Synthesis of novel chromene derivatives of expected antitumor activity

The chemistry of 2-hydroxy-β-nitrostyrenes: versatile intermediates in synthetic organic chemistry

The applications of 2-hydroxy-β-nitrostyrenes as efficient bifunctional intermediates in organic synthesis are investigated in this review. For this purpose, reactions of 2-hydroxy-β-nitrostyrenes with diverse molecules, including carbonyl compounds, 1,3-dicarbonyl compounds, α,β-unsaturated carbonyl compounds, hemiacetals, nitroalkenes, γ-butenolides, tetronic acid, azalactones, pyrazolones, enamines, malononitrile, methyleneindolinones, ylides, etc., were investigated to construct interesting biologically active scaffolds such as chromans, chromenes, coumarins, benzofurans and their fused and spiro rings, natural products, and other useful cyclic and acyclic compounds. The main focus is on the asymmetric synthesis of these compounds via cascade/domino/tandem reactions catalyzed by chiral organocatalysts. In this review, around 60 papers reported between the years 2000 and 2022 are presented.

Synthesis and biological evaluation of novel dialkyl (4-amino-5H-chromeno[2,3-d]pyrimidin-5-yl)phosphonates

This study reports the design and synthesis of novel dialkyl (4-amino-5H-chromeno[2,3-d]pyrimidin-5-yl)phosphonates as potential antitumor agents against A549 (lung cancer), DU-145 (prostate cancer), PC-3 (prostate cancer), HeLa (cervical cancer) and MCF-7 (breast cancer), cell lines evidenced from the in vitro antitumor studies performed by MTT assay (across 10-30 μM concentrations). The structural eminence of these synthesized molecules has emanated by designing the structural core by uniting the chromene, pyrimidine and phosphonate moieties into one, which has augmented their novelty and made them unreported. Further the deep structural activity relationship study investigations articulated that the title compounds are promising drug-like compounds and potential inhibitor of histidine amino acid residue present on the respective enzymatic proteins [3QJZ (A549), 3VHE (DU-145), 3V49 (PC-3), 3F81 (HeLa), & 3R7Q (MCF-7)] of the cell lines screened and are identified as responsible for the multi-faceted antitumor activities predicted in vitro. The obtained results were further supported by molecular docking studies, QSAR, ADMET, and bioactivity studies which have supported them as potential BBB penetrable molecules and proficient CNS active neuro-protective agents during drug delivery.

Characterization of novel heterocyclic compounds based on 4-aryl-4H-chromene scaffold as anticancer agents: Design, synthesis, antiprofilerative activity against resistant cancer cells, dual β-tubulin/c-Src inhibition, cell cycle arrest and apoptosis induction

In this study, three novel sets of 4-aryl-4H-chromene derivatives 4a-c, 6a-d and 7a-c were synthesized and evaluated for anticancer activity. Characterization of new compounds was established on basis of elemental analyses and spectral data. All new compounds were investigated for their antiproliferative activity against HCT-116, HepG-2 and MCF-7 cell lines using vinblastine and staurosporine as positive controls. Compounds 4b, 4c and 6d showed superior cytotoxicity against HCT-116, HepG-2 and MCF-7 cell lines, respectively with IC₅₀ ranged from 3.31 to 4.95 μM. Additionally, compound 4b showed excellent cytotoxic activity (IC₅₀ = 39.83 μM) against resistant HCT-116 better than doxorubicin (IC₅₀ = 164.60 μM), while compounds 4c and 6d exhibited moderate cytotoxic activity against resistant HepG-2 and resistant MCF-7 cell lines. The most potent compounds inhibited both β-tubulin polymerization (IC₅₀ = 8.78 - 16.47 μM) and c-Src kinase (IC₅₀ = 0.07 - 0.18 μM) enzymes. Compounds 4b, 4c and 6d activated caspase-3, caspase-7, and caspase-9 proteins relative to untreated cells, revealing apoptosis induction. Apoptosis was also confirmed through up-regulation of Bax and down-regulation of Bcl-2 protein expression levels. Cell cycle analysis of compound 6d showed accumulation of cells in pre-G1 phase and cell cycle arrest at S phase in MCF-7 treated cells. As well 6d caused 7- and 63- fold increase in apoptotic cell population at early and late apoptosis stages. Finally, molecular modeling study was performed to predict the binding pattern of the target compounds inside c-Src kinase receptor.

