Hybrid benzofuran–bisindole derivatives: New prototypes with promising anti-hyperlipidemic activities

Catalyst-Switchable Divergent Synthesis of Bis(indolyl)alkanes and 3-Alkylated Indoles from Styrene Oxides

A novel and effective Brønsted acid-catalyzed chemoselective synthesis of bis(indolyl)alkanes and 3-alkyl indoles is reported. The selectivity of two significant indole derivatives is attained by allowing the same substrates to go through divergent reaction routes catalyzed by different catalysts. Furthermore, this mild approach is applicable to a wide range of substrates and has high efficacy in large-scale reactions. A plausible mechanism is provided based on the control experiments and spectroscopic studies.

Structure-Activity Relationship of Benzofuran Derivatives with Potential Anticancer Activity

Simple Summary

Cancer is the leading cause of death worldwide and responsible for killing approximately 10 million people per year. Fused heterocyclic ring systems such as benzofuran have emerged as important scaffolds with many biological properties. Furthermore, derivatives of benzofurans demonstrate a wide range of biological and pharmacological activities, including anticancer properties. The main aim of this review is to highlight and discuss the contribution of benzofuran derivatives as anticancer agents by considering and discussing the chemical structure of 20 different compounds. Evaluating the chemical structure of these compounds will guide future medicinal chemists in designing new drugs for cancer therapy that might give excellent results in in vivo/in vitro applications.

Abstract

Benzofuran is a heterocyclic compound found naturally in plants and it can also be obtained through synthetic reactions. Multiple physicochemical characteristics and versatile features distinguish benzofuran, and its chemical structure is composed of fused benzene and furan rings. Benzofuran derivatives are essential compounds that hold vital biological activities to design novel therapies with enhanced efficacy compared to conventional treatments. Therefore, medicinal chemists used its core to synthesize new derivatives that can be applied to a variety of disorders. Benzofuran exhibited potential effectiveness in chronic diseases such as hypertension, neurodegenerative and oxidative conditions, and dyslipidemia. In acute infections, benzofuran revealed anti-infective properties against microorganisms like viruses, bacteria, and parasites. In recent years, the complex nature and the number of acquired or resistant cancer cases have been largely increasing. Benzofuran derivatives revealed potential anticancer activity with lower incidence or severity of adverse events normally encountered during chemotherapeutic treatments. This review discusses the structure–activity relationship (SAR) of several benzofuran derivatives in order to elucidate the possible substitution alternatives and structural requirements for a highly potent and selective anticancer activity.

Preparation of Tetrasubstituted Bis(3-indolyl)methanes from Indoles and Acetophenes Using 1,3-Dibromo-5,5-dimehtylhydantoin as an Efficient Catalyst

Abstract:

A new process that could efficiently prepare tetrasubstituted bis(3-indolyl)methanes from various indoles and acetophenones with 1,3-Dibromo-5,5-dimehtylhydantoin(DBDMH) as a catalyst was reported. The effects of catalysts, solvents, and reaction temperature were investigated. Under the optimal condition, most of the tetrasubstituted bis(3-indolyl)methanes were obtained in 90–99% yields.

Mahardhika A, L. Wendt L, E. Müller C. Iodine-catalyzed electrophilic substitution of indoles: Synthesis of (un)symmetrical diindolylmethanes with a quaternary carbon center

A novel, versatile approach for the synthesis of unsymmetrical 3,3'-diindolylmethanes (DIMs) with a quaternary carbon center has been developed via iodine-catalyzed coupling of trifluoromethyl(indolyl)phenylmethanols with indoles. In contrast to previously reported methods, the new procedure is characterized by chemoselectivity, mild conditions, high yields, and scalability to obtain gram amounts for biological studies. Selected compounds were found to display affinity for cannabinoid receptors, which are promising drug targets for the treatment of inflammatory and neurodegenerative diseases.

