Design,synthesis and biological evaluation of tricyclic pyrazolo[1,5-c][1,3]benzoxazin-5(5H)-one scaffolds as selective BuChE inhibitors

Based on the structural analysis of tricyclic scaffolds as butyrylcholinesterase (BuChE) inhibitors, a series of pyrazolo[1,5-c][1,3]benzoxazin-5(5H)-one derivatives were designed, synthesized and evaluated for their acetylcholinesterase (AChE) and BuChE inhibitory activity. Compounds with 5-carbonyl and 7- or/and 9-halogen substitutions showed potential BuChE inhibitory activity, among which compounds 6a, 6c and 6g showed the best BuChE inhibition (IC₅₀?=?1.06, 1.63 and 1.63?µM, respectively). The structure–activity relationship showed that the 5-carbonyl and halogen substituents significantly influenced BuChE activity. Compounds 6a and 6g were found nontoxic, lipophilic and exhibited remarkable neuroprotective activity and mixed-type inhibition against BuChE (K_i?=?7.46 and 3.09?µM, respectively). Docking studies revealed that compound 6a can be accommodated into BuChE via five hydrogen bonds, one Pi–Sigma interaction and three Pi–Alkyl interactions.     

Design and synthesis of novel 2-methyl-4,5-substitutedbenzo[f]-3,3a,4,5-tetrahydro-pyrazolo[1,5-d][1,4]oxazepin-8(7H)-one derivatives as telomerase inhibitors

Eight novel 4,5-tetrahydropyrazolo[1,5-d][1,4]oxazepine derivatives have been synthesized and purified to be screened for anticancer activity. By a modified TRAP assay, some titled compounds were tested against telomerase, and compound 4a showed the most potent inhibitory activity with IC₅₀ value at 0.78 ± 0.22 μM. Western blot assays showed that compounds 4a and 4b could inhibit expression of Cyclin D1, TERT, phospho-AKT and PI3K/AKT pathway.     

Design,synthesis and biological evaluation of novel human monoamine oxidase B inhibitors based on a fragment in an X-ray crystal structure

Herein we report our efforts of developing reversible selective hMAO-B inhibitors based on isatin, a fragment in an X-ray crystal structure. Five different scaffolds were designed and many compounds were synthesized. Among them, compound A3 demonstrated very high potency and isoform selectivity against hMAO-B, 11 and 13 times more potent (IC₅₀?=?3?nM) and 23.64 and 6.8 times more selective than the marked drugs, selegiline and safinamide. However, the endeavors to modify the polar 3-one group of isatin, that is in a hydrophobic environment in the binding site of hMAO-B, to small nonpolar hydrophobic groups did not bring about improved hMAO-B inhibitors, which may challenge our understanding of molecular interactions and molecular recognition in biological systems.     

Design,synthesis and molecular docking of novel pyrazolo[1,5-a][1,3,5]triazine derivatives as CDK2 inhibitors

Cyclin Dependent Kinases CDKs unpredictable activity has been accounted for a wide assortment of human malignancies, so it might be conceivable to design pharmacologically relevant ligands that go about as specific and potent inhibitors of CDK2 action. In this respect, a series of novel pyrazolo[1,5-a][1,3,5]triazine derivatives were designed, synthesized and evaluated for CDK2 enzyme inhibitory and anticancer activity. Compounds 9f and 10c showed best CDK2 inhibition among the newly synthesized compounds, with percent inhibition at 82.38%, and 81.96% against CDK2 and IC₅₀ of 1.85 and 2.09 µM, respectively. Additionally, the newly synthesized compounds were tested for their antiproliferative activity against 60 NCI cell lines. Molecular docking revealed the binding mode of these new compounds into the roscovitine binding site of CDK2 enzyme (PDB code: 3ddq). Conclusively, pyrazolotriazine derivatives represent a talented starting point for further study as anticancer drug.     

New coumarin derivatives: Design,synthesis and use as inhibitors of hMAO

A series new 2H-chromene-3-carboxamides (4a–4i) and S-2H-chromene-3-carbothioates (5j–5t) were synthesized and evaluated as monoamine oxidase A and B inhibitors. Among them, compound 5k (IC₅₀ = 0.21 μM, IC_{50 iproniazid} = 7.65 μM) showed the most activity and higher MAO-B selectivity (189.2-fold vs 1-fold) with respect to the MAO-A isoform. The need to clarify at a 3D level some important molecular aspects of discussed SAR, we undertaked a number of docking simulations to better assess. The steric effect was analyzed interms of both posing and scoring by investigating the nature of the binding interactions. The docking results of active compound 5k with hMAO-B complex indicated that conserved residue ILE 199 was important for ligand binding via Sigma–Pi interaction.     

