we extended these preceding hybrids into more varied functionality, bearing crucial thiazole scaffolds(5a-l). All the synthesized hybrids were evaluatedin vitroas COX-2/15-LOX dual inhibitors. Initially, series4a-cexhibited significant potency towards 15-LOX inhibition (IC50 = 5.454-4.509 µM) compared to meclofenamate sodium (IC50 = 3.837 µM). Moreover, they revealed reasonable inhibitory activities against the COX-2 enzyme in comparison to celecoxib.Otherwise, conjugates 5a-ldisclosed marked inhibitory activity against 15-LOX and strong inhibitory to COX-2. In particular, hybrids5d(IC50 = 0.239 µM, SI = 8.95), 5h(IC50 = 0.234 µM, SI = 20.35) and 5l (IC50 = 0.201 µM, SI = 14.42) revealed more potency and selectivity outperforming celecoxib (IC50 = 0.512 µM, SI = 4.28). In addition, the most potentcompounds, 4a, 5d, 5h, and 5l have been elected for further in vivoevaluation and displayed potent inhibition of edema in the carrageenan-induced rat paw edema test that surpassed indomethacin. Further, compounds5d, 5h, and 5l decreased serum inflammatory markers including oxidative biomarkersiNO, and pro-inflammatory mediators cytokines like TNF-α, IL-6, and PGE. Ulcerogenic liability for tested compounds demonstrated obvious gastric mucosal safety. Furthermore, a histopathological study for compound 5l suggested a confirmatory comprehensive safety profile for stomach, kidney, and heart tissues. Docking and drug-likeness studies offered a good convention with the obtained biological investigation.

Synthesis and evaluation of novel N1-acylated 5-(4-pyridinyl)indazole derivatives as potent and selective haspin inhibitors.

Protein kinase dysregulation was strongly linked to cancer pathogenesis. Moreover, histone alterations were found to be among the most important post-translational modifications that could contribute to cancer growth and development. In this context, haspin, an atypical serine/threonine kinase, phosphorylates histone H3 at threonine-3 and is notably overexpressed in various common cancer types. Herein, we report novel 5-(4-pyridinyl)indazole derivatives as potent and selective haspin inhibitors. Amide coupling at N1 of the indazole ring with m-hydroxyphenyl acetic acid yielded compound 21 with an IC50 value of 78 nM against haspin. This compound showed a meaningful selectivity over 15 of the most common off-targets, including Clk 1-3 and Dyrk1A, 1B, and 2. The most potent haspin inhibitors 5 and 21 effectively inhibited the growth of the NCI-60 cancer cell lines, further emphasizing the success of our scaffold as a new selective lead for the development of anti-cancer therapeutic agents.

N- and s-substituted Pyrazolopyrimidines: A promising new class of potent c-Src kinase inhibitors with prominent antitumor activity.

In this work, readily achievable synthetic pathways were utilized for construction of a library of N/S analogues based on the pyrazolopyrimidine scaffold with terminal alkyl or aryl fragments. Subsequently, we evaluated the anticancer effects of these novel analogs against the proliferation of various cancer cell lines, including breast, colon, and liver lines. The results were striking, most of the tested molecules exhibited strong and selective cytotoxic activity against the MDA-MB-231 cancer cell line; IC50 1.13 µM. Structure-activity relationship (SAR) analysis revealed that N-substituted derivatives generally enhanced the cytotoxic effect, particularly with aliphatic side chains that facilitated favorable target interactions. We also investigated apoptosis, DNA fragmentation, invasion assay, and anti-migration effects, and discussed their underlying molecular mechanisms for the most active compound 7c. We demonstrated that 7c N-propyl analogue could inhibit MDA-MB-231 TNBC cell proliferation by inducing apoptosis through the regulation of vital proteins, namely c-Src, p53, and Bax. In addition, our results also revealed the potential of these compounds against tumor metastasis by downregulating the invasion and migration modes. Moreover, the in vitro inhibitory effect of active analogs against c-Src kinase was studied and proved that might be the main cause of their antiproliferative effect. Overall, these compelling results point towards the therapeutic potential of these derivatives, particularly those with N-substitution as promising candidates for the treatment of TNBC type of breast cancer.

