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We report a method to furnish substituted 1H‐indazoles via a coupling of 3‐acetyl substituted nitroarenes and arylhydrazines. Reactions progressed in the presence of cobalt(II) acetylacetonate catalyst, TEMPO oxidant, and Cs2CO3 base. Functional groups including bromo, chloro, nitro, and trifluoromethoxy groups were compatible with reaction conditions. The proposed mechanism was based on a nucleophilic substitution of hydrogen para to nitro group. Our method feature a convenient pathway to directly obtain substituted 1H‐indazoles which avoid the use of pre‐functionalized starting materials. Indazole could play a role as the directing group for a palladium‐catalyzed C(sp2)─H arylation with iodobenzene. [ABSTRACT FROM AUTHOR]

Comprehensive Summary A variety of 3‐nitroindazoles and 3‐aminoindazoles were prepared in good to excellent yields with high regioselectivity through TBN‐mediated nitration at the C3‐position of indazoles under the air conditions and sequential reduction. Mechanistic studies revealed that TBN played crucial roles to produce •NO2 radical source in the presence of air conditions and C3‐nitration of indazoles was initiated by N1‐nitration and sequential migration of NO2 group to C3‐position. Moreover, this method could be easily applied in the gram scalable synthesis of ibuprofen and ciprofibrate‐derived 3‐aminoindazoles. The present method highlights air as mild oxidant, metal‐free radical nitration of indazole, N—N bond formation and cleavage, and late‐stage modification of drugs. [ABSTRACT FROM AUTHOR]

Amidst the escalating cancer cases and the relentless spread of multidrug‐resistant microbes, the urgency for effective medication is undeniable. In this context, our lab's continuous efforts have led to a promising discovery. We have conducted an extensive study on a series of new heterocycles with an indazolylthiazole component, which holds great promise as antimicrobial and anticancer drugs. The bioactivity tests, conducted with meticulous methodology, have demonstrated that the synthesized compounds possess remarkable antibacterial activity against various pathogenic strains. In a controlled lab setting, we have observed that derivatives 9, 11, and 12a effectively induce apoptosis in HCT‐166 and Huh‐7 (liver carcinoma) cell lines. Among these, derivative 11 has shown the highest selectivity (SI=14.54±1.2 and 16.51±1.4) and the lowest IC50 value. These compounds also exhibit broad‐spectrum antimicrobial activity. The anticancer activity of the synthesized compounds has been computationally confirmed through molecular modeling using MOE software and pharmacokinetic studies. Most of the tested compounds have shown significant cytotoxic activity against tumor cell lines, with high safety against normal human cells, thereby paving the way for a hopeful and promising future of antimicrobial and anticancer drugs, with potential applications in [specific_application_1] and [specific_application_2]. [ABSTRACT FROM AUTHOR]

The medicinal importance, natural rarity, and challenges associated with the synthesis of C3-functionalized 1 H -indazoles have propelled the development of novel and practical 1 H -indazole N-oxides for the production of diverse arrays of C3-functionalized 1 H -indazoles. The use of 1 H -indazole N-oxides has been remarkably effective for the selective introduction of diverse functional groups, including amino (NHAr), chloro (Cl), hydroxy (OH), sulfonyl (SO2 Ar), aromatic (Ar), olefin, alkyl, and N-formyl (NRCHO) groups, to indazole pharmacophore molecules. This review offers a concise overview of the synthetic approaches and practical applications of 1 H -indazole N-oxides, including recent studies conducted by the authors. Transformative reactions involving 1 H -indazole N-oxides not only offer strategies for synthesizing C3-functionalized 1 H -indazoles but also hold significant potential in medicinal chemistry. 1 Introduction 2 Synthetic Approaches and Applications of 1 H -Indazole N -Oxides 3 Summary and Outlook [ABSTRACT FROM AUTHOR]

Herein, we report a pair of regioselective N1- and N2-alkylations of a versatile indazole, methyl 5-bromo-1H-indazole-3-carboxylate (6) and the use of density functional theory (DFT) to evaluate their mechanisms. Over thirty N1- and N2-alkylated products were isolated in over 90% yield regardless of the conditions. DFT calculations suggest a chelation mechanism produces the N1-substituted products when cesium is present and other non-covalent interactions (NCIs) drive the N2-product formation. Methyl 1H-indazole-7-carboxylate (18) and 1H-indazole-3-carbonitrile (21) were also subjected to the reaction conditions and their mechanisms were evaluated. The N1- and N2-partial charges and Fukui indices were calculated for compounds 6, 18, and 21 via natural bond orbital (NBO) analyses which further support the suggested reaction pathways.

Antibiotic resistance is a critical public health issue. Among the multi-drug resistant microorganisms in question, Pseudomonas aeruginosa has been designated by the WHO as a priority threat. Its virulence is orchestrated through quorum sensing (QS). This sophisticated communication network relies on the release and perception of autoinducers acting as population density indicators. Therefore, the interest of a quorum silencing pharmacological approach has unfolded to quench bacterial pathogenicity without impairing growth. In this article, we reported the development of a family of indazole–quinolone hybrids as anti-virulence agents. These new biaromatic compounds were designed as potential specific QS quenchers against P. aeruginosa. Our transdisciplinary research methodology included their synthesis using palladocatalyzed cross-coupling reactions, as well as their in silico physicochemical and in vitro biological evaluation. The hit 7-chloro-2-indazolyl-4-quinolone Ie shows a promising anti-biofilm and anti-pyocyanin efficiency (35% inhibition at 25 µM and 35% inhibition at 100 µM, respectively) without an anti-pseudomonal bacteriostatic effect. It also demonstrated a moderate eukaryotic cytotoxicity. Its anti-QS properties have been investigated using metabolomic and molecular modelling studies. [ABSTRACT FROM AUTHOR]

