M-chloroperbenzoic Acid Research Articles

Manganese(II)-Porphyrin and Cumyl Hydroperoxide: An Efficient Catalyst for Aryl-Pentazole C-N Bond Cleavage.

The selective cleavage of C-N bonds in N-containing compounds holds significant research value in organic synthesis, particularly for the synthesis of promising polynitrogen species. For instance, the discovery of the cyclo-pentazolate (cyclo-N5-) anion in 2017 as a result of cleavage of the C-N bond has sparked interest within the field of high energy density materials. However, previous methods using ferrous glycinate and m-chloroperoxybenzoic acid generated the cyclo-N5- anion in a low yield of 19.5% after 24 hours, and the mechanism remained unclear. In this study, we developed an efficient catalytic system comprising Mn (II) tetraphenylporphyrin and cumyl hydroperoxide. This system enables the cyclo-N5- anion to be produced from 3,5-dimethyl-4-hydroxyphenylpentazole in 35.4% yield in 4 hours. Characterization of Mn(IV)-oxo porphyrins, •CH3, and •C8H8ON5 radicals provides evidence for the mechanism whereby the cyclo-N5- anion forms. Our study underscores the competitive potential of radical-initiated selective C-N bonds cleavage in N-arylazoles and opens avenues for further exploration in this field.

Integrating Epoxidation, High-Resolution Mass Spectrometry and Ultraviolet Spectroscopy to Unravel the Complex Profile of Boswellic Acids and Related Compounds in the Boswellia serrata Gum Resin Extract

The chemical characterization of natural products is often a complex task that demands powerful analytical techniques. Liquid chromatography with high-resolution tandem mass spectrometry (HRMS/MS) is often employed, yet it can face hard challenges when isomeric species are present, and reference standards are lacking. In such cases, the confidence level in compound identification can be significantly improved by the collection of orthogonal information on target analytes. In this work, 23 key compounds in Boswellia serrata extract (BSE), 12 of which correspond to boswellic acids (BAs) and 11 to triterpenoidic acid isomers, were identified by combining RPLC followed by serial UV and ESI(-)-FTMS and FTMS/MS detections with the evaluation of the reactivity towards C=C bond epoxidation with meta-chloroperoxybenzoic acid (m-CPBA), proposed as a fast chemical tool to gather information about C=C bond steric hindrance, a key structural feature of BAs and related compounds. The interpretation of UV spectra acquired after chromatographic separation corroborated the identification of the substitution patterns of enonic and dienic residues in ketoboswellic and dehydroboswellic acids. Moreover, MS/MS based on higher-energy collision-induced dissociation (HCD) unveiled new fragmentation pathways, providing important structural details on target analytes. The integrated approach developed during this study might pave the way for a deeper understanding of the BSE bioactive properties. Moreover, it can be considered an example of a more general strategy for the analysis of complex mixtures of natural compounds including also isomeric species.

CuI-Catalyzed Selenylation of Pyrrolo[2,1-a]isoquinolines and Other Electron-Rich Heteroarenes.

We have established a mild CuI-catalyzed selenylation of pyrrolo[2,1-a]isoquinoline derivatives in the presence of mCPBA (m-chloroperoxybenzoic acid) at ambient temperature. Corresponding organoselenides have been prepared readily in 53-92% yields. This process can also be expanded to the modification of pyrroles, azaindole, and indoles, delivering the desired heterocyclic selenides in moderate to good yields.

Synthesis, Material Properties, and Organocatalytic Performance of Hypervalent Iodine(III)-Oxidants in Core–Shell-Structured Magnetic Nanoparticles

Magnetic nanoparticles (MNPs) based on magnetite (Fe3O4) are attractive catalyst supports due to their high surface area, easy preparation, and facile separation, but they lack stability in acidic reaction media. The search for MNPs stable in oxidative acidic reaction media is a necessity if one wants to combine the advantages of MNPs as catalyst supports with those of iodine(III) reagents being environmentally benign oxidizers. In this work, immobilized iodophenyl organocatalysts on magnetite support (IMNPs) were obtained by crossed-linking polymerization of 4-iodostyrene with 1,4-divinylbenzene in the presence of MNPs. The obtained IMNPs were characterized by TGA, IR, SEM, STEM, and HAADF to gain information on catalyst morphology, average particle size (80–100 nm), and their core–shell structure. IMNP-catalysts tested in (i) the α-tosyloxylation of propiophenone 1 with meta-chloroperbenzoic acid (m-CPBA) and (ii) in the oxidation of 9,10-dimethoxyanthracene 3 with Oxone® as the side-oxidant showed a similar performance as reactions using stoichiometric amounts of iodophenyl. The developed IMNPs withstand strong acidic conditions and serve as reusable organocatalysts. They are recyclable up to four times for repeated organocatalytic oxidations with rates of recovery of 80–92%. This is the first example of a—(4-iodophenyl)polystyrene shell—magnetite core-structured organocatalyst withstanding strong acidic reaction conditions.

