Synthesis and structure-activity relationships of the first ferrocenyl-aryl-hydantoin derivatives of the nonsteroidal antiandrogen nilutamide

Design, synthesis and biological evaluation of novel 4,6-dimorpholino-1,3,5-triazin-2-amine ferrocenecarboxylate derivatives as potent PI3K inhibitors

Inhibitors of Phosphatidylinositol-3-kinase (PI3K) represent a classical tumor-specific therapeutic strategy that exerts anti-tumor effects by blocking the PI3K/AKT/mTOR signaling pathway involved in cancer cell proliferation and survival. However, their clinical efficacy is restricted by resistance mechanisms that are both inherent and acquired, including PI3K self-activation, activation of parallel signaling pathways, and the impact of the tumor microenvironment. Inspired by chemodynamic therapy, a series of ferrocene-modified PI3K inhibitors were synthesized for the first time in this study. These inhibitors were designed by combining the targeting properties of PI3K inhibitors with the chemokinetic effects of ferrocene and demonstrated to exhibit both PI3K-dependent inhibitory effects and PI3K-independent cytotoxicity in the evaluation. In vitro experiments showed that compound 3d possessed excellent antiproliferative activity against breast cancer 4T1 cells (IC50 = 3.70 ± 1.21 μM) and colon cancer CT26 cells (IC50 = 1.98 ± 1.33 μM). Further in vivo assays also proved that compound 3d exhibited good antitumor activity, which is worth further studies.

Structural Development of Androgen Receptor Antagonists Using Phenylferrocene Framework as a Hydrophobic Pharmacophore

We previously identified nitrophenylferrocenes and cyanophenylferrocenes as promising lead structures of novel androgen receptor (AR) antagonists, based on the structural similarity between ferrocene and the steroidal skeleton. In the present research, we explored the structure-activity relationship (SAR) of phenylferrocene derivatives. Introduction of a hydrophobic substituent such as a chlorine atom at the 2-position or 3-position of phenylferrocene derivatives significantly increased the antagonistic activity toward wild-type AR, and among the synthesized compounds, 3-chloro-4-cyanophenylferrocene (29) exhibited the most potent anti-proliferative activity toward the androgen-dependent growth of SC-3 cells expressing wild-type AR (IC50 14 nM). Like conventional antiandrogens such as hydroxyflutamide, the major active metabolite of flutamide, compound 29 exhibited agonistic activity toward T877A-AR, a mutant AR expressed in human prostate cancer cell line LNCaP. Notably, however, the 2-chloro isomer 27 showed potent antagonistic activity toward wild-type AR (IC50 49 nM) and also exhibited antagonistic activity toward T877A-AR. Our SAR data should prove helpful for the development of new-generation AR antagonists based on phenylferrocene as candidate agents to treat drug-resistant prostate cancer.

A review on metal complexes and its anti-cancer activities: Recent updates from in vivo studies

Research into cancer therapeutics has uncovered various potential medications based on metal-containing scaffolds after the discovery and clinical applications of cisplatin as an anti-cancer agent. This has resulted in many metallodrugs that can be put into medical applications. These metallodrugs have a wider variety of functions and mechanisms of action than pure organic molecules. Although platinum-based medicines are very efficient anti-cancer agents, they are often accompanied by significant side effects and toxicity and are limited by resistance. Some of the most studied and developed alternatives to platinum-based anti-cancer medications include metallodrugs based on ruthenium, gold, copper, iridium, and osmium, which showed effectiveness against many cancer cell lines. These metal-based medicines represent an exciting new category of potential cancer treatments and sparked a renewed interest in the search for effective anti-cancer therapies. Despite the widespread development of metal complexes touted as powerful and promising in vitro anti-cancer therapeutics, only a small percentage of these compounds have shown their worth in vivo models. Metallodrugs, which are more effective and less toxic than platinum-based drugs and can treat drug-resistant cancer cells, are the focus of this review. Here, we highlighted some of the most recently developed Pt, Ru, Au, Cu, Ir, and Os complexes that have shown significant in vivo antitumor properties between 2017 and 2023.

