Design,synthesis and biological evaluation of new potent and highly selective ROS1-tyrosine kinase inhibitor

ROS1 protein is a receptor tyrosine kinase that has been reported mainly in meningiomas and astrocytomas, and until now, there is no selective inhibitor for this kinase. In this study, we illustrate for the synthesis of a highly potent and selective inhibitor for ROS1 kinase. The synthesized compound 1 was tested initially at a single dose concentration of 10 μM over 45 different kinases. At this concentration, a 94% inhibition of the enzymatic activity of ROS1 kinase was observed, while the inhibition in activity was below 30% in all of the other kinases. The pyrazole compound 1 was further tested in a 10-dose IC₅₀ mode and showed an IC₅₀ value of 199 nM for ROS1 kinase. The compound 1 can be used as a promising lead for the development of new selective inhibitors for ROS1 kinase, and it may open the way for new selective therapeutics for astrocytomas.     

Structure-based optimization and biological evaluation of trisubstituted pyrazole as a core structure of potent ROS1 kinase inhibitors

Recently inhibition of ROS1 kinase has proven to be a promising strategy for several indications such as glioblastoma, non-small cell lung cancer (NSCLC), and cholangiocarcinoma. Our team reported trisubstituted pyrazole-based ROS1 inhibitors by which two inhibitors showed good IC₅₀ values in enzyme-based screening. To develop more advanced ROS1 inhibitors through SAR this trisubstituted pyrazole-based scaffold has been built. Consequently, 16 compounds have been designed, synthesized and shown potent IC₅₀ values in the enzymatic assay, which are from 13.6 to 283 nM. Molecular modeling studies explain how these ROS1 kinase inhibitors revealed effectively the key interactions with ROS1 ATP binding site. Among these compounds, compound 9a (IC₅₀ = 13.6 nM) has exerted 5 fold potency than crizotinib and exhibited high degree of selectivity (selectivity score value = 0.028) representing the number of non-mutant kinases with biological activity over 90% at 10 μM.     

Synthesis and structure–activity relationships of N-benzyl-N-(X-2-hydroxybenzyl)-N′-phenylureas and thioureas as antitumor agents

Two series of novel N-benzyl-N-(X-2-hydroxybenzyl)-N′-phenylureas and thioureas (1a–18a; 1b–18b) as potential EGFR and HER-2 kinase inhibitors have been discovered. These compounds displayed good EGFR and HER-2 inhibitory activity and the SARs are also been studied. Especially compound 7b demonstrated significant EGFR and HER-2 inhibitory activity (IC₅₀ = 0.08 μM for EGFR and IC₅₀ = 0.35 μM for HER-2). Docking simulation was performed to position compound 7b into the EGFR active site to determine the probable binding conformation and antiproliferative assay results indicating that these series of urea and thioureas own high antiproliferative activity against MCF-7. Above all, thiourea 7b would be a potential anticancer agent deserves further research.     

Synthesis and biological evaluation of pyrido[2,3-d]pyrimidine-2,4-dione derivatives as eEF-2K inhibitors

A small molecule library of pyrido[2,3-d]pyrimidine-2,4-dione derivatives 6–16 was synthesized from 6-amino-1,3-disubstituted uracils 18, characterized, and screened for inhibitory activity against eukaryotic elongation factor-2 kinase (eEF-2K). To understand the binding pocket of eEF-2K, structural modifications of the pyrido[2,3-d]pyrimidine were made at three regions (R¹, R², and R³). A homology model of eEF-2K was created, and compound 6 (A-484954, Abbott laboratories) was docked in the catalytic domain of eEF-2K. Compounds 6 (IC₅₀ = 420 nM) and 9 (IC₅₀ = 930 nM) are found to be better molecules in this preliminary series of pyrido[2,3-d]pyrimidine analogs. eEF-2K activity in MDA-MB-231 breast cancer cells is significantly reduced by compound 6, to a lesser extent by compound 9, and is unaffected by compound 12. Similar inhibitory results are observed when eEF-2K activity is stimulated by 2-deoxy-d-glucose (2-DOG) treatment, suggesting that compounds 6 and 9 are able to inhibit AMPK-mediated activation of eEF-2K to a notable extent. The results of this work will shed light on the further design and optimization of novel pyrido[2,3-d]pyrimidine analogs as eEF-2K inhibitors.     

