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The strategy of inhibiting angiogenesis, specifically by targeting vascular endothelial growth factor receptor 2 (VEGFR-2), has been proven effective in tumor treatment. In this study, we designed several VEGFR-2 kinase inhibitors based on an indazole scaffold. Among them, the most potent compound, 30, inhibits VEGFR-2 (IC 50  = 1.24 nM) with subtle selectivity over other kinases. It demonstrates significant inhibitory activity against HUVEC angiogenesis and inhibits cell migration in a dose-dependent manner. Additionally, it exhibits low acute toxicity in mice. In vivo studies, compound 30 demonstrates favorable pharmacokinetic profiles. It suppresses tumor angiogenesis in the zebrafish subintestinal vessel model, indicating that it may be a potential angiogenesis inhibitor for further development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

The calcium release activated calcium (CRAC) channel is highly expressed in T lymphocytes and plays a critical role in regulating T cell proliferation and functions including activation of the transcription factor nuclear factor of activated T cells (NFAT), cytokine production and cytotoxicity. The CRAC channel consists of the Orai pore subunit and STIM (stromal interacting molecule) endoplasmic reticulum calcium sensor. Loss of CRAC channel mediated calcium signaling has been identified as an underlying cause of severe combined immunodeficiency (SCID), leading to drastically weakened immunity against infections. Gain-of-function mutations in Orai and STIM have been associated with tubular aggregated myopathy (TAM), a skeletal muscle disease. While a number of small molecules have shown activity in inhibiting the CRAC signaling pathway, the usefulness of those tool compounds is limited by their off-target activity against TRPM4 and TRPM7 ion channels, high lipophilicity, and a lack of understanding of their mechanism of action. We report structure-activity relationship (SAR) studies that resulted in the characterization of compound 4k [1-(cyclopropylmethyl)-N-(3-fluoropyridin-4-yl)-1H-indazole-3-carboxamie] as a fast onset, reversible, and selective CRAC channel blocker. 4k fully blocked the CRAC current (IC 50 : 4.9 μM) and the nuclear translocation of NFAT at 30 and 10 μM, respectively, without affecting the electrophysiological function of TRPM4 and TRPM7 channels. Computational modeling appears to support its direction binding to Orai proteins that form the transmembrane CRACchannel., Competing Interests: Declaration of competing interest All authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Administration of negative allosteric modulators of GluN2B subunit-containing NMDA receptors such as Ro 25-6981 ( 1 ) and ifenprodil ( 2 ) results in neuroprotective effects. In this study, the phenol of 1 and 2 was replaced bioisosterically by an indazole to inhibit glucuronidation. The γ- and β-aminoalcohols 10 and 11 were prepared without installing a protective group at the indazole ring using the ketone 6 as a common intermediate. All four stereoisomeric γ- and β-aminoalcohols 10 and 11 were obtained by diastereoselective reduction of ketones 7 and 9 followed by separation of enantiomers. The analogously structured γ-aminoalcohol (1 S ,2 S )- 10c (Ro 25-6981 bioisostere) and β-aminoalcohol (1 R ,2 R )- 11c (ifenprodil bioisostere) exhibited high GluN2B affinity ( K i = 50 and 66 nM, respectively) and high to moderate inhibitory activity in two-electrode voltage clamp experiments. The indazole bioisosteres 10 and 11 showed higher metabolic stability than 1 . In the presence of uridinyldiphosphate activated glucuronic acid, glucuronidation of 10 and 11 was not observed.

Inflammatory bowel disease (IBD) is a chronic and progressive condition with a significant global burden. Currently, available treatments primarily provide symptomatic relief and retard disease progression, yet they do not offer a cure and are frequently associated with adverse effects. Therefore, the discovery of new targets and therapeutic drugs for IBD is crucial. Phosphodiesterase 4 (PDE4) inhibitors have emerged as promising candidates in the search for effective IBD treatments, although dose-dependent side effects hamper their clinical utility. In this study, building upon heterocyclic biaryl derivatives (TPA16), we designed and synthesized a series of N 2 -substituted indazole-based PDE4D inhibitors, emphasizing improving safety profiles. An enzyme activity screening discovered an optimized compound, LZ-14 (Z21115), which exhibited high PDE4D7 (IC 50  = 10.5 nM) inhibitory activity and good selectivity. More interestingly, LZ-14 has demonstrated promising effects in treating IBD in mouse models by improving the inflammatory response and colon injury. Furthermore, LZ-14 displayed low emetogenic potential in ketamine/xylazine anesthesia mice alternative models., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

NTRK gene fusion leads to the activation of downstream signaling pathways, which is a oncogenic driver in various cancers. NTRK fusion-positive cancers can be treated with the first-generation TRK inhibitors, larotrectinib and entrectinib. Unfortunately, the patients eventually face the dilemma of no drugs available as the emergence of certain resistance mutations. The development of efficient and broad-spectrum second-generation TRK inhibitors is still of great significance. Here, we analyzed the binding modes of compounds 6, 10 with TRKA protein, respectively, a series of novel indazole TRK inhibitors were designed and synthesized using molecular hybridization strategy. Among them, the optimal compound B31 showed strong antiproliferative activities against Km-12, Ba/F3-TRKA G595R , and Ba/F3-TRKA G667C cell lines with IC 50 values of 0.3, 4.7, and 9.9 nM, respectively. And the inhibitory effect against TRKA G667C (IC 50  = 9.9 nM) was better than that of selitrectinib (IC 50  = 113.1 nM). Further, compound B31 exhibited moderate kinase selectivity and excellent plasma stability (t 1/2  > 480 min). In vivo pharmacokinetic studies in Sprague-Dawley rats showed that B31 had acceptable pharmacokinetic properties., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