Two dimensional architectures of graphitic carbon nitride with the substitution of heteroatoms for bifunctional electrochemical detection of nilutamide

The exploration of graphitic carbon nitride (g-C₃N₄), a two-dimensional (2D) metal-free polymer semiconducting material, is largely discussed due to its large specific surface area, high electrical conductivity, thermal stability, and adaptable electronic structure. The adaption of sulfur (S) and phosphorous (P) atoms into the layers of g-C₃N₄ increases the electrochemical performance of detecting nilutamide (NT). The aggregation severity can be decreased by integrating S/P into g-C₃N₄, thereby improving surface area and electrical conductance. The g-C₃N₄, S/gC₃N₄, P/g-C₃N₄, and S/P/g-C₃N₄ were studied with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), Fourier transform infrared (FTIR), Ultraviolet visible spectroscopy (UV), Thermogravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET). The well-assigned S/P/g-C₃N₄ exhibited a good crystalline structure with more active sites for improved electron transfer toward NT detection. Both differential pulse voltammetry (DPV) and amperometry (IT) was studied for NT detection. The electrochemical studies were done with a linear range of 0.019-1.17 μM to 5.36-1891.98 μM in DPV and 0.01 μM-158.3 μM in IT technique. The attained limit of detection in DPV analysis was 3.2 nM and with IT analysis 2.4 nM. The nanocomposite S/P/g-C₃N₄ shows good selectivity towards NT. The fabricated electrode showed excellent repeatability, reproducibility, and stability, with a significant recovery range in real sample analysis.

Targeting androgen receptor degradation with PROTACs from bench to bedside

Inhibition of androgen receptor (AR) has been extensively investigated to treat prostate cancer. Resistance mechanisms such as increased levels of androgen production, increased AR gene, enhancer expression and AR point mutations always reduce the clinical efficacy. Design and discovery of small-molecule PROTAC AR degraders have been pursued as a new therapeutic strategy to overcome common resistance mechanisms developed during prostate cancer treatment. In the last two decades, potent and efficacious PROTAC AR degraders have been gotten rapid development and several such compounds have been advanced into preclinical phase and phase I/II trials for the treatment of human prostate cancers. Especially, the first PROTAC to enter the clinic, ARV-110, has shown good clinical effects in patients with mCRPC. This fully demonstrates the high clinical value of PROTAC strategy in treatment of human diseases. Here, we summarized the recent advances in the development of these potential clinical-stage PROTAC AR degraders.

Structural activity relationship of metallo-aminoquines as a next generation antimalarials

Apicomplexian parasite of the genus Plasmodium is the causative agent of malaria, one of the most devastating, furious and common infectious disease throughout the world. According to the latest World malaria report, there were 229 million cases of malaria in 2019 majorly consisting of children under 5 years of age. Some of known analogues viz. quinine, quinoline-containing compounds have been used for last century in the clinical treatment of malaria. Past few decades have witnessed the emergence of multi-drug resistance (MDR) strains of Plasmodium species to existing antimalarials pressing the need for new drug candidates. For the past few decades bioorganometallic approach to malaria therapy has been introduced which led to the discovery of noval metalcontaining aminoquinolines analogues viz. ferroquine (FQ or 1), Ruthenoquine (RQ or 2) and other related potent metal-analogues. It observed that some metal containing analogues (Fe-, Rh-, Ru-, Re-, Au-, Zn-, Cr-, Pd-, Sn-, Cd-, Ir-, Co-, Cu-, and Mn-aminoquines) were more potent; however, some were equally potent as Chloroquine (CQ) and 1. This is probably due to the intertion of metals in the CQ via various approaches, which might be a very attractive strategy to develop a SAR of novel metal containing antimalarials. Thus, this review aims to summarize the SAR of metal containing aminoquines towards the discovery of potent antimalarial hybrids to provide an insight for rational designs of more effective and less toxic metal containing amoniquines.

Transamidation and Decarbonylation of N-Phthaloyl-Amino Acid Amides Enabled by Palladium-Catalyzed Selective C-N Bond Cleavage

Amides are important functional synthons that have been widely used in the construction of peptides, natural products, and drugs. The C-N bond cleavage provides the direct method for amide conversion. However, amides, especially secondary amides, tend to be chemically inert due to the resonance of the amide bond. Here, we describe an efficient Pd-catalyzed transamidation and decarbonylation of multiamide structure molecules through C-N bond cleavage with excellent chemoselectivity. The transamidation of secondary amides and the decarbonylation of phthalimide provide meaningful tools for the modification of amino acid derivatives. Moreover, further transformations of azidation and C(sp³)-H monoarylation emphasized the potential utility of this selective C-N bond cleavage method.

