Functionalized spirooxindole-indolizine hybrids: Stereoselective green synthesis and evaluation of anti-inflammatory effect involving TNF-α and nitrite inhibition

Discovery and evaluation of novel spiroheterocyclic protective agents via a SIRT1 upregulation mechanism in cisplatin-induced premature ovarian failure

Currently, no effective treatment exists for premature ovarian failure (POF). To obtain compounds with protective effects against POF, we aimed to design and synthesize a series of spiroheterocyclic protective agents with a focus on minimizing toxicity while enhancing their protective effect against cisplatin-induced POF. This was achieved through systematic modifications of Michael receptors and linkers within the molecular structure of 1,5-diphenylpenta-1,4-dien-3-one analogs. To assess the cytotoxicity and activity of these compounds, we constructed quantitative conformational relationship models using an artificial intelligence random forest algorithm, resulting in R2 values exceeding 0.87. Among these compounds, j2 exhibited optimal protective activity. It significantly increased the survival of cisplatin-injured ovarian granulosa KGN cells, improved post-injury cell morphology, reduced apoptosis, and enhanced cellular estradiol (E2) levels. Subsequent investigations revealed that j2 may exert its protective effect via a novel mechanism involving the activation of the SIRT1/AKT signal pathway. Furthermore, in cisplatin-injured POF in rats, j2 was effective in increasing body, ovarian, and uterine weights, elevating the number of follicles at all levels in the ovary, improving ovarian and uterine structures, and increasing serum E2 levels in rats with cisplatin-injured POF. In conclusion, this study introduces a promising compound j2 and a novel target SIRT1 with substantial protective activity against cisplatin-induced POF.

Leveraging Pyrazolium Ylide Reactivity to Access Indolizine and 1,2-Dihydropyrimidine Derivatives

N-Heterocyclic ylides are important synthetic precursors to rapidly build molecular complexity. Pyrazolium ylides have largely been unexplored, and we demonstrate their diverse utility in this report. We show that these readily accessible building blocks can be used to construct different heterocyclic skeletons by varying the coupling partner. Indolizines can be formed via an N-deletion type mechanism when reacting pyrazolium salts with electron deficient alkynes. 1,2-Dihydropyrimidines can be formed via a rearrangement mechanism when reacting pyrazolium ylides with isocyanates. These reactions enable access to valuable heteroarenes without the need for transition metal catalysis, high temperatures, or strong bases.

Tandem Reactions of Electrophilic Indoles toward Indolizines and Their Subsequent Transformations through Pd(II)-Mediated C-H Functionalization to Access Polyring-Fused N-Heterocycles

A simple and efficient synthetic approach for generating a library of structurally novel indolizines has been developed via sequential 1,3-dipolar cycloaddition-ring opening processes. Using this methodology, a series of indolizines bearing different substituents were made in moderate to good yields. The presence of two functionalizable C-H bonds in these indolizine motifs makes them attractive for accessing fused indolizine scaffolds. In this line, we have introduced palladium-mediated site-selective C-H functionalizations, where the N-center and the two C-H centers of the indolizine moiety can be readily functionalized to generate fused N-heterocycles. Utilizing a Pd-mediated dual C-H activation of 5-benzoyl-substituted indolizine afforded 6H-indeno-indolizine, and a tetracene, viz., indolizino[2,1-b]indoles, was produced in the same substrate by the Pd-catalyzed selective C-H amination in the presence of oxygen.

Antineoplastic indole-containing compounds with potential VEGFR inhibitory properties

Cancer is one of the most significant health challenges worldwide. Various techniques, tools and therapeutics/materials have been developed in the last few decades for the treatment of cancer, together with great interest, funding and efforts from the scientific society. However, all the reported studies and efforts seem insufficient to combat the various types of cancer, especially the advanced ones. The overexpression of tyrosine kinases is associated with cancer proliferation and/or metastasis. VEGF, an important category of tyrosine kinases, and its receptors (VEGFR) are hyper-activated in different cancers. Accordingly, they are known as important factors in the angiogenesis of different tumors and are considered in the development of effective therapeutic approaches for controlling many types of cancer. In this case, targeted therapeutic approaches are preferable to the traditional non-selective approaches to minimize the side effects and drawbacks associated with treatment. Several indole-containing compounds have been identified as effective agents against VEGFR. Herein, we present a summary of the recent indolyl analogs reported within the last decade (2012-2023) with potential antineoplastic and VEGFR inhibitory properties. The most important drugs, natural products, synthesized potent compounds and promising hits/leads are highlighted. Indoles functionalized and conjugated with various heterocycles beside spiroindoles are also considered.