Synthesis,biological evaluation,and physicochemical property assessment of 4-substituted 2-phenylaminoquinazolines as Mer tyrosine kinase inhibitors

Current results identified 4-substituted 2-phenylaminoquinazoline compounds as novel Mer tyrosine kinase (Mer TK) inhibitors with a new scaffold. Twenty-one 2,4-disubstituted quinazolines (series 4–7) were designed, synthesized, and evaluated against Mer TK and a panel of human tumor cell lines aimed at exploring new Mer TK inhibitors as novel potential antitumor agents. A new lead, 4b, was discovered with a good balance between high potency (IC₅₀ 0.68 μM) in the Mer TK assay and antiproliferative activity against MV4-11 (GI₅₀ 8.54 μM), as well as other human tumor cell lines (GI₅₀ < 20 μM), and a desirable druglike property profile with low log P value (2.54) and high aqueous solubility (95.6 μg/mL). Molecular modeling elucidated an expected binding mode of 4b with Mer TK and necessary interactions between them, thus supporting the hypothesis that Mer TK might be a biologic target of this kind of new active compound.     

Design,synthesis, ADME characterization and antileishmanial evaluation of novel substituted quinoline analogs

In vitro ADME characterization of the lead compound 1 identified for visceral leishmaniasis was undertaken and further structural analogs were synthesized for antileishmanial screening. Compound 1 was highly permeable in intestinal PAMPA model (31 × 10⁻⁶ cm/s) and was moderately bound to mouse and human plasma proteins (% bound 85–95%), its blood to plasma concentration ratio was less than 1, but the compound was unstable in blood. Compound 1 was found to have no CYP450 liability with CYP2C9, 2C19, 2D6 and 3A4. It showed inhibition with CYP1A2 with an IC₅₀ value of 0.50 μM. Analogs of 1 were synthesized and subsequently characterized for in vitro activity against the intracellular form of Leishmania donovani. Resulting quinolines were found to have similar efficacy as 1 against the parasite. Compounds 8b and 8f were found to be the most active with IC₅₀ values of 0.84 μM and 0.17 μM, respectively compared to 0.22 μM for compound 1. Of all the analogs tested, 8d was stable in hamster, mouse and human liver microsomes but lost the efficacy with an IC₅₀ of 6.42 μM. Based on the in vitro efficacy and DMPK profile, compounds 8b and 8f seem the best candidates to be screened in further assays.     

Discovery of imidazopyridine derivatives as novel c-Met kinase inhibitors: Synthesis,SAR study,and biological activity

Receptor tyrosine kinase c-Met acts as an alternative angiogenic pathway in the process and contents of cancers. A series of imidazopyridine derivatives were designed and synthesized according to the established docking studies as possible c-Met inhibitors. Most of these imidazopyridine derivatives displayed nanomolar potency against c-Met in both biochemical enzymatic screens and cellular pharmacology studies. Especially, compound 7 g exhibited the most inhibitory activity against c-Met with IC₅₀ of 53.4 nM and 253 nM in enzymatic and cellular level, respectively. Following that, the compound 7 g was docked into the protein of c-Met and the structure-activity relationship was analyzed in detail. These findings indicated that the novel imidazopyridine derivative compound 7 g was a potential c-Met inhibitor deserving further investigation for cancer treatment.     

Inhibition of eEF2-K by thieno[2,3-b]pyridine analogues

Several series of thieno[2-3-b]pyridine analogues were synthesized and screened for inhibitory activity against eukaryotic elongation factor-2 kinase (eEF2-K). Modifications around several regions of the lead molecules were made, with a ring fusion adjacent to the nitrogen on the thienopyridine core being critical for activity. The most active compound 34 shows an IC₅₀ of 170 nM against eEF2-K in vitro.     