N1-Benzoylated 5-(4-pyridinyl)indazole-based kinase inhibitors: Attaining haspin and Clk4 selectivity via modulation of the benzoyl substituents.

Haspin and Clk4 are both understudied protein kinases (PKs), offering potential targets for the development of new anticancer agents. Thus, the identification of new inhibitors targeting these PKs is of high interest. However, the inhibitors targeting haspin or Clk4 developed to date show a poor selectivity profile over other closely related PKs, increasing the risk of side effects. Herein, we present two newly developed N1-benzyolated 5-(4-pyridinyl)indazole-based inhibitors (18 and 19), derived from a newly identified indazole hit. These inhibitors exhibit an exceptional inhibitory profile toward haspin and/or Clk4. Compound 18 (2-acetyl benzoyl) showed a preference to inhibit Clk4 and haspin over a panel of closely related kinases, with sixfold selectivity for Clk4 (IC50 = 0.088 and 0.542 µM, respectively). Compound 19 (4-acetyl benzoyl) showed high selectivity against haspin over the common off-target kinases (Dyrks and Clks) with an IC50 of 0.155 µM for haspin. Molecular docking studies explained the remarkable selectivity of 18 and 19, elucidating how the new scaffold can be modified to toggle between inhibition of haspin or Clk4, despite the high homology of the ATP-binding sites. Their distinguished profile allows these compounds to be marked as interesting chemical probes to assess the selective inhibition of haspin and/or Clk4.

Development and evaluation of 2,4-disubstituted-5-aryl pyrimidine derivatives as antibacterial agents.

Designing novel candidates as potential antibacterial scaffolds has become crucial due to the lack of new antibiotics entering the market and the persistent rise in multidrug resistance. Here, we describe a new class of potent antibacterial agents based on a 5-aryl-N2,N4-dibutylpyrimidine-2,4-diamine scaffold. Structural optimization focused on the 5-aryl moiety and the bioisosteric replacement of the side chain linker atom. Screening of the synthesized compounds focused on a panel of bacterial strains, including gram-positive Staphylococcus aureus strains (Newman MSSA, methicillin- and vancomycin-resistant), and the gram-negative Escherichia coli (ΔAcrB strain). Several compounds showed broad-spectrum antibacterial activity with compound 12, bearing a 4-chlorophenyl substituent, being the most potent among this series of compounds. This frontrunner compound revealed a minimum inhibitory concentration (MIC) value of 1 µg/mL against the S. aureus strain (Mu50 methicillin-resistant S. aureus/vancomycin-intermediate S. aureus) and an MIC of 2 µg/mL against other tested strains. The most potent derivatives were further tested against a wider panel of bacteria and evaluated for their cytotoxicity, revealing further potent activities toward Streptococcus pneumoniae, Enterococcus faecium, and Enterococcus faecalis. To explore the mode of action, compound 12 was tested in a macromolecule inhibition assay. The obtained data were supported by the safety profile of compound 12, which possessed an IC50 of 12.3 µg/mL against HepG2 cells. The current results hold good potential for a new class of extended-spectrum antibacterial agents.

An overview of cdc2-like kinase 1 (Clk1) inhibitors and their therapeutic indications.

Over the past decade, Clk1 has been identified as a promising target for the treatment of various diseases, in which deregulated alternative splicing plays a role. First small molecules targeting Clk1 are in clinical trials for the treatment of solid cancer, where variants of oncogenic proteins derived from alternative splicing promote tumor progression. Since many infectious pathogens hi-jack the host cell's splicing machinery to ensure efficient replication, further indications in this area are under investigation, such as Influenza A, HIV-1 virus, and Trypanosoma infections, and more will likely be discovered in the future. In addition, Clk1 was found to contribute to the progression of Alzheimer's disease through causing an imbalance of tau splicing products. Interestingly, homozygous Clk1 knockout mice showed a rather mild phenotype, opposed to what might be expected in view of the profound role of Clk1 in alternative splicing. A major drawback of most Clk1 inhibitors is their insufficient selectivity; in particular, Dyrk kinases and haspin were frequently identified as off-targets, besides the other Clk isoforms. Only few inhibitors were shown to be selective over Dyrk1A and haspin, whereas no Clk1 inhibitor so far achieved selectivity over the Clk4 isoform. In this review, we carefully compiled all Clk1 inhibitors from the scientific literature and summarized their structure-activity relationships (SAR). In addition, we critically discuss the available selectivity data and describe the inhibitor's efficacy in cellular models, if reported. Thus, we provide a comprehensive overview on the current state of Clk1 drug discovery and highlight the most promising chemotypes.