C3-Spirooxindoles: Divergent chemical synthesis and bioactivities (2018-2023)

This scientific review documents the recent progress of C3-spirooxindoles chemistry (synthesis and reaction mechanism) and their bioactivities, focusing on the promising results as well as highlighting the biological mechanism via the reported molecular docking findings of the most bioactive derivatives. C3-Spirooxindoles are attractive bioactive agents and have been found in a variety of natural compounds, including alkaloids. They are widely investigated in the field of medicinal chemistry and play a key role in medication development, such as antivirals, anticancer agents, antimicrobials, etc. Regarding organic synthesis, several traditional and advanced strategies have been reported, particularly those that started with isatin derivatives.

Azomethine Ylides-Versatile Synthons for Pyrrolidinyl-Heterocyclic Compounds

Azomethine ylides are nitrogen-based three-atom components commonly used in [3+2]-cycloaddition reactions with various unsaturated 2π-electron components. These reactions are highly regio- and stereoselective and have attracted the attention of organic chemists with respect to the construction of diverse heterocycles potentially bearing four new contiguous stereogenic centers. This review article complies the most important [3+2]-cycloaddition reactions of azomethine ylides with various olefinic, unsaturated 2π-electron components (acyclic, alicyclic, heterocyclic, and exocyclic ones) reported over the past two decades.

Spirooxindole: A Versatile Biologically Active Heterocyclic Scaffold

Spirooxindoles occupy an important place in heterocyclic chemistry. Many natural spirooxindole-containing compounds have been identified as bio-promising agents. Synthetic analogs have also been synthesized utilizing different pathways. The present article summarizes the recent development of both natural and synthetic spirooxindole-containing compounds prepared from isatin or its derivatives reported in the last five years. The spirooxindoles are categorized based on their mentioned biological properties.

The crystal structure of dimethylammonium 8-[(7,9-dioxo-6,10-dioxaspiro[4.5]decan-8-ylidene)methyl]-9-oxo-6,10-dioxaspiro[4.5]dec-7-en-7-olate, C19H25NO8

C19H25NO8, monoclinic, P21/n (no. 14), a = 10.149(2) Å, b = 12.338(3) Å, c = 15.898(3) Å, β = 97.58(3)°, V = 1973.2(7) Å3, Z = 4, R gt (F) = 0.0581, wR ref (F 2) = 0.1842, T = 293(2) K.

Design of Novel Enantiopure Dispirooxindolopyrrolidine-Piperidones as Promising Candidates toward COVID-19: Asymmetric Synthesis, Crystal Structure and In Silico Studies

Despite the effectiveness of COVID-19 vaccines, there is still an urgent need for discovering new anti-viral drugs to address the awful spread and transmission of the rapidly modifiable virus. In this study, the ability of a small library of enantiomerically pure spirooxindolopyrrolidine-grafted piperidones to inhibit the main protease of SARS-CoV-2 (M^pro) is evaluated. These spiroheterocycles were synthesized by 1,3-dipolar cycloaddition of various stabilized azomethine ylides with chiral dipolarophiles derived from N-[(S)-(-)-methylbenzyl]-4-piperidone. The absolute configuration of contiguous carbons was confirmed by a single crystal X-ray diffraction analysis. The binding of these compounds to SARS-CoV-2 M^pro was investigated using molecular docking and molecular dynamics simulation. Three compounds 4a, 4b and 4e exhibited stable binding modes interacting with the key subsites of the substrate-binding pocket of SARS-CoV-2 M^pro. The synthesized compounds represent potential leads for the development of novel inhibitors of SARS-CoV-2 main protease protein for COVID-19 treatment.