Chemo-Enzymatic Depolymerization of Functionalized Low-Molecular-Weight Polyethylene.

Polyethylene (PE) is the most commonly used plastic type in the world, contributing significantly to the plastic waste crisis. Microbial degradation of PE in natural environments is unlikely due to its inert saturated carbon-carbon backbones, which are difficult to break down by enzymes, challenging the development of a biocatalytic recycling method for PE waste. Here, we demonstrated the depolymerization of low-molecular-weight (LMW) PE using an enzyme cascade that included a catalase-peroxidase, an alcohol dehydrogenase, a Baeyer Villiger monooxygenase, and a lipase after the polymer was chemically pretreated with m-chloroperoxybenzoic acid (mCPBA) and ultrasonication. In a preparative experiment with gram-scale pretreated polymers, GC-MS and weight loss determinations confirmed ~27% polymer conversion including the formation of medium-size functionalized molecules such as ω-hydroxy acids and α,ω-carboxylic acids. Additional polymer property analyses using AFM showed that enzymatic depolymerization reduced the particle sizes of this mCPBA- and enzyme-treated LMWPE. This multi-enzyme catalytic concept with distinct chemical steps represents a unique starting point for future development of bio-based recycling methods for polyolefin waste.

Chemical, antimicrobial, antioxidant, and molecular dynamic studies of spiro[chromane-3',2''-thiopyran]-4'-one 1''-oxide and spiro[chromane-3',2''-thiopyran]-4'-one 1'',1''-dioxide

Some of spiro[chromane-3',2''-thiopyran]-4'-ones were oxidized via m-chloroperbenzoic acid and/or hydrogen peroxide to afford the corresponding nine spiro[chromane-3',2''-thiopyran]-4'-one 1''-oxides and three spiro[chromane-3',2''-thiopyran]-4'-one 1'',1''-dioxides, which were confirmed by spectral data (IR, 1H NMR, 13C NMR, MS-ESI, and MS-EI). Whereas, the yield of oxidation using hydrogen peroxide is higher than that of oxidation using m-chloroperbenzoic acid. Moreover, Gram-negative bacteria (Escherichia coli ATCC 25922), and Gram-positive bacteria (Staphylococcus aureus ATCC 6538) were adopted to test the antimicrobial activity of 12 newly synthesized compounds (7a, 8a-c, 9a, 10a-c, 11a, 12a-c). The three sulfoxide derivatives 8b, 10b, and 10c showed antimicrobial activity. Also, antioxidant activity was evaluated for the newly synthesized compounds and shows that, all newly synthesized compounds (7a, 8a-c, 9a, 10a-c, 11a, 12a-c) have antioxidant activity. Molecular dynamic and system stability, Binding interaction mechanism based on binding free energy calculation, Identification of the critical residues responsible for ligands binding, Ligand–residue interaction network profiles, and In silico ADMET properties prediction were studied for the new compounds. The results of molecular dynamic studies were consistent with the in vitro antibacterial and antioxidant activity.

Synthetic Process Development of (R)-(+)-1,2-Epoxy-5-hexene: An Important Chiral Building Block.

Herein, we describe two practical approaches to synthesize (R)-(+)-1,2-epoxy-5-hexene from inexpensive and readily available raw materials and reagents. The first approach is a two-step sequence, involving an epoxidation with meta-chloroperoxybenzoic acid (mCPBA) and a chiral resolution with (salen)Co(II), producing (R)-(+)-1,2-epoxy-5-hexene in 24-30% overall yield. The second approach utilizes readily available (R)-epichlorohydrin as the starting material and features an epoxide ring-opening reaction with allylMgCl and the NaOH-mediated ring closure reaction. Development of this two-step process affords R-(+)-1,2-epoxy-5-hexene in overall isolated yields of 55-60% with an exceptional purity profile. Both approaches have been successfully demonstrated on 100-200 g scales.