Human 'knockouts' of CSF3 display severe congenital neutropenia.

Colony-stimulating factor 3 (CSF3) is a key factor in neutrophil production and function, and recombinant forms have been used clinically for decades to treat congenital and acquired neutropenia. Although biallelic inactivation of its receptor CSF3R is a well-established cause of severe congenital neutropenia (SCN), no corresponding Mendelian disease has been ascribed to date to CSF3. Here, we describe three patients from two families each segregating a different biallelic inactivating variant in CSF3 with SCN. Complete deficiency of CSF3 as a result of nonsense-mediated decay (NMD) could be demonstrated on RT-PCR using skin fibroblasts-derived RNA. The phenotype observed in this cohort mirrors that documented in mouse and zebrafish models of CSF3 deficiency. Our results suggest that CSF3 deficiency in humans causes a novel autosomal recessive form of SCN.

Design, synthesis, and metabolite identification of Tamoxifen esterase-activatable prodrugs.

Tamoxifen (TAM) is used in treatment of hormonal dependent breast cancer, both in premenopausal and postmenopausal women. TAM is intrinsically metabolized by CYP450 enzymes to more active metabolites. Recent reports identified CYP2D6, an enzyme involved in the conversion of TAM to the more potent 4-OH-TAM, is encoded by theCYP2D6gene, which is highly polymorphic. Women with inactive alleles are poor metabolizers; in many cases they suffer acquired TAM resistance. Herein we report synthesis and biological evaluation of novel TAM analogues. The novel analogues are designed to elude CYP2D6 metabolism. Hydrolysis of the carbamate moiety on ring C is mediated via carboxylesterases. Compound 3d [E/Z Benzyl-carbamic acid4-{2-benzyl-1-[4-(2-pyrrolidin-1-yl-ethoxy)-phenyl]-but-1-enyl}-phenyl ester] showed GI50 = 0.09 µM on MCF-7 and GI50 = 1.84 µM on MDA-MB231 cell lines. To further validate our hypothesis, metabolites of selected novel analogues were determined in vitro under different incubation conditions. The hydroxylated analogues were obtained under non CYP2D6 dependent conditions. Compound 8d, a benzyl carbamate derivative, was the least-stable analog and showed the highest rate of metabolism among all tested analogues. Our in silico model showed the novel flexible analogues can still adopt an antiestrogenic binding profile occupying the same pocket as 4-OH-TAM.

Novel benzothiazole derivatives as multitargeted-directed ligands for the treatment of Alzheimer's disease.

Neurodegenerative diseases such as Alzheimer's disease (AD) are multifactorial with several different pathologic mechanisms. Therefore, it is assumed that multitargeted-directed ligands (MTDLs) which interact with different biological targets relevant to the diseases, might offer an improved therapeutic alternative than using the traditional "one-target, one-molecule" approach. Herein, we describe new benzothiazole-based derivatives as a privileged scaffold for histamine H3 receptor ligands (H3R). The most affine compound, the 3-(azepan-1-yl)propyloxy-linked benzothiazole derivative 4b, displayed a Ki value of 0.012 µM. The multitargeting potential of these H3R ligands towards AChE, BuChE and MAO-B enzymes was evaluated to yield compound 3s (pyrrolidin-1-yl-(6-((5-(pyrrolidin-1-yl)pentyl)oxy)benzo[d]thiazol-2-yl)methanone) as the most promising MTDL with a Ki value of 0.036 µM at H3R and IC50 values of 6.7 µM, 2.35 µM, and 1.6 µM towards AChE, BuChE, and MAO-B, respectively. These findings suggest that compound 3s can be a lead structure for developing new multi-targeting anti-AD agents.

