Arbuzov Reaction Research Articles

Synthesis of novel chromenyl phosphonates via nano-ZnO-catalyzed microwave method: Exploring potential anti-diabetic agents through molecular docking, ADMET analysis, and α-amylase inhibition

A more efficient and environmentally friendly approach has been developed for synthesizing phosphonates through the Michaelis-Arbuzov reaction, catalyzed by nano-ZnO in a solvent-free environment, utilizing microwave irradiation. Before synthesis, each compound underwent in silico ADMET analysis and molecular docking to assess drug-like characteristics and their potential to inhibit α-amylase. The structure of the newly synthesized compounds was validated using spectroscopic analysis, and their in vitro inhibitory effects on α-amylase were assessed. Among the compounds, dimethyl 2-(anthracen-10-yl)-4-oxo-4H-chromen-6-yl-6-phosphonate (6j), dimethyl 2-(naphthalen-1-yl)-4-oxo-4H-chromen-6-yl-6-phosphonate (6h), and dimethyl 2-(1-methyl-1H-indol-3-yl)-4-oxo-4H-chromen-6-yl-6-phosphonate (6e) displayed the highest inhibitory activity compared to the reference substance, acarbose. Additionally, compounds dimethyl 2-(benzo[d][1,3]dioxol-4-yl)-4-oxo-4H-chromen-6-yl-6-phosphonate (6i), dimethyl 4-oxo-2-phenyl-4H-chromen-6-yl-6-phosphonate (6a), and dimethyl 2-(1H-indol-5-yl)-4-oxo-4H-chromen-6-yl-6-phosphonate (6g) exhibited nearly equivalent effective inhibitory activity when compared to the standard. The remaining compounds demonstrated moderate to good enzyme inhibition.

Calcium phosphate graphene with tailorable phosphate and oxygen content for increased osteogenic activity

The treatment of critical bone injuries using autografts and metallic hardware, though effective, carries drawbacks yet to be addressed by modern interventions. One way that researchers have sought to avoid these complications is using bioresorbable synthetic grafts. Ideally, these materials possess mechanical properties like that of bone and support the site of injury until absorbed and replaced by native bone. In this work we seek to continue the work of optimizing the synthesis of one synthetic graft candidate, calcium phosphate graphene (CaPG). CaPG is a functional graphenic material (FGM) made using the Arbuzov reaction to covalently seed polyphosphates on the graphenic backbone. This material releases calcium and phosphate ions and has been shown to induce osteogenesis. Herein, we investigate reaction conditions and demonstrate the ability to tailor the functionalization of CaPG. The differences in these properties were found to affect mechanical properties, ion elution, as well as calcium deposition of stem cells when measured via Alizarin Red S (ARS). These results continue to demonstrate the potential of CaPG scaffolds as tunable materials to promote bone regeneration.

Palladium-Catalyzed Decarbonylative Michaelis-Arbuzov Reaction of Carboxylic Acids and Triaryl Phosphites.

A Pd-catalyzed decarbonylative Michaelis-Arbuzov reaction of carboxylic acids and triaryl phosphites for preparing aryl phosphonates under anhydride-free conditions has been reported. In this context, triaryl phosphites serve as both reagents for activating the carboxylic acids and substrates for the reaction. There have been no reports to date of efficient and direct methods for the in situ activation of carboxylic acids using triaryl phosphites. In comparison to known methods, this reaction avoids the use of organohalides and has an excellent functional group tolerance for the synthesis of various aryl phosphonates from triaryl phosphites and carboxylic acids. This reaction is scalable and applicable to the synthesis of aryl phosphonates featuring bioactive fragments.

