Synthesis and in vitro anticancer activity evaluation of spiro[indolo[2,1-b]quinazoline-pyrano[2,3-c]pyrazole] via sequential four-component reaction

Current scenario of pyrazole hybrids with anti-breast cancer therapeutic applications

Breast cancer stands as the leading cause of cancer-related deaths among women globally, but current therapy is restricted to the serious adverse effects and multidrug resistance, necessitating the exploration of novel, safe, and efficient anti-breast cancer chemotherapeutic agents. Pyrazoles exhibit excellent potential for utilization as effective anti-breast cancer agents due to their ability to act on various biological targets. Particularly, pyrazole hybrids demonstrated the advantage of targeting multiple pathways, and some of them, which are exemplified by larotrectinib (pyrazolo[1,5-a]pyrimidine hybrid), can be applied for breast cancer therapy. Thus, pyrazole hybrids hold great promise as useful therapeutic interventions for breast cancer. The aim of this review is to summarize the current scenario of pyrazole hybrids with in vitro and/or in vivo anti-breast cancer potential, along with the modes of action and structure-activity relationships, covering articles published from 2020 to the present, to streamline the development of rational, effective and safe anti-breast cancer candidates.

Recent advances of tryptanthrin and its derivatives as potential anticancer agents

Tryptanthrin is one of the well-known natural alkaloids with a broad spectrum of biological activities and can act as anti-inflammatory, anticancer, antibacterial, antifungal, antiviral, antitubercular, and other agents. Owing to its potent anticancer activity, tryptanthrin has been widely explored for the therapy of various cancers besides being effective against other diseases. Tryptanthrin with a pharmacological indoloquinazoline moiety can not only be modified by different functional groups to achieve various tryptanthrin derivatives, which may realize the improvement of anticancer activity, but also bind with different metal ions to obtain varied tryptanthrin metal complexes as potential anticancer agents, due to their higher anticancer activities in comparison with tryptanthrin (or its derivatives) and cisplatin. This review outlines the recent advances in the syntheses, structures, and anticancer activities of tryptanthrin derivatives and their metal complexes, trying to reveal their structure-activity relationships and to provide a helpful way for medicinal chemists in the development of new and effective tryptanthrin-based anticancer agents.

New pyranopyrazole based derivatives: Design, synthesis, and biological evaluation as potential topoisomerase II inhibitors, apoptotic inducers, and antiproliferative agents

A new series of pyranopyrazole-based derivatives were designed and synthesized. The synthesized compounds were assessed for their cytotoxic efficacy against A549 human lung carcinoma and MCF-7 human breast carcinoma cell lines. Three compounds (1b, 4b, and 7b) exhibited 1.3- to 2.3-fold more antiproliferative activity than that of doxorubicin against the A549 cell line. In comparison to doxorubicin, compounds 1d and 3b were 4.1- and 1.04-fold, respectively more powerful against MCF-7 cancer cells. All the synthesized compounds were found to be more selective toward A549 cancer cells than the normal human fibroblast BJ cells. Of interest, compounds 1b and 7b exhibited promising cytotoxicity and SIs of 27.72 and 25.30, respectively, towards A549 cancer cells, higher than that of doxorubicin (SI 4.81). The most potent compounds 1b, 1d, 3b, 4b, and 7b were then subjected to in vitro Topo II inhibition assay. They showed IC50 values in the range of 2.07 to 8.86 µM. Of particular interest, compound 7b (IC50 = 2.07 µM), exhibited higher Topo II inhibitory activity than that of doxorubicin (IC50 = 2.56 µM). The significant Topo II inhibition of compound 7b was explained by molecular docking simulations into the Topo II active site. Compound 7b halted the cell cycle in the S phase in A549 cancer cells. It induced total apoptosis and necrosis of 20.73- and 4-fold, respectively, greater than the control. This evidence was supported by a 3.59-fold increase in the level of apoptotic caspase-9 and a remarkable elevation of the Bax/BCL-2 ratio. The physiochemical parameters of compound 7b were aligned with Lipinski's rule of five.