Recent advances in the development of active hybrid molecules in the treatment of cardiovascular diseases

Multifactorial nature of the underlying pathophysiology of chronic disorders hinders in the effective treatment and management of many complex diseases. The conventional targeted therapies have limited applications due to highly complicated disease etiology. Cardiovascular diseases (CVDs) are the group of disorders of the heart and blood vessels. Currently, there is limited knowledge on the underlying cellular and molecular mechanisms of many of the CVDs due to their complex pathophysiology and co-morbidities. Their management with conventional medications results in failure due to adverse drug reactions and clinical specificity of solo-targeting drug therapy. Therefore, it is critical to introduce an alternative strategy to treat multi-factorial diseases. In the past few years, discovery and use of multi-targeted drug therapy with hybrid molecules have shown promising results with minimal side effects, and thus considered a most effective approach. In this review article, prominent hybrid molecules combining with different active moieties are reported to synergistically and simultaneously block different pathways involved in CVDs. Here, we provide a critical evaluation and discussion on their pharmacology with mechanistic insights and the structure activity relationship. The timely information provided in this article reveals the recent trends of molecular hybridization to the scientific community interested in CVDs and help them in designing the next generation of multi-targeting drug therapeutics.

Synthesis and evaluation of ursolic acid-based 1,2,4-triazolo[1,5-a]pyrimidines derivatives as anti-inflammatory agents

Here, two series of novel ursolic acid-based 1,2,4-triazolo[1,5-a]pyrimidines derivatives were synthesized and screened for their anti-inflammatory activity by evaluating their inhibition effect of using LPS-induced inflammatory response in RAW 264.7 macrophages in vitro; the effects of different concentrations of the compounds on the secretion of nitric oxide (NO) and inflammatory cytokines including TNF-α and IL-6 were evaluated. Their toxicity was also assessed in vitro. Results showed that the most prominent compound 3 could significantly decrease production of the above inflammatory factors. Docking study was performed for the representative compounds 3, UA, and Celecoxib to explain their interaction with cyclooxygenase-2 (COX-2) receptor active site. In vitro enzyme study implied that compound 3 exerted its anti-inflammatory activity through COX-2 inhibition.

Enantioselective Construction of Spirooxindole-Fused Cyclopentanes

The present study reports an asymmetric organocatalytic cascade reaction of oxindole derivates with α,β-unsaturated aldehydes efficiently catalyzed by simple chiral secondary amine. Spirooxindole-fused cyclopentanes were produced in excellent isolated yields (up to 98%) with excellent enantiopurities (up to 99% ee) and moderate to high diastereoselectivities. The synthetic utility of the protocol was exemplified on a set of additional transformations of the corresponding spiro compounds. In addition, a study showing the promising biological activity of selected enantioenriched products was accomplished.

TCCA-mediated oxidative rearrangement of tetrahydro-β-carbolines: facile access to spirooxindoles and the total synthesis of (±)-coerulescine and (±)-horsfiline

Multi-reactive centered reagents are beneficial in chemical synthesis due to their advantage of minimal material utilization and formation of less by-products. Trichloroisocyanuric acid (TCCA), a reagent with three reactive centers, was employed in the synthesis of spirooxindoles through the oxidative rearrangement of various N-protected tetrahydro-β-carbolines. In this protocol, low equivalents of TCCA were required to access spirooxindoles (up to 99% yield) with a wide substrate scope. Furthermore, the applicability and robustness of this protocol were proven for the gram-scale total synthesis of natural alkaloids such as (±)-coerulescine (1) and (±)-horsfiline (2) in excellent yields.

Three-reactive centered reagent (TCCA) mediated construction of spirooxindoles through an oxidative rearrangement of various N-protected tetrahydro-β-carbolines and total synthesis of natural alkaloids (±)-coerulescine and (±)-horsfiline.