Has Ferrocene Really Delivered Its Role in Accentuating the Bioactivity of Organic Scaffolds?

Ferrocene is an important structural core in bioorganometallic chemistry because of its inherent stability, excellent redox properties, and low toxicity. Ferroquine and ferrocifen are two of the most notable contributions of ferrocene to medicinal chemistry with remarkable antimalarial and anticancer properties. The improved medicinal properties of these drug candidates highlight the impact that ferrocene can have on the molecular and biological properties of the bioactive compounds. In this Perspective, we investigate the scope and limitations of ferrocene incorporation into organic compounds/natural products on their mode of action and biological activities. We have also discussed the detailed role of ferrocene modifications in influencing the anticancer, antimalarial, and antimicrobial properties of various bioactive moieties to design safer and promising ferrocene-based drugs.

Structure-property and structure-activity relationships of phenylferrocene derivatives as androgen receptor antagonists

Ferrocene is a representative organometallic compound having a sandwich structure with high stability and hydrophobicity. In this study, we determined the physicochemical properties of a series of nitro- and cyanophenylferrocenes, and evaluated their biological activity as androgen receptor (AR) antagonists. Ferrocene derivatives exhibited hydrophobicity parameter π values in the range between 2.54 and 3.23, depending on the substituents, indicating that the hydrophobicity of ferrocene is suitable for its application as a hydrophobic core structure of nuclear receptor ligands. The synthesized ferrocene derivatives showed AR-antagonistic activity, and among them, 3-nitrophenylferrocene 14 exhibited the most potent activity with an IC₅₀ value of 0.28 μM. The developed compounds may be candidates for further structural development as AR antagonists. These findings also support the utility of organometallic species as structural options for drug discovery.

Rational design and preparation of copper vanadate anchored on sulfur doped reduced graphene oxide nanocomposite for electrochemical sensing of antiandrogen drug nilutamide using flexible electrodes

Copper vanadate nanoparticles (Cu₂V₂O₇) are synthesized by using a simple hydrothermal method and later anchored with sulfur-doped reduced graphene oxide (S-rGO) by using ultrasonication to form a hybrid nanocomposite. The synthesized composite underwent characterizations like X-ray diffraction analysis (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), Dynamic ray scattering-Ultra violet-visible spectroscopy (DRS-UV-visible) and X-ray photoelectron spectroscopically revealed the triclinic pattern of the P 1̅ space group of α-Cu₂V₂O₇ and the reduced oxygen deficiency state of metal centers (Cu⁺ or V⁴⁺) resulting with oxides of mixed-valence oxidative states and forming of Cu-O bond. Morphological analysis was carried out by using transmission electron microscopy (TEM) and Field emission scanning electron microscopy (FE-SEM) with elemental mapping and EDX analysis. Furthermore, a novel electrochemical sensor is prepared by using the hybrid sCu₂V₂O₇/S-rGO nanocomposite on to a disposable screen-printed carbon paste electrode (SPCE) for electrochemical sensing of antiandrogen drug nilutamide (NLT). This report reveals excellent activity in determining NLT with a low detection limit of 0.00459 nM for the linear range of 0.001-15 μM with high sensitivity of 26.2605 µA µM^-1 cm^-2. Further, electrode performance showed appreciable performance in real-time monitoring of biological samples like human blood serum, urine samples.

Cu-catalyzed N-3-Arylation of Hydantoins Using Diaryliodonium Salts

A general Cu-catalyzed, regioselective method for the N-3-arylation of hydantoins is described. The protocol utilizes aryl(trimethoxyphenyl)iodonium tosylate as the arylating agent in the presence of triethylamine and a catalytic amount of a simple Cu-salt. The method is compatible with structurally diverse hydantoins and operates well with neutral aryl groups or aryl groups bearing weakly donating/withdrawing elements. It is also applicable for the rapid diversification of pharmaceutically relevant hydantoins.