Development of potential anticancer agents and apoptotic inducers based on 4-aryl-4H chromene scaffold: Design, synthesis, biological evaluation and insight on their proliferation inhibition mechanism

An array of 4-aryl-2-amino-4H chromene derivatives were designed, synthesized, and evaluated for cytotoxic activity against four cancer cell lines and two non-cancerous cell lines. The most active candidates were further screened for their in vitro anticancer activity on NCI panel of 60 human cancer cell lines where compounds 2a, 2b, 4a-2, and 2e showed promising activity against various leukemia, non-small lung, renal, prostate, and breast cancer cell lines, particularly against NCI-H522 non-small lung cancer cell line (GI₅₀ of 0.35-0.60 µM), MCF7 breast cancer cell line (GI₅₀ of 0.34-0.59 µM), and MDA-MB-468 breast cancer cell line (GI₅₀ of 0.23-0.40 µM). Compound 2b was the most potent against all leukemia and prostate cancer cell lines with GI₅₀ values (0.29-0.60 µM). Compound 2b inhibited the proliferation of MCF-7 and HepG2 cells by inducing cell cycle arrest and apopotosis. 2b downregulated the mRNA abundance of BAX, Apaf-1 and caspase-3 and upregulated BCL-2. The activities of caspase-3 and caspase-9 were declined in MCF-7 and HepG2 cells treated with compound 2b. Compounds 2b and 4a-2 inhibited tubulin polymerization, with an IC₅₀ values of 0.92 and 1.13 µM, respectively. These findings indicate that these synthesized compounds may represent potential drug candidates to inhibit the proliferation of different types of cancer cells.

An insight on medicinal attributes of 1,2,4-triazoles

The present review aims to summarize the pharmacological profile of 1,2,4-triazole, one of the emerging privileged scaffold, as antifungal, antibacterial, anticancer, anticonvulsant, antituberculosis, antiviral, antiparasitic, analgesic and anti-inflammatory agents, etc. along with structure-activity relationship. The comprehensive compilation of work carried out in the last decade on 1,2,4-triazole nucleus will provide inevitable scope for researchers for the advancement of novel potential drug candidates having better efficacy and selectivity.

2H/4H-Chromenes-A Versatile Biologically Attractive Scaffold

2H/4H-chromene (2H/4H-ch) is an important class of heterocyclic compounds with versatile biological profiles, a simple structure, and mild adverse effects. Researchers discovered several routes for the synthesis of a variety of 2H/4H-ch analogs that exhibited unusual activities by multiple mechanisms. The direct assessment of activities with the parent 2H/4H-ch derivative enables an orderly analysis of the structure-activity relationship (SAR) among the series. Additionally, 2H/4H-ch have numerous exciting biological activities, such as anticancer, anticonvulsant, antimicrobial, anticholinesterase, antituberculosis, and antidiabetic activities. This review is consequently an endeavor to highlight the diverse synthetic strategies, synthetic mechanism, various biological profiles, and SARs regarding the bioactive heterocycle, 2H/4H-ch. The presented scaffold work compiled in this article will be helpful to the scientific community for designing and developing potent leads of 2H/4H-ch analogs for their promising biological activities.

Application of triazoles as bioisosteres and linkers in the development of microtubule targeting agents

The triazole ring system has emerged as an exciting prospect in the optimization studies of promising lead molecules in the quest for new drugs for clinical usage. Several marketed drugs possess these versatile moieties that are used in a wide range of medical indications. This stems from the unique intrinsic properties of triazoles, which impart stability to the basic pharmacophoric unit with an added advantage of being a bioisostere of different chemical functionalities. In the last decade, the use of triazoles as bioisosteres and linkers in the development of microtubule targeting agents has been extensively investigated. The present review highlights the advances in this promising area of drug discovery and development.

Synthesis and characterization of a novel Fe3O4@SiO2–BenzIm-Fc[Cl]/BiOCl nano-composite and its efficient catalytic activity in the ultrasound-assisted synthesis of diverse chromene analogs

A new magnetic nano-catalyst bearing ionic liquid, ferrocene and BiOCl was synthesized and its catalytic activities were evaluated in the synthesis of a wide variety of 2-amino-3-cyano-4H-chromene derivatives (54 compounds) under ultrasound irradiation.

Facile Construction of Novel Fused Chromeno[2,3-d]Thiazolo[3,2-a]Pyrimidine Derivatives in Biocompatible Ionic Liquid under Solvent-Free Conditions

A simple and efficient three-component reaction is reported between 2,3-dihydro-7-hydroxythiazolo[3,2-a]pyrimidin-5-one, dimedone and aromatic aldehydes for synthesis of biologically important novel heterocycles containing thiazolo[3,2-a]pyrimidine and chromene as biologically active moieties. The SO3H-functionalised halogen-free ionic liquid [MIM(CH2)4SO3H][HSO4-] is found to be an environmentally benign catalyst for this reaction without using any solvent. This SO3H-functionalised ionic liquid could be recovered and used at least four times without considerable reduction in activity. Good functional group tolerance, broad scope of usable substrates and good to excellent yields of products are the other prominent features of the present synthetic protocol.