Stereoselective synthesis and discovery of novel spirooxindolopyrrolidine engrafted indandione heterocyclic hybrids as antimycobacterial agents

Novel spirooxindolopyrrolidine embedded indandione heterocyclic hybrids were obtained in excellent yields via a regio- and stereoselective one-pot three component reaction between Baylis-Hillman adduct and non-stabilized azomethine ylides. The structure of newly synthesized compounds was elucidated through 1D and 2D spectroscopic data and the stereochemistry was determined by single crystal X-ray diffraction analysis. In vitro tubercular activity against Mycobacterium tuberculosis H37Rv using MABA assay reveals that the compound bearing chlorine substituted on the oxindole ring displayed the most potent activity with MIC 0.78 μg/mL and is two-fold active than the standard drug, ethambutol (MIC 1.56 μg/mL).

Transition metal-catalyzed synthesis of spirooxindoles

Spirooxindole is a principal bioactive agent and is observed in several natural products including alkaloids. They are broadly studied in the pharmaceutical field and have a significant role in the evolution of drugs such as anti-viral, anti-cancer, anti-microbial etc. In organic chemistry, an indispensable role is presented by transition metal catalysts. An effective synthetic perspective to spirooxindoles is the use of transition metals as the catalyst. This review discusses the synthesis of spirooxindoles catalyzed by transition metals and covers literature up to 2020.

Access to 6-hydroxy indolizines and related imidazo[1,5-a]pyridines through the SN2 substitution/condensation/tautomerization cascade process

A simple and efficient cascade reaction was developed for the construction of hydroxy substituted indolizines from pyrrole-2-carbaldehydes and commercially available 4-halogenated acetoacetic esters.

Highly stereoselective dearomative [3 + 2] cycloadditon of cyclic pyridinium ylides to access spiro-indolizidine scaffolds

A novel type of pyridinium salt bearing a EWG on the pyridine was developed as an efficient pyridinium ylide precursor in the [3 + 2] cycloaddition with nitroolefins to construct various spiro-indolizidine scaffolds via a dearomative pathway.

In-silico driven design and development of spirobenzimidazo-quinazolines as potential DNA gyrase inhibitors

DNA gyrase and Topoisomerase IV are promising antibacterial drug targets as they regulate bacterial DNA replication and topology. In a quest for novel DNA topoisomerase inhibitors, a multidisciplinary approach was adopted that involves computational prediction of binding sites and molecular modelling followed by green synthesis and biological evaluation of antibacterial activity of spirobenzimidazo quinazolines derivatives. Using basic quantum chemistry principles, we evaluated spirobenzimidazo quinazolines derivatives with their pharmacokinetic profiles. Based on the results of the aforesaid in-silico studies, we synthesized a series of titled compounds using green synthetic methodology that were validated as potential antimicrobial agents. Quantum chemoinformatics based predicted activity for the synthesized compounds 9b, 9c, and 9j was concomitant with biological evaluation of broadspectrum antibacterial activity. Biological evaluation revealed that inhibition of biofilm formation was due to their potential antibacterial activity. We believe that the novel spirobenzimidazo quinazolines have the potential to be alternatives to aminocoumarins and classical quinazolines upon detailed target specific biological studies.

Inhibitory activities of indolizine derivatives: a patent review

INTRODUCTION

Indolizines are structural isomers with indoles. Although several indole-based commercial drugs are available in the market, none of the indolizine-based drugs are available up-to-date. Natural and synthetic indolizines have a wide-range of pharmaceutical importance such as antitumor, antimycobacterial, antagonist, and antiproliferative activities. This prompted us to search and collect all possible data about the pharmacological importance of indolizine to open an avenue to the researchers in exploring more medicinal applications of such biologically important compounds.

AREAS COVERED

The current review article covers the advancements in the biological and pharmacological activities of indolizine-based compounds during the last decade. The covered areas of this work involved anticancer, anti-HIV-1, anti-inflammatory, antimicrobial, anti-tubercular, larvicidal, anti-schizophrenia, CRTh2 antagonist's activities in addition to enzymatic inhibitory activity.