A series of indazole analogs, derived from the B,C-ring-truncated scaffold of deguelin, were designed to function as C-terminal inhibitors of heat shock protein 90 (HSP90) and investigated as novel antitumor agents against HER2-positive breast cancer. Among the synthesized compounds, compound 12d exhibited substantial inhibitory effects in trastuzumab-sensitive (BT474) and trastuzumab-resistant (JIMT-1) breast cancer cells, with IC 50 values of 6.86 and 4.42 μM, respectively. Notably, compound 12d exhibited no cytotoxicity in normal cells. Compound 12d markedly downregulated the expression of the major HSP90 client proteins in both cell types, attributing its cytotoxicity to the destabilization and inactivation of HSP90 client proteins. Molecular docking studies using the homology model of an HSP90 homodimer demonstrated that inhibitor 12d fit nicely into the C-terminal domain, boasting a higher electrostatic complementary score than ATP. In vivo pharmacokinetic study indicated the high oral bioavailability of compound 12 d at F = 66.9 %, while toxicological studies indicated its negligible impact on hERG channels and CYP isozymes. Genotoxicity tests further confirmed its safety profile. The findings collectively position compound 12d as a promising candidate for further development as an antitumor agent against HER2-positive breast cancer., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Inhibition of leucine-rich repeat kinase 2 is a genetically supported mechanism for the treatment of Parkinson's disease. We previously disclosed the discovery of an indazole series lead that demonstrated both safety and translational risks. The safety risks were hypothesized to be of unknown origin, so structural diversity in subsequent chemical matter was prioritized. The translational risks were identified due to a low brain Kp u,u in nonhuman primate studies, which raised concern over the use of an established peripheral biomarker as a surrogate for central target engagement. Given these challenges, the team sought to leverage structure- and property-based drug design and expanded efflux transporter profiling to identify structurally distinct leads with enhanced CNS drug-likeness. Herein, we describe the discovery of a "reinvented" indazole series with improved physicochemical properties and efflux transporter profiles while maintaining excellent potency and off-target kinase selectivity, which resulted in advanced lead, compound 23 .

Herein, we describe the design and synthesis of novel aryl pyrimidine benzenesulfonamides APBSs 5a-n, 6a-c, 7a-b, and 8 as pazopanib analogues to explore new potent and selective inhibitors for the CA IX. All APBSs were examined in vitro for their promising inhibition activity against a small panel of hCAs (isoforms I, II, IX, and XII). The X-ray crystal structure of CA I in adduct with a representative APBS analogue was solved. APBS-5m, endowed with the best hCA IX inhibitory efficacy and selectivity, was evaluated for antiproliferative activity against a small panel of different cancer cell lines, SK-MEL-173, MDA-MB-231, A549, HCT-116, and HeLa, and it demonstrated one-digit IC 50 values range from 2.93 μM (MDA-MB-231) to 5.86 μM (A549). Furthermore, compound APBS-5m was evaluated for its influence on hypoxia-inducible factor (HIF-1α) production, apoptosis induction, and colony formation in MDA-MB-231 cancer cells. The in vivo efficacy of APBS-5m as an antitumor agent was additionally investigated in an animal model of Solid Ehrlich Carcinoma (SEC). In order to offer perceptions into the conveyed hCA IX inhibitory efficacy and selectivity in silico, a molecular docking investigation was also carried out., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

The inhibitory-kappaB kinases (IKKs) IKKα and IKKβ play central roles in regulating the non-canonical and canonical NF-κB signalling pathways. Whilst the proteins that transduce the signals of each pathway have been extensively characterised, the clear dissection of the functional roles of IKKα-mediated non-canonical NF-κB signalling versus IKKβ-driven canonical signalling remains to be fully elucidated. Progress has relied upon complementary molecular and pharmacological tools; however, the lack of highly potent and selective IKKα inhibitors has limited advances. Herein, we report the development of an aminoindazole-pyrrolo[2,3- b ]pyridine scaffold into a novel series of IKKα inhibitors. We demonstrate high potency and selectivity against IKKα over IKKβ in vitro and explain the structure-activity relationships using structure-based molecular modelling. We show selective target engagement with IKKα in the non-canonical NF-κB pathway for both U2OS osteosarcoma and PC-3M prostate cancer cells by employing isoform-related pharmacodynamic markers from both pathways. Two compounds ( SU1261 [IKKα K i = 10 nM; IKKβ K i = 680 nM] and SU1349 [IKKα K i = 16 nM; IKKβ K i = 3352 nM]) represent the first selective and potent pharmacological tools that can be used to interrogate the different signalling functions of IKKα and IKKβ in cells. Our understanding of the regulatory role of IKKα in various inflammatory-based conditions will be advanced using these pharmacological agents.

In this work, a highly effective synthesis technique for obtaining aryl indazole under mild circumstances is provided, using trimethyl phosphine as a powerful reagent. The procedure shows that a wide range of substrates can be investigated, yielding various 2-aryl indazole derivatives with acceptable to exceptional yields and a wide range of functional group tolerance. Additionally, based on In Silico studies tests were conducted to determine the anticancer activity In Vitro for all produced compounds (3 a-3 j) against A549, HT-29 and HepG2 cell lines. Compounds 3 c and 3 d, with IC 50 values of 15, 53.55, 7.34, 7.10, 56.28, and 17.87 (μM) against A549, HT-29 and HepG2 respectively, showed significant anticancer activity., (© 2024 Wiley-VHCA AG, Zurich, Switzerland.)

Synthetic cannabinoid receptor agonists (SCRAs) are a growing class of new psychoactive substances (NPS) commonly derived from an N -alkylated indole, indazole, or 7-azaindole scaffold. Diversification of this core (at the 3-position) with amide-linked pendant amino acid groups and modular N -alkylation (of the indole/indazole/7-azaindole core) ensures that novel SCRAs continue to enter the illicit drug market rapidly. In response to the large number of SCRAs that have been detected, pharmacological evaluation of this NPS class has become increasingly common. Adamantane-derived SCRAs have consistently appeared throughout the market since 2011, and as such, a systematic set of these derivatives was synthesized and pharmacologically evaluated. Deuterated and fluorinated adamantane derivatives were prepared to evaluate typical hydrogen bioisosteres, as well as evaluation of the newly detected AFUBIATA.

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 N 1 -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 (IC 50  = 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 IC 50 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., (© 2024 The Authors. Archiv der Pharmazie published by Wiley‐VCH GmbH on behalf of Deutsche Pharmazeutische Gesellschaft.)