Multi-Substituted Phosphonated and Sulfonated Polymer Materials: Characterization and Blends with Basic Polymers

The growing demand for energy, limited resources, and climate warming call for alternative sustainable energy production. A promising candidate is the proton-exchange membrane fuel cell (PEMFC) using a proton conducting polymer as an electrolyte membrane. The most common proton-exchange membranes are based on sulfonated polymers, such as Nafion®. Since their proton conduction is driven by hydronium ions (H3O+) and hence require water, the operating temperature is limited to 100°C. Unlike in sulfonated polymer materials, the proton conduction in materials with phosphonic acid groups occurs via a hopping process and does not require water.1 This study introduces a highly substituted phosphonated and sulfonated polymer based on poly(pentafluorostyrene), which makes the material adaptable in anhydrous and hydrous operating conditions since the phosphonic acid and sulfonic acid units can conduct cooperatively. The phosphonic acid group is introduced via the nucleophilic aromatic substitution Michaelis-Arbuzov reaction. The Para-Fluoro-Thiol reaction was used to introduce sulfonic acid groups into the polymer backbone. In the past, both reaction steps were well investigated.2,3 The highly substituted polymer material was blended with a basic polymer to circumvent water solubility and investigated according to its proton conductivity, thermal stability, and mechanical properties.(1) Kumar, A. J. Mater. Chem. A 2020, 8 (43), 22632–22636. DOI: 10.1039/d0ta07732a.(2) Atanasov, V.; Oleynikov, A.; Xia, J.; Lyonnard, S.; Kerres, J. Journal of Power Sources 2017, 343, 364–372. DOI: 10.1016/j.jpowsour.2017.01.085.(3) Delaittre, G.; Barner, L. Polym. Chem. 2018, 9 (20), 2679–2684. DOI: 10.1039/c8py00287h.

Enhancement of Mass Transport in Catalyst Layers of HT-PEMFC with Tetrafluorophenyl Phosphonic Acid Binder.

The design and development of new and efficient catalyst binder materials are important for improving cell performance in high-temperature proton-exchange membrane fuel cells (HT-PEMFCs). In this study, a series of tetrafluorophenyl phosphonic acid-based binder materials (PF-y-P, y = 1, 0.83, and 0.67) with rigid structures and controllable degrees of phosphonation were prepared and used in HT-PEMFCs using the ultra-strong acid-catalyzed Friedel-Crafts reaction and the combined Michaelis-Arbuzov reaction. The samples exhibited high stability, low water uptake, superior proton conductivity, and cell performance. In addition, the oxygen mass transport properties of the PF-1-P binder were investigated using high-temperature microelectrode electrochemical testing techniques. Compared with the phosphoric acid-doped polybenzimidazole (PBI) binder, the O2 solubility of PF-1-P binder material increased by 30% (5.36 × 10-6 mol cm-3) and the PF-1-P binder material exhibited better cell stability in HT-PEMFCs. After 10.5 h of discharge at a constant current of 0.12 A cm-2, the MEA voltage decreased by 7.1% and 20.8% in case of the PF-1-P and PBI binders, respectively.

Catalysis of an SN2 pathway by geometric preorganization.

Bimolecular nucleophilic substitution (SN2) mechanisms occupy a central place in the historical development and teaching of the field of organic chemistry1. Despite the importance of SN2 pathways in synthesis, catalytic control of ionic SN2 pathways is rare and notably uncommon even in biocatalysis2,3, reflecting the fact that any electrostatic interaction between a catalyst and the reacting ion pair necessarily stabilizes its charge and, by extension, reduces polar reactivity. Nucleophilic halogenase enzymes navigate this tradeoff by desolvating and positioning the halide nucleophile precisely on the SN2 trajectory, using geometric preorganization to compensate for the attenuation of nucleophilicity4. Here we show that a small-molecule (646 Da) hydrogen-bond-donor catalyst accelerates the SN2 step of an enantioselective Michaelis-Arbuzov reaction by recapitulating the geometric preorganization principle used by enzymes. Mechanistic and computational investigations show that the hydrogen-bond donor diminishes the reactivity of the chloride nucleophile yet accelerates the rate-determining dealkylation step by reorganizing both the phosphonium cation and the chloride anion into a geometry that is primed to enter the SN2 transition state. This new enantioselective Arbuzov reaction affords highly enantioselective access to an array of H-phosphinates, which are in turn versatile P-stereogenic building blocks amenable to myriad derivatizations. This work constitutes, to our knowledge, the first demonstration of catalytic enantiocontrol of the phosphonium dealkylation step, establishing a new platform for the synthesis of P-stereogenic compounds.