Identification of substituted pyrazolo[1,5-a]quinazolin-5(4H)-one as potent poly(ADP-ribose)polymerase-1 (PARP-1) inhibitors

A novel series of pyrazolo[1,5-a]quinazolin-5(4H)-one derivatives proved to be a potent class of PARP-1 inhibitors. An extensive SAR around the 3-position of pyrazole in the scaffold led to the discovery of amides derivatives as low nanomolar PARP-1 inhibitors.     

Design and synthesis of pyrazolo[3,4-d]pyrimidinone derivatives: Discovery of selective phosphodiesterase-5 inhibitors

A novel series of 1,6-disubstituted pyrazolo[3,4-d]pyrimidin-7-one derivatives, 2a-h, 4a-d, 5 and 6, were successfully synthesized, which showed promising, and potent inhibition of phosphodiesterase 5 (PDE5). The inhibitory activities of 5, 4b, 2a, 2d, 2f, 4d and 4a against PDE5 were similar to that of sildenafil (100%). These compounds exhibited potent relaxant effects on isolated rat cavernosum tissue with pEC₅₀ values ranging from 8.31 to 5.16 µM. Pyrazolo[3,4-d]pyrimidin-7-one scaffolds have been rationally designed via consecutive molecular modelling studies prior to their synthesis and biological evaluation. In addition, the results of the pharmacophore-based virtual screening revealed that 1v0p_PVB might have promising activity as a PDE-5 inhibitor.     

Design,synthesis and antitumor activity of novel pyrazolo[3,4-d]pyrimidine derivatives as EGFR-TK inhibitors

A novel series of 2-(3,6-dimethyl-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-yloxy)-N-(4-substitutedbenzylidene)acetohydrazide (12a–g) was prepared and their structures were confirmed by spectral and elemental analyses. The cytotoxic activity of the newly synthesized compounds was evaluated against breast carcinoma (MCF-7), non-small cell lung cancer (A549) and human colorectal adenocarcinoma (HT-29) cell lines using MTT and colony formation assays. The tested compounds showed a marked anticancer activity against all the tested cell lines, especially compound 12g, which was the most potent anticancer agent with half maximal inhibitory concentrations (IC₅₀) between 5.36 and 9.09 μM. Docking studies into ATP binding site of EGFR protein tyrosine kinase were performed to predict their scores and mode of binding to amino acids, In addition, the inhibitory activity of the target compounds against epidermal growth factor receptor tyrosine kinase (EGFR-TK) was evaluated. Results indicated the ability of the target compounds to inhibit EGFR-TK with half maximal inhibitory concentrations (IC₅₀) in the range of 4.18–35.88 μM. Furthermore, The most active compounds 12g, 12c and 12d were assayed against Fibroblast Growth Factor Receptor (FGFR), Insulin Receptor (IR) and Vascular Endothelial Growth Factor Receptor (VEGFR). The activity of the reported compounds warrants further optimization as novel members in cancer treatment protocols.     

Design,synthesis and biological evaluation of imidazo[1,5-a]pyrazin-8(7H)-one derivatives as BRD9 inhibitors

BRD9 is the subunit of mammalian SWI/SNF chromatin remodeling complex (BAF). SWI/SNF complex mutations were found in nearly 20% of human cancers. The biological role played by BRD9 bromodomain remains poorly understood, and it is therefore imperative to identify potent and highly selective inhibitors to effectively explore the biology of individual bromodomain proteins. In this paper, we synthesized a series of imidazo[1,5-a]pyrazin-8(7H)-one derivatives as potent BRD9 inhibitors and evaluated their BRD9 inhibitory activity in vitro and anti-proliferation effects against tumor cells. Gratifyingly, compound 27 and 29 exhibited robust potency of BRD9 inhibition with IC₅₀ values of 35 and 103?nM respectively. Docking studies were performed to explain the structure-activity relationship. Furthermore, compound 27 potently inhibited cell proliferation in cell lines A549 and EOL-1 with an IC₅₀ value of 6.12?μM and 1.76?μM respectively. The chemical probe, compound 27, was identified that should prove to be useful in further exploring BRD9 bromodomain biology in both in vitro and in vivo settings.     

Synthesis of 2H-benzo[b][1,4]oxazin-3(4H)-one derivatives as platelet aggregation inhibitors

Novel 2H-benzo[b][1,4]oxazin-3(4H)-ones have been synthesized by condensation, reduction, O-alkylation and Smiles rearrangement using 3-bromo-4-hydroxy benzaldehyde, anilines, and chloroacetyl chloride as starting materials. All the synthesized compounds have been characterized by (1)H NMR, (13)C NMR, and HRMS, and tested for the inhibitory ability on platelet aggregation. The results have shown that the ADP (adenosine 5'-diphosphate)-induced platelet aggregation was inhibited by 7a-g with the IC(50) value at 10.14-18.83 μmol/L. Compound 7a exhibited the most potent inhibitory effect (IC(50)=10.14 μmol/L) among all the compounds, but less potent than the control drug ticlopidine (3.18 μmol/L) and aspirin (6.07 μmol/L). The preliminary structure-activity relationship (SAR) was initially investigated in the study.     