The inhibition of the programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) pathway with small molecules is a promising approach for cancer immunotherapy. Herein, novel small molecules compounds bearing various scaffolds including thiophene, thiazole, tetrahydroquinoline, benzimidazole and indazole were designed, synthesized and evaluated for their inhibitory activity against the PD-1/PD-L1 interaction. Among them, compound Z13 exhibited the most potent activity with IC 50 of 189.6 nM in the homogeneous time-resolved fluorescence (HTRF) binding assay. Surface plasmon resonance (SPR) assay demonstrated that Z13 bound to PD-L1 with high affinity (K D values of 231 nM and 311 nM for hPD-L1 and mPD-L1, respectively). In the HepG2/Jurkat T co-culture cell model, Z13 decreased the viability rate of HepG2 cells in a concentration-dependent manner. In addition, Z13 showed significant in vivo antitumor efficacy (TGI = 52.6 % at 40 mg/kg) without obvious toxicity in the B16-F10 melanoma model. Furthermore, flow cytometry analysis demonstrated that Z13 inhibited tumor growth in vivo by activating the tumor immune microenvironment. These findings indicate that Z13 is a promising PD-1/PD-L1 inhibitor deserving further investigation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Apoptosis signal regulated kinase 1 (ASK1, MAP3K5) is a member of the mitogen activated protein kinase (MAPK) signaling pathway, involved in cell survival, differentiation, stress response, and apoptosis. ASK1 kinase inhibition has become a promising strategy for the treatment of Non-alcoholic steatohepatitis (NASH) disease. A series of novel ASK1 inhibitors with indazole scaffolds were designed and synthesized, and their ASK1 kinase activities were evaluated. The System Structure Activity Relationship (SAR) study discovered a promising compound 33c, which has a strong inhibitory effect on ASK1. Noteworthy observations included a discernible reduction in lipid droplets within LO2 cells stained with Oil Red O, coupled with a decrease in LDL, CHO, and TG content within the NASH model cell group. Mechanistic inquiries revealed that compound 33c could inhibit the protein expression levels of the upregulated ASK1-p38/JNK signaling pathway in TNF-α treated HGC-27 cells and regulate apoptotic proteins. In summary, these findings suggest that compound 33c may be valuable for further research as a potential candidate compound against NASH., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

In this work, we have investigated the one pot strategy for the Cu(I)-mediated synthesis of new triazoles bearing nitroindazole moieties using different copper catalysts. The biological activity of newly synthesized nitroindazolyltriazoles towards Alzheimer's disease-related targets, namely cholinesterases, monoamine oxidases, and amyloid aggregation, were investigated. Predictions of target affinity, physicochemical parameters, gastrointestinal absorption and brain penetration were achieved by means of in silico tools., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

An efficient pathway was disclosed for the synthesis of 3-chloro-6-nitro-1 H -indazole derivatives by 1,3-dipolar cycloaddition on dipolarophile compounds 2 and 3 . Faced the problem of separation of two regioisomers, a click chemistry method has allowed us to obtain regioisomers of triazole-1,4 with good yields from 82 to 90% were employed. Also, the antileishmanial biological potency of the compounds was achieved using an MTT assay that reported compound 13 as a promising growth inhibitor of Leishmania major . Molecular docking demonstrated highly stable binding with the Leishmania trypanothione reductase enzyme and produced a network of hydrophobic and hydrophilic interactions. Molecular dynamics simulations were performed for TryR- 13 complex to understand its structural and intermolecular affinity stability in a biological environment. The studied complex remained in good equilibrium with a structure deviation of ∼1-3 Å. MM/GBSA binding free energies illustrated the high stability of TryR- 13 complex. The studied compounds are promising leads for structural optimisation to enhance the antileishmanial activity.

Mutations in the Leucine Rich Repeat Protein Kinase 2 gene (LRRK2) are the most common genetic causes of Parkinson's Disease (PD). The G2019S mutation is the most common inherited LRRK2 mutation, occurs in the kinase domain, and results in increased kinase activity. We report the discovery and development of compound 38, an indazole-based, G2019S-selective (>2000-fold vs. WT) LRRK2 inhibitor capable of entering rodent brain (K p  = 0.5) and selectively inhibiting G2019S-LRRK2. The compounds disclosed herein present a starting point for further development of brain penetrant G2019S selective inhibitors that hopefully reduce lung phenotype side-effects and pave the way to providing a precision medicine for people with PD who carry the G2019S mutation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

AXL is a member of the TAM (TYRO3, AXL, MER) subfamily of receptor tyrosine kinases. It is upregulated in a variety of cancers and its overexpression is associated with poor disease prognosis and acquired drug resistance. Utilizing a fragment-based lead discovery approach, a new indazole-based AXL inhibitor was obtained. The indazole fragment hit 11, identified through a high concentration biochemical screen, was expeditiously improved to fragment 24 by screening our in-house expanded library of fragments (ELF) collection. Subsequent fragment optimization guided by docking studies provided potent inhibitor 54 with moderate exposure levels in mice. X-ray crystal structure of analog 50 complexed with the I650M mutated kinase domain of Mer revealed the key binding interactions for the scaffold. The good potency coupled with reasonable kinase selectivity, moderate in vivo exposure levels, and availability of structural information for the series makes it a suitable starting point for further optimization efforts., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

An organophosphorus-catalyzed method for the synthesis of unsymmetrical hydrazines by cross-selective intermolecular N-N reductive coupling is reported. This method employs a small ring phosphacycle (phosphetane) catalyst together with hydrosilane as the terminal reductant to drive reductive coupling of nitroarenes and anilines with good chemoselectivity and functional group tolerance. Mechanistic investigations support an autotandem catalytic reaction cascade in which the organophosphorus catalyst drives two sequential and mechanistically distinct reduction events via P III /P V ═O cycling in order to furnish the target N-N bond.

