Synthesis of pyrazolo[3,4-d]pyrimidin-4(5H)-ones tethered to 1,2,3-triazoles and their evaluation as potential anticancer agents

Cyclizations of Alkenyl(Alkynyl)-Functionalized Quinazolinones and their Heteroanalogues: A Powerful Strategy for the Construction of Polyheterocyclic Structures

Quinazolin-4-one, its heteroanalogues, and derivatives represent an outstandingly important class of compounds in modern organic, medicinal, and pharmaceutical chemistry, as these molecular structures are noted for their wide synthetic and pharmacological potential. In the last years, ever-increasing research attention has been paid to quinazolinone derivatives bearing alkenyl and alkynyl substituents on the pyrimidinone nucleus. The original structural combination of synthetically powerful endocyclic amidine (or amidine-related) and exocyclic unsaturated moieties provides a driving force for cyclizations, which offer an efficient toolkit to construct a variety of fused pyrimidine systems with saturated N- and N,S-heterocycles. In this connection, the present review article is mainly aimed at systematic coverage of the progress in using alkenyl(alkynyl)quinazolinones and their heteroanalogues as convenient bifunctional substrates for regioselective annulation of small- and medium-sized heterocyclic nuclei. Much attention is paid to elucidating the structural and electronic effects of reagents on the regio- and stereoselectivity of the cyclizations as well as to clarifying the relevant reaction mechanisms.

Genome-wide identification and functional characterization of borneol dehydrogenases in Wurfbainia villosa

MAIN CONCLUSION

Genome-wide screening of short-chain dehydrogenases/reductases (SDR) family reveals functional diversification of borneol dehydrogenase (BDH) in Wurfbainia villosa. Wurfbainia villosa is an important medicinal plant, the fruits of which accumulate abundant terpenoids, especially bornane-type including borneol and camphor. The borneol dehydrogenase (BDH) responsible for the conversion of borneol to camphor in W. villosa remains unknown. BDH is one member of short-chain dehydrogenases/reductases (SDR) family. Here, a total of 115 classical WvSDR genes were identified through genome-wide screening. These WvSDRs were unevenly distributed on different chromosomes. Seven candidate WvBDHs based on phylogenetic analysis and expression levels were selected for cloning. Of them, four BDHs can catalyze different configurations of borneol and other monoterpene alcohol substrates to generate the corresponding oxidized products. WvBDH1 and WvBDH2, preferred (+)-borneol to (-)-borneol, producing the predominant ( +)-camphor. WvBDH3 yielded approximate equivalent amount of (+)-camphor and (-)-camphor, in contrast, WvBDH4 generated exclusively (+)-camphor. The metabolic profiles of the seeds showed that the borneol and camphor present were in the dextrorotatory configuration. Enzyme kinetics and expression pattern in different tissues suggested WvBDH2 might be involved in the biosynthesis of camphor in W. villosa. All results will increase the understanding of functional diversity of BDHs.

Recent Advances in the Development of Pyrazole Derivatives as Anticancer Agents

Pyrazole derivatives, as a class of heterocyclic compounds, possess unique chemical structures that confer them with a broad spectrum of pharmacological activities. They have been extensively explored for designing potent and selective anticancer agents. In recent years, numerous pyrazole derivatives have been synthesized and evaluated for their anticancer potential against various cancer cell lines. Structure-activity relationship studies have shown that appropriate substitution on different positions of the pyrazole ring can significantly enhance anticancer efficacy and tumor selectivity. It is noteworthy that many pyrazole derivatives have demonstrated multiple mechanisms of anticancer action by interacting with various targets including tubulin, EGFR, CDK, BTK, and DNA. Therefore, this review summarizes the current understanding on the structural features of pyrazole derivatives and their structure-activity relationships with different targets, aiming to facilitate the development of potential pyrazole-based anticancer drugs. We focus on the latest research advances in anticancer activities of pyrazole compounds reported from 2018 to present.