New pyrazolo[1',5':1,6]pyrimido[4,5-d]pyridazin-4(3H)-ones as potent and selective PDE5 inhibitors

A series of potent PDE5 inhibitors with high selectivity versus PDE6 isoenzymes was identified.     

Discovery of thieno[2,3-d]pyrimidin-4(3H)-one derivatives as a new class of ROCK inhibitors

Herein, we report the discovery of a series of thieno[2,3-d]pyrimidin-4(3H)-one derivatives as a new class of ROCK inhibitors. Structure-activity relationship studies of these compounds led to the identification of the most potent compound, 3-(3-methoxybenzyl)-6-(1H-pyrrolo[2,3-b]pyridin-4-yl)thieno[2,3-d]pyrimidin-4(3H)-one (8k), which showed IC₅₀ values of 0.004 μM and 0.001 μM against ROCK Ⅰ and ROCK Ⅱ, respectively. In vitro, 8k significantly reduced the phosphorylation level of ROCK downstream signaling protein and induce changes in cell morphology and migration. Overall, this study provides a promising lead compound for drug discovery targeting ROCKs.     

Synthesis,modeling and biological evaluation of some pyrazolo[3,4-d]pyrimidinones and pyrazolo[4,3-e][1,2,4]triazolo[4,3-a]pyrimidinones as anti-inflammatory agents

New pyrazolo[3,4-d]pyrimidinone and pyrazolo[4,3-e][1,2,4]triazolo[4,3-a]pyrimidinone derivatives were synthesized. They have been evaluated for their anti-inflammatory activity using in vitro (COX-1/COX-2) inhibitory assay. Moreover, compounds with promising in vitro activity and COX-1/COX-2 selectivity indices were subjected for in vivo anti-inflammatory testing using formalin induced paw edema and cotton-pellet induced granuloma assays for acute and chronic models, respectively. Compounds (2c, 3i, 6a, 8 and 12) showed promising COX-2 inhibitory activity and high selectivity compared to celecoxib. Most of the compounds exhibited potential anti-inflammatory activity for both in vivo acute and chronic models. Almost all compounds displayed safe gastrointestinal profile and low ulcerogenic potential guided by histopathological examination. Furthermore, molecular docking experiments rationalized the observed in vitro anti-inflammatory activity of selected candidates. In silico predictions of the pharmacokinetic and drug-likeness properties recommended accepted profiles of the majority of compounds. In conclusion, this work provides an extension of the chemical space of pyrazolopyrimidinone and pyrazolotriazolopyrimidinone chemotypes for the anti-inflammatory activity.     

Design and synthesis of a pyrido[2,3-d]pyrimidin-5-one class of anti-inflammatory FMS inhibitors

A series of pyrimidinopyridones has been designed, synthesized and shown to be potent and selective inhibitors of the FMS tyrosine kinase. Introduction of an amide substituent at the 6-position of the pyridone core resulted in a significant potency increase. Compound 24 effectively inhibited in vivo LPS-induced TNF in mice greater than 80%.     

Design and synthesis of pyrimido[4,5-b][1,4]benzothiazine derivatives, as potent 15-lipoxygenase inhibitors

A group of 2-substituted pyrimido[4,5-b][1,4]benzothiazines were designed, synthesized, and evaluated as potential inhibitors of 15-lipoxygenase (15-LO). Compounds 4d and 4e showed the best IC50 of 15-LO inhibition (IC50=18 and 34 microM, respectively). All compounds were docked into 15-LO. As a result the sulfur atom was oriented toward the iron atom of the active site of 15-LO. We suggest the interaction of the iron atom is essential for the activity of the inhibitors.     

Development of 2-aryl substituted quinazolin-4(3H)-one,pyrido[4,3-d]pyrimidin-4(3H)-one and pyrido[2,3-d]pyrimidin-4(3H)-one derivatives as microsomal prostaglandin E2 synthase-1 inhibitors

mPGES-1 is inducible terminal synthase acting downstream of COX enzymes in arachidonic acid pathway, regulates the biosynthesis of pro-inflammatory prostaglandin PGE₂. Cardiovascular side effect of coxibs and NSAIDs, selective for COX-2 inhibition, stimulated interest in mPGES-1, a therapeutic target with potential to deliver safe and effective anti-inflammatory drugs. The synthesis and structure activity relationship of a series of compounds from 2-aryl substituted quinazolin-4(3H)-one, pyrido[4,3-d]pyrimidin-4(3H)-one and pyrido[2,3-d]pyrimidin-4(3H)-one scaffolds as mPGES-1 inhibitor are discussed. A set of analogs (28, 48, 49) were identified with <10 nM potencies in the recombinant human mPGES-1 enzyme and in the A549 cellular assays. These analogs were also found to be potent in the human whole blood assay (<400 nM). Furthermore, the representative compound 48 was shown to be selective with other prostanoid synthases and was able to effectively regulate PGE₂ biosynthesis in clinically relevant inflammatory settings, in comparison with celecoxib.     