EXPERT OPINION

The discovery of indolizine drugs will be a major breakthrough as compared with their widely available drug-containing indole isosteres. Major work collected here was focused on anticancer, anti-tubercular, anti-inflammatory, and enzymatic inhibitory activities. The SAR study of the reported biologically active indolizines is summarized throughout the review whenever highlighted to the rationale the behavior of inhibitory action. Several indolizines with certain functions provided great enhancement in the therapeutic activities comparing with reference drugs.

Synthesis, in vitro and in vivo biological evaluation of novel lappaconitine derivatives as potential anti-inflammatory agents

Lappaconitine (LA), a natural compound with a novel C18-diterpenoid alkaloid skeleton, displayed extensive biological profile. Recent research on LA is focused mainly on its anti-tumor and analgesic effects, and therefore we aimed to investigate its anti-inflammatory potential. A series of novel LA derivatives with various substituents on the 20-N position was designed and synthesized. In the initial screening of LA derivatives against NO production, all the target compounds, except compound E2, exhibited excellent inhibitory ability relative to that of LA. Particularly, compound A4 exhibited the most potent inhibition with IC₅₀ of 12.91 μmol/L. The elementary structure-activity relationships (SARs) of NO inhibitory activity indicated that replacement of the benzene ring with an electron donating group could improve the anti-inflammatory efficacy. Furthermore, compound A4 shows an anti-inflammatory mechanism by inhibiting NO, PGE2, and TNF-α generation via the suppression of NF-κB and MAPK signaling pathways. Notably, compound A4 could exert a significant therapeutic effect on LPS-induced acute lung injury (ALI) in vivo. Based on the above research, we further investigated the preliminary pharmacokinetic property of A4 in rats. Therefore, compound A4 could be a promising candidate for the development of anti-inflammatory agents in the future.

An overview of spirooxindole as a promising scaffold for novel drug discovery

Introduction: Spirooxindole, a unique and versatile scaffold, has been widely studied in some fields such as pharmaceutical chemistry and synthetic chemistry. Especially in the application of medicine, quite a few compounds featuring spirooxindole motif have displayed excellent and broad pharmacological activities. Many identified candidate molecules have been used in clinical trials, showing promising prospects.Areas covered: This article offers an overview of different applications and developments of spirooxindoles (including the related natural products and their derivatives) in the process of drug innovation, including such as in anticancer, antimicrobial, anti-inflammatory, analgesic, antioxidant, antimalarial, and antiviral activities. Furthermore, the crucial structure-activity relationships, molecular mechanisms, pharmacokinetic properties, and main synthetic methods of spirooxindoles-based derivatives are also reviewed.Expert opinion: Recent progress in the biological activity profiles of spirooxindole derivatives have demonstrated their significant position in present-day drug discovery. Furthermore, we believe that the multidirectional development of novel drugs containing this core scaffold will continue to be the research hotspot in medicinal chemistry in the future.

Access to highly enantioselective and diastereoselective spirooxindole dihydrofuran fused pyrazolones

Access to highly enantioselective and diastereoselective spirooxindole dihydrofuran fused pyrazolones from MBH-carbonates and pyrazole 4,5-diones.

An expeditious and environmentally benign synthesis of dispiro-3-phenylpyrrolothiazoles in ACI/EG eutectic mixture and its antioxidant and antimicrobial activities against urinary tract pathogens

The present study reveals the robust and facile methodology for the synthesis of massively selective dispiro-3-phenylpyrrolothiazole hybrids via one-pot 1,3-dipolar cycloaddition reaction by environmentally supported solvents and to evaluate their biological activities. The quaternary ammonium salt eutectic mixture, acetylcholine iodide-ethylene glycol (ACI/EG) medium brings an efficient environment for the synthesis of dispiropyrrolothiazole with excellent yield in shorter reaction time than imidazolium ionic liquids. The eutectic mixture was recovered and reused without any significant drop in their catalytic activity. Among the eight synthesized compounds 4a-h, halogen derivatives are exhibiting significant antimicrobial activities against selected uropathogens pathogens. Interestingly, chloro and bromo derivatives exhibits the minimum inhibitory concentration (MIC) of 12.5 μg/ml and 6.25 μg/ml towards Escherichia coli, Klebsiella pneumonia, and Staphylococcus aureus respectively. In addition, the IC50 values of DPPH radicals with synthesized compounds are interesting, particularly compounds 4a, 4d and 4e shows lower than the control BHA indicating their potent scavenging ability of free radicals.