Development of Novel Class of Phenylpyrazolo[3,4-d]pyrimidine-Based Analogs with Potent Anticancer Activity and Multitarget Enzyme Inhibition Supported by Docking Studies.

Phenylpyrazolo[3,4-d]pyrimidine is considered a milestone scaffold known to possess various biological activities such as antiparasitic, antifungal, antimicrobial, and antiproliferative activities. In addition, the urgent need for selective and potent novel anticancer agents represents a major route in the drug discovery process. Herein, new aryl analogs were synthesized and evaluated for their anticancer effects on a panel of cancer cell lines: MCF-7, HCT116, and HePG-2. Some of these compounds showed potent cytotoxicity, with variable degrees of potency and cell line selectivity in antiproliferative assays with low resistance. As the analogs carry the pyrazolopyrimidine scaffold, which looks structurally very similar to tyrosine and receptor kinase inhibitors, the potent compounds were evaluated for their inhibitory effects on three essential cancer targets: EGFRWT, EGFRT790M, VGFR2, and Top-II. The data obtained revealed that most of these compounds were potent, with variable degrees of target selectivity and dual EGFR/VGFR2 inhibitors at the IC50 value range, i.e., 0.3-24 µM. Among these, compound 5i was the most potent non-selective dual EGFR/VGFR2 inhibitor, with inhibitory concentrations of 0.3 and 7.60 µM, respectively. When 5i was tested in an MCF-7 model, it effectively inhibited tumor growth, strongly induced cancer cell apoptosis, inhibited cell migration, and suppressed cell cycle progression leading to DNA fragmentation. Molecular docking studies were performed to explore the binding mode and mechanism of such compounds on protein targets and mapped with reference ligands. The results of our studies indicate that the newly discovered phenylpyrazolo[3,4-d]pyrimidine-based multitarget inhibitors have significant potential for anticancer treatment.

Implementation of Biopolymeric Nanomaterials to Reduce the Negative Impacts of Salinity on Tomato Quantity and Quality.

Sustainable waste reduction strategies and innovative waste reduction concepts, as well as their application in the creation of compounds and products with added value, can benefit the economy while reducing environmental pressures. This research aimed to use biopolymeric nanomaterials to reduce the negative effects of salinity on tomato yield and quality. Three types of biopolymers (cellulose, pectin, and starch) were synthesized and characterized using natural materials such as rice straw, orange peel, and potato peel. The polymer's ability to retain sodium ions was investigated. A greenhouse experiment was conducted to assess the potential of natural polymers (cellulose, starch, and pectin individually or in combination) to reduce the salinity side effects on tomato plants (Solanum Lycopersicon L.) cultivar (Super Strain B). Tomato seeds were germinated on soil bits for 20 days before planting five seedlings in each pot (20 cm diameter) with three replicates and filling each pot with sandy loam soil, with or without natural polymers at a rate of 2 g/Kg. The results revealed that all the polymers utilized had a superlative capability to hold sodium ions for both soluble and exchanged sodium. The use of various natural polymer hydrogels increased the number and fresh weight of tomato fruits. Data showed that using biopolymers hydrogels reduced salinity stress by rising the content of phenol, flavonoid, and antioxidant enzymes such as catalase and peroxidase. The use of natural biopolymers significantly improved total soluble solids, pH, and juice substance. Implementing biopolymeric materials could reduce environmental pressures while increasing farm income. Innovative waste reduction strategies, such as the creation of value-added products, will benefit the economy, and this work is a good start in that direction.

Novel 9-Benzylaminoacridine Derivatives as Dual Inhibitors of Phosphodiesterase 5 and Topoisomerase II for the Treatment of Colon Cancer.