Apoptosis signal-regulating kinase 1 (ASK1, MAP3K5), a member of the mitogen-activated protein kinase (MAPK) signaling pathway, is involved in cell survival, differentiation, stress response, and apoptosis. ASK1 kinase inhibition has emerged as a promising therapeutic strategy for inflammatory disease. A series of novel ASK1 inhibitors with 1H-indazole scaffold were designed, synthesized and evaluated for their ASK1 kinase activity and AP1-HEK293 cell inhibitory effect. Systematic structure-activity relationship (SAR) efforts led to the discovery of promising compound 15, which showed excellent in vitro ASK1 kinase activity and potent inhibitory effects on ASK1 in AP1-HEK293 cells. In a tumor necrosis factor-α (TNF-α)-induced HT-29 intestinal epithelial cell model, compound 15 exhibited a significantly protective effect on cell viability comparable to that of GS-4997; moreover, compound 15 exhibited no obvious cytotoxicity against HT-29 cells at concentrations up to 25 μM. Mechanistic research demonstrated that compound 15 suppresses phosphorylation in the ASK1-p38/JNK signaling pathway in HT-29 cells, and regulates the expression levels of apoptosis-related proteins. Altogether, these results show that compound 15 may serve as a potential candidate compound for the treatment of inflammatory bowel disease (IBD)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

The present work is the last of a three-part study investigating a panel of 30 systematically designed synthetic cannabinoid receptor agonists (SCRAs) including features such as the 4-pentenyl tail and varying head groups including amides and esters of l-valine (MMB, AB), l-tert-leucine (ADB), and l-phenylalanine (APP), as well as adamantyl (A) and cumyl moieties (CUMYL). Here, we evaluated these SCRAs for their capacity to activate the human cannabinoid receptor 1 (CB 1 ) via indirect measurement of G protein recruitment. Furthermore, we comparatively evaluated the results obtained from three in vitro assays, based on the recruitment of β-arrestin 2 (βarr2 assay) or Gα i protein (mini-Gα i assay), or binding of [ 35 S]-GTPγS. The observed efficacies (E max ) varied depending on the conducted assay. Statistical analysis suggests that the population means of the relative intrinsic activity (RA i ) significantly differ for the [ 35 S]-GTPγS assay and the other two assays, but the population means of the βarr2 and mini-Gα i assays were not statistically different. Our data suggest that differences observed between the βarr2 and mini-Gα i assays are the best predictor for 'biased agonism' towards βarr or G protein recruitment in our study. SCRAs carrying an ADB or MPP moiety as a head group tended to produce elevated E max values in the βarr2 assay, which might result in a tendency of these compounds to cause pronounced tolerance in users-a hypothesis that should be evaluated further by future studies. In general, a comparison of efficacies derived from different assays is difficult and should only be conducted very cautiously., (© 2021 The Authors. Drug Testing and Analysis published by John Wiley & Sons Ltd.)

Synthetic cannabinoid receptor agonists (SCRAs) are one of the largest and most structurally diverse classes of new psychoactive substances (NPS). Despite this, pharmacological data are often lacking following the identification of a new SCRA in drug markets. In this first of a three-part series, we describe the synthesis, analytical characterization, and binding affinity of a proactively generated, systematic library of 30 indole, indazole, and 7-azaindole SCRAs related to MMB-4en-PICA, MDMB-4en-PINACA, ADB-4en-PINACA, and MMB-4CN-BUTINACA featuring a 4-pentenyl (4en-P), butyl (B/BUT), or 4-cyanobutyl (4CN-B/BUT) tail and a methyl l-valinate (MMB), methyl l-tert-leucinate (MDMB), methyl l-phenylalaninate (MPP), l-valinamide (AB), l-tert-leucinamide (ADB), l-phenylalaninamide (APP), adamantyl (A), or cumyl head group. Competitive radioligand binding assays demonstrated that the indazole core conferred the highest CB 1 binding affinity (K i  = 0.17-39 nM), followed by indole- (K i  = 0.95-160 nM) and then 7-azaindole-derived SCRAs (K i  = 5.4-271 nM). Variation of the head group had the greatest effect on binding, with tert-leucine amides and methyl esters (K i  = 0.17-14 nM) generally showing the greatest affinities, followed by valine derivatives (K i  = 0.72-180 nM), and then phenylalanine derivatives (K i  = 2.5-271 nM). Adamantyl head groups (K i  = 8.8-59 nM) were suboptimal for binding, whereas the cumyl analogues consistently conferred high affinity (K i  = 0.62-36 nM). Finally, both butyl (K i  = 3.1-163 nM) and 4-cyanobutyl (K i  = 5.5-44 nM) tail groups were less favorable for CB 1 binding than their corresponding 4-pentenyl counterparts (K i  = 0.72-25 nM)., (© 2021 John Wiley & Sons, Ltd.)

Human indoleamine 2,3-dioxygenase 1 (hIDO1) and tryptophan 2,3-dioxygenase (hTDO) have been closely linked to the pathogenesis of Parkinson's disease (PD); nevertheless, development of dual hIDO1 and hTDO inhibitors to evaluate their potential efficacy against PD is still lacking. Here, we report biochemical, biophysical, and computational analyses revealing that 1 H -indazole-4-amines inhibit both hIDO1 and hTDO by a mechanism involving direct coordination with the heme ferrous and ferric states. Crystal structure-guided optimization led to 23 , which manifested IC 50 values of 0.64 and 0.04 μM to hIDO1 and hTDO, respectively, and had good pharmacokinetic properties and brain penetration in mice. 23 showed efficacy against the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse motor coordination deficits, comparable to Madopar, an anti-PD medicine. Further studies revealed that different from Madopar, 23 likely has specific anti-PD mechanisms involving lowering IDO1 expression, alleviating dopaminergic neurodegeneration, reducing inflammatory cytokines and quinolinic acid in mouse brain, and increasing kynurenic acid in mouse blood.

A series of compounds were designed and synthesized based on the compound 11i bearing phenylpyrazole scaffold with histone deacetylase 6 (HDAC6) inhibitory activity. Most of the compounds showed considerable inhibitory activity against HDAC6 and compound A16 with good inhibitory activity was found therein. We further found that A16 had an inhibitory effect on inflammatory mediators (NO, TNF-α, IL-6) involved in inflammatory response and neuroendocrine regulation. In addition, A16 has a certain neuroprotective effect on PC12 cells injured by hydrogen peroxide. Acute toxicity assay showed that the LD 50 of A16 was 274.47 mg/kg in mouse model. Furthermore, A16 displayed good stability properties in microsomes and plasma., (Copyright © 2021. Published by Elsevier Inc.)