Discovery and evaluation of novel synthetic 5-alkyl-4-oxo-4,5-dihydro-[1,2,4]triazolo[4,3-a]quinoxaline-1-carbox-amide derivatives as anti-inflammatory agents

To develop novel anti-inflammatory agents, a series of 5-alkyl-4-oxo-4,5-dihydro-[1, 2, 4]triazolo[4,3-a]quinoxaline-1-carboxamide derivatives were designed, synthesised, and evaluated for anti-inflammatory effects using RAW264.7 cells. Structures of the synthesised compounds were determined using ¹H NMR, ¹³C NMR, and HRMS. All the compounds were screened for anti-inflammatory activity based on their inhibitory effects against LPS-induced NO release. Among them, 5-(3,4,5-trimethoxybenzyl)-4-oxo-4,5-dihydro-[1, 2, 4]triazolo[4,3-a]quinoxaline-1-carboxamide (6p) showed the highest anti-inflammatory activity and inhibited NO release more potently than the lead compound D1. Further studies revealed that compound 6p reduced the levels of NO, TNF-α, and IL-6, and that its anti-inflammatory activity involves the inhibition of COX-2 and iNOS and downregulation of the mitogen-activated protein kinases (MAPK) signal pathway. Notably, compound 6p displayed more prominent anti-inflammatory activity than D1 and the positive control ibuprofen in the in vivo acute inflammatory model. Overall, these findings indicate that compound 6p is a therapeutic candidate for the treatment of inflammation.

Glucosamine-6-phosphate synthase inhibiting C3-β-cholesterol tethered spiro heterocyclic conjugates: Synthesis and their insight of DFT and docking study

A series of novel covalent cholesterol-spiro pyrrolidine/pyrrolizidine heterocyclic hybrids possessing biologically active oxindole, indanedione, and acenaphthylene-1-one have been synthesized by the reaction of C3-β-cholesteroalacrylate with heterocyclic di- and tri-ketones. All the sixteen compounds were obtained as a single isomer in good yield through a stereo- and regio- selective 1,3-dipolar cycloaddition methodology. Stereochemistry of the spiranic cycloadducts has been established by spectroscopic analysis and the regioselectivity outcome of the spiro adducts has been accomplished by DFT calculations at B3LYP/6-31G (d,p) level study. In vitro antibacterial activity of the newly synthesized cycloadducts were evaluated against highly pathogenic Gram-positive and Gram-negative bacteria and the most active compounds 5a, 13, and 14 underwent automated in silico molecular docking analysis in order to validate their effective orientation as a inhibitors bound in the active site of glucosamine-6-phosphate synthase (1XFF) enzyme by employing AutoDock Tools.

Synthesis of new ent-labdane diterpene derivatives from andrographolide and evaluation of their anti-inflammatory activities

Two series of andrographolide derivatives with nitrogen-containing heterocycles, phenols and aromatic acids as bioisostere moiety of lactone ring were synthesized. 8 from 18 tested compounds showed stronger inhibitory effect on LPS-induced NO production in RAW264.7 macrophage than hydrocortisone. Among them, compound 8m exhibited the most potent inhibition with IC₅₀ of 3.38 ± 1.03 μM. The structure-activity relationships (SARs) suggested that the replacement of lactone ring with small-molecule phenols could improve the anti-inflammatory efficacy. Furthermore, compound 8m significantly reduced the levels of pro-inflammatory cytokine IL-1β and IL-6 with no influence on cell survival, decreased the expression of iNOS and COX-2, and down-regulated the level and phosphorylation of IκBα, as well as the expression of NF-κB. Also it blocked the nuclear translocation of NF-κB in LPS-induced macrophage. Therefore, the anti-inflammation mechanism of compound 8m was related to the inhibition of COX-2, iNOS and NF-κB signal pathway.