Indazoles are a very important group of nitrogen-containing heterocycles with a wide range of biological and medicinal applications. These properties make them highly attractive for drug development, particularly when combined with sulfonamides to enhance their medicinal potential. In this work, we synthesized an indazole-based sulfonamide, namely the 1-((2-chloro-5-methoxyphenyl)sulfonyl)-5-nitro-1H-indazole (3). The reduction of the nitro group of 5-nitroindazole (1) to its corresponding amine was also performed to yield compound (4). Both compounds' structures were elucidated using various spectroscopic techniques such as 1H NMR, 13C NMR, infrared (IR), and high-resolution mass spectrometry (HRMS). Our molecular docking studies suggest that compounds (3) and (4) have a strong affinity for MAPK1, indicating their potential as cancer treatments. [ABSTRACT FROM AUTHOR]

A theoretical study of the formation of carbamic acids of pyrazole and indazole has been carried out using DFT computational methods. The effects of the substituents and the solvent (using explicit and implicit solvent models) have been considered. In addition, the deprotonation of the carbamic acid and its influence on the stability of the system has been calculated. In the neutral systems, only the formation of indazole-1-carbamic acid derivatives is favored vs. the non-covalent complexes between pyrazole or indazole with CO2. The deprotonation of the carbamic acid highly stabilizes the system preventing its dissociation. [ABSTRACT FROM AUTHOR]

Aim of the study was designed for the design of novel indazole derivatives and evaluation of their docking against topoisomerase-II DNA gyrase enzyme for the antibacterial screening. Different novel substituted indazol-3-yl benzenesulfonamide derivatives were designed for the synthesis from o-chlorobenzonitrile and phenyl hydrazine reaction and further, with benzene sulphonyl chloride reaction. These were evaluated for their docking targeting topoisomerase-II DNA gyrase enzyme for the antibacterial screening. A range of binding affinity (-12.2 to -9.6 kcal/mol) was observed. Compound, 4-chloro-N-(1-phenyl-1H-indazol-3-yl)benzenesulfonamide had the highest binding affinity (-12.2 kcal/mol) which is better than the standard norfloxacin (-10.7 kcal/mol). Compounds (12a, 12c, 12e and 12g) with chloro-substitution at para position of sulfonamide had higher affinity as compared to the compounds (12b, 12d, 12f and 12h) with methyl substitution. A convenient method for the synthesis of indazole derivatives has been developed. 4-chloro-N-(1-phenyl-1H-indazol-3-yl)benzenesulfonamide had shown the best binding affinity. Further, more diverse bioactive moieties may be incorporated into indazole scaffold in the near future by future researchers and a great amount of effort may be dedicated to the exploration of medicinal approaches for their preparation and evaluation of their biological activities. [ABSTRACT FROM AUTHOR]

Indazoles are a very important group of nitrogen-containing heterocycles with a wide range of biological and medicinal applications. These properties make them highly attractive for drug development, particularly when combined with sulfonamides to enhance their medicinal potential. In this work, we synthesized an indazole-based sulfonamide, namely the 1-((2-chloro-5-methoxyphenyl)sulfonyl)-5-nitro-1H-indazole (3). The reduction of the nitro group of 5-nitroindazole (1) to its corresponding amine was also performed to yield compound (4). Both compounds’ structures were elucidated using various spectroscopic techniques such as 1H NMR, 13C NMR, infrared (IR), and high-resolution mass spectrometry (HRMS). Our molecular docking studies suggest that compounds (3) and (4) have a strong affinity for MAPK1, indicating their potential as cancer treatments.

Indazole is a very significant group of heterocyclics. Aim of the research was thus planned to synthesize novel derivatives of indazole and evaluate their anti-inflammatory activity. Novel compounds of indazole were first synthesized from reaction of 2-chlorobenzonitrile with phenylhydrazine in presence of catalyst potassium tbutoxide (t-BuOK) and the solvent diglyme. Synthesized derivatives of indazole were analyzed by ¹H-NMR and MS spectroscopic techniques. All the synthesized derivatives of indazole were evaluated for their antiinflammatory activity in Sprague Dawley rats by carrageenan-induced rat paw edema method. All the synthesized derivatives of indazole had shown very good activity in both docking and anti-inflammatory activity in rats in comparison to the standard etoricoxib. Compound 1a in a dose of 30 mg/kg body weight had shown most significant inhibition of edema as compared to toxic group and the inhibition was comparable to that of the standard drug, etoricoxib in a dose of 10 mg/kg body weight. A convenient means for the synthesis of derivatives of indazole was developed which may find applications in heterocyclic synthesis of derivatives of indazole. Compound 1a i.e., 3-(4-carboxyphenyl)amino-1-phenyl-1H-indazole had shown best anti-inflammatory activity amongst all the synthesized compounds. [ABSTRACT FROM AUTHOR]

Aim of the study was designed to synthesize and evaluate antibacterial activity of novel heterocyclic compounds, 3-methyl-1H-indazole derivatives. The heterocyclic compounds, 3-methyl-¹H-indazole derivatives (1a-1d and 2a- 2d) were synthesized; all of them characterized physically by melting point, Rf value, appearance & solubility; and some of them characterized spectroscopically by IR and 1H NMR spectroscopy. All the synthesized derivatives were evaluated for their antibacterial activity against both Gram positive bacteria, Bacillus subtilis and Gram negative bacteria, Escherichia coli by cup plate method using ciprofloxacin as a standard drug. All the synthesized heterocyclic compounds, 3-methyl-1H-indazole derivatives (1a-1d and 2a-2d), had shown antibacterial activity against the B. subtilis and E. coli. Compound 1d i.e., 1-(2-(piperidin-1-yl)ethan-1-oyl)-3-methyl-1H-indazole at the concentration of 300 μg/ml showed best antibacterial activity against the bacteria B. subtilis and E. coli as compared to standard drug, ciprofloxacin. The methodology for the synthesis of heterocyclic compounds, 3- methyl-1H-indazol-1-yl derivatives was simple as well as economical and gave better yield of the synthesized compounds. The compound, 1-(2-(piperidin-1-yl)ethan-1-oyl)-3-methyl-1H-indazole had shown best antibacterial activity against the bacteria B. subtilis and E. coli. [ABSTRACT FROM AUTHOR]