It has been shown that phosphodiesterase 5 (PDE5) inhibitors have anticancer effects in a variety of malignancies in both in vivo and in vitro experiments. The role of cGMP elevation in colorectal carcinoma (CRC) has been extensively studied. Additionally, DNA topoisomerase II (Topo II) inhibition is a well-established mechanism of action that mediates the effects of several approved anticancer drugs such as doxorubicin and mitoxantrone. Herein, we present 9-benzylaminoacridine derivatives as dual inhibitors of the PDE5 and Topo II enzymes. We synthesized 31 derivatives and evaluated them against PDE5, whereby 22 compounds showed micromolar or sub-micromolar inhibition. The anticancer activity of the compounds was evaluated with the NCI 60-cell line testing. Moreover, the effects of the compounds on HCT-116 colorectal carcinoma (CRC) were extensively studied, and potent compounds against HCT-116 cells were studied for their effects on Topo II, cell cycle progression, and apoptosis. In addition to exhibiting significant growth inhibition against HCT116 cells, compounds 11, 12, and 28 also exhibited the most superior Topo II inhibitory activity and low micromolar PDE5 inhibition and affected cell cycle progression. Knowing that compounds that combat cancer through multiple mechanisms are among the best candidates for effective therapy, we believe that the current class of compounds merits further optimization and investigation to unleash their full therapeutic potential.

Novel 2,4-disubstituted quinazoline analogs as antibacterial agents with improved cytotoxicity profile: Modification of the benzenoid part.

Bacterial resistance to currently used antibiotics demands the development of novel antibacterial agents with good safety margins and sufficient efficacy against multi-drug resistant isolates. We have previously described the synthesis of N-butyl-2-(butylthio)quinazolin-4-amine (I) as an optimized hit with broad-spectrum antibacterial activity and low cytotoxicity. In addition, we have identified a potential growing vector for this series of compounds. Herein, we describe further hit optimization which includes systematic diversifications of both the benzenoid part and the substituents at position 6 and 7 of compound I. Growing of the molecule beside the core modifications yielded several compounds with remarkable anti(myco)bacterial activity against a panel of pathogenic bacteria, including drug-resistant strains. Compound 12 showed a 2-4 fold improvement in activity than I against S. aureus Newman, S. pneumoniae DSM-20566 and E. faecalis DSM-20478. The compounds also showed a good safety profile towards human HepG2 cells.

From EGFR kinase inhibitors to anti-inflammatory drugs: Optimization and biological evaluation of (4-(phenylamino)quinazolinyl)-phenylthiourea derivatives as novel NF-κB inhibitors.

The transcription factor NF-κB is a pivotal mediator of chronic inflammatory and autoimmune diseases. Based on our previously published dual EGFR/NF-κB inhibitors, we designed and synthesized new thiourea quinazoline derivatives that retained only the NF-κB inhibitory activity. Several congeners displayed a strong suppression of NF-κB activity in a reporter gene assay, yet low cytotoxicity, and were further evaluated in differentiated macrophage-like THP-1 cells. The compounds exhibited a strong inhibition of IL-6 and, less potently, of TNFα release, which was accompanied by a selective induction of macrophage cell death. The mode of action was investigated with a selected inhibitor, 18, revealing that the translocation of p65/RelA to the nucleus but not its release from the IκB complex was inhibited. Eventually, 18 was identified as the first small molecule inhibitor affecting only the phosphorylation of p65-Ser468 but not of Ser536, which may be causally related to the retention of NF-κB in the cytoplasm. Altogether, our novel NF-κB inhibitors seem applicable for the suppression of cytokine release and the additional selective depletion of activated macrophages in various inflammatory diseases.

From triazolophthalazines to triazoloquinazolines: A bioisosterism-guided approach toward the identification of novel PCAF inhibitors with potential anticancer activity.

Inhibition of PCAF bromodomain has been validated as a promising strategy for the treatment of cancer. In this study, we report the bioisosteric modification of the first reported potent PCAF bromodomain inhibitor, L-45 to its triazoloquinazoline bioisosteres. Accordingly, three new series of triazoloquinazoline derivatives were designed, synthesized, and assessed for their anticancer activity against a panel of four human cancer cells. Three derivatives demonstrated comparable cytotoxic activity with the reference drug doxorubicin. Among them, compound 22 showed the most potent activity with IC50 values of 15.07, 9.86, 5.75, and 10.79 µM against Hep-G2, MCF-7, PC3, and HCT-116 respectively. Also, compound 24 exhibited remarkable cytotoxicity effects against the selected cancer cell lines with IC50 values of 20.49, 12.56, 17.18, and 11.50 µM. Compounds 22 and 25 were the most potent PCAF inhibitors (IC50, 2.88 and 3.19 µM, respectively) compared with bromosporine (IC50, 2.10 µM). Follow up apoptosis induction and cell cycle analysis studies revealed that the bioisostere 22 could induce apoptotic cell death and arrest the cell cycle of PC3 at the G2/M phase. The in silico molecular docking studies were additionally performed to rationalize the PCAF inhibitory effects of new triazoloquinazoline bioisosteres.