Design, synthesis and biological evaluation of chromenopyrimidines as potential cytotoxic agents

Aim: The design and synthesis of chromenopyrimidines as microtubule destabilizing agents. Materials & methods: Novel chromenopyrimidines and chromenotriazolopyrimidines were prepared and evaluated for their cytotoxicity against MCF-7 cell line. The most potent compound was tested for its possible effect on tubulin inhibition, cell cycle distribution, apoptosis initiation and caspase-3 activation. Results: All the prepared compounds showed potent cytotoxic activity. Compound 13 was the most prominent (IC50 = 0.13 μM on tumor cell line MCF-7 and 14.06 μM on mammary epithelial cell line MCF-10A). Compound 13 inhibited tubulin polymerization (IC50 = 8.39 μM), caused cell cycle arrest at G2/M phase (fivefold more than control) and cellular apoptosis. Compound 13 increased the level of active caspase-3, 12-fold compared with control.

Design and synthesis of new coumarin hybrids and insight into their mode of antiproliferative action

Molecular hybridization approach was used to synthesize three series of coumarin based hybrids by conglomerate a substituted chalcones, acrylohydrazides, and pyridines moieties with 8-methoxy coumarin. The hybrids showed significant cytotoxic activity against liver cancer Hep G2 and Leukemia K562 cell lines with IC₅₀ values 0.49-3.96μM, comparable to the positive controls and exhibited weak activity against the normal cell line WI-38, thus indicating selectivity toward the tumor cells. Coumarin-chalcone hybrids 2a-c have demonstrated the most promising activity against both cancer cell lines with IC₅₀ values of 0.65-2.02μM. Interestingly, the acrylohydrazide hybrid 4c showed the highest cytotoxic activity against the leukemia cell line (K562) with IC₅₀ value of 0.49μM. All the investigated coumarin hybrids were able to increase the caspase-3 and caspase-9 proteins level expression relative to that of the untreated cells suggesting that coumarin hybrids-induced apoptosis was, in part, due to activation of caspases 3 and 9. Apoptosis was further confirmed with down-regulation of Bcl-2 and up-regulation of Bax protein expression level. Furthermore, cell cycle analysis of 2a and 4c showed apoptotic signals activation, as a consequence of arrest in G2/M phase. Results of our study can shed light on coumarin-based hybrids as promising anticancer leads.

Enantioselective synthesis of spiro[indoline-3,4′-pyrano[2,3-c]pyrazole] derivatives via an organocatalytic asymmetric Michael/cyclization cascade reaction

Pyrazolones have been firstly employed to react with isatylidene malononitriles, and chiral multicyclic spirooxindoles have been constructed with a low loading of commercially available catalysts.

One-pot synthesis of tetrahydro-4H-chromenes by supramolecular catalysis in water

Tetrahydro-4H-chromenes were synthesizedviaan efficient one-pot three-component protocol by supramolecular catalysis with β-cyclodextrin in water.

Synthesis of Novel 2-Methyl and 2-Cyanomethyl-12-Aryl-8,12-Dihydro-9H-cHromeno[3,2-e][1,2,4]Triazolo[1,5-c]Pyrimidin-11(10H)-One Derivatives

2-Methyl and 2-cyanomethyl-12-aryl-8,12-dihydro-9H-chromeno[3,2-e][1,2,4]triazolo[1,5-c]pyrimidin-11(10H)-one derivatives were synthesised by the cyclisations of acetic anhydride or ethyl cyanoacetate with chromeno[2,3-d]pyrimidine derivatives, which were obtained by the reactions of hydrazine monohydrate and formimidate derivatives. In addition, 2,9,9-trimethyl-12-(p-tolyl)-8,12-dihydro-9H-chromeno[3,2-e][1,2,4]triazolo[1,5-c]pyrimidin-11(10H)-one and 2-cyanomethyl-12-phenyl-8,12-dihydro-9H-chromeno[3,2-e][1,2,4]triazolo[1,5-c]pyrimidin-11(10H)-one were further determined by single-crystal X-ray diffraction analysis.

"One-pot" access to dihydrofurans via tandem oxidative difunctionalization and ring contraction of aminopyrans

An operationally simple and efficient protocol for the construction of dihydrofuran derivatives has been accomplished via a sequential addition of N-chlorosuccinimide and a base to 2-amino-4H-pyran derivatives in alcohol medium. The one-pot protocol proceeding via tandem oxidative difunctionalization and ring contraction provides an entirely new strategy for the construction of the dihydrofuran skeleton.

Synthesis and isomerization of some novel pyrazolopyrimidine and pyrazolotriazolopyrimidine derivatives

4-Imino-1-p-tolyl-1,4-dihydropyrazolo[3,4-d]pyrimidin-5-ylamine (2) and (1-p-tolyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl)-hydrazine (3) were prepared starting from ethyl 4-cyano-1-p-tolyl-1H-pyrazol-5-ylimidoformate (1). The structure of compound 3 was confirmed through preparation of the pyrazole derivatives 4 and 5. Also, the synthesis and structural characterization of pyrazolo[4,3-e][1,2,4]triazolo[4,3-c]pyrimidine derivatives 7 and 9 and their isomerization to pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine derivatives 6 and 8, respectively, under different suitable reaction conditions were reported. Moreover, the syntheses of 2-substituted-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine derivatives 10 and 11 was described.