Synthesis of N-(4-chlorophenyl) substituted pyrano[2,3-c]pyrazoles enabling PKBβ/AKT2 inhibitory and in vitro anti-glioma activity

A series of N-(4-chlorophenyl) substituted pyrano[2,3-c]pyrazoles was synthesised and screened for their potential to inhibit kinases and exhibit anticancer activity against primary patient-derived glioblastoma 2D cells and 3D neurospheres. A collection of 10 compounds was evaluated against glioma cell lines, with compound 4j exhibiting promising glioma growth inhibitory properties. Compound 4j was screened against 139 purified kinases and exhibited low micromolar activity against kinase AKT2/PKBβ. AKT signalling is one of the main oncogenic pathways in glioma and is often targeted for novel therapeutics. Indeed, AKT2 levels correlated with glioma malignancy and poorer patient survival. Compound 4j inhibited the 3D neurosphere formation in primary patient-derived glioma stem cells and exhibited potent EC₅₀ against glioblastoma cell lines. Although exhibiting potency against glioma cells, 4j exhibited significantly less cytotoxicity against non-cancerous cells even at fourfold-fivefold the concentration. Herein we establish a novel biochemical kinase inhibitory function for N-(4-chlorophenyl) substituted pyrano[2,3-c]pyrazoles and further report their anti-glioma activity in vitro for the first time.KEY MESSAGEAnti-glioma pyrano[2,3-c]pyrazole 4j inhibited the 3D neurosphere formation in primary patient-derived glioma stem cells. 4j also displayed PKBβ/AKT2 inhibitory activity. 4j is nontoxic towards non-cancerous cells.

Pyrazolopyrimidines as attractive pharmacophores in efficient drug design: A recent update

Among the menacing diseases, cancer needs the most attention as millions of people are affected by it worldwide. Genetic and environmental factors play a pivotal role in causing cancer. Although a wide range of underlying mechanisms of cancer has been discovered, efficient treatments have not been discovered to date. Additionally, diseases caused by microbes such as viruses, bacteria, protozoa, and so forth, persistently result in several deaths. Also, inflammation is a major factor that leads to several health issues. For decades, drug design has become a major part of drug discovery and development for curing various diseases. Among the large number of pharmacological agents that have been synthesized, only very few have emerged as efficient drug molecules. Most of them are heterocyclic compounds, which are promising candidates for the design of efficient drug molecules. Furthermore, fused heterocycles showed comparatively stronger pharmacological activities than monocyclic heterocycles. The literature reveals that pyrazolopyrimidines have outstanding biological activity. Hence, here, the diverse pharmacological activities shown by pyrazolopyrimidine derivatives reported in the last 5 years are collated and reviewed systematically. This review is classified into various sections focusing on anticancer, antimicrobial, anti-inflammatory, and enzyme inhibitors. Structure-activity relationships are discussed in brief, which will help researchers design potent pharmacological agents.

Azole-pyrimidine Hybrid Anticancer Agents: A Review of Molecular Structure, Structure Activity Relationship and Molecular Docking

Cancer has emerged as one of the leading causes of deaths globally partly due to the steady rise in anticancer drug resistance. Pyrimidine and pyrimidine-fused heterocycles are some of the privileged scaffolds in medicine, as they possess diverse biological properties. Pyrimidines containing azole nucleus possesses inestimable anticancer potency and has enormous potential to conduct the regulation of cellular pathways for selective anticancer activity. The present review outlines the molecular structure of pyrimidine-fused azoles with significant anticancer activity. The structure activity relationship and molecular docking studies have also been discussed. The current review is the first complete compilation of significant literature on the proposed topic from 2016 to 2020. The information contained in this review offers a useful insight to chemists in the design of new and potent anticancer azole-pyrimidine analogues.

Three-component microwave-assisted synthesis of 3,5-disubstituted pyrazolo[3,4-d]pyrimidin-4-ones

A practical three-component method for the synthesis of pyrazolo[3,4-d]pyrimidin-4-ones was developed. The reaction was performed in a one-pot manner under controlled microwave irradiation using easily accessible methyl 5-aminopyrazole-4-carboxylates, trimethyl orthoformate, and primary amines. Under the optimized conditions, challenging substrates, such as N-1 unsubstituted 5-aminopyrazole-4-carboxylates with another substituted amino group in position 3, reacted selectively affording 5-substituted 3-arylamino-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-ones. The reaction tolerated a range of primary amines, including anilines. The advantages of the developed protocol include short reaction time, pot- and step-economy, and convenient chromatography-free product isolation. The structural features of representative products were explored by X-ray crystallography.