The oxidant‐controlled divergent synthesis of C‐2′ formyl 2H‐indazoles and indazoloindazolediones has been developed through Mn(I)‐ catalyzed ortho C−H functionalization of 2H‐indazoles with para‐formaldehyde to afford C‐2′ hydroxymethylated 2H‐indazoles and subsequently oxidation with varying the amount of DDQ in one‐pot. By employing selectfluor as the oxidant instead of DDQ, this reaction exclusively provided indazolebenzoxazine derivatives. This strategy delivered unsymmetrical indazoloindazoledione and indazolobenzoxazine with varied functional group tolerance in moderate to good yields. [ABSTRACT FROM AUTHOR]

A new series of 1,2,4-oxadiazole incorporated indazole-isoxazole (12a-j) derivatives were designed, synthesized and confirmed their structures by ¹HNMR, 13CNMR and mass spectral analysis. Further, all compounds were evaluated for their anticancer activity against a panel of human cell lines like breast cancer (MCF-7), lung cancer (A549), prostate cancer (DU-145) and breast cancer (MDA MB-231) by using MTT assay. The etoposide used as a reference drug and the results were expressed with IC50 (µM). Most of the compounds were showed good to moderate activity with respective cell lines. Among them, compounds 12b, 12e, 12 g, 12h and 12i have exhibited more potent activity as compared with the reference drug etoposide. In which one of the compound 12i has showed most significant activity. Molecular docking studies were carried out using PyRx tool and visualized through Chimera and Pymol visualization tools, revealed that the interactions between the active site of the tubulin with the selected compound 12i exhibited good interactions with the active site amino acids. These findings suggested that the 12i compound acts as a potential binder to the tubulin complex. These results revealed that the selected synthesized compounds were used in anticancer therapies. [ABSTRACT FROM AUTHOR]

A new series of indazole-indolizine-triazine hybrid molecules was obtained by [3 + 2] cycloaddition reaction between newly synthesized nitrogen ylides with indazole skeleton and previously reported dipolarophile 2‐ethynyl‐4,6‐dimethoxy‐1,3,5‐triazine and fully characterized. The biological evaluation of hybrids revealed good antitumor growth inhibitory activity against UO-31 renal cancer cell line for the (1H-indazole-1-yl)(1-(4,6-dimethoxy-1,3,5-triazin-2-yl)-7-methylindolizin-3-yl)methanone derivative 7a. Also, for the same compound, a moderate farnesyltransferase inhibitory activity (IC50 = 52.50 ± 16.07 µM) was observed. However, the best result as farnesyltransferase inhibitor of the series was registered for the 5-bromoindazole substituted analogue 7e (IC50 = 27.08 ± 4.93 µM).

A hybrid library of compounds based on indazole-based thiadiazole containing thiazolidinone moieties (1–17) was synthesized. The synthesized compounds were screened in vitro for their inhibition profile against targetedacetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities. All the derivatives demonstrated a varied range of inhibitory activities having IC50 values ranging from 0.86 ± 0.33 μM to 26.73 ± 0.84 μM (AChE) and 0.89 ± 0.12 μM to 27.08 ± 0.19 μM (BuChE), respectively. The results obtained were compared with standard Donepezil drugs (IC50 = 1.26 ± 0.18 μM for AChE) and (1.35 ± 0.37 μM for BuChE), respectively. Specifically, the derivatives 1–17, 1, 9, and 14 were found to be significantly active, with IC50 values of 0.86 ± 0.30, 0.92 ± 0.10, and 1.10 ± 0.37 μM (against AChE) and 0.89 ± 0.12, 0.98 ± 0.48 and 1.19 ± 0.42 μM (against BuChE), respectively.The structure–activity relationship (SAR) studies revealed that derivatives bearing para-CF3, ortho-OH, and para-F substitutions on the phenyl ring attached to the thiadiazole skeleton, as well as meta-Cl, -NO2, and para-chloro substitutions on the phenyl ring, having a significant effect on inhibitory potential. The synthesized scaffolds have been further characterized by using 1H-NMR, 13C-NMR, and (HR-MS) to confirm the precise structures of the synthesized compounds. Additionally, the molecular docking approach was carried out for most active compounds to explore the binding interactions established by most active compounds, with the active sites of targeted enzymes and obtained results supporting the experimental data. [ABSTRACT FROM AUTHOR]

Indazole-based HDAC6 inhibitors with novel zinc-binding modifications were synthesized and evaluated to determine their potential to inhibit HDAC6. The analogs were subjected to a histone deacetylase (HDAC) enzyme assay, which led to identification of compounds 3a and 3b. Both compounds demonstrated higher potency and selectivity as HDAC6 inhibitors with IC50 values of 9.1 nM and 9.0 nM, respectively, and highlighted the importance of the hydroxamic acid moiety for binding to Zn2+ inside the catalytic pocket of HDAC enzymes. In the neuroblastoma SH-SY5Y cell line, both compounds efficiently acetylated α-tubulin but not histone H3 at a low concentration of 0.5 µM. Moreover, compounds 3a and 3b effectively reversed the deacetylation of α-tubulin caused by methamphetamine in the SH-SY5Y cell line, suggesting the potential usefulness of HDAC6 selective inhibition in restoring blood brain barrier integrity by reversing methamphetamine-induced deacetylation. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of cyclic ketone‐fused pyrazoles via [3+2] annulation reaction between hydrazones and cyclic enones (five‐, six‐ and seven‐membered) catalyzed by Cu(II) under aerobic conditions. These compounds were further functionalized by reactions such as Suzuki‐Miyaura cross‐coupling, Heck coupling, and Aldol reaction to afford diverse molecular scaffolds in good yield, selectivity and functional group tolerance. [ABSTRACT FROM AUTHOR]

Fms-like tyrosine kinase 3 (FLT3) has been verified as a therapeutic target for acute myeloid leukaemia (AML). In this study, we report a series of 2-(1H-indazol-6-yl)-1H-benzo[d]imidazol-5-yl benzamide and phenyl urea derivatives as potent FLT3 inhibitors based on the structural optimisation of previous FLT3 inhibitors. Derivatives were synthesised as benzamide 8a–k, 8n–z, and phenyl urea 8l–m, with various substituents. The most potent inhibitor, 8r, demonstrated strong inhibitory activity against FLT3 and FLT3 mutants with a nanomolar IC50 and high selectivity profiles over 42 protein kinases. In addition, these type II FLT3 inhibitors were more potent against FLT3 mutants correlated with drug resistance. Overall, we provide a theoretical basis for the structural optimisation of novel benzimidazole analogues to develop strong inhibitors against FLT3 mutants for AML therapeutics.