Synthesis of Mesylated and Tosylated α-Hydroxy-Benzylphosphonates; Their Reactivity and Cytostatic Activity.

α-Hydroxyphosphonates and their acylated and phosphorylated derivatives may be of significant biological activity including cytotoxic effects. To extend the pool of the potentially bioactive species, new methane- and arenesulfonyloxyphosphonates were synthesized by the sulfonylation of differently substituted α-hydroxy-benzylphosphonates using methanesulfonyl chloride or p-toluenesulfonyl chloride at 25 °C in the presence of triethylamine in toluene. The new sulfonyl derivatives were obtained in 54-80% yields. In the case of the 4- or 2-methoxy substituent in the aromatic ring, surprisingly the corresponding α-chlorophosphonates were the exclusive products, whose formation was explained assuming a quinoid intermediate and supported by theoretical calculations. With a 3-methoxyphenyl substituent, the expected mesylation of the hydroxy group took place. Attempted alcoholyses of the diethyl α-methanesulfonyloxy-benzylphosphonates with different substituents in the benzyl ring at ∼140 °C in the presence of triethylamine under microwave irradiation left the P-function intact under the conditions applied, instead, the mesyloxy group was substituted by an alkoxy unit in a selective new reaction. The α-alkoxy-benzylphosphonates were isolated in 60-77% yields. While α-chloro- or α-bromo-benzylphosphonates proved to be rather inefficient in the Michaelis-Arbuzov reaction with triethyl phosphite, according to a new possibility, the α-methansulfonyloxy-benzylphosphonates underwent an efficient Arbuzov fission using the phosphite in excess at 135 °C. The arylmethylenebisphosphonates were obtained in yields of 76-81%. Bioactivity studies with the members of the phosphonate library revealed pronounced in vitro cytostatic effect of the α-hydroxy- and α-mesyloxy-3,5-di-tert-butylbenzylphosphonates on human breast carcinoma cell culture with IC50 values of 16.4 and 28.0 μM, respectively. The mesyloxy species was also cytostatic on melanoma cells (IC50 = 34.9).

Synthetic Methods for Azaheterocyclic Phosphonates and Their Biological Activity: An Update 2004-2024.

The increasing importance of azaheterocyclic phosphonates in the agrochemical, synthetic, and medicinal field has provoked an intense search in the development of synthetic routes for obtaining novel members of this family of compounds. This updated review covers methodologies established since 2004, focusing on the synthesis of azaheterocyclic phosphonates, of which the phosphonate moiety is directly substituted onto to the azaheterocyclic structure. Emphasizing recent advances, this review classifies newly developed synthetic approaches according to the ring size and providing information on biological activities whenever available. Furthermore, this review summarizes information on various methods for the formation of C-P bonds, examining sustainable approaches such as the Michaelis-Arbuzov reaction, the Michaelis-Becker reaction, the Pudovik reaction, the Hirao coupling, and the Kabachnik-Fields reaction. After analyzing the biological activities and applications of azaheterocyclic phosphonates investigated in recent years, a predominant focus on the evaluation of these compounds as anticancer agents is evident. Furthermore, emerging applications underline the versatility and potential of these compounds, highlighting the need for continued research on synthetic methods to expand this interesting family.

Photo‐Arbuzov Reactions as a Broadly Applicable Surface Modification Strategy

AbstractChemical vapor deposition (CVD) polymerization is a commonly used approach in surface chemistry, providing a substrate‐independent platform for bioactive surface functionalization strategies. This work investigates the Arbuzov reaction of halogenated polymer coatings readily available via CVD polymerization, using poly(4‐chloro‐para‐xylylene) (Parylene C) as a model substance. Postpolymerization modification of these coatings via catalyst‐free and UV‐induced Arbuzov reaction using phosphites results in phosphonate‐functionalized polymers. The combination of infrared reflection‐absorption spectroscopy (IRRAS), X‐ray photoelectron spectroscopy (XPS), and time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) provides detailed insights into the reaction progress. Time‐dependent studies suggest that the non‐polar phosphites penetrate deep into the CVD films and react with the polymer film. In addition, ToF‐SIMS, scanning electron microscopy (SEM), and atomic force microscopy (AFM) confirm spatial control of the reaction, resulting in localized chemical and topographical surface modification, recognizable by changes in interference color, fluorescence, and wettability. Preliminary 3D fluorescence spectroscopy investigations indicate tunable near‐infrared emission of these polymer films. This work is the first step toward generating multifunctional polymer coatings based on chemically modifiable, CVD polymers with potential applications in biomaterials, sensors, or optoelectronics.

