Synthesis and anticancer activity of new tetrahydroquinoline hybrid derivatives tethered to isoxazoline moiety

Mothana R, M. Noman O, Eto B, Chigr F, Chigr M. Synthesis and In Silico Analysis of New Polyheterocyclic Molecules Derived from [1,4]-Benzoxazin-3-one and Their Inhibitory Effect against Pancreatic α-Amylase and Intestinal α-Glucosidase

This study focuses on synthesizing a new series of isoxazolinyl-1,2,3-triazolyl-[1,4]-benzoxazin-3-one derivatives 5a-5o. The synthesis method involves a double 1,3-dipolar cycloaddition reaction following a "click chemistry" approach, starting from the respective [1,4]-benzoxazin-3-ones. Additionally, the study aims to evaluate the antidiabetic potential of these newly synthesized compounds through in silico methods. This synthesis approach allows for the combination of three heterocyclic components: [1,4]-benzoxazin-3-one, 1,2,3-triazole, and isoxazoline, known for their diverse biological activities. The synthesis procedure involved a two-step process. Firstly, a 1,3-dipolar cycloaddition reaction was performed involving the propargylic moiety linked to the [1,4]-benzoxazin-3-one and the allylic azide. Secondly, a second cycloaddition reaction was conducted using the product from the first step, containing the allylic part and an oxime. The synthesized compounds were thoroughly characterized using spectroscopic methods, including 1H NMR, 13C NMR, DEPT-135, and IR. This molecular docking method revealed a promising antidiabetic potential of the synthesized compounds, particularly against two key diabetes-related enzymes: pancreatic α-amylase, with the two synthetic molecules 5a and 5o showing the highest affinity values of 9.2 and 9.1 kcal/mol, respectively, and intestinal α-glucosidase, with the two synthetic molecules 5n and 5e showing the highest affinity values of -9.9 and -9.6 kcal/mol, respectively. Indeed, the synthesized compounds have shown significant potential as antidiabetic agents, as indicated by molecular docking studies against the enzymes α-amylase and α-glucosidase. Additionally, ADME analyses have revealed that all the synthetic compounds examined in our study demonstrate high intestinal absorption, meet Lipinski's criteria, and fall within the required range for oral bioavailability, indicating their potential suitability for oral drug development.

New Oxazolo[5,4-d]pyrimidines as Potential Anticancer Agents: Their Design, Synthesis, and In Vitro Biological Activity Research

Cancer is a large group of diseases in which the rapid proliferation of abnormal cells generally leads to metastasis to surrounding tissues or more distant ones through the lymphatic and blood vessels, making it the second leading cause of death worldwide. The main challenge in designing a modern anticancer therapy is to develop selective compounds that exploit specific molecular targets. In this work, novel oxazolo[5,4-d]pyrimidine derivatives were designed, synthesized, and evaluated in vitro for their cytotoxic activity against a panel of four human cancer cell lines (lung carcinoma: A549, breast adenocarcinoma: MCF7, metastatic colon adenocarcinoma: LoVo, primary colon adenocarcinoma: HT29), along with their P-glycoprotein-inhibitory ability and pro-apoptotic activity. These oxazolo[5,4-d]pyrimidine derivatives, which are structurally similar to nucleic purine bases in general, are characterized by the presence of a pharmacologically favorable isoxazole substituent at position 2 and aliphatic amino chains at position 7 of the condensed heterocyclic system. In silico analysis of the obtained compounds identified their potent inhibitory activity towards human vascular endothelial growth factor receptor-2 (VEGFR-2). Molecular docking was performed to assess the binding mode of new derivatives to the VEGFR-2 active site. Then, their physicochemical, pharmacokinetic, and pharmacological properties (i.e., ADME-administration, distribution, metabolism, and excretion) were also predicted to assess their druglikeness. In particular, compound 3g (with a 3-(N,N-dimethylamino)propyl substituent) was found to be the most potent against the HT29 cell line, with a 50% cytotoxic concentration (CC₅₀) of 58.4 µM, exceeding the activity of fluorouracil (CC₅₀ = 381.2 μM) and equaling the activity of cisplatin (CC₅₀ = 47.2 µM), while being less toxic to healthy human cells (such as normal human dermal fibroblasts (NHDFs)) than these reference drugs. The results suggest that compound 3g is a potentially promising candidate for the treatment of primary colorectal cancer.