Recent advances in synthesis and anticancer potential of triazole containing scaffolds

Cancer is the most lethal disease that may be found anywhere on the globe. Approximately 10% of individuals die as a result of cancer of various types, with 19.3 million new cancer cases and 10 million deaths expected in 2020. More than 100 medications are commercially available for the treatment of cancer, but only a few candidates have high specificity, resulting in several side effects. The scientific community has spent the past decades focusing on drug discovery. Natural resources are used to isolate pharmaceutically active candidates, which are then synthesized in laboratories. More than 60% of all prescribed drugs are made from natural ingredients. Unique five-membered heteroaromatic center motifs with sulfur, oxygen and nitrogen atoms are found in heterocyclic compounds such as indazole, thiazole, triazole, triazole, and oxazole, and are used as a core scaffold in many medicinally important therapies. Triazole possesses a wide range of pharmacological activities including anticancer, antibacterial, antifungal, antibiotic antiviral, analgesic, anti-inflammatory, anti-HIV, antidiabetic, and antiprotozoal activities. Novel Triazole motifs with a variety of biological characteristics have been successfully synthesized using versatile synthetic methods. We intend here to facilitate the rational design and development of innovative triazole-based anti-cancer medicines with increased selectivity for various cancer cell lines by providing insight into various ligand-receptor interactions.

New 1,2,3-Triazoles from (R)-Carvone: Synthesis, DFT Mechanistic Study and In Vitro Cytotoxic Evaluation

Aseries of novel 1,4-disubstituted 1,2,3-triazoles were synthesized from an (R)-carvone terminal alkyne derivative via a Cu (I)-catalyzed azide–alkyne cycloaddition reaction using CuSO₄,5H₂O as the copper (II) source and sodium ascorbate as a reducing agent which reduces Cu (II) into Cu (I). All the newly synthesized 1,2,3-triazoles 9a–h were fully identified on the basis of their HRMS and NMR spectral data and then evaluated for their cell growth inhibition potential by MTS assay against HT-1080 fibrosarcoma, A-549 lung carcinoma, and two breast adenocarcinoma (MCF-7 and MDA-MB-231) cell lines. Compound 9d showed notable cytotoxic effects against the HT-1080 and MCF-7 cells with IC₅₀ values of 25.77 and 27.89 µM, respectively, while compound 9c displayed significant activity against MCF-7 cells with an IC₅₀ value of 25.03 µM. Density functional calculations at the B3LYP/6-31G* level of theory were used to confirm the high reactivity of the terminal alkyne as a dipolarophile. Quantum calculations were also used to investigate the mechanism of both the uncatalyzed and copper (I)-catalyzed azide–alkyne cycloaddition reaction (CuAAC). The catalyzed reaction gives complete regioselectivity via a stepwise mechanism streamlining experimental observations. The calculated free-energy barriers 4.33 kcal/mol and 29.35 kcal/mol for the 1,4- and 1,5-regioisomers, respectively, explain the marked regioselectivity of the CuAAC reaction.

Ru(III) complexes with pyrazolopyrimidines as anticancer agents: bioactivities and the underlying mechanisms

Three ruthenium(III) complexes with pyrazolopyrimidine [Ru(Lⁿ)(H₂O)Cl₃] (1-3, n = 1-3) were prepared and characterized. These Ru(III) compounds show strong cytotoxicity against six cancer cell lines and low toxicity to normal human liver cells. Particularly, they exhibited stronger cytotoxicity to SK-OV-3 cells than cisplatin. Mechanism studies revealed that complex 1 inhibited tumor cell invasion and suppressed cell proliferation, induced apoptosis by elevating the levels of intracellular ROS (reactive oxygen species) and free calcium (Ca²⁺), and reduced mitochondrial membrane potential (ΔΨ). It also activated the caspase cascade, accompanied with upregulation of cytochrome c, Bax, p53, Apaf-1 and downregulation of Bcl-2. Moreover, complex 1 caused cell cycle arrest at S phase by inhibiting the expression of CDC 25, cyclin A2 and CDK 2 proteins, and induced DNA damage by interacting with DNA and inhibiting the topoisomerase I enzyme. Complex 1 exhibited efficient in vivo anticancer activity in a model of SK-OV-3 tumor xenograft.

Design, Synthesis and In Vitro Anticancer Activity of Benzo[c]chromen-6-one -linked 1,2,3-Triazole

Background:

The 1,2,3-triazole hybrids and conjugates containing natural or related compounds motif demonstrate diverse biological activities, including anticancer, antimicrobial, anti-tubercular, antiviral, antidiabetic, antimalarial, anti-leishmanial, and neuroprotective ones. Among a wide range of pharmacological applications, considerable attention is paid to the study of anticancer activity. In anticancer research, combining of 1,2,3-triazoles with other motifs, previously demonstrating antiproliferative activity into one hybrid molecule, is a common strategy for the creation of new bioactive molecules. The CuAAC (copper-catalyzed azide–alkyne cycloaddition) is a very convenient reaction for the rapid construction of drug-like 1,2,3-triazoles at room temperature in a short time.