Indazole is an important scaffold in medicinal chemistry. At present, the progress on synthetic methodologies has allowed the preparation of several new indazole derivatives with interesting pharmacological properties. Particularly, the antiprotozoal activity of indazole derivatives have been recently reported. Herein, a series of 22 indazole derivatives was synthesized and studied as antiprotozoals. The 2-phenyl-2 H -indazole scaffold was accessed by a one-pot procedure, which includes a combination of ultrasound synthesis under neat conditions as well as Cadogan's cyclization. Moreover, some compounds were derivatized to have an appropriate set to provide structure-activity relationships (SAR) information. Whereas the antiprotozoal activity of six of these compounds against E. histolytica , G. intestinalis , and T. vaginalis had been previously reported, the activity of the additional 16 compounds was evaluated against these same protozoa. The biological assays revealed structural features that favor the antiprotozoal activity against the three protozoans tested, e.g., electron withdrawing groups at the 2-phenyl ring. It is important to mention that the indazole derivatives possess strong antiprotozoal activity and are also characterized by a continuous SAR.

A series of 11 3-(ω-aminoalkoxy)-1-benzyl-5-nitroindazoles (2-12) has been prepared starting from 1-benzyl-5-nitroindazol-3-ol 13, and evaluated against sensitive and resistant isolates of the sexually transmitted protozoan Trichomonas vaginalis. Compounds 2, 3, 6, 9, 10 and 11 showed trichomonacidal profiles with IC 50  < 20 µM against the metronidazole-sensitive isolate. Moreover, all these compounds submitted to cytotoxicity assays against mammalian cells exhibited low non-specific cytotoxic effects, except compounds 3 and 9 which displayed moderate cytotoxicity (CC 50  = 74.7 and 59.1 µM, respectively). Those compounds with trichomonacidal effect were also evaluated against a metronidazole-resistant culture. Special mention deserve compounds 6 and 10, which displayed better IC 50 values (1.3 and 0.5 µM respectively) than that of the reference drug (IC 50 MTZ = 3.0 µM). The high activity of these compounds against the resistant isolate reinforces the absence of cross-resistance with the reference drug. The remarkable trichomonacidal results against resistant T. vaginalis isolates suggest the interest of 3-(ω-aminoalkoxy)-1-benzyl-5-nitroindazoles to be considered as good prototypes to continue in the development of new drugs with enhanced trichomonacidal activity, aiming to increase the non-existent drugs to face clinical resistance efficiently for those patients in whom therapy with 5-nitroimidazoles is contraindicated., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Fibroblast growth factor receptor 4 (FGFR4) is a member of the fibroblast growth factor receptor family, which is closely related to the occurrence and development of hepatocellular carcinoma (HCC). In this article, a series of indazole derivatives were designed and synthesized by using computer-aided drug design (CADD) and structure-based design strategies, and then they were evaluated for their inhibition of FGFR4 kinase and antitumor activity. F-30 was subtly selective for FGFR4 compared to FGFR1; it affected cell growth and migration by inhibiting FGFR4 pathways in HCC cell lines in a dose-dependent manner., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Over 50 tetrahydroindazoles were synthesized after 7-bromo-3,6,6-trimethyl-1-(pyridin-2-yl)-5,6,7,7a-tetrahydro-1H-indazol-4(3aH)-one (3) was identified as a hit compound in a high throughput screen for inhibition of CDK2 in complex with cyclin A. The activity of the most promising analogues was evaluated by inhibition of CDK2 enzyme complexes with various cyclins. Analogues 53 and 59 showed 3-fold better binding affinity for CDK2 and 2- to 10-fold improved inhibitory activity against CDK2/cyclin A1, E, and O compared to screening hit 3. The data from the enzyme and binding assays indicate that the binding of the analogues to a CDK2/cyclin complex is favored over binding to free CDK2. Computational analysis was used to predict a potential binding site at the CDK2/cyclin E1 interface., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

IRAK4 is a key mediator of innate immunity. There is a high interest in identifying novel IRAK4 inhibitors for the treatment of inflammatory autoimmune diseases. We describe here a highly potent and selective IRAK4 inhibitor (HS271) that exhibited superior enzymatic and cellular activities, as well as excellent pharmacokinetic properties. HS271 displayed robust in vivo anti-inflammatory efficacy as evaluated in rat models of LPS induced TNFα production and collagen-induced arthritis., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Structurally diverse heterotricyclic compounds are recognized as monoamine oxidase (MAO) inhibitors and thus represent an appealing scaffold in development and optimization of novel MAO inhibitors. Herein we explored the chemical space of pyrimido[1,2-b]indazoles as MAO inhibitors by preparing a small library of (hetero)aryl derivatives. An efficient synthetic strategy was developed starting from commercially available 1H-indazol-3-amines, which were converted to various 3-bromoheterotricyclic derivatives and further functionalized via Suzuki-Miyaura coupling reaction. Derivatives 4a-t selectively inhibited human MAO-B isoform in a reversible and competitive manner as confirmed by kinetic experiments and docking studies. Selected derivatives were not cytotoxic to neuroblastoma SH-SY5Y cells. Moreover, analogue 4i protected human neuroblastoma SH-SY5Y cells against 6-hydroxydopamine-induced cell death, which confirms the applicability of the pyrimido[1,2-b]indazoles as potential antiparkinsonian agents., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Pathogenic variants in the leucine-rich repeat kinase 2 (LRRK2) gene have been identified that increase the risk for developing Parkinson's disease in a dominantly inherited fashion. These pathogenic variants, of which G2019S is the most common, cause abnormally high kinase activity, and compounds that inhibit this activity are being pursued as potentially disease-modifying therapeutics. Because LRRK2 regulates important cellular processes, developing inhibitors that can selectively target the pathogenic variant while sparing normal LRRK2 activity could offer potential advantages in heterozygous carriers. We conducted a high-throughput screen and identified a single selective compound that preferentially inhibited G2019S-LRRK2. Optimization of this scaffold led to a series of novel, potent, and highly selective G2019S-LRRK2 inhibitors.

To develop potent and selective anticancer agents, a series of novel polysubstituted indazoles was synthesized and evaluated for their in vitro antiproliferative and apoptotic activities against two selected human cancer cell lines (A2780 and A549). Several compounds showed an interesting antiproliferative activity, with IC 50 values ranging from 0.64 to 17 µM against both cell lines. The most active indazoles were then tested in different pharmacological dilution conditions, adding five new cell lines (A2780, A549, IMR32, MDA-MB-231, and T47D) as targets, confirming their antiproliferative activity. Furthermore, selected compounds were able to trigger apoptosis to a significant extent and to cause, in part, a block of cells in the S phase of the cell cycle, with a concomitant decrease of cells in the G2/M and/or G0/G1 phases and the generation of hypodiploid peaks. However, molecule 7d caused a great increase of cells in G2/M and the appearance of polyploid cells. Altogether, our results suggest a good pharmacological activity for our selected polysubstituted indazoles, which are suggestive of a preferential mechanism of action as cell cycle-specific antimetabolites or as an inhibitor of enzyme activities involved in DNA synthesis, except for 7d, which, on the contrary, seems to have a mechanism involving the microtubule system., (© 2020 Deutsche Pharmazeutische Gesellschaft.)