Multitarget drugs are a promising therapeutic approach against Alzheimer’s disease. In this work, a new family of 5-substituted indazole derivatives with a multitarget profile including cholinesterase and BACE1 inhibition is described. Thus, the synthesis and evaluation of a new class of 5-substituted indazoles has been performed. Pharmacological evaluation includes in vitro inhibitory assays on AChE/BuChE and BACE1 enzymes. Also, the corresponding competition studies on BuChE were carried out. Additionally, antioxidant properties have been calculated from ORAC assays. Furthermore, studies of anti-inflammatory properties on Raw 264.7 cells and neuroprotective effects in human neuroblastoma SH-SY5Y cells have been performed. The results of pharmacological tests have shown that some of these 5-substituted indazole derivatives 1–4 and 6 behave as AChE/BuChE and BACE1 inhibitors, simultaneously. In addition, some indazole derivatives showed anti-inflammatory (3, 6) and neuroprotective (1–4 and 6) effects against Aβ-induced cell death in human neuroblastoma SH-SY5Y cells with antioxidant properties.

The synthesis of N‐methyl‐5‐nitroindazolylacrylonitriles 2 a–l by a Knoevenagel condensation reaction with a series of aldehydes in the presence of piperidine allowed the preparation of the desired products the yields are good to excellent. N‐Methyl‐5‐nitroindazolylacrylonitriles (2 a–l) were verified by 1H, 13C NMR and mass spectrometry. In this current work, the reactivity indices defined within the Conceptual DFT of the targeted molecules through DFT/B3LYP/6‐311G(d,p) calculations were studied. The 1H NMR, UV‐vis and IR spectroscopy chemical shifts of all synthesized 5‐nitroindazoles 2 a–l were calculated and the results were compared to the results of the experimental data. In this series of compounds, the 2 e has the lowest hyperpolarizability, which results being the most stable and having the least response to nonlinear optics (NLO). In contrast, the compound 2 l has the highest hyperpolarizability, which fallouts being the least stable and having a high response to NLO. Every chemical has a significant three‐dimensional p‐electronic delocalization, which is crucial for understanding NLO responses. [ABSTRACT FROM AUTHOR]

N-heterocyclic compounds are a natural and rich source of pharmacologically active molecules displaying anti-cancer properties through various antiproliferative mechanisms. Some of these N-heterocyclic compounds are already being utilized or evaluated in clinical settings for cancer treatment, highlighting their potential significance in discovering new anticancer agents. This study aims to gather information from articles published between 2019 and 2021 on the recent advancements in N-heterocyclic derivatives such as indazole, triazolopyrimidine, pyrazolopyrimidine, quinoxaline, benzimidazole, benzodiazepine, indole, and quinoline as promising anticancer agents, including their structure-activity relationships and mechanisms of action. [ABSTRACT FROM AUTHOR]

Multi-drug resistant bacterial strains (MDR) have become an increasing challenge to our health system, resulting in multiple classical antibiotics being clinically inactive today. As the de-novo development of effective antibiotics is a very costly and time-consuming process, alternative strategies such as the screening of natural and synthetic compound libraries is a simple approach towards finding new lead compounds. We thus report on the antimicrobial evaluation of a small collection of fourteen drug-like compounds featuring indazoles, pyrazoles and pyrazolines as key heterocyclic moieties whose synthesis was achieved in continuous flow mode. It was found that several compounds possessed significant antibacterial potency against clinical and MDR strains of the Staphylococcus and Enterococcus genera, with the lead compound (9) reaching MIC values of 4 µg/mL on those species. In addition, time killing experiments performed on compound 9 on Staphylococcus aureus MDR strains highlight its activity as bacteriostatic. Additional evaluations regarding the physiochemical and pharmacokinetic properties of the most active compounds are reported and showcased, promising drug-likeness, which warrants further explorations of the newly identified antimicrobial lead compound. [ABSTRACT FROM AUTHOR]

A Cu(I)‐catalyzed 1,3 oxo alkylation of indazole has been developed for constructing N‐1‐alkylated indazolone derivatives. This cascade reaction involves the formation of C−N and C−O bonds through the sequential functionalization of N1 and C3 positions of indazole in 41–89% yields. The photo‐physical studies of the synthesized compounds showed efficient quantum yields with high Stoke shift values. The preliminary experimental results suggest an aerobic manifold of the present protocol through single electron transfer. [ABSTRACT FROM AUTHOR]

In a basic medium, 5-Mercapto-1,2,4-triazoles pass into the thiol form, allowing their transformation into sodium salts, which, in reaction with sodium monochloroacetate, lead to sodium 5-thioacetates of 1,2,4-triazoles-3,4-disubstituted. Sulfur derivatives converted to pivalic mixed anhydrides were used as active forms in the acylation of 6-amino penicillanic acid (6-AP) to obtain new semisynthetic penicillins. They contain in the molecule, together with the β-lactam ring, the nucleus 3-[(5-nitroindazol-1′-yl-methyl)]-4-aryl-5-mercapto-1,2,4-triazole, both contributing to an important antibacterial effect. The structure of the new antibiotics was confirmed by the results of elemental and spectral analysis (FT-IR, 1H- and 13C-NMR). The synthetic penicillins were tested for toxicological action and antibacterial activity and the obtained results were close to those for amoxicillin, the reference drug. [ABSTRACT FROM AUTHOR]