Novel 1H-imidazol-2-amine derivatives as potent and orally active vascular adhesion protein-1 (VAP-1) inhibitors for diabetic macular edema treatment

Novel thiazole derivatives were synthesized and evaluated as vascular adhesion protein-1 (VAP-1) inhibitors. Although we previously identified a compound (2) with potent VAP-1 inhibitory activity in rats, the human activity was relatively weak. Here, to improve the human VAP-1 inhibitory activity of compound 2, we first evaluated the structure–activity relationships of guanidine bioisosteres as simple small molecules and identified a 1H-benzimidazol-2-amine (5) with potent activity compared to phenylguanidine (1). Based on the structure of compound 5, we synthesized a highly potent VAP-1 inhibitor (37b; human IC₅₀ = 0.019 μM, rat IC₅₀ = 0.0051 μM). Orally administered compound 37b also markedly inhibited ocular permeability in streptozotocin-induced diabetic rats after oral administration, suggesting it is a promising compound for the treatment of diabetic macular edema.     

Design,synthesis and biological evaluation of thiazolidinone derivatives as potential EGFR and HER-2 kinase inhibitors

Two series of thiazolidinone derivatives designing for potential EGFR and HER-2 kinase inhibitors have been discovered. Some of them exhibited significant EGFR and HER-2 inhibitory activity. Compound 2-(2-(5-bromo-2-hydroxybenzylidene)hydrazinyl)thiazol-4(5H)-one (12) displayed the most potent inhibitory activity (IC₅₀ = 0.09 μM for EGFR and IC₅₀ = 0.42 μM for HER-2), comparable to the positive control erlotinib. Docking simulation was performed to position compound 12 into the EGFR active site to determine the probable binding model. Antiproliferative assay results indicating that some of the thiazolidinone derivatives own high antiproliferative activity against MCF-7. Compound 12 with potent inhibitory activity in tumor growth inhibition would be a potential anticancer agent.     

Potent,orally bioavailable,liver-selective stearoyl-CoA desaturase (SCD) inhibitors

Two structurally distinct series of SCD (Δ9 desaturase) inhibitors (1 and 2) have been previously reported by our group. In the present work, we merged the structural features of the two series. This led to the discovery of compound 5b (CVT-12,012) which is highly potent in a human cell-based (HEPG2) SCD assay (IC₅₀ = 6 nM). This compound has 78% oral bioavailability in rats and is preferentially distributed into liver (76 times vs plasma) with relatively low brain penetration. In a five-day study (sucrose fed rats) compound 5b significantly reduced SCD activity in a dose-dependent manner as determined by GC analysis of fatty acid composition in plasma and liver, and significantly reduced liver triglycerides versus the control group (～50%).     

Molecular design,synthesis and biological evaluation of cyclic imides bearing benzenesulfonamide fragment as potential COX-2 inhibitors. Part 2

A group of cyclic imides (1–10) was designed for evaluation as a selective COX-2 inhibitors and investigated in vivo for their anti-inflammatory activity. Compounds 6a, 6b, 8a, 8b, 9a, 9b, 10a and 10b were proved to be potent COX-2 inhibitors with IC₅₀ range of 0.1–4.0 μM. In vitro COX-1/COX-2 inhibition structure–activity studies identified compound 8a as a highly potent (IC₅₀ = 0.1 μM), and an extremely selective [COX-2 (SI) > 1000] comparable to celecoxib [COX-2 (SI) > 384], COX-2 inhibitor that showed superior anti-inflammatory activity (ED₅₀ = 72.4 mg/kg) relative to diclofenac (ED₅₀ = 114 mg/kg). Molecular modeling was carried out through docking the designed compounds into the COX-2 binding site to predict if these compounds have analogous binding mode to the COX-2 inhibitors. The study showed that the homosulfonamide fragment of 8a inserted deep inside the 2°-pocket of the COX-2 active site, where the SO₂NH₂ group underwent H-bonding interaction with Gln¹⁹²(2.95 Å), Phe⁵¹⁸(2.82 Å) and Arg⁵¹³(2.63 and 2.73 Å). Docking study of the synthesized compound 8a into the active site of COX-2 revealed a similar binding mode to SC-558, a selective COX-2 inhibitor.     