Fibroblast growth-factor receptor (FGFR) is a potential target for cancer therapy. We designed three novel series of FGFR1 inhibitors bearing indazole, benzothiazole, and 1 H -1,2,4-triazole scaffold via fragment-based virtual screening. All the newly synthesised compounds were evaluated in vitro for their inhibitory activities against FGFR1. Compound 9d bearing an indazole scaffold was first identified as a hit compound, with excellent kinase inhibitory activity (IC 50 = 15.0 nM) and modest anti-proliferative activity (IC 50 = 785.8 nM). Through two rounds of optimisation, the indazole derivative 9 u stood out as the most potent FGFR1 inhibitors with the best enzyme inhibitory activity (IC 50 = 3.3 nM) and cellular activity (IC 50 = 468.2 nM). Moreover, 9 u also exhibited good kinase selectivity. In addition, molecular docking study was performed to investigate the binding mode between target compounds and FGFR1.

Breakpoint cluster region-Abelson (Bcr-Abl) kinase is a key driver in the pathophysiology of chronic myelogenous leukemia (CML). Broadening the chemical diversity of Bcr-Abl kinase inhibitors with novel chemical entities possessing favorable target potency and cellular efficacy is a current medical demand for CML treatment. In this respect, a new series of ethynyl bearing 3-aminoindazole based Bcr-Abl inhibitors has been designed, synthesized, and biologically evaluated. The target compounds were designed based on introducing the key structural features of ponatinib, alkyne spacer and diarylamide, into the previously reported indazole II to improve its Bcr-Abl inhibitory activity and overcome its poor cellular potency. All target compounds elicited potent activity against Bcr-Abl WT with sub-micromolar IC 50 values ranging 4.6-667 nM. In addition, certain derivatives exhibited promising potency over the clinically imatinib-resistant Bcr-Abl T315I . Among the target molecules, compounds 9c, 9h and 10c stood as the most potent derivatives with IC 50 values of 15.4 nM, 4.6 nM, and 25.8 nM, respectively, against Bcr-Abl WT . Interestingly, 9h showed 2 folds and 3.6 times superior potency to the lead indazole II and 10c, respectively, against Bcr-Abl T315I . Molecular docking of 9h pointed out its possibility to be a type II kinase inhibitor. Furthermore, all compounds, except 9b, showed highly potent antiproliferative activity against the Bcr-Abl positive leukemia K562 cell (MTT assay) surpassing the modest activity of lead indazole II. Moreover, the most potent members 9h and 10c exerted potent antileukemic activity against NCI leukemia panel, particularly K562 cell (SRB assay) with GI 50 less than 10 nM, being superior to the FDA approved drug imatinib. Further biochemical hERG and cellular toxicity, phosphorylation assay, and NanoBRET target engagement of 9h underscored its merits as a promising candidate for CML therapy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

A series of 1-indazol-3-(1-phenylpyrazol-5-yl)methyl ureas were investigated as hTRPV1 antagonists. The structure-activity relationship study was conducted systematically for both the indazole A-region and the 3-trifluoromethyl/t-butyl pyrazole C-region to optimize the antagonism toward the activation by capsaicin. Among them, the antagonists 26, 50 and 51 displayed highly potent antagonism with K i (CAP)  = 0.4-0.5 nM. Further, in vivo studies in mice indicated that these derivatives both antagonized capsaicin induced hypothermia, consistent with their in vitro activity, and themselves did not induce hyperthermia. In the formalin model, 51 showed anti-nociceptive activity in a dose-dependent manner., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Haspin is a mitotic protein kinase required for proper cell division by modulating Aurora B kinase localisation and activity as well as histone phosphorylation. Here a series of imidazopyridazines based on the CHR-6494 and Structure Activity Relationship was established. An assessment of the inhibitory activity of the lead structures on human Haspin and several other protein kinases is presented. The lead structure was rapidly optimised using a combination of crystal structures and effective docking models, with the best inhibitors exhibiting potent inhibitory activity on Haspin with IC 50 between 6 and 100 nM in vitro . The developed inhibitors displayed anti-proliferative properties against various human cancer cell lines in 2D and spheroid cultures and significantly inhibited the migration ability of osteosarcoma U-2 OS cells. Notably, we show that our lead compounds are powerful Haspin inhibitors in human cells, and did not block G2/M cell cycle transition due to improved selectivity against CDK1/CyclinB.

In 2020, nearly one-third of new drugs on the global market were synthetic cannabinoids including the drug of abuse N -(1-adamantyl)-1-(5-pentyl)-1 H -indazole-3-carboxamide (5F-APINACA, 5F-AKB48). Knowledge of 5F-APINACA metabolism provides a critical mechanistic basis to interpret and predict abuser outcomes. Prior qualitative studies identified which metabolic processes occur but not the order and extent of them and often relied on problematic "semi-quantitative" mass spectroscopic (MS) approaches. We capitalized on 5F-APINACA absorbance for quantitation while leveraging MS to characterize metabolite structures for measuring 5F-APINACA steady-state kinetics. We demonstrated the reliability of absorbance and not MS for inferring metabolite levels. Human liver microsomal reactions yielded eight metabolites by MS but only five by absorbance. Subsequent kinetic studies on primary and secondary metabolites revealed highly efficient mono- and dihydroxylation of the adamantyl group and much less efficient oxidative defluorination at the N -pentyl terminus. Based on regiospecificity and kinetics, we constructed pathways for competing and intersecting steps in 5F-APINACA metabolism. Overall efficiency for adamantyl oxidation was 17-fold higher than that for oxidative defluorination, showing significant bias in metabolic flux and subsequent metabolite profile compositions. Lastly, our analytical approach provides a powerful new strategy to more accurately assess metabolic kinetics for other understudied synthetic cannabinoids possessing the indazole chromophore.