Selectfluor facilitated bridging of indoles to bis(indolyl)methanes using methyl tert-butyl ether as a new methylene precursor

A novel, green and efficient method is developed for the synthesis of methylene bridged bis(indolyl)methanes in good to excellent yields. The reaction employs methyl tert-butyl ether (MTBE) as the methylene source and selectfluor as an oxidizing agent. The scope and versatility of the methods have been successfully demonstrated with 48 examples. The metal-free transformation process is suitable for scale-up production. A selectfluor-promoted oxidative reaction mechanism is proposed based on the results of the experimental studies.

Commiphora myrrha Resin Alcoholic Extract Ameliorates High Fat Diet Induced Obesity via Regulation of UCP1 and Adiponectin Proteins Expression in Rats

This study was performed to evaluate anti-obesity potential of Commiphora myrrha resin ethanolic extract (CME) with the respect to expression of leptin, adiponectin and uncoupling protein 1 (UCP1) in rats. Control rats fed basal diet. Second group fed basal diet and administered CME (500 mg/kg bw) orally for 14 weeks. Third group fed high fat diet (HFD) for 14 weeks. Fourth group fed HFD and administered CME as second group. Fifth group fed HFD for 8 weeks then fed basal diet and administered CME as third group for another 6 weeks. Phytochemical analysis of CME identified the presence of germacrene B, 1,4-benzoquinone, benzofuran, hexadecanoic acid, 9,12-octadecnoic acid methyl ester, reynosin, 11, 14-eicosadienoic acid, isochiapin B, bisabolene epixod, elemene and 1-heptatriacotanol. High fat diet significantly increased food intake, body weight, hyperglycemia, serum levels of total cholesterol, triacylglycerol, low density lipoprotein and ketone bodies, AST and AST activities, concentration of malondialdehyde and histopathological changes in hepatic tissues. However, it significantly reduced serum levels of high density lipoprotein, leptin and adiponectin, activity of hepatic glutathione reductase (GR) and brown adipose tissue UCP1 protein expression. In contrast, CME ameliorated HFD increased body weight, hyperglycemia, dyslipidemia, ketonemia, hepatic tissues lipid peroxidation, restored hepatic tissue architecture and enhanced protein expression of leptin, adiponectin and UCP1 and activity of hepatic GR. This study indicated that CME ameliorated HFD induced hyperglycemia and dyslipidemia through normalization of HFD reduced leptin, adiponectin and UCP1 proteins production and antioxidant activity.

Spiroindolone Analogues as Potential Hypoglycemic with Dual Inhibitory Activity on α-Amylase and α-Glucosidase

Inhibition of α-amylase and α-glucosidase by specified synthetic compounds during the digestion of starch helps control post-prandial hyperglycemia and could represent a potential therapy for type II diabetes mellitus. A new series of spiroheterocyclic compounds bearing oxindole/benzofuran/pyrrolidine/thiazolidine motifs were synthesized via a 1,3-dipolar cyclo-addition reaction approach. The specific compounds were obtained by reactions of chalcones having a benzo[b]furan scaffold (compounds 2a-f), with a substituted isatin (compounds 3a-c) and heterocyclic amino acids (compounds 4a,b). The target spiroindolone analogues 5a-r were evaluated for their potential inhibitory activities against the enzymes α-amylase and α-glucosidase. Preliminary results indicated that some of the target compounds exhibit promising α-amylase and α-glucosidase inhibitory activity. Among the tested spiroindolone analogues, the cycloadduct 5r was found to be the most active (IC50 = 22.61 ± 0.54 μM and 14.05 ± 1.03 μM) as α-amylase and α-glucosidase inhibitors, with selectivity indexes of 0.62 and 1.60, respectively. Docking studies were carried out to confirm the binding interaction between the enzyme active site and the spiroindolone analogues.

Cu/Pd-Catalyzed chemoselective synthesis of C-3 dicarbonyl indoles and bis(indolyl)alkanes from aldehydes and indoles

A novel Cu/Pd-catalyzed chemoselective synthesis of C-3 dicarbonyl indoles and bis(indolyl)alkanes from aldehydes and indoles has been achieved, which has good substrate universality and high efficacy on large-scale.