Design,synthesis and anticholinesterase activity of a novel series of 1-benzyl-4-((6-alkoxy-3-oxobenzofuran-2(3H)-ylidene) methyl) pyridinium derivatives

A novel series of benzofuranone-ylidene-methyl benzylpyridinium derivatives (6a–u) were synthesized as acetylcholinesterase inhibitors. The anticholinesterase activity of synthesized compounds was measured using colorimetric Ellman’s method. It was revealed that some synthesized compounds exhibited high anticholinesterase activity, among them compound 6b was the most active compound (IC₅₀ = 10 ± 6.87 nM).     

Synthesis,biological evaluation and docking analysis of 3-methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones as potential cyclooxygenase-2 (COX-2) inhibitors

As a part of our continued efforts to discover new COX inhibitors, a series of 3-methyl-1-phenylchromeno[4,3-c]pyrazol-4(1H)-ones were synthesized and evaluated for in vitro COX inhibitory potential. Within this series, seven compounds (3a–d, 3h, 3k and 3q) were identified as potential and selective COX-2 inhibitors (COX-2 IC₅₀’s in 1.79–4.35 μM range; COX-2 selectivity index (SI) = 6.8–16.7 range). Compound 3b emerged as most potent (COX-2 IC₅₀ = 1.79 μM; COX-1 IC₅₀ >30 μM) and selective COX-2 inhibitor (SI >16.7). Further, compound 3b displayed superior anti-inflammatory activity (59.86% inhibition of edema at 5 h) in comparison to celecoxib (51.44% inhibition of edema at 5 h) in carrageenan-induced rat paw edema assay. Structure–activity relationship studies suggested that N-phenyl ring substituted with p-CF₃ substituent (3b, 3k and 3q) leads to more selective inhibition of COX-2. To corroborate obtained experimental biological data, molecular docking study was carried out which revealed that compound 3b showed stronger binding interaction with COX-2 as compared to COX-1.     

Design,synthesis, molecular docking and biological evaluation of thiophen-2-iminothiazolidine derivatives for use against Trypanosoma cruzi

In this study, we designed and synthesized a series of thiophen-2-iminothiazolidine derivatives from thiophen-2-thioureic with good anti-Trypanosoma cruzi activity. Several of the final compounds displayed remarkable trypanocidal activity. The ability of the new compounds to inhibit the activity of the enzyme cruzain, the major cysteine protease of T. cruzi, was also explored. The compounds 3b, 4b, 8b and 8c were the most active derivatives against amastigote form, with significant IC₅₀ values between 9.7 and 6.03 μM. The 8c derivative showed the highest potency against cruzain (IC₅₀ = 2.4 μM). Molecular docking study showed that this compound can interact with subsites S1 and S2 simultaneously, and the negative values for the theoretical energy binding (E_b = −7.39 kcal·mol⁻¹) indicates interaction (via dipole–dipole) between the hybridized sulfur sp³ atom at the thiazolidine ring and Gly66. Finally, the results suggest that the thiophen-2-iminothiazolidines synthesized are important lead compounds for the continuing battle against Chagas disease.     

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.     

Synthesis,biological evaluation,and molecular docking studies of novel 2-styryl-5-nitroimidazole derivatives containing 1,4-benzodioxan moiety as FAK inhibitors with anticancer activity

A series of 2-styryl-5-nitroimidazole derivatives containing 1,4-benzodioxan moiety (3a–3r) has been designed, synthesized and their biological activities were also evaluated as potential antiproliferation and focal adhesion kinase (FAK) inhibitors. Among all the compounds, 3p showed the most potent activity in vitro which inhibited the growth of A549 with IC₅₀ value of 3.11 μM and Hela with IC₅₀ value of 2.54 μM respectively. Compound 3p also exhibited significant FAK inhibitory activity (IC₅₀ = 0.45 μM). Docking simulation was performed for compound 3p into the FAK structure active site to determine the probable binding model.     