Synthesis and pharmacological evaluation of a new series of cannabinoid receptor antagonists of indazole ether derivatives have been performed. Pharmacological evaluation includes radioligand binding assays with [ 3 H]-CP55940 for CB1 and CB2 receptors and functional activity for cannabinoid receptors on isolated tissue. In addition, functional activity of the two synthetic cannabinoids antagonists 18 (PGN36) and 17 (PGN38) were carried out in the osteoblastic cell line MC3T3-E1 that is able to express CB2R upon osteogenic conditions. Both antagonists abolished the increase in collagen type I gene expression by the well-known inducer of bone activity, the HU308 agonist. The results of pharmacological tests have revealed that four of these derivatives behave as CB2R cannabinoid antagonists. In particular, the compounds 17 (PGN38) and 18 (PGN36) highlight as promising candidates as pharmacological tools., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Spleen tyrosine kinase (SYK) is a non-receptor cytosolic kinase. Due to its pivotal role in B cell receptor and Fc-receptor signaling, inhibition of SYK has been targeted in a variety of disease areas. Herein, we report the optimization of a series of potent and selective SYK inhibitors, focusing on improving metabolic stability, pharmacokinetics and hERG inhibition. As a result, we identified 30, which exhibited no hERG activity but unfortunately was poorly absorbed in rats and mice. We also identified a SYK chemical probe, 17, which exhibits excellent potency at SYK, and an adequate rodent PK profile to support in vivo efficacy/PD studies., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Neurotrophic receptor tyrosine kinase (NTRK) fusions are oncogenic drivers for a variety of adult and pediatric tumors, validated by the US FDA approval of small molecular Trk inhibitors Larotrectinib (1, LOXO-101) and Entrectinib (2). However, gene mutation mediated resistance becomes a major challenge for Trk inhibitor therapies. Herein, we report the design, synthesis and Structure-Activity Relationship investigation of a series of 3-vinylindazole derivatives as new Trk inhibitors with low nanomolar potencies. A representative compound, 7mb, binds to TrkA/B/C with K d values of 1.6, 3.1 and 4.9 nM, and suppresses their kinase functions with IC 50 values of 1.6, 2.9 and 2.0 nM, respectively, but is obviously less potent for the majority of a panel of 403 wild-type kinases in a KINOMEscan selectivity investigation. The compound also potently suppresses proliferation of a panel of BaF3 cells stably transformed with NTRK fusions with IC 50 values in low nM ranges. Additionally, the compound exhibits strong inhibition against the Larotrectinib-resistant cells with NTRK1-G667C or NTRK3-G696A mutations with IC 50 values of 0.031 and 0.018 μM, respectively. Although the relatively poor oral bioavailability of 7mb will limit its further development, this compound may be utilized a lead molecule for further structural optimization., Competing Interests: Declaration of competing interest The authors declare no interest of conflict., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Aberrant activation of p21-activated kinase 1 (PAK1) is associated with tumour progression, and PAK1 has been recognized as a promising target for anticancer drug discovery. However, the development of potent PAK1 inhibitors with satisfactory kinase selectivity and favourable physicochemical properties remains a daunting challenge. Herein, we identified the 1H-indazole-3-carboxamide derivatives as potential PAK1 inhibitors using a fragment-based screening approach. The representative compound 30l exhibited excellent enzyme inhibition (PAK1 IC 50  = 9.8 nM) and high PAK1 selectivity toward a panel of 29 kinases. The Structure-activity relationship (SAR) analysis showed that substituting of an appropriate hydrophobic ring in the deep back pocket and introducing a hydrophilic group in the bulk solvent region were critical for PAK1 inhibitory activity and selectivity. Additionally, the hERG channel activity of 30l demonstrated its low risk of hERG toxicity. Furthermore, it significantly suppressed the migration and invasion of MDA-MB-231 cells by downregulating Snail expression without affecting the tumour growth. These results provide a new type of chemical scaffolds targeting PAK1 and suggested that 1H-indazole-3-carboxamide derivatives may serve as lead compounds for the development of potential and selective PAK1 inhibitors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Indazolone cores are among the most common structural components in medicinal chemistry and can be found in many biologically active molecules. In this report, a mild and efficient approach to 2-substituted indazolones via B 2 (OH) 4 -mediated reductive N - N bond formation is developed. This strategy features mild conditions, no request for a metal catalyst, and a wide scope for both aliphatic and aromatic amines. Meanwhile, this method was further successfully applied on DNA to construct indazolone cores for a DNA-encoded library. This will enable the production of a very attractive indazolone-cored library from simple amines and scaffolds, which will provide considerable diversity.

With the selection of partially saturated 2H-indazoles as model compounds, we demonstrate the possibility to use Whelk-O1 chiral stationary phases (CSPs) to succeed in efficient small-scale preparative enantioseparations. Runs of three consecutive liquid chromatography injections (about 300 μg of racemate repeatedly injected in a 100 μL loop) produced groups of peaks without band contamination (α = 1.2 and R S  = 2.57). With this procedure approximately 3.0 mg of each enantiomer, with enantiomeric excess ≥ 97% were obtained. Very profitably, the high volatility of n-hexane used as the sole eluent facilitated the solvent evaporation after the enantiomer recovery. High resolution mass spectrometry analysis confirmed that the chemical identity of the two enantiomers was preserved along the entire process. The ability of Whelk-O1 phases in enantioseparating structurally similar compounds was confirmed with the analysis of other two racemates. Moreover, the relevant chemoselectivity exhibited by the CSP towards the three racemates should allow to simultaneously optimizing the enantioselectivity of different analytes and perform small-scale enantioresolutions of different compounds during the same run. In this study, the integration of experimental off-line electronic circular dichroism analysis with ab initio time-dependent density-functional theory simulations facilitated the assignment of the absolute configuration of the single enantiomers, while a molecular dynamics protocol can be useful to make a priori predictions of the enantioseparation ability of CSP towards selected compounds., Competing Interests: Declaration of Competing Interest None., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The synthesis of new porphyrin-indazole hybrids by a Knoevenagel condensation of 2-formyl-5,10,15,20-tetraphenylporphyrin and N-methyl-nitroindazolylacetonitrile derivatives is reported. The target compounds were isolated in moderate to good yields (32-57%) and some of the isolated porphyrin-indazole conjugates showed good performance in the generation of singlet oxygen when irradiated with visible light. Their efficiency as photosensitizers in the photoinactivation of methicillin resistant Staphylococcus aureus-MRSA was evaluated. All derivatives showed to be able to photoinactivate the MRSA bacteria. Compound 3a appears to be the most promising photosensitiser (PS) in the photoinactivation of these bacteria, despite being the least efficient in singlet oxygen generation. The addition of potassium iodide (KI) significantly potentiated the antimicrobial Photodynamic Therapy (aPDT) process mediated by all the analysed porphyrin-indazole conjugates. The combined action of nitroindazole-porphyrins with potassium iodide (KI) action appears to be promising in the photoinactivation of MRSA., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Structure-based drug design enabled the discovery of 8 , HTL22562, a calcitonin gene-related peptide (CGRP) receptor antagonist. The structure of 8 complexed with the CGRP receptor was determined at a 1.6 Å resolution. Compound 8 is a highly potent, selective, metabolically stable, and soluble compound suitable for a range of administration routes that have the potential to provide rapid systemic exposures with resultant high levels of receptor coverage (e.g., subcutaneous). The low lipophilicity coupled with a low anticipated clinically efficacious plasma exposure for migraine also suggests a reduced potential for hepatotoxicity. These properties have led to 8 being selected as a clinical candidate for acute treatment of migraine.