A benzofuran-β-alaninamide based “turn-on” fluorescent chemosensor for selective recognition of Fe3+ ions

A benzofuran-β-alaninamide based chemosensor, 3-(3-((4-methylbenzyl)amino)propanamido)benzofuran-2-carboxamide (BAA), was designed and synthesized for selective detection of Fe³⁺ ions.

Benzofuran hydrazones as potential scaffold in the development of multifunctional drugs: Synthesis and evaluation of antioxidant, photoprotective and antiproliferative activity

New benzofuranhydrazones 3-12 were easily prepared and assayed for their radical-scavenging ability. Hydrazones 3-12 showed different extent antioxidant activity in DPPH, FRAP and ORAC assays. Good antioxidant activity is related to the number and position of hydroxyl groups on the arylidene moiety. High antioxidant activity is showed by the 2-hydroxy-4-(diethylamino)benzylidene derivative 11. Furthermore, hydrazones 3-12 showed photoprotective capacities with satisfactory in vitro SPF as compared to the commercial PBSA sunscreen filter. The antiproliferative effects of the hydrazones 3-12 was tested on erythroleukemia K562 and Colo-38 melanoma human cells. All the compounds showed growth inhibition in the micromolar to sub micromolar concentration range. If taken together these results points to benzofuran hydrazones as potential multifunctional molecules especially in the treatment of neoplastic diseases being the good antioxidant properties of 5, 7 and 11 correlated to their high antiproliferative activity.

Triazole-diindolylmethane conjugates as new antitubercular agents: synthesis, bioevaluation, and molecular docking

We describe the synthesis of novel triazole-incorporated diindolylmethanes (DIMs) using a molecular hybridization approach. The in vitro antitubercular activity of the DIMs against Mycobacterium tuberculosis H37Ra (ATCC 25177) was tested in the active and dormant state. Among all the synthesized conjugates, the compounds 6b, 6f, 6l, 6n, 6q, 6r, and 6s displayed good antitubercular activity against both the active and dormant Mtb H37Ra strain. The compound 6l exhibited good antitubercular activity against dormant Mtb H37Ra with an IC₅₀ value of 1 μg mL^-1 and IC₉₀ (MIC) value of 3 μg mL^-1. The compounds 6b, 6l, and 6r displayed good antitubercular activity against active Mtb H37Ra with IC₅₀ values of 2.19, 1.52, and 0.22 μg mL^-1, respectively. The compounds 6b, 6h, 6l, and 6s displayed more than 70% inhibition against the Gram-positive Bacillus subtilus strain at 3 μg mL^-1. The molecular docking study showed the binding modes of the titled compounds in the active site of the DprE1 enzyme and assisted with elucidating a structural basis for the inhibition of Mycobacteria.

Transition-metal-free base catalyzed intramolecular cyclization of 2-ynylphenols for efficient and facile synthesis of 2-substituted benzo[b]furans

An efficient and practical transition-metal-free synthesis of 2-substituted benzo[b]furans catalyzed by readily accessible base was developed with broad substrates scope.

Photoredox Catalysis Induced Bisindolylation of Ethers/Alcohols via Sequential C-H and C-O Bond Cleavage

A visible-light-engaged 2-fold site-selective alkylation of indole derivatives with aliphatic ethers or alcohols has been accomplished for easy access to symmetric 3,3'-bisindolylmethane derivatives. The experimental data suggest a sequential photoredox catalysis induced radical addition and proton-mediated Friedel-Crafts alkylation mechanism.