Discovery of Pyrano[2,3-c]pyrazole Derivatives as Novel Potential Human Coronavirus Inhibitors: Design, Synthesis, In Silico, In Vitro, and ADME Studies

The SARS-CoV-2 pandemic at the end of 2019 had major worldwide health and economic consequences. Until effective vaccination approaches were created, the healthcare sectors endured a shortage of operative treatments that might prevent the infection's spread. As a result, academia and the pharmaceutical industry prioritized the development of SARS-CoV2 antiviral medication. Pyranopyrazoles have been shown to play a prominent function in pharmaceutical chemistry and drug sighting because of their significant bioactive properties. We provide herein a novel sequence of pyranopyrazoles and their annulated systems whose antiviral efficacy and cytotoxicity were explored versus human coronavirus 229E (HCoV-229E) Vero-E6 cell lines as a model for the Coronaviridae family. Fifteen synthetic congeners pointed out miscellaneous antiviral efficacies against HCoV-229E with variable inhibition degrees. Compound 18 showed a high selectivity index (SI = 12.6) that established spectacular inhibitory capacity against human coronavirus 229E. Compounds 6, 7, and 14 exposed moderate efficacies. Compounds 6, 7, 14, and 18 exhibited substantial antiviral action through the replication phase with reduction percentages extending from 53.6%, 60.7%, and 55% to 82.2%, correspondingly. Likewise, when assessed to the positive control tipranavir (88.6%), the inhibitory efficiency of compounds 6, 7, 14, and 18 versus the SARS-CoV2 Mpro provided high percentages of 80.4%, 73.1%, 81.4% and up to 84.5%, respectively. In silico studies were performed to investigate further the biological activity and the target compounds' physical and chemical features, including molecular dynamic (MD) simulations, protein-ligand docking, ADME studies, and density functional theory (DFT) calculations. These inquiries demonstrated that this series of metabolically stable pyranopyrazoles and their annulated systems are effective human coronavirus inhibitors that inhibit the viral Mpro protein and may have emerged as a novel COVID-19 curative option.

Synthesis of Luminescent Indolo[2,1-b]quinazolin-6(12H)-ones via a Sequential Ugi/Iodine-Promoted Cyclization/Staudinger/Aza-Wittig Reaction

A new efficient synthesis of indolo[2,1-b]quinazolin-6(12H)-ones via a sequential Ugi/iodine-promoted cyclization/Staudinger/aza-Wittig reaction was developed. The acid catalyzed three-component reactions of 2-azidobenzaldehydes, 2-[2-(trimethylsilyl)ethynyl]benzenamines (or o-aminoacetophenones), and isocyanides gave Ugi-3CR intermediates, which reacted subsequently with I2/DMSO and triphenylphosphine to produce indolo[2,1-b]quinazolin-6(12H)-ones in good overall yields. The obtained indolo[2,1-b]quinazolin-6(12H)-ones were all colored in bright red or orange. Their luminescent property was studied preliminarily and some of them showed high molar absorption coefficients, strong fluorescence emission intensity, and good absolute light quantum yields.

Efficient synthesis of new indenopyridotriazine [4.3.3]propellanes and spiroindenopyridotriazine-4H-pyran derivatives

The pyrido[1,2,4]triazines as substrates, generated from 1,6-diaminopyridinone derivatives and ninhydrin, were reacted with malononitrile and CH-acids to afford a new library spiro[indeno[1,2-e]pyrido[1,2-b][1,2,4]triazine-7,5'-pyran]-1,3,6'-tricarbonitrile in ethanol at reflux condition in excellent yield. Also, novel indenopyridotriazine [4.3.3]propellanes were synthesized via the reaction of pyrido[1,2,4]triazine and N-methyl-1-(methylthio)-2-nitroethenamine (NMSM) by using of HOAc in ethanol. The important aspects of this protocol are the abundance of starting materials, mild conditions, structural diversity of products, excellent yields and easy isolation of products with no chromatographic technique.

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 and in vitro evaluation of antitumor activity of spiro[indolo[2,1-b]quinazoline-pyrano[2,3-d]pyrimidine] and spiro[indolo[2,1-b]quinazoline-pyrido[2,3-d]pyrimidine] derivatives by using 2D and 3D cell culture models

Cancer as one of the biggest human health problems remains unsolved. The identification of novel platforms with the highest efficacy and low toxicity is a big challenge among interested researchers. In this regard, we are interested to synthesis and evaluate antitumor activity of spiro[indolo[2,1-b]quinazoline-pyrano[2,3-d]pyrimidine] and spiro[indolo[2,1-b]quinazoline-pyrido[2,3-d]pyrimidine] derivatives. The spiro heterocycles were synthesized via four-component reaction of isatoic anhydride, isatins, malononitrile, and some CH-acids including barbituric acid/thiobarbituric acid and 4(6)-aminouracil in CH₂Cl₂ under reflux condition. The significant features of this process are short reaction time, easy purification without chromatographic process, and high yields which make it attractive. Next, we employed 2D and 3D cell culture models to evaluate biological activity of our compounds. Our results showed that among our seven products (4a-g), the compounds 4a and 4e are the best with 50% growth inhibitory concentration (IC₅₀) value lower than etoposide. Our results support this idea that the compounds 4a and 4e may be potential for drug designing in cancer therapy. However, more experiments will be required to find possible side effects of related compounds in vivo.