C3-substituted 1 H -indazoles are useful and important substructures in many pharmaceuticals. Methods for direct C3-functionalization of indazoles are relatively rare, compared to reactions developed for the more nucleophilic N1 and N2 positions. Herein, we report a highly C3-selective allylation reaction of 1 H - N -(benzoyloxy)indazoles using CuH catalysis. A variety of C3-allyl 1 H -indazoles with quaternary stereocenters were efficiently prepared with high levels of enantioselectivity. Density functional theory (DFT) calculations were performed to explain the reactivity differences between indazole and indole electrophiles, the latter of which was used in our previously reported method. The calculations suggest that the indazole allylation reaction proceeds through an enantioselectivity-determining six-membered Zimmerman-Traxler-type transition state, rather than an oxidative addition/reductive elimination sequence, as we proposed in the case of indole alkylation. The enantioselectivity of the reaction is governed by both ligand-substrate steric interactions and steric repulsions involving the pseudoaxial substituent in the six-membered allylation transition state.

Giardiasis and other protozoan infections are major worldwide causes of morbidity and mortality, yet development of new antimicrobial agents with improved efficacy and ability to override increasingly common drug resistance remains a major challenge. Antimicrobial drug development typically proceeds by broad functional screens of large chemical libraries or hypothesis-driven exploration of single microbial targets, but both strategies have challenges that have limited the introduction of new antimicrobials. Here, we describe an alternative drug development strategy that identifies a sufficient but manageable number of promising targets, while reducing the risk of pursuing targets of unproven value. The strategy is based on defining and exploiting the incompletely understood adduction targets of 5-nitroimidazoles, which are proven antimicrobials against a wide range of anaerobic protozoan and bacterial pathogens. Comprehensive adductome analysis by modified click chemistry and multi-dimensional proteomics were applied to the model pathogen Giardia lamblia to identify dozens of adducted protein targets common to both 5'-nitroimidazole-sensitive and -resistant cells. The list was highly enriched for known targets in G. lamblia, including arginine deiminase, α-tubulin, carbamate kinase, and heat shock protein 90, demonstrating the utility of the approach. Importantly, over twenty potential novel drug targets were identified. Inhibitors of two representative new targets, NADP-specific glutamate dehydrogenase and peroxiredoxin, were found to have significant antigiardial activity. Furthermore, all the identified targets remained available in resistant cells, since giardicidal activity of the respective inhibitors was not impacted by resistance to 5'-nitroimidazoles. These results demonstrate that the combined use of click chemistry and proteomics has the potential to reveal alternative drug targets for overcoming antimicrobial drug resistance in protozoan parasites., Competing Interests: The authors have declared that no competing interests exist.

Based on fragment-based virtual screening and bioisoterism strategies, novel indazole and pyrazolo[3,4-b] pyridine derivatives as HDACs inhibitors were designed, synthesized and evaluated. Most of these compounds displayed good to excellent inhibitory activities against HDACs, especially compounds 15k and 15m were identified as potent inhibitors of HDAC1 (IC 50  = 2.7 nM and IC 50  = 3.1 nM), HDAC2 (IC 50  = 4.2 nM and IC 50  = 3.6 nM) and HDAC8 (IC 50  = 3.6 nM and IC 50  = 3.3 nM). Further anti-proliferation assays revealed that compounds 15k and 15m showed better anti-proliferative activities against HCT-116 and HeLa cells than positive control SAHA. The western blot analysis results indicated that compounds 15k and 15m noticeably up-regulated the level of acetylated α-tubulin and histone H3. In addition, the two compounds 15k and 15m could arrest cell cycle in G2/M phase and promote cell apoptosis, which was similar as the reference compound SAHA. Through the molecular docking and dynamic studies, the potent HDAC inhibitory activities mainly caused by van der Waals and electrostatic interactions with the HDACs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Series of 7-aryl- (3a-f), 7-arylvinyl- (3g-k) and 7-(arylethynyl)-5-bromo-3-methylindazoles (4a-f) have been evaluated through enzymatic assay in vitro for inhibitory effect against α-glucosidase activity and for antioxidant potential through the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Compounds 3a-k and 4a-f showed significant to moderate α-glucosidase inhibition with IC 50 values in the range of 0.50-51.51 μM and 0.42-23.71 μM compared with acarbose drug (IC 50  = 0.82 μM), respectively. 5-Bromo-3-methyl-7-phenyl-1H-indazole (3a), 5-bromo-3-methyl-7-styryl-1H-indazole (3h) and 5-bromo-3-methyl-7-styryl-1H-indazole (4a) exhibited moderate to significant antigrowth effect against the breast MCF-7 cancer cell line and reduced cytotoxicity against the human embryonic kidney derived Hek293-T cells when compared to doxorubicin as reference standard. Non-covalent (alkyl, π-alkyl and π-π T shaped), electrostatic (π-sulfur and/or π-anion) and hydrogen bonding interactions are predicted to increase interactions with protein residues, thereby enhancing the inhibitory effect of these compounds against α-glucosidase., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)