Methods:

Based on the pharmacophore strategy, a virtual combinatorial library of benzo[c]chromen-6-one -linked 1,2,3-triazole derivatives was designed and lead-likeness and molecular analysis were performed. Selected compounds were synthesized via CuAAC click reaction and the chemical structures of all new 1,2,3-triazole hybrids were proved by 1H, 13C NMR, MS and elemental analyses. Their anti-cancer activity in the human cancer cell lines was evaluated using the MTT assay.

Results:

A virtual in silico screening of novel benzo[c]chromen-6-one -linked 1,2,3-triazoles was carried out in order to discover potential antitumor agents. The synthesis of promising compounds was carried out via СuAAC reaction, and their antineoplastic action was studied on human tumor cells of HL-60, HCT116, HCT116 p53-/-, Skov3, U251, MDA231 lines. Their cytotoxic effect towards pseudo-normal human cells of HaCaT line was also evaluated. 2-((1H-1,2,3-triazol-4-yl)methoxy)-6H-benzo[c]chromen-6-one (4c) with pyridin-3-yl substituent demonstrated the highest antiproliferative action in vitro (IC50 79.5 μM) towards human leukemia cells of HL-60 line, while all tested compounds at >100 μM concentration were tolerant for non-tumor human keratinocytes of HaCaT line.

Conclusion:

A novel benzo[c]chromen-6-one -linked 1,2,3-triazoles exhibiting promising in vitro anti-cancer activity and low toxicity were designed. This study suggests new scaffolds for the development of anti-cancer drugs, which could be easily further optimized via the convenient synthetic procedure.

Pyrazolopyrimidines as anticancer agents: A review on structural and target-based approaches

Pyrazolopyrimidine scaffold is one of the privileged heterocycles in drug discovery. This scaffold produced numerous biological activities in which anticancer is important one. Previous studies showed its importance in interactions with various receptors such as growth factor receptor, TGFBR2 gene, CDK2/cyclin E and Abl kinase, adenosine receptor, calcium-dependent Protein Kinase, Pim-1 kinase, Potent Janus kinase 2, BTK kinase, P21-activated kinase 1, extracellular signal-regulated kinase 2, histone lysine demethylase and Human Kinesin-5. However, there is a need of numerous studies for the discovery of target based potential compounds. The structure activity relationship studies may help to explore the generation of potential compounds in short time period. Therefore, in the present review we tried to explore the structural aspects of Pyrazolopyrimidine with their structure activity relationship against various targets for the development of potential compounds. The current review is the compilation of significant advances made on Pyrazolopyrimidines reported between 2015 and 2020.

Novel Pyrazolo[3,4-d]pyrimidin-4-one Derivatives as Potential Antifungal Agents: Design, Synthesis, and Biological Evaluation

Plant pathogenic fungi seriously threaten agricultural production. There is an urgent need to develop novel fungicides with low toxicity and high efficiency. In this study, we designed and synthesized 44 pyrazolo[3,4-d]pyrimidin-4-one derivatives and evaluated them for their fungicidal activities. The bioassay data revealed that most of the target compounds possessed moderate to high in vitro antifungal activities. Especially compound g22 exhibited remarkable antifungal activity against Sclerotinia sclerotiorum with an EC₅₀ value of 1.25 mg/L, close to that of commercial fungicide boscalid (EC₅₀ = 0.96 mg/L) and fluopyram (EC₅₀ = 1.91 mg/L). Moreover, compound g22 possessed prominent protective activity against S. sclerotiorum in vivo for 24 h (95.23%) and 48 h (93.78%), comparable to positive control boscalid (24 h (96.63%); 48 h (93.23%)). Subsequent studies indicated that compound g22 may impede the growth and reproduction of S. sclerotiorum by affecting the morphology of mycelium, destroying cell membrane integrity, and increasing cell membrane permeability. In addition, the application of compound g22 did not injure the growth or reproduction of Italian bees. This study revealed that compound g22 is expected to be developed for efficient and safe agricultural fungicides.