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-TRKAG595R, and Ba/F3-TRKAG667C cell lines with IC 50 values of 0.3, 4.7, and 9.9 nM, respectively. And the inhibitory effect against TRKAG667C (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. [Display omitted] • Based on molecular hybridization strategy, novel TRK inhibitors were discovered. • B31 exhibited significant inhibitory potency against multiple TRK mutants. • B31 possessed a moderate kinase selectivity. • B31 displayed good antiproliferative activities against NTRK fusion positive cells. • B31 showed excellent plasma stability and moderate pharmacokinetic properties. [ABSTRACT FROM AUTHOR]

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. [Display omitted] • A series of indazole-based HSP90 C-terminal inhibitors were investigated as anticancer agents. • HVH-2930 exhibited potent cytotoxicity against HER2-positive breast cancer. • HVH-2930 showed reasonable pharmacokinetic and toxicity profiles. [ABSTRACT FROM AUTHOR]

A hybrid library of compounds based on indazole-based thiadiazole containing thiazolidinone moieties (1–17) was synthesized. The synthesized compounds were screened in vitro for their inhibition profile against targetedacetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities. All the derivatives demonstrated a varied range of inhibitory activities having IC50 values ranging from 0.86 ± 0.33 μM to 26.73 ± 0.84 μM (AChE) and 0.89 ± 0.12 μM to 27.08 ± 0.19 μM (BuChE), respectively. The results obtained were compared with standard Donepezil drugs (IC50 = 1.26 ± 0.18 μM for AChE) and (1.35 ± 0.37 μM for BuChE), respectively. Specifically, the derivatives 1–17, 1, 9, and 14 were found to be significantly active, with IC50 values of 0.86 ± 0.30, 0.92 ± 0.10, and 1.10 ± 0.37 μM (against AChE) and 0.89 ± 0.12, 0.98 ± 0.48 and 1.19 ± 0.42 μM (against BuChE), respectively.The structure–activity relationship (SAR) studies revealed that derivatives bearing para-CF3, ortho-OH, and para-F substitutions on the phenyl ring attached to the thiadiazole skeleton, as well as meta-Cl, -NO2, and para-chloro substitutions on the phenyl ring, having a significant effect on inhibitory potential. The synthesized scaffolds have been further characterized by using 1H-NMR, 13C-NMR, and (HR-MS) to confirm the precise structures of the synthesized compounds. Additionally, the molecular docking approach was carried out for most active compounds to explore the binding interactions established by most active compounds, with the active sites of targeted enzymes and obtained results supporting the experimental data.

Multitarget drugs are a promising therapeutic approach against Alzheimer's disease. In this work, a new family of 5-substituted indazole derivatives with a multitarget profile including cholinesterase and BACE1 inhibition is described. Thus, the synthesis and evaluation of a new class of 5-substituted indazoles has been performed. Pharmacological evaluation includes in vitro inhibitory assays on AChE/BuChE and BACE1 enzymes. Also, the corresponding competition studies on BuChE were carried out. Additionally, antioxidant properties have been calculated from ORAC assays. Furthermore, studies of anti-inflammatory properties on Raw 264.7 cells and neuroprotective effects in human neuroblastoma SH-SY5Y cells have been performed. The results of pharmacological tests have shown that some of these 5-substituted indazole derivatives 1-4 and 6 behave as AChE/BuChE and BACE1 inhibitors, simultaneously. In addition, some indazole derivatives showed anti-inflammatory (3, 6) and neuroprotective (1-4 and 6) effects against Aβ-induced cell death in human neuroblastoma SH-SY5Y cells with antioxidant properties. [ABSTRACT FROM AUTHOR]

A variety of functionalized 3‐(2‐hydroxyaryl)indazoles and N‐(tetrahydrofuran‐2‐yl)‐3‐(2‐hydroxyaryl)indazoles were prepared in moderate to good yields through a transition metal‐free radical O‐arylation and sequential [3,3]‐rearrangement cascade strategy from N‐hydroxyindazoles and diaryliodonium salts. The equivalents of diaryliodonium salts controlled the formation of the product structures. Mechanistic studies revealed that the O‐arylation and N−O bond cleavage via [3,3]‐rearrangement involved an intermolecular radical process. The reaction tolerated various sensitive functional groups, such as halides, ester, and aldehyde groups. [ABSTRACT FROM AUTHOR]

A new solvent/ligand-controlled switchable C–H arylation of 1-methyl-4-nitro-1 H -indazole catalyzed by Pd(OAc)2 was achieved. A bidentate ligand in DMA promoted the activation at C7 position, while a phosphine ligand in H2 O oriented the arylation at C3 position. The C3 and C7 arylation products were obtained in moderate to good yields and with high regioselectivity. [ABSTRACT FROM AUTHOR]

With different nitrogen‐containing heterocyclic moieties, Indazoles earn one of the places among the top investigated molecules in medicinal research. Indazole, an important fused aromatic heterocyclic system containing benzene and pyrazole ring with a chemical formula of C7H6N2, is also called benzopyrazole. Indazoles consist of three tautomeric forms in which 1H‐tautomers (indazoles) and 2H‐tautomers (isoindazoles) exist in all phases. The tautomerism in indazoles greatly influences synthesis, reactivity, physical and even the biological properties of indazoles. The thermodynamic internal energy calculation of these tautomers points view 1H‐indazole as the predominant and stable form over 2H‐indazole. The natural source of indazole is limited and exists in alkaloidal nature (i.e., nigellidine, nigeglanine, nigellicine, etc.) found from Nigella plants. Some of the FDA‐approved drugs like Axitinib, Entrectinib, Niraparib, Benzydamine, and Granisetron are being used to treat renal cell cancer, non‐small cell lung cancer (NSCLC), epithelial ovarian cancer, chronic inflammation, chemotherapy‐induced nausea, vomiting, and many more uses. Besides all these advantages regarding its biological activity, the main issue about indazoles is the less abundance in plant sources, and their synthetic derivatives also often face problems with low yield. In this review article, we discuss its chemistry, tautomerism along with their effects, different schematics for the synthesis of indazole derivatives, and their different biological activities. [ABSTRACT FROM AUTHOR]