Scope of organometallic compounds based on transition metal-arene systems as anticancer agents: starting from the classical paradigm to targeting multiple strategies

The advent of the clinically approved drug cisplatin started a new era in the design of metallodrugs for cancer chemotherapy. However, to date, there has not been much success in this field due to the persistence of some side effects and multi-drug resistance of cancer cells. In recent years, there has been increasing interest in the design of metal chemotherapeutics using organometallic complexes due to their good stability and unique properties in comparison to normal coordination complexes. Their intermediate properties between that of traditional inorganic and organic materials provide researchers with a new platform for the development of more promising cancer therapeutics. Classical metal-based drugs exert their therapeutic potential by targeting only DNA, but in the case of organometallic complexes, their molecular target is quite distinct to avoid drug resistance by cancer cells. Some organometallic drugs act by targeting a protein or inhibition of enzymes such as thioredoxin reductase (TrRx), while some target mitochondria and endoplasmic reticulum. In this review, we mainly discuss organometallic complexes of Ru, Ti, Au, Fe and Os and their mechanisms of action and how new approaches improve their therapeutic potential towards various cancer phenotypes. Herein, we discuss the role of structure-reactivity relationships in enhancing the anticancer potential of drugs for the benefit of humans both in vitro and in vivo. Besides, we also include in vivo tumor models that mimic human physiology to accelerate the development of more efficient clinical organometallic chemotherapeutics.

Imide arylation with aryl(TMP)iodonium tosylates

Herein, we describe the synthesis of N-aryl phthalimides by metal-free coupling of potassium phthalimide with unsymmetrical aryl(TMP)iodonium tosylate salts. The aryl transfer from the iodonium moiety occurs under electronic control with the electron-rich trimethoxyphenyl group acting as a competent dummy ligand. The yields of N-aryl phthalimides are moderate to high and the coupling reaction is compatible with electron-deficient and sterically encumbered aryl groups.

Azide-Alkyne Cycloaddition En Route to 1H-1,2,3-Triazole-Tethered Isatin-Ferrocene, Ferrocenylmethoxy-Isatin, and Isatin-Ferrocenylchalcone Conjugates: Synthesis and Antiproliferative Evaluation

Diverse series of isatin-ferrocene conjugates were synthesized via Cu-promoted azide-alkyne cycloaddition reaction with an aim of probing their antiproliferative structure-activity relationship against MCF-7 (estrogen receptor positive) and MDA-MB-231 (triple negative) cell lines. Among the synthesized conjugates, isatin-ferrocenes proved to be more potent against MCF-7, whereas ferrocenylmethoxy-isatins exhibited activity against MDA-MB-231 cell lines. However, the introduction of chalcone moiety among these hybrids resulted in the complete loss of activity against the tested cell lines, as evident by isatin-ferrocenylchalcones. The conjugates 5a and 9c proved to be the most potent among the series against MCF-7 and MDA-MB-213 cell lines, exhibiting IC₅₀ values of 31.62 and 20.26 μM, respectively.

A new generation of ferrociphenols leads to a great diversity of reactive metabolites, and exhibits remarkable antiproliferative properties

Organometallic compounds bearing the redox motif [ferrocenyl-ene-phenol] have very promising antiproliferative properties which have been further improved by incorporating pertinent substituents able to engender new mechanisms. Here we show that novel ferrociphenols bearing a hydroxypropyl chain exhibit strong antiproliferative effects, in most cases much better than those of cisplatin, tamoxifen, or of previously described ferrociphenols devoid of this terminal OH. This is illustrated, in the case of one of these compounds, by its IC50 values of 110 nM for MDA-MB-231 triple negative breast cancer cells and of 300 nM for cisplatin-resistant A2780cisR human ovarian cancer cells, and by its GI50 values lower than 100 nM towards a series of melanoma and renal cancer cell lines of the NCI-60 panel. Interestingly, oxidative metabolism of these hydroxypropyl-ferrociphenols yields two kinds of quinone methides (QMs) that readily react with various nucleophiles, such as glutathione, to give 1,6- and 1,8-adducts. Protonation of these quinone methides generates numerous reactive metabolites leading eventually to many rearrangement and cleavage products. This unprecedented and fully characterized metabolic profile involving a wide range of electrophilic metabolites that should react with cell macromolecules may be linked to the remarkable profile of antiproliferative activities of this new series. Indeed, the great diversity of unexpected reactive metabolites found upon oxidation will allow them to adapt to various situations present in the cancer cell. These data initiate a novel strategy for the rational design of anticancer molecules, thus opening the way to new organometallic potent anticancer drug candidates for the treatment of chemoresistant cancers.