Synthesis,molecular docking and antitumor activity of novel pyrrolizines with potential as EGFR-TK inhibitors

A new series of pyrrolizine derivatives 4–8c were synthesized, their structures were confirmed by spectral and elemental analyses. Cytotoxic activity of these compounds was evaluated against breast (MCF7), colon (HCT116) and liver (HEPG2) cancer cell lines using sulphorhodamine-B (SRB) assay method. All the tested compounds showed highly potent activity against MCF7 cell line with IC₅₀ range equal 8–194 nM/ml and compound 8c was the best active one (IC₅₀ = 8.6 nM/ml). 8b was the best active compound on both HCT116 and HEPG-2 cancer cell lines; its IC₅₀ is 26.5 and 12.3 nM/ml respectively. Docking studies into ATP binding site of EGFR tyrosine kinase were performed to predict their scores and mode of binding to amino acids, moreover, inhibitory activity of these compounds against EGFR-TKs was evaluated; their inhibitory percent ranged from 40.4 to 97.6, compound 8c and 8b showed inhibitory activity at 97.6% and 88.4% respectively.     

Design,synthesis, and docking studies of phenylpicolinamide derivatives bearing 1H-pyrrolo[2,3-b]pyridine moiety as c-Met inhibitors

Four series of phenylpicolinamide derivatives bearing 1H-pyrrolo[2,3-b]pyridine moiety (12a–e, 13a–f, 14a–f and 15a–i) were designed, synthesized and evaluated for the IC₅₀ values against three cancer cell lines (A549, PC-3 and MCF-7) and c-Met kinase. Five selected compounds (13b, 15b, 15d, 15e and 15f) were further evaluated for the activity against HepG2 and Hela cell lines. Eighteen of the compounds showed excellent cytotoxicity activity and selectivity with the IC₅₀ valuables in single-digit μM to nanomole range. Seven of them are equal to more active than positive control Foretinib against one or more cell lines. The most promising compound 15f showed superior activity to Foretinib, with the IC₅₀ values of 1.04 ± 0.11 μM, 0.02 ± 0.01 μM and 9.11 ± 0.55 μM against A549, PC-3 and MCF-7 cell lines, which were 0.62 to 19.5 times more active than Foretinib (IC₅₀ values: 0.64 ± 0.26 μM, 0.39 ± 0.11 μM, 9.47 ± 0.22 μM), respectively. Structure–activity relationships (SARs) and docking studies indicated that replacement of quinoline nucleus of the previous active compounds with 1H-pyrrolo[2,3-b]pyridine moiety maintained even improved the potent cytotoxic activity. The results suggested that the introduction of fluoro atoms to the aminophenoxy part of target compounds or the phenyl group of pyrimidine substituted on C-4 position was benefit for the activity.     

Anti-tubercular agents. Part 8: Synthesis,antibacterial and antitubercular activity of 5-nitrofuran based 1,2,3-triazoles

A series of 5-nitrofuran–triazole conjugates were synthesized and evaluated for their antimicrobial activity against both Gram-positive and Gram-negative bacterial strains. All the compounds exhibited promising inhibition towards Gram-positive pathogenic strains, while mild inhibitory effects were observed towards Gram-negative bacterial strains. Some of the compounds 8a, 8b, 8e, 8f, 8h are most active among the series exhibiting MIC value of 1.17 μg/ml against different bacterial strains. The bactericidal activity is found to be in accordance with the bacterial growth inhibition data. Compound 8e was found to be equipotent to the standard drug Ciprofloxacin displaying MBC value of 1.17 μg/ml against the bacterial strain Bacillus subtilis. The compounds have also demonstrated promising antibacterial activity against the resistant strain MRSA and were found to be effective inhibitors of biofilm formation. The compound 8b exhibited excellent anti-biofilm activity with IC₅₀ value as low as 0.8 μg/ml. These conjugates were also screened for antitubercular activity against Mycobacterium tuberculosis H₃₇Rv strain. Compound 8e showed promising antitubercular activity with MIC value of 0.25 μg/ml. Most of these compounds are less toxic to normal mammalian cells than the widely used antibacterial drug Ciprofloxacin.