Diversity-Oriented Synthesis of Highly Functionalized Alicycles across Dipolar Cycloaddition/Metathesis Reaction

This Account gives an insight into the selective functionalization of some readily available commercial cyclodienes across simple chemical transformations into functionalized small-molecular scaffolds. The syntheses involved selective cycloadditions, followed by ring-opening metathesis (ROM) of the resulting azetidin-2-one derivatives or isoxazoline frameworks and selective cross metathesis (CM) by discrimination of the C=C bonds on the alkenylated heterocycles. The CM protocols have been described when investigated under various conditions with the purpose on exploring chemodifferentiation of the olefin bonds and a study on the access of the corresponding functionalized β-lactam or isoxazoline derivatives is presented. Due to the expanding importance of organofluorine chemistry in drug research as well as of the high biological potential of β-lactam derivatives several illustrative examples to the access of some fluorine-containing molecular entities is also presented in this synopsis.

1 Introduction

2 Ring C=C Bond Functionalization of Some Cycloalkene β-Amino Acid Derivatives across Chlorosulfonyl Isocyanate Cycloaddition

3 Ring C=C Bond Functionalization of Some Cycloalkene β-Amino Acid Derivatives across Nitrile Oxide Cycloaddition

4 Ring C=C Bond Functionalization of Some Cycloalkene β-Amino Acid Derivatives across Metathesis

5 Functionalization of sSome Cyclodienes across Nitrile Oxide Cycloaddition

6 Selective Synthesis of Functionalized Alicycles across Ring-Opening Metathesis

7 Selective Synthesis of Functionalized Alicycles through Cross Metathesis

8 Summary and Outlook

9 List of Abbreviations

Tetrahydroquinoline/4,5-Dihydroisoxazole Molecular Hybrids as Inhibitors of Breast Cancer Resistance Protein (BCRP/ABCG2)

Multidrug resistance (MDR) is one of the major factors in the failure of many chemotherapy approaches. In cancer cells, MDR is mainly associated with the expression of ABC transporters such as P-glycoprotein, MRP1 and ABCG2. Despite major efforts to develop new selective and potent inhibitors of ABC drug transporters, no ABCG2-specific inhibitors for clinical use are yet available. Here, we report the evaluation of sixteen tetrahydroquinoline/4,5-dihydroisoxazole derivatives as a new class of ABCG2 inhibitors. The affinity of the five best inhibitors was further investigated by the vanadate-sensitive ATPase assay. Molecular modelling data, proposing a potential binding mode, suggest that they can inhibit the ABCG2 activity by binding on site S1, previously reported as inhibitors binding region, as well targeting site S2, a selective region for substrates, and by specifically interacting with residues Asn436, Gln398, and Leu555. Altogether, this study provided new insights into THQ/4,5-dihydroisoxazole molecular hybrids, generating great potential for the development of novel most potent ABCG2 inhibitors.

Isoxazole derivatives as anticancer agent: A review on synthetic strategies, mechanism of action and SAR studies

Breast cancer is the second most leading cause of death among women. Multiple drugs have been approved by FDA for the treatment of BC. The major drawbacks of existing drugs are the development of resistance, toxicity, selectivity problem. The other therapies like hormonal therapy, surgery, radiotherapy, and immune therapy are in use but showed many side effects like bioavailability issues, non-selectivity, pharmacokinetic-pharmacodynamic problems. Therefore, there is an urgent need to develop new moieties that are nonviolent and more effective in the treatment of cancer. Isoxazole derivatives have gain popularity in recent years due to anticancer potential with the least side effects. These derivatives act as an anticancer agent with different mechanisms like inducing apoptosis, aromatase inhibition, disturbing tubulin congregation, topoisomerase inhibition, HDAC inhibition, and ERα inhibition. In this article, we have explored the synthetic strategies, anticancer mechanism of action along with SAR studies of isoxazole derivatives.

Removal and modification of directing groups used in metal-catalyzed C–H functionalization: the magical step of conversion into ‘conventional’ functional groups

This feature review is focused on recent approaches for removing versatile directing groups.

2-Isoxazolines: A Synthetic and Medicinal Overview

Isoxazolines are nitrogen- and oxygen-containing five-membered heterocyclic scaffolds with extensive biological activities. This framework can be readily obtained in good to excellent yields through 1,3-dipolar cycloaddition between nitrones with alkynes or allenes, aryl/alkyl halides, alkynes, and oxaziridines under mild conditions. This scaffold has been an emerging area of interest for many researchers given their wide range of bioactivities. Herein we review synthetic strategies toward isoxazolines and the role these efforts have had in enhancing the biological activity of natural products and synthetic compounds such as antitubercular agents, COX-1 inhibitors, COX-2 inhibitors (e. g., valdecoxib), nicotinic receptor modulators, and MIF inhibitors. With a focus on efforts from 2010 onward, this review provides in-depth coverage of the design and biological evaluation of isoxazoline systems and their impact on various pathologies.