Recent Advances in the Synthesis of Hydantoins: The State of the Art of a Valuable Scaffold

The review highlights the hydantoin syntheses presented from the point of view of the preparation methods. Novel synthetic routes to various hydantoin structures, the advances brought to the classical methods in the aim of producing more sustainable and environmentally friendly procedures for the preparation of these biomolecules, and a critical comparison of the different synthetic approaches developed in the last twelve years are also described. The review is composed of 95 schemes, 8 figures and 528 references for the last 12 years and includes the description of the hydantoin-based marketed drugs and clinical candidates.

Synthesis, characterization, optical and electrochemical properties and antifungal and anticancer activities of ferrocenyl conjugated novel dendrimers

A new class of triazoloferrocenyl conjugates was prepared by copper(i) catalyzed click chemistry, which shows good antifungal activity against fungal pathogens, and also shows excellent anticancer activity against MCF-7 cells.

Organometallic derivatives of natural products: dicobalt hexacarbonyl complexes of geranyl-alkynes

Di- and tri-cobalt carbonyl clusters bearing geranyl or neryl substituents offer potential routes to novel terpenoid systems.

Expanding the chemical space of hydrophobic pharmacophores: the role of hydrophobic substructures in the development of novel transcription modulators

Interactions between biologically active compounds and their targets often involve hydrophobic interactions, and hydrophobicity also influences the pharmacokinetic profile.

Recent advances in iron complexes as potential anticancer agents

The iron complexes discussed in this review highlight their promising future as anticancer agents.

Ferrocene incorporated selenoureas as anticancer agents

For a compound to be a best chemopreventive agent it should be a descent DNA binder and at the same time should be active against any of the three stages of carcinogenesis i.e. cancer initiation, cancer propagation and tumor growth. Most of the problems associated with chemotherapy can be overcome if the chemopreventive agent is active against all the three stages of cancer development. Cancer may be initiated by higher concentration of free radicals, inflammating agents and phase I enzymes (Cytochrome P450) in the body. Cancer propagation can be very efficiently controlled by inducing the phase II enzymes (glutathione S-transferases (GSTs), UDP-glucuronosyl transferases, and quinone reductases) in the body and cancer termination depends on the killing of the faulty cells i.e. cytotoxic actions. This article reports comprehensively the comparative DNA binding studies (with, cyclic voltammetry, UV-vis spectroscopy and viscometry), antioxidant activities (DPPH scavenging), anti-inflammatory activities (nitrite inhibition), phase I enzyme inhibition activities (aromatase inhibition), phase II enzyme induction studies (quinone reductase induction) and cytotoxic studies against neuroblastoma (MYCN2 and SK-N-SH), liver cancer (Hepa 1c1c7) and breast cancer (MCF-7) of seventeen ferrocene incorporated selenoureas.

Ferrocifen type anti cancer drugs

The mechanisms of action of ferrocifens depend on several features: chemical structures, used concentrations, nature of cancer cells.

1H-1,2,3-triazole tethered isatin-ferrocene conjugates: Synthesis and in vitro antimalarial evaluation

1H-1,2,3-triazole tethered isatin-ferrocene conjugates were synthesized and evaluated for their antiplasmodial activities against chloroquine-susceptible (3D7) and chloroquine-resistant (W2) strains of Plasmodium falciparum. The conjugates 5f and 5h with an optimum combination of electron-withdrawing halogen substituent at C-5 position of isatin ring and a propyl chain, introduced as linker, proved to be most potent and non-cytotoxic among the series with IC50 values of 3.76 and 4.58 μM against 3D7 and W2 strains, respectively.

Development of anticancer agents: wizardry with osmium

Platinum compounds are one of the pillars of modern cancer chemotherapy. The apparent disadvantages of existing chemotherapeutics have led to the development of novel anticancer agents with alternative modes of action. Many complexes of the heavy metal osmium (Os) are potent growth inhibitors of human cancer cells and are active in vivo, often superior or comparable to cisplatin, as the benchmark metal-based anticancer agent, or clinically tested ruthenium (Ru) drug candidates. Depending on the choice of ligand system, osmium compounds exhibit diverse modes of action, including redox activation, DNA targeting or inhibition of protein kinases. In this review, we highlight recent advances in the development of osmium anticancer drug candidates and discuss their cellular mechanisms of action.