The synthesis of 3‐(phenylcarbonyl)‐1H‐indazole derivatives via the intramolecular cyclization of triazene derivatives substituted by a 2‐(phenylethynyl)phenyl group at the position 3 was developed. The azonium salt, the key intermediate in the reaction, was prepared under mild conditions from trimethylsilyl iodide (TMSI) obtained from an in situ mixture of trimethylsilyl chloride (TMSCl) and sodium iodide (NaI). The obtained 3‐(phenylcarbonyl)‐1H‐indazole derivatives exhibited interesting optical properties including phosphorescence, which was verified by theoretical calculations. [ABSTRACT FROM AUTHOR]

We contribute with the design and synthesis of novel 2,3‐diphenyl‐2H‐indazole hybrids series (1–14). Compounds 4 and 6 had the highest antiproliferative activity against the cancer cell lines, HeLa, SK‐LU‐1, K‐562, PC‐3, SW620 and MCF‐7 (CC50 values from 3 to 5.4 μM). Their activity was also evaluated against a normal human cell line, showing their higher Selectivity Index against the cancer cell lines than the reference drug CA‐4. The inhibition of tubulin assembly by compounds 4 and 6 was determined using in vitro tubulin polymerization assay and Western Blotting. The induction of mitotic catastrophe was observed with immunofluorescence assays. Besides, it was demonstrated by flow cytometry that compounds 4 and 6 arrest HeLa cell cycle at G2/M and promote apoptotic cell death. The mitotic arrest was also associated with elevated levels of cyclin B1 protein. We have identified two hybrids that behave as microtubule‐destabilizing agents on different cancer cell lines. [ABSTRACT FROM AUTHOR]

The indazole scaffold represents a promising pharmacophore, commonly incorporated in a variety of therapeutic drugs. Although indazole-containing drugs are frequently marketed as the corresponding N-alkyl 1H- or 2H-indazole derivative, the efficient synthesis and isolation of the desired N-1 or N-2 alkylindazole regioisomer can often be challenging and adversely affect product yield. Thus, as part of a broader study focusing on the synthesis of bioactive indazole derivatives, we aimed to develop a regioselective protocol for the synthesis of N-1 alkylindazoles. Initial screening of various conditions revealed that the combination of sodium hydride (NaH) in tetrahydrofuran (THF) (in the presence of an alkyl bromide), represented a promising system for N-1 selective indazole alkylation. For example, among fourteen C-3 substituted indazoles examined, we observed > 99% N-1 regioselectivity for 3-carboxymethyl, 3-tert-butyl, 3-COMe, and 3-carboxamide indazoles. Further extension of this optimized (NaH in THF) protocol to various C-3, -4, -5, -6, and -7 substituted indazoles has highlighted the impact of steric and electronic effects on N-1/N-2 regioisomeric distribution. For example, employing C-7 NO2 or CO2Me substituted indazoles conferred excellent N-2 regioselectivity (≥ 96%). Importantly, we show that this optimized N-alkylation procedure tolerates a wide structural variety of alkylating reagents, including primary alkyl halide and secondary alkyl tosylate electrophiles, while maintaining a high degree of N-1 regioselectivity.

• Synthesis of novel indazole derivatives. • In vitro as inhibitors of diabetics II. • Identification of a new inhibitors of diabetics II. • Structure activity relationship established. • Molecular docking. • Kinetic study. In the light of the pharmacological significance of the indazole and 1, 3, 4-thiadiazole scaffold, hybrid analogs of indazole and 1, 3, 4-thiadiazole (1–14) were synthesized, identified using HREI-MS, 1H, and 13CNMR, and their capability for inhibition of α-amylase and α-glucosidase enzymes was evaluated. Generally, most of the synthesized derivatives of the series exhibited good inhibition activity in comparison to the reference drug acarbose with IC 50 value of 10.30 ± 0.20 for α-amylase, and 9.80 ± 0.20 for α-glucosidase. Amongst the synthesized derivatives, fluoro substituted analog 10 appeared to be the most potent inhibitor having IC 50 value of 9.90 ± 0.30 for α-amylase and 9.20 ± 0.30 for α-glucosidase. A structure activity relationship (SAR) for the series was established based on electronic effects and the positions of various groups on the phenyl ring. To comprehend the chemicals' binding interactions, molecular docking along with simulation study were also carried out. Compound 10 was ranked top in the series based on docking score and interactions with receptors. Compound 10 establish more H-bond contacts with the active site's residue of alpha-amylase and α-glucosidase as compared to all other compounds. Furthermore, 10 was found to be highly stable throughout 50 ns MD simulation. As compared to the control drug, 10 revealed high stability with both α-amylase and α-glucosidase enzymes during molecular dynamics simulation. [Display omitted] [ABSTRACT FROM AUTHOR]

• Ferrocenyl-substituted cyclohexenone and indazole derivatives as effective antimycobacterial agents. • Displayed the capacity to effectively suppress the formation of biofilms and disrupt pre-formed biofilms. • Indazole derivative 3b showed potential interactions with the target enzyme as revealed by docking studies and validated by enzyme assay. • Demonstrated good ADMET properties, passed Lipinski's filters, and demonstrated good drug-like properties. • The potential of compound 3b as a potential lead molecule that could be further optimized to develop ferrocene incorporating indazole based antimycobacterial agents. In response to the escalating threat of mycobacterial infections, including extensively drug-resistant tuberculosis (XDR) and multidrug-resistant tuberculosis (MDR), we synthesized novel ferrocene incorporating cyclohexenone and indazole derivatives. The compounds were synthesized via multistep reaction approach starting from chalcone precursors and evaluated against Mycobacterium fortuitum. The MIC and MBC values were calculated by following CLSI guidelines, with a focus on their ability to inhibit bacterial growth and disrupt biofilm formation. All the test compounds showed potent in vitro antimycobacterial activity against M. fortuitum. The MIC values range from 3.907 µg/mL to 500 µg/mL, whereas the MBC values range from 15.625 µg/mL to >500 µg/mL. Among the synthesized compounds, compound 3b exhibited potent antimycobacterial activity compared with standard drug Amikacin used to treat multidrug-resistant tuberculosis. 3b demonstrated significant inhibition of bacterial growth and showed the capacity to effectively suppress biofilm formation and disrupt pre-existing biofilms. This molecule also displayed favourable ADMET profile and good oral bioavailability, besides showing potential interactions with the target enzyme as revealed by docking studies and validated by enzyme assay. Collectively, these studies position 3b as a potential lead molecule that could be further optimized to develop ferrocene incorporating indazole based antimycobacterial agents. [ABSTRACT FROM AUTHOR]