In vivo screening and toxicity studies of indolinone incorporated thiosemicarbazone, thiazole and piperidinosulfonyl moieties as anticonvulsant agents.

Based on the biological importance of the thiazole nucleus, we decided to prepare and evaluate the biological activity of some new isatin derivatives containing thiazole moiety. The 5-(piperidin-1-ylsulfonyl)indoline-2,3-dione (1) was prepared and used as a starting material in the synthesis of many isatin derivatives for anticonvulsant evaluation. All the newly synthesized thiazlidino/thiosemicarbazide-indolin-2-one derivatives screened in vivo for their anticonvulsant activity against pentylenetetrazole-induced convulsions in mice. The results were compared with phenobarbitone sodium as a standard anticonvulsant drug. Most of the tested compounds exhibited anticonvulsant activity with relative potency ranging from 0.02 to 0.2 in comparison to standard drug phenobarbitone. The most active compounds 3, 6a, 6c and 8, were exposed to further investigations in rats to evaluate the effect of most active derivatives on the haematological, liver, kidney functions as well as histopathological studies of the liver and kidney tissues. Finally, the most potent compounds 3, 6a, 6c and 8 observed good toxic properties for both liver and kidney function with mild variability changes on RBCs, WBCs, Platelets, Hb, AST, ALT, and creatinine level, as well as kidney and liver tissue and these good results obtained rather than used low dose from phenobarbitone.

Design, Synthesis, biological Evaluation, and molecular docking studies of novel Pyrazolo[3,4-d]Pyrimidine derivative scaffolds as potent EGFR inhibitors and cell apoptosis inducers.

A series of novel hybrid pyrazolo[3,4-d]pyramidine derivatives was designed and chemically synthesized in useful yields. The synthesized compounds were structurally characterized by the usual techniques. All the new synthesized compounds were biologically screened in vitro for their antiproliferative activities against a panel of four cancer cell lines, namely HepG-2, MCF-7, HCT-116, and Hela. The results of cytotoxic evaluation indicated that compound 14d was appeared to be the most prominent broad-spectrum cytotoxic activity and significantly more potent than sorafenib with IC50 values of 4.28, 5.18, 3.97, and 9.85 µM against four cell lines (HePG2, Hela, HCT-116 and MCF-7). In addition, compound 15 was displayed promising antiproliferative effect against all tested cell lines with IC50 value less than 11 µM compared with sorafenib as a control drug. Besides, structurally pharmacophoric features indicated that pyrazolo[3,4-d]pyrimidine scaffold having an amide linker and substituted with phenyl moiety at the 5-position was more potent than those possessing azomethine methyl, azomethine proton and carbomethene linkers, which lead to significant decrease in antiproliferative activity. The most potent compounds were further selected and evaluated for their activities against epidermal growth factor receptor (EGFR) kinase inhibitors according to homogenous time resolved fluorescence (HTRF) assay. The most potent compound 14d exhibited the most promising inhibitory activity against EGFRWT with IC50 value of 56.02 ± 1.38 µM compared with gefitinib as control drug with IC50 value of 41.79 ± 1.07 µM. Moreover, the inhibition of cell cycle progression and induction of apoptosis in the A549 cell line at G2/M and pre-G1 phases of cell cycle might contribute to cancer treatment that evaluated by Annexin V-FITC/PI double staining detection method. Finally, molecular docking studies were conducted to investigate that probable binding conformations of these anticancer agents and ADME properties were calculated to predict pharmacokinetics and toxic properties of the target compounds.

Development of fluorinated and methoxylated benzothiazole derivatives as highly potent and selective cannabinoid CB2 receptor ligands.