Mechanism and stereoselectivity of epoxidation reaction of a β-himachalene derivative: Insights from DFT, molecular docking, ADMET, and molecular dynamics investigations

Epoxidation of a β-himachalene derivative (A) can be carried out using meta-chloroperoxybenzoic acid (m-CPBA). An oxygen atom is added to the double bond C9C10, during the process, producing the epoxides P1 and P2. DFT calculations at the B3LYP/6-31G(d) level were used to study, Theoretically, the mechanism and stereoselectivity of the epoxidation reaction of compound A with m-CPBA. The calculation of activation energies associated with both possible reaction pathways, indicated that this epoxidation reaction is exothermic and highly stereoselective, favoring the formation of product P1 which is in agreement with the experimental results. Additionally, the IRC calculation shows that this reaction occurs via a one-step mechanism. The products P1, P2, and the starting compound A were evaluated for their antidiabetic activity and their potential to inhibit alpha-amylase and alpha-glucosidase through molecular docking, molecular dynamics, and ADMET studies. The evaluation of these three compounds aimed to study the effect of epoxidation and stereoselectivity on their inhibitory activity against the two enzymes.

Modulation of Properties in [1]Benzothieno[3,2-b][1]benzothiophene Derivatives through Sulfur Oxidation.

This study explores the impact of sulfur oxidation on the structural, optical, and electronic properties of [1]benzothieno[3,2-b][1]benzothiophene (BTBT) derivatives, specifically focusing on 2,7-dibromo BTBT (2,7-diBr-BTBT) and its oxidized forms, 5,5-dioxide (2,7-diBr-BTBTDO) and 5,5,10,10-tetraoxide (2,7-diBr-BTBTTO). The bromination of BTBT followed by sequential oxidation with m-chloroperoxybenzoic acid yielded the target compounds in good yields. They were characterized using a wide array of analytical techniques including different spectroscopic methods, X-ray analysis, thermal analysis, and quantum chemical calculations. The results revealed that sulfur oxidation significantly alters the crystal packing, thermal stability, and optoelectronic properties of BTBT derivatives. Notably, the oxidized forms exhibited increased thermal stability and enhanced emission properties, with quantum yields exceeding 99%. These findings provide valuable insights for designing advanced organic semiconductors and fluorescent materials with tunable properties, based on the BTBT core.

Deep eutectic solvents as sustainable and extraordinary all-in-one systems for oxidative desulfurization

Deep oxidative desulfurization (ODS) using deep eutectic solvents (DESs) was a promising and environmentally friendly technique. Herein, we report an innovative and straightforward approach for achieving efficient oxidative desulfurization using DESs. These DESs serve as all-in-one systems, encompassing catalysts, oxidants, and solvents. The results demonstrate the excellent desulfurization performance of a DES derived from meta-chloroperoxybenzoic acid (mCPBA) and dimethylethanolamine (DMAE) for the removal of dibenzothiophene (DBT) from model oil. The use of multi-component DES systems enhances efficiency and reduces toxicity compared to individual solvent components, resulting in deep desulfurization levels. The influence of crucial extraction parameters, such as extraction time, temperature, and amount of DES, was investigated. The results demonstrated that the mCPBA/DMAE-based DES exhibited the highest desulfurization efficiency, reaching up to 99 % under optimal conditions (60 °C, 90 min, and 1 mL of DES). Moreover, the exceptional stability and reusability of DESs were confirmed, as they maintained sustained desulfurization efficiency even after six cycles of reuse.

Structural diversity in nudibranch chemistry: elucidation of norditerpenes with a dendrillane scaffold from the Australian nudibranch Goniobranchus coi

In addition to three known compounds (1–3), two new rearranged spongian diterpenes (4 and 5) with perhydroazulene and dioxabicyclooctane ring systems were isolated from the mantle and viscera of the Australian nudibranch Goniobranchus coi. The relative configuration of the major spiroepoxide 4 was explored by comparison with those of m-chloroperbenzoic acid oxidation products derived from dendrillolide A (1). Aldehydes 6 and 7 were identified as the ring-opened artefacts of the spiroepoxides 5 and 4 respectively, and yielded ketone 3 on storage. The relative configurations of lactols 8 and 9, isolated as an inseparable mixture of diastereomers, were deduced by molecular modelling and computational studies. Acetylation of the lactol mixture provided dendrillolide A (1), further confirming the structural assignments of 8 and 9. Dissection of animal tissue established that the norditerpenoid metabolites were present in both mantle and viscera tissues.