Benzofuran-dihydropyridine hybrids: A new class of potential bone anabolic agents

A series of novel benzofuran-dihydropyridine hybrids were designed by molecular hybridization approach and evaluated for bone anabolic activities. Among the screened library, ethyl 4-(7-(sec-butyl)-2-(4-methylbenzoyl)benzofuran-5-yl)-2-methyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate (compound 21) significantly enhanced the ALP production and mineralized nodule formation, which are primary requisites in the process of in vitro osteogenesis. Oral administration of compound 21 at 10 mg.kg^-1 day^-1 for two weeks led to restoration of trabecular bone microarchitecture in drill hole fracture model by significantly increasing BV/TV and Tb.N. Furthermore, histological and molecular studies showed compound 21 triggering the new bone regeneration in a drill hole defect site by increasing BMP expression. Furthermore, molecular modeling studies were performed to gain insight into the binding approach, which revealed that both benzofuran and dihydropyridine moieties are essential to show similar binding interactions to fit into the active site of BMP2 receptor, an important target of the osteogenic agents. Our results suggest that compound 21 stimulates BMP2 synthesis in osteoblast cells that promotes new bone formation (∼40%) at the fracture site which helps in shorten the healing period.

A review on antioxidant potential of bioactive heterocycle benzofuran: Natural and synthetic derivatives

The majority of heterocycle compounds and typically common heterocycle fragments present in most pharmaceuticals currently marketed, alongside with their intrinsic versatility and unique physicochemical properties, have poised them as true cornerstones of medicinal chemistry. In this context, oxygen heterocycles exhibit diverse biological and pharmacological activities due in part to the similarities with many natural and synthetic molecules with known biological activity. Among oxygen containing heterocycles, benzofuran (synthetic and natural isolated) and its derivatives have attracted medicinal chemists and pharmacologists due to their pronounced biological activities and their potential applications as pharmacological agents such as antioxidant, antitumor, antiplatelet, antimalarial, antiinflammatory, antidepressant and anticonvulsant properties. There are also an amazing number of approved benzofuran-containing drugs in the market as well as compounds currently going through different clinical phases or registration statuses. Due to the wide range of biological activities of benzofurans, their structure activity relationships have generated interest among medicinal chemists, and this has culminated in the discovery of several lead molecules in numerous disease conditions. Recently, this scaffold has emerged as a pharmacophore of choice for designing antioxidant drug development as their derivatives have shown excellent results through different mechanism of action. This review focused on the recent development of benzofuran derivatives as antioxidant agents (including natural products) and their antioxidant activities; summarize the structure property, hoping to inspire new and even more creative approaches. Also, this study systematically provides a comprehensive report on current developments in benzofuran-based compounds as antioxidant agents and is also helpful for the researchers working on a substitution pattern around the nucleus, with an aim to help medicinal chemists to develop structure activity relationships (SAR) on these derivatives as antioxidant drugs.

Synthesis of pyrazolylbisindoles over mesoporous Lewis acidic ZrTUD-1: Potential application in selective Cu(2+) colorimetric detection

A series of pyrazolylbisindole (PBI) derivatives were prepared by simple condensation of indole and pyrazole aldehyde utilizing amorphous mesoporous ZrTUD-1 having predominant Lewis acid sites. The applicability of pyrazolylbisindolyl derivate as a colorimetric chemosensor with high selectivity toward Cu(2+) over other cations were tested. Among heavy and transition metal (HTM) ions in CH3CN solution, the probe only sensed Cu(2+) detectable by naked eye. The sensor exhibited a new absorption band at 488 nm (a red shift of 206 nm from 282 nm) with a large colorimetric response and affinity to Cu(2+) over other cations tested (Al(3+), Pb(2+), Cd(2+), Mg(2+), Mn(2+), Zn(2+), K(+), Fe(2+), Ca(2+), Cu(2+) and Hg(2+)).

Synthesis and pharmacological evaluation of novel bisindole derivatives bearing oximes moiety: identification of novel proapoptotic agents

In an effort to develop potent anti-cancer chemopreventive agents, a novel series of bisindole derivatives bearing oxime moiety were synthesized. Structures of all compounds were characterized by NMR and HRMS. Anti-proliferative activities for all of these compounds were investigated by the method of MTT assay on 7 human cancer lines and the normal cell lines (HUVEC). Most of them showed a noteworthy anti-cancer activity in vitro, the half maximal inhibitory concentration (IC50) value is 4.31 μM of 4e against T24. The results from Hoechst 33258 and acridine orange/propidium iodide staining as well as annexinV-FITC assays provided evidence for an apoptotic cell death. The further mechanisms of compound 4e-induced apoptosis in T24 cells demonstrated that compound 4e induced the productions of ROS, and altered anti- and pro-apoptotic proteins, leading to mitochondrial dysfunction and activations of caspase-9 and caspase-3 for causing cell apoptosis. Moreover, the cell cycle analysis and western-blot analysis indicated that compound 4e effectively arrested T24 cells in G1 stage and possibly has an effect on cell cycle regulatory proteins particularly cyclin D1.