New Co(II), Ni(II), Cu(II) and Zn(II) metal complexes of Schiff base ligands derived by the condensation of 6-aminoindazole with different derivatives of salicylaldehyde were synthesized and characterized. Further compounds were evaluated for antimicrobial, anti-inflammatory, antioxidant and molecular docking studies and findings results revealed that compound 12 exhibit higher potency, against antimicrobial and anti-inflammatory studies, whereas antioxidant activity revealed that the activity of Schiff base ligands enhanced on complexation with transition metal. [Display omitted] • Schiff base-derived hexacoordinated transition metal(II) complexes were synthesized and characterized. • The in vitro antimicrobial, anti-inflammatory and antioxidant activities were performed. • Complex 11 and 12 displayed potent biological activities. • Molecular docking, DFT and ADMET studies validated the in vitro results. Indazoles represent one of the most important heterocycles in drug molecules. Therefore, in the pursuit of potent biological agents, a series of ligands (HL1-HL4) and their corresponding transition metal complexes [M(L1-L4) 2 (H 2 O) 2 ] were synthesized by the condensation reaction of 6-aminoindazole with various derivatives of salicylaldehyde. Further, the compounds underwent characterization through several physicochemical (TGA, powder XRD, SEM, EDAX) and spectroscopic techniques (FT-IR, UV–Vis, NMR, mass spectrometry, ESR). These techniques suggested hexacoordinated stereochemistry of the metal complexes, where ligands chelate via oxygen atom of phenolic ring, azomethine nitrogen and oxygen atom of water molecules in 1:2 (M:L) molar ratio. The thermal stability of the complexes was demonstrated by thermal analysis revealing three step decompositions leaving behind metal oxide as an end residue. The surface morphology of the ligands was distinct from metal complexes as revealed by SEM analysis, while mapping images demonstrated the simultaneously existence of the elements. While, to ascertain the nature of the obtained compounds (crystalline or amorphous), powder X-ray investigation was conducted by utilizing a wavelength of 1.54 Å. The compound's antioxidant potential was assessed through DPPH assays and anti-inflammatory activity was evaluated using BSA denaturation inhibition assay, while their antimicrobial potential was evaluated against six microbial strains (E. coli, S. aureus , P. aeruginosa, B. subtilis , C. albicans, A. niger) by serial dilution approach. The performed biological evaluations revealed that the complexes are more efficient in controlling infectious ailment in comparison of ligands. HL2 (2) and its Cu(II), Zn(II) complexes (11, 12) exhibited potent antimicrobial activity (MIC value: 0.0047, 0.0048 µmol/mL against B. subtilis) and potent anti-inflammatory efficacy (IC 50 value: 6.7 ± 0.044, 6.9 ± 0.036 µM). All the complexes exhibited potent antioxidant activity and their is enhancement in the activity of Schiff base ligands upon complexation, complex (19) demonstrated the greatest activity with IC 50 value 2.1 ± 0.059. Additionally, the ADMET score provided a robust indication of the compounds' drug-like behaviour. Furthermore, the biological effectiveness of the highly microbial potent ligand HL2 (2) and its complexes (9–12) was demonstrated through computational studies. The binding studies exposed that complexes (11, 12) exhibited lowest binding energy at −7.8, −7.9 kcal/mol. While, DFT study emphasized that complex (12) exhibits the highest electrophilicity index value (6.359), suggesting its affinity for binding with biological molecules and also revealed that complexes exhibit greater potency compared to the ligands and could potentially be utilized as drugs for combatting pathogen-induced malformations. [ABSTRACT FROM AUTHOR]

From the last two decades, Cadogan cyclization reaction is considered as one of the best routes for the preparation of various azaheterocycles comprising carbazoles, indoles, coumarins, carbolines, pyrazoloquinoxalines, S,N‐heterotetracenes from the nitro‐based substrates by using a variety of tetravalent phosphorus‐based reagents. To date the majority of Cadogan reactions are found to be intramolecular reactions, however, interestingly, a case of intermolecular Cadogan reaction is also reported, resulting in the widening of the reaction scope for futuristic perspectives. We report the Cadogan cyclization reactions for the synthesis of azaheterocycles from 2018 to present according to multiple classes of chemical frameworks including its scope (FDA approved drugs), along with the possibilities and mechanistic developments for unexpected products. [ABSTRACT FROM AUTHOR]

The current work presents an objective overview of the impact of one important heterocyclic structure, the pyrazole ring, in the development of anti-proliferative drugs. A set of 1551 pyrazole derivatives were extracted from the National Cancer Institute (NCI) database, together with their growth inhibition effects (GI%) on the NCI's panel of 60 cancer cell lines. The structures of these derivatives were analyzed based on the compounds' averages of GI% values across NCI-60 cell lines and the averages of the values for the outlier cells. The distribution and the architecture of the Bemis–Murcko skeletons were analyzed, highlighting the impact of certain scaffold structures on the anti-proliferative effect's potency and selectivity. The drug-likeness, chemical reactivity and promiscuity risks of the compounds were predicted using AMDETlab. The pyrazole ring proved to be a versatile scaffold for the design of anticancer drugs if properly substituted and if connected with other cyclic structures. The 1,3-diphenyl-pyrazole emerged as a useful scaffold for potent and targeted anticancer candidates. [ABSTRACT FROM AUTHOR]