Thiazolidinone-linked1,2,3-triazoles with monoterpenic skeleton as new potential anticancer agents: Design, synthesis and molecular docking studies

A novel series of 1,2,3-triazole-thiazolidinone-carvone hybrid compounds has been designed and synthesized using the copper-catalyzed Huisgen azide-alkyne 1,3-dipolar cycloaddition (CuAAC) process based on (R)-Carvone-O-propargylated 5-hydroxybenzylidene-thiazolidin-4-one derivative as starting material. All compounds were characterized and identified based on their NMR and HRMS spectroscopic data. HMBC correlations confirm that under the CuAAC reaction conditions, only the 1,4-disubstituted triazole regioisomers were formed. The targeted 1,2,3-triazole-thiazolidinone-carvone hybrids and their precursors were evaluated for their cytotoxic activity against four human cancer cell lines, including fibrosarcoma (HT-1080), lung carcinoma (A-549), and breast carcinoma (MCF-7 and MDA-MB-231). The obtained data showed that most of these compounds have moderate anti-proliferative activity with IC₅₀ values between 15.04 ± 0.71 and 42.22 ± 1.20 µM. The mechanism of action of the most active compounds 14e and 14f suggested that they induce apoptosis through caspase-3/7 activation, and the compound 14e elicited S-phase arrest, while compound 14f evoked G2/M phase blockade. The molecular docking confirmed that compounds 14e and 14f were nicely bonded with caspace-3 leading up to stable protein-ligand complexes.

Glioblastoma-specific anticancer activity of newly synthetized 3,5-disubstituted isoxazole and 1,4-disubstituted triazole-linked tyrosol conjugates

Two series of 3,5-disubstituted isoxazoles (6a-e) and 1,4-disubstituted triazoles (8a-e) derivatives have been synthesized from tyrosol (1), a natural phenolic compound, detected in several natural sources such as olive oil, and well-known by its wide spectrum of biological activities. Copper-catalyzed microwave-assisted 1,3-dipolar cycloaddition reactions between tyrosol-alkyne derivative 2 and two series of aryl nitrile oxides (5a-e) and azides (7a-e) regiospecifically afforded 3,5-disubstituted isoxazoles (6a-e) and 1,4-triazole derivatives (8a-e), respectively in quantitative yields. Synthesized compounds were purified and characterized by spectroscopic means including 1D and 2D NMR techniques and HRMS analysis. The newly prepared hybrid molecules have been evaluated for their anticancer and hemolytic activities. Results showed that most derivatives displayed significant antiproliferative activity against human glioblastoma cancer cells (U87) in a dose-dependent manner. Compounds 6d (IC₅₀ = 15.2 ± 1.0 μg/mL) and 8e (IC₅₀ = 21.0 ± 0.9 μg/mL) exhibited more potent anticancer activity. Moreover, most derivatives displayed low hemolytic activity, even at higher concentrations which suggested that these classes of compounds are suitable candidates for further in vivo investigations. The obtained results allow us to consider the newly synthesized isoxazole- and triazole-linked tyrosol derivatives as promising scaffolds for the development of effective anticancer agents.

Developments of small molecules as inhibitors for carbonic anhydrase isoforms

Carbonic anhydrases are ubiquitous, and their role in the hydration of carbon dioxide is essential for the survival of many tissues and organs. However, their association with many pathological diseases, especially in glaucoma, Alzheimer's, obesity, epilepsy, and tumorigenesis, has prompted the design and synthesis of novel carbonic anhydrase inhibitors (CAIs). Herein we describe (1) approaches used in the design of CAIs and (2) synthesis of small molecules as CAIs within the last five years. Despite the active research in this area, there are still more avenues to explore, especially selective inhibition of CA I, CA IX, and XII. These isoforms would continue to open up a diversity of carbonic anhydrase inhibitors containing 1,2,3-triazoles, imidazolone, pyrrolidone, thiadiazole, isatin, and glycoconjugates as part of their molecular frameworks.

Recent Progress on Anticancer Agents Incorporating Pyrazole Scaffold

The search of new anticancer agents is considered as a dynamic field of medicinal chemistry. In recent years, the synthesis of compounds with anticancer potential has increased and a large number of structurally varied compounds displaying potent anticancer activities have been published. Pyrazole is an important biologically active scaffold that possessed nearly all types of biological activities. The aim of this review is to collate literature work reported by researchers to provide an overview on in vivo and in vitro anticancer activities of pyrazole based derivatives among the diverse biological activities displayed by them and also presents recent efforts made on this heterocyclic moiety regarding anticancer activities. This review has been driven from the increasing number of publications, on this issue, which have been reported in the literature since the ending of the 20th century (from 1995-to date).