Water-Promoted Mild and General Michaelis-Arbuzov Reaction of Triaryl Phosphites and Aryl Iodides by Palladium Catalysis.

A Pd-catalyzed relatively general Michaelis-Arbuzov reaction of triaryl phosphites and aryl iodides for preparing useful aryl phosphonates was developed. Interestingly, water can greatly facilitate the reaction through a water-participating phosphonium intermediate rearrangement process, which also makes the reaction conditions rather mild. In comparison with the known methods, this reaction is milder and more general, as it exhibits excellent functional group tolerance, can be applied to various triaryl phosphites and aryl iodides, and can be extended to aryl phosphonites and phosphinites. A gram-scale reaction with a low catalyst loading also revealed its practicality and potential in large-scale preparation.

Chemistry of (η6-C6Me6)Ru(Cl)2(P(OMe)3) with AgOTf in different solvents, the high affinity for traces of water and structural characterization of mono-, di- and trinuclear derivatives

An extensive study of the reactions of (η6-C6Me6)Ru(Cl)2(P(OMe)3) (1) with AgOTf in three different deuterated and non-deuterated solvents: chloroform, acetone and nitromethane is described. A series of compounds with the moiety (η6-C6Me6)Ru(P(OMe)3) is isolated and characterized, along with their crystalline structures. A simple associative step assisted by coordination of the silver cation to two molecules of 1 through the Cl-Ru-Cl bonds affords [{(η6-C6Me6)Ru(Cl)2(P(OMe)3)}2(μ-Ag)](OTf) (2), loss of AgCl from 2 gives 1 and (η6-C6Me6)RuCl(OTf)(P(OMe)3) (3), meanwhile 3 dimerizes to [(η6-C6Me6)Ru(μ-Cl)(P(OMe)3)]2(OTf)2 (4) which in presence of P(OMe)3 gives [(η6-C6Me6)RuCl(P(OMe)3)2](OTf) (11OTf). A comparative study of the influence of the counterions OTf− and BF4− was carried out with the analogue [(η6-C6Me6)RuCl(P(OMe)3)2](BF4) (11BF4), as well as the corresponding demethylation of the coordinated trimethylphosphite ligands by the classical Michaelis-Arbuzov reactions. The resulting “quasi-chelate” (η6-C6Me6)RuCl(P(O)(OMe)2)(P(OH)(OMe)2) (17) where a bridging proton in the phosphinito-phosphinous acid ligands is replaced by BF2 affords (η6-C6Me6)RuCl({P(OMe)2(O)}2BF2) (18) which contains the chelating structure [Me2POBF2OPMe2]. The chemistry in solution at room temperature of 1 with AgOTf shows non-selective reactions, as can be determined by multinuclear NMR spectroscopy (1H, 13C{1H}, 31P, 19F). The mixture of products shows a great preference to coordinate water, even when it is in traces, as observed for the formation of [(η6-C6Me6)RuCl(H2O)(P(OMe)3)](OTf) (5), [(η6-C6Me6)Ru(H2O)(OTf)(P(OMe)3)]OTf (6) and [(η6-C6Me6)Ru(H2O)2(P(OMe)3)](OTf)2 (7), being the latter 7 the “sink” product. Also, in presence of anhydrous AgOTf compound 1 can be transformed into the highly hygroscopic (η6-C6Me6)Ru(OTf)2(P(OMe)3) (8) which readily replaces triflate ligands by trace water. Structural characterization by single crystal X-ray diffraction of trinuclear compound 2, dinuclear 4 and mononuclear 7, 11X (X = OTf, BF4), 18 and nitrile derivatives [(η6-C6Me6)Ru(NCR)2(P(OMe)3)](OTf)2 (R = Et, 9; Me,10) is discussed.