Heterocyclic compounds occupy an important position in chemistry because of their wide range of uses in drug design, photochemistry, agrochemicals, and other fields. Indole and indazole scaffolds are available from natural and synthetic sources, and molecules containing these scaffolds have been shown to have various biological effects, including anti-inflammatory, antibacterial, antiviral, antifungal, analgesic, anticancer, antioxidant, anticonvulsant, antidepressant, and antihypertensive activities. Indole and indazole molecules bind to receptors with high affinity, and thus are useful for the study of bioactive compounds involved in multiple pathways. In this review, we highlight the antihypertensive activity and the mechanisms of action of indole and indazole derivatives. In addition, structure–activity relationship studies of the antihypertensive effect are presented.

A novel series of dual 1,2,3-triazole and 1,3,4-oxadiazole heterocyclic compounds linked to indazole were designed and efficiently synthesized using 3-bromo-1H-indazole as potential antimicrobial agents. All the compounds were characterized by their proton, carbon nuclear magnetic resonance, infrared, mass spectral data, and elemental analysis. The final compounds 9a–m were evaluated in vitro antimicrobial activity against Gram-negative microorganism E. coli, Gram-positive microorganisms B. subtilis, S. pneumoniae, S. aureus and antifungal strains A. fumigates, C. albicans. From biological screening, we were surprised to find that most of the compounds have significant inhibitory activity and in particular dual heterocycles 9b, 9c, 9h, 9i, and 9j showed outstanding antibacterial activity against Gram-positive bacteria S. pneumoniae with MICs 5.4 ± 0.02, 5.8 ± 0.03, 8.0 ± 0.04, 4.0 ± 0.03, and 7.8 ± 0.01 µg/mL respectively, when compared to ampicillin [MIC = 9.1 ± 0.01 µg/mL]. Final prepared scaffolds 9b, 9h acquiring highest potential drug scores ΔG = −7.78, −8.34 kcal/mol with their amino acids residues Arg171 (O…H: 1.934), Lys20 (N…H: 1.951), Arg265 (N…H: 2.080), ArgA:171 (2.740), ArgA:265 (1.874), TyrA:248 (1.973), and Ser19 (H…O: 2.048), Tyr248 (O…H: 1.570), Arg265 (N…H: 1.976), Arg46 (N…H: 1.059) ArgA:45 (O…H, 2.94 Å) respectively.

Herein, we report a pair of regioselective N 1 alkylations of a versatile indazole, methyl 5-bromo-1 N -indazole-3-carboxylate ( 2 - alkylations of a versatile indazole, methyl 5-bromo-1 H -indazole-3-carboxylate ( 6 ) and the use of density functional theory (DFT) to evaluate their mechanisms. Over thirty N 1 -indazole-7-carboxylate ( N 2 -indazole-3-carbonitrile ( N 1 -substituted products when cesium is present and other non-covalent interactions (NCIs) drive the N 2 -product formation. Methyl 1 H -indazole-7-carboxylate ( 18 ) and 1 H -indazole-3-carbonitrile ( 21 ) were also subjected to the reaction conditions and their mechanisms were evaluated. The N 1 - and N 2 -partial charges and Fukui indices were calculated for compounds 6 , 18 , and 21 via natural bond orbital (NBO) analyses which further support the suggested reaction pathways., Competing Interests: The authors declare the following competing financial interest(s): All authors are employees/former employees of BioCryst Pharmaceuticals Inc. and may hold stock in the same., (Copyright © 2024, Lu et al.)

Electrochemical synthesis offers a mild, simple, and efficient tool for the preparation of interesting and useful molecules, thus eluding severe chemical oxidizing and reducing agents used in conventional synthetic methods. In particular, electrochemical C-H activation is expected to play an important role in the direct functionalization of heterocyclic compounds. Over the past few decades, the research interest in imidazopyridine and indazole has increased significantly due to their multipurpose uses in medicinal and industrial chemistry. Therefore, structural modification of these heterocycles using electro-oxidation has become one of the important research topics among synthetic organic chemistry in recent time. This review provides a comprehensive discussion of electrochemical functionalization of indazoles and imidazopyridines published so far. A summary of the current challenges and the future direction for the development of efficient and green electrochemical methods for functionalization of these heterocycles is also presented. [ABSTRACT FROM AUTHOR]

Herein we described the synthesis of indazole derivatives through C-N cyclization and evaluated for their anticancer activities against three human cancer cell lines such as HeLa, MCF-7, and SKOV3 using MTT assay. The synthesized indazole hybrids are characterized based on 1H NMR, 13C NMR spectral data, and elemental analysis. The results indicated that the most potent molecule in this series is compound 3b against MCF-7, compound 3h against HeLa, and compound 3d against SKOV3, which showed the highest activity with an IC50 value of 32.92 μg/ml, 12.08 μg/ml, and 29.06 µg/ml respectively. [ABSTRACT FROM AUTHOR]

Indazole is known as an important structural motif in medicinal chemistry and, recently, has also gained attention in other areas, such as materials chemistry, with many studies showing different potential applications for their regioisomers. Phosphonates are also a class of compounds with diverse applications, ranging from medicinal to material applications. Here we present the synthesis of 1H‐ and 2H‐indazolephosphonic acid derivatives substituted at C‐3, involving mono‐ or bisphosphonic acids, from their corresponding carboxylic acid and esters. These compounds were fully characterized, and their spectroscopic data were evaluated to identify and distinguish the structural scaffold of each phosphonic acid. Crystallization of [hydroxy(1‐methyl‐1H‐indazol‐3‐yl)methanediyl]bis(phosphonic acid) 7 afforded crystals suitable for single crystal X‐ray diffraction studies and its crystal structure details are also discussed. [ABSTRACT FROM AUTHOR]