Discovery of an orally active antitumor agent that induces apoptosis and suppresses EMT through heat shock protein 90 inhibition

Background Nowadays, lung cancer seriously affects human health in the world. Therefore, it is of great significance to develop effective anti-lung cancer drugs. Methods In this work, chalcone derivative HYQ97 was designed via a molecular hybridization strategy. It was synthesized by the cycloaddition in the presence of sodium ascorbate under mild conditions. Lung cancer cell lines were cultured to investigate its antitumor effects in vitro and in vivo. Results HYQ97 inhibited the proliferation of lung cancer cell lines. Specifically, its IC₅₀ value against lung cancer A549 cells was 74.26 nM. It could inhibit heat shock protein 90 (Hsp90) and degrade its client proteins in a dose-dependent manner. Furthermore, HYQ97 suppressed the epithelial mesenchymal transition process and induced apoptosis of A549 cells. Importantly, HYQ97 also had significant inhibitory effects on tumor growth in vivo. Conclusions Chalcone derivative HYQ97 is a promising candidate for lung cancer treatment.

A copper-catalyzed synthesis of aryloxy-tethered symmetrical 1,2,3-triazoles as potential antifungal agents targeting 14 α-demethylase

The search for potent therapeutic agents has prompted the design and synthesis of a library of twenty-six aryloxy-tethered and amide-linked symmetrical 1,2,3-triazoles (8a–z) using a copper(i)-catalyzed click chemistry approach.

Discovery of fast-acting dual-stage antimalarial agents by profiling pyridylvinylquinoline chemical space via copper catalyzed azide-alkyne cycloadditions

To identity fast-acting, multistage antimalarial agents, a series of pyridylvinylquinoline-triazole analogues have been synthesized via CuAAC. Most of the compounds display significant inhibitory effect on the drug-resistant malarial Dd2 strain at low submicromolar concentrations. Among the tested analogues, compound 60 is the most potent molecule with an EC₅₀ value of 0.04 ± 0.01 μM. Our current study indicates that compound 60 is a fast-acting antimalarial compound and it demonstrates stage specific action at the trophozoite phase in the P. falciparum asexual life cycle. In addition, compound 60 is active against both early and late stage P. falciparum gametocytes. From a mechanistic perspective, compound 60 shows good activity as an inhibitor of β-hematin formation. Collectively, our findings suggest that fast-acting agent 60 targets dual life stages of the malarial parasites and warrant further investigation of pyridylvinylquinoline hybrids as new antimalarials.

Synthesis, cytotoxicity of some pyrazoles and pyrazolo[1,5-a]pyrimidines bearing benzothiazole moiety and investigation of their mechanism of action

A novel series of pyrazoles and pyrazolo[1,5-a]pyrimidines bearing benzothiazole moiety were designed and synthesized. Chemical structures were confirmed by spectral data and elemental analyses. Nine compounds were selected and screened for their cytotoxic activity at the National Cancer Institute (NCI), USA against 60 cancer cell lines in a single dose assay. Compounds 4 and 5 exerted the most potent growth inhibitory activity against most cancer cell lines with growth inhibition (GI%) ranges from 44.86% to 84.59% and 31.20% to 52.36%, respectively. Consequently, they were further investigated through IC₅₀ determination using five dose MTT colorimetric assay against three sensitive cell lines, leukemia CCRF-CEM, non-small cell lung cancer HOP-92 and liver cancer Hep-G2. Compound 4 exhibited potent cytotoxic activity against the three tested cell lines with IC₅₀ 16.34, 3.45 and 7.79 μM, respectively representing half potency, 3.5 folds potency and nearly equipotent to roscovitine. To investigate its mechanism of action, cell cycle analysis of compound 4 was conducted and showed that it induced cell cycle arrest at G2/M phase and apoptosis in HOP-92 cells. In correlation with the previous results, caspase-3 activation was tested and illustrated elevation in its concentration by nearly 14 folds than control. Besides, enzyme inhibition assay of compound 4 was evaluated towards two common antitumor targets namely KDM1 and CDK1 showing significant inhibitory activity with IC₅₀ 0.096 and 0.078 μM, respectively.

An assessment study of known pyrazolopyrimidines: Chemical methodology and cellular activity

Heterocyclic compounds with nitrogen atom play a key role in the normal life cycle of a cell. Pyrazolopyrimidine is a privileged class of nitrogen containing fused heterocyclic compound contributing to a major portion of all lead molecules in medicinal chemistry. The thumbprint of pyrazolopyrimidine as a pharmacophore is always noticeable due to its analogy with the adenine base in DNA. Pyrazolopyrimidines are divided into five types [I, II, III, IV, V] based on the mechanism of action on the specific target conferring a wide scope of research which has accelerated the interest of researchers to investigate its biological profile. In 1956, the anti-cancer activity of pyrazolopyrimidine was evaluated for the first time with appreciable results. Since then, medicinal chemists centered their work on various methods of synthesis and evaluating the biological profile of pyrazolopyrimidine isomers. This report consists of novel methodologies followed to synthesize pyrazolopyrimidine isomers along with a note on their biological significance. To the best of our knowledge, this review article will be first of its kind to encompass different synthetic procedures along with anti-cancer, kinase inhibition, phosphodiesterase inhibition and receptor blocking activity of pyrazolopyrimidine moieties. IC₅₀ values of potent compounds are added wherever necessary to understand the suitability of pyrazolopyrimidine skeletons for a specific biological activity.