R. C, Chand K, Santos MA, Keri RS. Benzofuran: an emerging scaffold for antimicrobial agents

The present article systematically gives a comprehensive review of current development of benzofuran-based compounds as antimicrobial agents and the perspectives that they hold for future research.

Benzofuran-chalcone hybrids as potential multifunctional agents against Alzheimer's disease: synthesis and in vivo studies with transgenic Caenorhabditis elegans

In the search for effective multifunctional agents for the treatment of Alzheimer's disease (AD), a series of novel hybrids incorporating benzofuran and chalcone fragments were designed and synthesized. These hybrids were screened by using a transgenic Caenorhabditis elegans model that expresses the human β-amyloid (Aβ) peptide. Among the hybrids investigated, (E)-3-(7-methyl-2-(4-methylbenzoyl)benzofuran-5-yl)-1-phenylprop-2-en-1-one (4 f), (E)-3-(2-benzoyl-7-methylbenzofuran-5-yl)-1-phenylprop-2-en-1-one (4 i), and (E)-3-(2-benzoyl-7-methylbenzofuran-5-yl)-1-(thiophen-2-yl)prop-2-en-1-one (4 m) significantly decreased Aβ aggregation and increased acetylcholine (ACh) levels along with the overall availability of ACh at the synaptic junction. These compounds were also found to decrease acetylcholinesterase (AChE) levels, reduce oxidative stress in the worms, lower lipid content, and to provide protection against chemically induced cholinergic neurodegeneration. Overall, the multifunctional effects of these hybrids qualify them as potential drug leads for further development in AD therapy.

Synthesis and evaluation of new 3-phenylcoumarin derivatives as potential antidepressant agents

A series of amine substituted 3-phenyl coumarin derivatives were designed and synthesized as potential antidepressant agents. In preliminary screening, all compounds were evaluated in forced swimming test (FST), a model to screen antidepressant activity in rodents. Among the series, compounds 5c and 6a potentially decreased the immobility time by 73.4% and 79.7% at a low dose of 0.5 mg/kg as compared to standard drug fluoxetine (FXT) which reduced the immobility time by 74% at a dose of 20 mg/kg, ip. Additionally, these active compounds also exhibited significant efficacy in tail suspension test (TST) (another model to screen antidepressant compounds). Interestingly, rotarod and locomotor activity tests confirmed that these two compounds do not have any motor impairment effect and neurotoxicity in mice. Our studies demonstrate that the new 3-phenylcoumarin derivatives may serve as a promising antidepressant lead and hence pave the way for further investigation around this chemical space.

Synthesis of new N-acryl-1-amino-2-phenylethanol and N-acyl-1-amino-3-aryloxypropanols and evaluation of their antihyperlipidemic, LDL-oxidation and antioxidant activity

As a part of our drug discovery program, we identified an alkaloidal amide i.e. Aegeline (V) isolated from the leaves of Aegle marmelos as a dual acting agent (antihyperlipidemic and antihyperglycemic). In continuation of this program, we synthesized new N-acyl-1-amino-2-alcohols (N-acrylated-1-amino-2-phenylethanol and N-acylated-1-amino-3-aryloxypropanols) via Ritter reaction and screened for their in-vivo antihyperlipdemic activity in Triton induced hyperlipidemia model, LDL-oxidation and antioxidant activity. Compounds 3, 11 and 13 showed good antihyperlipidemic activity, LDL-oxidation as well as antioxidant activity and comparable activity with marketed antidyslipidemic drug.