Radical Arbuzov Reaction

Radical Arbuzov Reaction

Asymmetrically Substituted s-Triazine Phosphonates by One-Step Synthesis.

Asymmetrically substituted s-triazine phosphonates with up to three different phosphonate groups C3 N3 RR'R" with R, R', R"=PO(OR"') and R"'=for example, methyl, ethyl, isopropyl or n-butyl are interesting as polymer additives like flame retardants. Typically, these compounds are obtained by multiple synthesis steps. However, this leads to high production costs, which are a disadvantage for commercial use. Here we report the one-step synthesis of mixtures of asymmetrical s-triazine phosphonates which is an easy way to adjust the thermal behaviour and other properties such as viscosities of the compounds. The synthesis is based on a Michaelis-Arbuzov reaction. A complete conversion of the reactants to the target compounds is observed which was proofed by detailed 1 H, 13 C and 31 P NMR investigations and elemental analysis. The thermal behaviour was compared with thermogravimetric analysis (TGA).

Phosphorus fluoride exchange: Multidimensional catalytic click chemistry from phosphorus connective hubs

Phosphorus Fluoride Exchange (PFEx) represents a cutting-edge advancement in catalytic click-reaction technology. Drawing inspiration from Nature's phosphate connectors, PFEx facilitates the reliable coupling of P(V)-F loaded hubs with aryl alcohols, alkyl alcohols, and amines to produce stable, multidimensional P(V)-O and P(V)-N linked products. The rate of P-F exchange is significantly enhanced by Lewis amine base catalysis, such as 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). PFEx substrates containing multiple P-F bonds are capable of selective, serial exchange reactions via judicious catalyst selection. In fewer than four synthetic steps, controlled projections can be deliberately incorporated along three of the four tetrahedral axes departing from the P(V) central hub, thus taking full advantage of the potential for generating three-dimensional diversity. Furthermore, late-stage functionalization of drugs and drug fragments can be achieved with the polyvalent PFEx hub, hexafluorocyclotriphosphazene (HFP), as has been demonstrated in prior research.

An Alternative to the Arbuzov Reaction: Generation and Transformation of α-Dialkyl-Substituted Methylphosphonate Carbanions via an SET Reduction Process

AbstractWith B-alkyl Suzuki cross-coupling as the strategy, 1-alkyl-substituted ethenylphosphonates could be efficiently accessed via palladium­-catalyzed reactions of α-phosphonovinyl tosylates with B-alkyl-9-borabicyclo[3.3.1]nonane (B-alkyl-9-BBN). Using the α-alkylethenylphosphonates as radical acceptors, visible-light-driven photocatalytic Giese-type and cyclopropanation reactions based on reductive radical-polar crossover have been successfully developed. The redox-neutral photocatalysis serves as a viable strategy for the preparation of various 1,1-dialkyl-substituted methylphosphonates and 1-alkylcyclopropylphosphonates.

Access to new phosphonate- and imidazolidine-benzopyrimidinone derivatives as antityrosinase and anti-acetylcholinesterase agents: Design, synthesis and molecular docking

To discover new acetylcholinesterase and tyrosinase inhibitors, a series of dialkyl phosphonate-benzopyrimidinones 4a-b was prepared via Michaelis-Arbuzov rearrangement (Arbusov reaction) of benzopyrimidinone chloride 2 with trialkyl phosphate, as well as a series of imidazolidine-benzopyrimidinone derivatives 5a-g synthesized by Mannich reaction of 2-((arylamino)methyl) benzopyrimidin-4(3H)-one 3 with formaldehyde. The structures of the new target compounds were investigated by 1H NMR, 13C NMR and ESI-HRMS. All synthesized compounds were evaluated for their anti-acetylcholinesterase and antityrosinase activities. Compounds 5f, 3g and 4b showed the highest tyrosinase inhibition and compounds 3g, 3d and 5g were found to be the most anti-acetylcholinesterase agents. Moreover, structure activity relationship (SAR) was discussed for all synthesized compounds and the interaction modes of the most potent inhibitors were confirmed through molecular docking studies.