CuAAC-ensembled 1,2,3-triazole-linked isosteres as pharmacophores in drug discovery: review

The review lays emphasis on the significance of 1,2,3-triazoles synthesized via CuAAC reaction having potential to act as anti-microbial, anti-cancer, anti-viral, anti-inflammatory, anti-tuberculosis, anti-diabetic, and anti-Alzheimer drugs. The importance of click chemistry is due to its 'quicker' methodology that has the capability to create complex and efficient drugs with high yield and purity from simple and cheap starting materials. The activity of different triazolyl compounds was compiled considering MIC, IC50, and EC50 values against different species of microbes. In addition to this, the anti-oxidant property of triazolyl compounds have also been reviewed and discussed.

Phenothiazine and amide-ornamented novel nitrogen heterocyclic hybrids: synthesis, biological and molecular docking studies

The synthesis of phenothiazine and amide-ornamented nitrogen heterocycles (25–34) has been accomplished utilizing a multi-step synthetic protocol and the structures have been established based on physical and spectral techniques.

Continued exploration and tail approach synthesis of benzenesulfonamides containing triazole and dual triazole moieties as carbonic anhydrase I, II, IV and IX inhibitors

A library of twenty two novel 1,2,3-triazole benzenesulfonamides incorporating thiosemicarbazide, 5(4H)-thione-1,2,4-triazole and variously substituted phenacyl appended 1,2,4-triazole as tail were designed, synthesized and assessed for their efficacy as inhibitors against carbonic anhydrase human (h) isoforms hCA I, II, IV and IX. The physiologically important and off-target cytosolic isoform hCA I was weakly inhibited by most of the newly synthesized sulfonamides while the glaucoma associated isoform hCA II was moderately inhibited with KIs spanning in low nanomolar range (KI = 8.0 nM-0.903 μM). The membrane bound isoform hCA IV, which is known to be involved in glaucoma and retinitis pigmentosa among others, was strongly inhibited by all newly synthesized sulfonamides out of which nine compounds inhibited isoform hCA IV even more effectively as compared to standard drug acetazolamide (AAZ). The membrane bound isoform hCA IX, associated with growth of tumor cells, was moderately inhibited with KIs ranging between 51 nM-3.198 μM. The effect of appending variously substituted tails on heterocyclic moieties over inhibition potential of synthesized sulfonamides is also disclosed which can be of further interest in pharmacological studies for exploring synthesis of isoform selective inhibitors.

Novel camphor-based pyrimidine derivatives induced cancer cell death through a ROS-mediated mitochondrial apoptosis pathway

A series of novel camphor-based pyrimidine derivatives (3a–3x) have been synthesized; their structures were determined by using conventional methods and compound 3f was further confirmed through single crystal XRD analysis. The cytotoxic activity of the target compounds against a panel of human normal (GES-1) and cancer cell lines (MDA-MB-231, RPMI-8226, A549) was evaluated by MTS assay. Here we found that compound 3f exhibited the strongest anti-tumor activity, comparable to that of etoposide, and had much lower cytotoxicity to normal GES-1 cells (IC₅₀ > 50 μM) than the reference drug (IC₅₀ = 8.89 μM). Subsequent mechanism studies in MDA-MB-231 cells revealed that compound 3f caused G0/G1 phase arrest and apoptosis in a dose dependent manner. Moreover, the loss of mitochondrial membrane potential and enhancement of cellular ROS levels were also observed upon 3f treatment, which indicated that 3f exerted cytotoxic activity by a ROS-mediated mitochondrial apoptosis pathway. This result was confirmed by a significant increase in the expression of pro-apoptotic proteins Bax, cytochrome C and caspase-3, and downregulation of anti-apoptosis protein Bcl-2. Overall, 3f can be adopted for further investigation in the development of antitumor agents based on natural products.

A series of novel camphor-based pyrimidine derivatives were synthesized and characterized. We found the compound 3f exhibited strongest anti-tumor activity via ROS-mediated mitochondrial apoptosis pathway.