The upregulation of the CB2 receptors in neuroinflammation and cancer and their potential visualization with PET (positron emission tomography) could provide a valuable diagnostic and therapy-monitoring tool in such disorders. However, the availability of reliable CB2-selective imaging probes is still lacking in clinical practice. We have recently identified a benzothiazole-2-ylidine amide hit (6a) as a highly potent CB2 ligand. With the aim of enhancing its CB2 over CB1 selectivity and introducing structural sites suitable for radiolabeling, we herein describe the development of fluorinated and methoxylated benzothiazole derivatives endowed with extremely high CB2 binding affinity and an exclusive selectivity to the CB2 receptor. Compounds 14, 15, 18, 19, 21, 24 and 25 displayed subnanomolar CB2Ki values (ranging from 0.16 nM to 0.68 nM) and interestingly, all of the synthesized compounds completely lacked affinity at the CB1 receptor (Ki > 10,000 nM for all compounds), indicating their remarkably high CB2 over CB1 selectivity factors. The fluorinated analogs, 15 and 21, were evaluated for their in vitro metabolic stability in mouse and human liver microsomes (MLM and HLM). Both 15 and 21 displayed an exceptionally high stability (98% and 91% intact compounds, respectively) after 60 min incubation with MLM. Contrastingly, a 5- and 2.8-fold lower stability was demonstrated for compounds 15 and 21, respectively, upon incubation with HLM for 60 min. Taken together, our data present extremely potent and selective CB2 ligands as credible leads that can be further exploited for 18F- or 11C-radiolabeling and utilization as PET tracers.

In vivo and in vitro anti-inflammatory, antipyretic and ulcerogenic activities of pyridone and chromenopyridone derivatives, physicochemical and pharmacokinetic studies.

Throughout this study, we present the victorious synthesis of a novel class of 2(1H)-pyridone molecules, bearing a 4-hydroxyphenyl moiety through a one-pot reaction of 2-cyano-N-(4-hydroxyphenyl)acetamide with cyanoacetamide, acetylacetone or ethyl acetoacetate, and their corresponding aldehydes. In addition, the chromene moiety was introduced into the pyridine skeleton through the cyclization of the cyanoacetamide 2 with salicylaldehyde, followed by treatment with malononitrile, ethyl cyanoacetate, and cyanoacetamide, in order to improve their biological behaviour. Due to their anti-inflammatory, ulcerogenic, and antipyretic characters, the target molecules have undergone in-vitro and in-vivo examination, that display promising results. Moreover, in order to predict the physicochemical and ADME traits of all synthesized compounds and standard reference drugs, paracetamol and phenylbutazone, the in-silico prediction methodology was provided.

Novel 2,4-disubstituted quinazoline analogs as antibacterial agents with improved cytotoxicity profile: Optimization of the 2,4-substituents.

The emergence of bacterial resistance has triggered a multitude of efforts to develop new antibacterial agents. There are many compounds in literature that were reported as potent antibacterial agents, however, they lacked the required safety to mammalian cells or no clear picture about their toxicity profile was presented. Inspired by discovered hit from our in-house library and by previously reported 2,4-diaminosubstituted quinazolines, we describe the design and synthesis of novel 2,4-disubstituted-thioquinazolines (3-13 and 36), 2-thio-4-amino substituted quinazolines (14-33) and 6-substituted 2,4-diamonsubstituted quinazolines (37-39). The synthesized compounds showed potent antibacterial activity against a panel of Gram-positive, efflux deficient E.coli and Mycobacterium smegmatis. The panel also involved resistant strains including methicillin-resistant Staphylococcus aureus, penicillin-resistant Streptococcus pneumoniae, vancomycin-resistant Enterococcus faecalis and vancomycin-resistant Enterococcus faecium, in addition to Mycobacterium smegmatis. The newly synthesized compounds revealed MIC values against the tested strains ranging from 1 to 64 µg/mL with a good safety profile. Most of the 2-thio-4-amino substituted-quinazolines showed significant antimycobacterial activity with the variations at position 2 and 4 offering additional antibacterial activity against the different strains. Compared to previously reported 2,4-diaminosubstituted quinazolines, the bioisosteric replacement of the 2-amino with sulfur offered a successful approach to keep the high antibacterial potency while substantially improving safety profile as indicated by the reduced activity on different cell lines and a lack of hemolytic activity.