Recent Advances in the Synthesis of 5'-deoxynucleoside Phosphonate Analogs.

The present review focuses on the synthesis of cyclic 5'-deoxynucleoside phosphonate analogs. The formation of various phosphonate alkyl moieties is accomplished through (i) Wittig (or HWE) type condensation to the nucleoside aldehyde moiety; (ii) nucleophilic displacement reaction using phosphonate anion or Lewis acid; (iii) Arbuzov reaction; (iv) olefin cross-metathesis between vinyl phosphonates and vinylated nucleosides; and (v) radical reaction and Pd catalyzed alkyne. For the coupling of nucleobases with cyclic moieties, the Mitsunobu reaction and Sonogashira-type cross-coupling are usually applied. For the coupling of furanose moieties with nucleobases, Vorbrüggentype condensation is generally applied. Addition reactions mediated by selenium ions are mainly applied for the coupling of carbocyclic moieties. Their biological activity results have been summarized.

Improvements, Variations and Biomedical Applications of the Michaelis-Arbuzov Reaction.

Compounds bearing the phosphorus–carbon (P–C) bond have important pharmacological, biochemical, and toxicological properties. Historically, the most notable reaction for the formation of the P–C bond is the Michaelis–Arbuzov reaction, first described in 1898. The classical Michaelis–Arbuzov reaction entails a reaction between an alkyl halide and a trialkyl phosphite to yield a dialkylalkylphosphonate. Nonetheless, deviations from the classical mechanisms and new modifications have appeared that allowed the expansion of the library of reactants and consequently the chemical space of the yielded products. These involve the use of Lewis acid catalysts, green methods, ultrasound, microwave, photochemically-assisted reactions, aryne-based reactions, etc. Here, a detailed presentation of the Michaelis–Arbuzov reaction and its developments and applications in the synthesis of biomedically important agents is provided. Certain examples of such applications include the development of alkylphosphonofluoridates as serine hydrolase inhibitors and activity-based probes, and the P–C containing antiviral and anticancer agents.

Nanoarchitectonics of phosphorylated graphitic carbon nitride for sustainable, selective and metal-free synthesis of primary amides

• Phosphorylation of GCN nanosheets via Arbuzov reaction. • Metal-free, selective catalysts for amidation reactions under ambient conditions. • Detailed optimization of reaction conditions and examination of wide substrate scope. • High turnover numbers and high yields with desirable green metric parameters. Current strategies for the synthesis of primary amides from aldehydes requires expensive metal-based catalysts and high reaction temperature, which limits their potential applications. Herein, a highly selective, metal-free catalyst, phosphorylated graphitic carbon nitride (P-GCN) nanosheets is proposed for the amidation of aldehydes under ambient reaction conditions. The phosphorylation of graphitic carbon nitride (GCN) nanosheets via Arbuzov reaction leads to generation of Brønsted acidic sites onto the catalyst surface which behaves as active centers for the amidation reaction. The amidation reaction using P-GCN catalyst is carried out in environmentally benign solvents, eliminating the use of harsh toxic solvents. The detailed optimization of reaction parameters was done in order to attain high catalytic efficiency. The catalytic potential of P-GCN catalyst is investigated for a broad range of substrates demonstrating the versatility of the developed protocol. In addition to excellent recyclability, the sustainable nature of the developed protocol was examined using the Green metric parameters. The P-GCN catalyst exhibits excellent catalytic performance with high product yields and turnover numbers under optimized reaction conditions. Overall, the developed protocol for the amidation reaction using P-GCN nanosheets as a heterogeneous catalyst provides a useful and sustainable approach for the preparation of molecules of high significance.

Intensified Continuous Flow Michaelis–Arbuzov Rearrangement toward Alkyl Phosphonates

Intensified Continuous Flow Michaelis–Arbuzov Rearrangement toward Alkyl Phosphonates