1,2,3-Triazole-containing hybrids as potential anticancer agents: Current developments, action mechanisms and structure-activity relationships

Anticancer agents are critical for the cancer treatment, but side effects and the drug resistance associated with the currently used anticancer agents create an urgent need to explore novel drugs with low side effects and high efficacy. 1,2,3-Triazole is privileged building block in the discovery of new anticancer agents, and some of its derivatives have already been applied in clinics or under clinical trials for fighting against cancers. Hybrid molecules occupy an important position in cancer control, and hybridization of 1,2,3-triazole framework with other anticancer pharmacophores may provide valuable therapeutic intervention for the treatment of cancer, especially drug-resistant cancer. This review emphasizes the recent advances in 1,2,3-triazole-containing hybrids with anticancer potential, covering articles published between 2015 and 2019, and the structure-activity relationships, together with mechanisms of action are also discussed.

1,2,3-Triazole-containing hybrids as leads in medicinal chemistry: A recent overview

The 1,2,3-triazole ring is a major pharmacophore system among nitrogen-containing heterocycles. These five-membered heterocyclic motifs with three nitrogen heteroatoms can be prepared easily using 'click' chemistry with copper- or ruthenium-catalysed azide-alkyne cycloaddition reactions. Recently, the 'linker' property of 1,2,3-triazoles was demonstrated, and a novel class of 1,2,3-triazole-containing hybrids and conjugates was synthesised and evaluated as lead compounds for diverse biological targets. These lead compounds have been demonstrated as anticancer, antimicrobial, anti-tubercular, antiviral, antidiabetic, antimalarial, anti-leishmanial, and neuroprotective agents. The present review summarises advances in lead compounds of 1,2,3-triazole-containing hybrids, conjugates, and their related heterocycles in medicinal chemistry published in 2018. This review will be useful to scientists in research fields of organic synthesis, medicinal chemistry, phytochemistry, and pharmacology.

NewN-phenylacetamide-incorporated 1,2,3-triazoles: [Et3NH][OAc]-mediated efficient synthesis and biological evaluation

A facile, highly efficient, and greener method for the synthesis of new 1,4-disubstituted-1,2,3-triazoles was conducted using [Et₃NH][OAc] as a medium by the implementation of ultrasound irradiation via click chemistry, affording excellent yields. The present synthetic method exhibited numerous advantages such as mild reaction conditions, excellent product yields, minimal chemical waste, operational simplicity, shorter reaction time, and a wide range of substrate scope. The synthesized compounds were further evaluated for in vitro antifungal activity against five fungal strains, and some of the compounds displayed equivalent or greater potency than the standard drug. A molecular docking study against the modelled three-dimensional structure of cytochrome P450 lanosterol 14α-demethylase was also performed to understand the binding affinity and binding interactions of the enzyme. Furthermore, the synthesized compounds were evaluated for DPPH radical scavenging activity and antitubercular activity against Mycobacterium tuberculosis H37Rv strain.

A facile, highly efficient, and greener method for the synthesis of new 1,4-disubstituted-1,2,3-triazoles was conducted using [Et₃NH][OAc] as a medium by the implementation of ultrasound irradiation via click chemistry, affording excellent yields.

Antitumor evaluation of novel phenothiazine derivatives that inhibit migration and tubulin polymerization against gastric cancer MGC-803 cells

Two novel series of 1,2,3-triazole-phenothiazine hybrids and dithiocarbamate-phenothiazine hybrids were designed and synthesized by molecular hybridization strategy. Their antiproliferative activity against three gastric cancer cell lines (MKN28, MGC-803 and MKN45) were evaluated. Among them, hybrid 13h displayed the most potent inhibitory activity against gastric cancer MGC-803 cells with an IC₅₀ value of 1.2 μM. Hybrid 13h could inhibit migration by regulating the expression level of N-cadherin, E-cadherin, Vimentin, and actived-MMP2. Furthermore, it could regulate wnt/β-catenin signaling pathway on MGC-803 cells in a concentration-dependent manner by decreasing the expression level of Wnt5α, β-catenin and TCF4. From the tubulin polymerization assay results in vitro, hybrid 13h was a novel tubulin polymerization inhibitor. By oral administration assay, compound 13h could effectively inhibit MGC-803 xenograft tumor growth in vivo without obvious side effects. In summary, compound 13h might be an orally active antitumor agent with clinical applications to the treatment of gastric cancer. Graphical abstract Antitumor mechanisms of novel phenothiazine derivative.

Synthesis and biological evaluation of triazole and isoxazole-tagged benzothiazole/benzoxazole derivatives as potent cytotoxic agents

Cancer is a major health problem and the most upsetting disease in humans, leading to death in both developed and developing countries.