Structure-based design, synthesis, and study of pyrazolo[1,5-a][1,3,5]triazine derivatives as potent inhibitors of protein kinase CK2

The structure-based design, synthesis, and anticancer activity of novel inhibitors of protein kinase CK2 are described. Using pyrazolo[1,5-a][1,3,5]triazine as the core scaffold, a structure-guided series of modifications provided pM inhibitors with microM-level cytotoxic activity in cell-based assays with prostate and colon cancer cell lines.     

Design and synthesis of 2-amino-6-(1H,3H-benzo[de]isochromen-6-yl)-1,3,5-triazines as novel Hsp90 inhibitors

A novel series of 2-amino-1,3,5-triazines bearing a tricyclic moiety as heat shock protein 90 (Hsp90) inhibitors is described. Molecular design was performed using X-ray cocrystal structures of the lead compound CH5015765 and natural Hsp90 inhibitor geldanamycin with Hsp90. We optimized affinity to Hsp90, in vitro cell growth inhibitory activity, water solubility, and liver microsomal stability of inhibitors and identified CH5138303. This compound showed high binding affinity for N-terminal Hsp90α (K_d = 0.52 nM) and strong in vitro cell growth inhibition against human cancer cell lines (HCT116 IC₅₀ = 0.098 μM, NCI-N87 IC₅₀ = 0.066 μM) and also displayed high oral bioavailability in mice (F = 44.0%) and potent antitumor efficacy in a human NCI-N87 gastric cancer xenograft model (tumor growth inhibition = 136%).     

Synthesis and biological evaluation of benzo[b]furo[3,4-e][1,4]diazepin-1-one derivatives as anti-cancer agents

A new series of novel Podophyllotoxin-like benzo[b]furo[3,4-e][1,4]diazepin-1-ones possessing structural elements of 4-aza-2,3-didehydropodophyllotoxins with central diazepine ring was designed and synthesized as anti-cancer agents. In initial assessment, the cytotoxic activity of the synthesized compounds was evaluated against three cancer cell lines including MCF-7, PC3 and B16-F10 employing the MTT assay. Some of compounds (12h, 13a, 13c and 14b) showed significant cytotoxic activity. So, we investigated the cytotoxicity of compounds 12h, 13a, 13c and 14b, along with podophyllotoxin as the reference drug in different cancer cell lines including A549, A2780, DU145, HeLa, and normal Huvec cell line. Among these four compounds, 13c showed promising antiproliferative activity against all cancer cells stronger than the other compounds and comparable to reference drug podophyllotoxin in some cancer cells. All these four compounds did not show significant cytotoxicity on normal Huvec cell line. The flow cytometry analysis of the MCF-7, PC3 and A2780 human cancer cell lines treated with 13c showed that 13c, induced apoptosis in the MCF-7, PC3 and A2780 human cancer cell lines, which is in good agreement to its cytotoxic activity as well. Compound 13c did not show significant influence on tubulin assembly and exert its cytotoxic effects via induction of apoptosis and has potent and selective cytotoxic effects in cancer cells.     

Design,synthesis and biological evaluation of novel 6H-benzo[c]chromen-6-one,and 7,8,9,10-tetrahydro-benzo[c]chromen-6-one derivatives as potential cholinesterase inhibitors

Hydroxylated 6H-benzo[c]chromen-6-one derivatives (i.e., urolithins) are the main bioavailable metabolites, and biomarkers of ellagitannins present in various nutrition. Although these dietaries, the sources of urolithins, are employed in folk medicine as cognitive enhancer in the treatment of Alzheimer’s Disease, urolithins have negligible potential to inhibit acetylcholinesterase and butyrylcholinesterase enzymes, the validated targets of Alzheimer’s Disease. Therefore, within this research, a series of 6H-benzo[c]chromen-6-one, and 7,8,9,10-tetrahydro-benzo[c]chromen-6-one derivatives has been designed, synthesized, and their biological activities were evaluated as potential acetylcholinesterase and butyrylcholinesterase inhibitors. The compounds synthesized exerted comparable activity in comparison to rivastigmine, galantamine, and donepezil both in in vitro and in vivo studies.