Identification and structural elucidation of an oxidation product generated during stability studies of Cabergoline drug product

Cabergoline is a dopamine agonist with applications as anti-Parkinson drug and prolactin inhibitor. The cabergoline drug product Laktostop® 50 µg/mL is used in veterinary medicine for lactation suppression in cats and dogs e.g. during false pregnancy. Recently, during ongoing HPLC stability testing of Laktostop® 50 µg/mL a new oxidation product of Cabergoline was identified. A synthesis starting from Cabergoline was developed, followed by full characterization of the unknown impurity. Preliminary HPLC and LC-MS analyses indicated the unknown impurity as mono-oxygenated product of Cabergoline (Cabergoline N-oxide) that is presumably formed with oxygen by a radical mechanism. Thus, Cabergoline was treated with oxidizing agents such as m-chloroperoxybenzoic acid to afford the desired Cabergoline-N-oxide as a byproduct. After isolation by column chromatography, NMR and LC-MS-MS studies provided evidence that oxidation occurred at the N-allyl nitrogen of Cabergoline to form Cabergoline-N-oxide. © 1905 Elsevier Science. All rights reserved

A Family of Hexacopper Phenylsilsesquioxane/Acetate Complexes: Synthesis, Solvent-Controlled Cage Structures, and Catalytic Activity.

Convenient self-assembly synthesis of copper(II) complexes via double (phenylsilsesquioxane and acetate) ligation allows to isolate a family of impressive sandwich-like cage compounds. An intriguing feature of these complexes is the difference in the structure of a pair of silsesquioxane ligands despite identical (Cu6) nuclearity and number (four) of acetate fragments. Formation of particular combination of silsesquioxane ligands (cyclic/cyclic vs condensed/condensed vs cyclic/condensed) was found to be dependent on the synthesis/crystallization media. A combination of Si4-cyclic and Si6-condensed silsesquioxane ligands is a brand new feature of cage metallasilsesquioxanes. A representative Cu6-complex (4) (with cyclic silsesquioxanes) exhibited high catalytic activity in the oxidation of alkanes and alcohols with peroxides. Maximum yield of the products of cyclohexane oxidation attained 30 %. The compound 4 was also tested as catalyst in the Baeyer-Villiger oxidation of cyclohexanone by m-chloroperoxybenzoic acid: maximum yields of 88 % and 100 % of ϵ-caprolactone were achieved upon conventional heating at 50 °C for 4 h and MW irradiation at 70 or 80 °C during 30 min, respectively. It was also possible to obtain the lactone (up to 16 % yield) directly from the cyclohexane via a tandem oxidation/Baeyer-Villiger oxidation reaction using the same oxidant.

Synthesis and photoinitiated cationic polymerization of epoxy monomers derived from oleic acid comprising one to three epoxy groups

A series of bio-based epoxy compounds based on oleic acid combined with aliphatic or aromatic structures were studied regarding selected properties such as melting behavior and viscosity as well as their reactivity in a photoinitiated cationic polymerization. The new epoxy compounds derived from oleic acid and either eugenol or isoeugenol, epoxidized triolein, and an epoxy compound derived from oleic acid and popane diol-1,3 contain 100 % renewable carbon. Atom economy differs not only for the esterification and epoxidation reaction, also selection of hydrogen peroxide or m-chloroperbenzoic acid for the epoxidation significantly influences the atom economy of this reaction step. Variation of the chemical structure of the bio-based epoxy compounds derived from oleic acid and either an aliphatic alcohol or a phenolic compound results in differences in both melting behavior and viscosity of the epoxy monomers that is important for the photoinitiated cationic polymerization. Kinetic investigation of the photoinitiated cationic polymerization of the bio-based epoxy compounds using photo-DSC shows significant differences in the polymerization rate and conversion as a function of the irradiation time for the epoxy monomers. RT-FTIR spectroscopy gives additional information about the polymerization kinetics for epoxy monomers that are liquid at room temperature. The glass transition temperature of the photopolymers analyzed by DSC is mostly below room temperature that is attributed to the high content of flexible structures containing in the polymers. Additional investigation of the soluble photopolymers by GPC resulted in a molecular weight corresponding to the oligomer region and a dispersity higher than one. The bio-based epoxy monomers comprising two or three epoxy groups may be interesting for application, e. g. in coatings or adhesives, because photoinitiated polymerization results in crosslinking. Epoxy compounds containing only one epoxy group may be useful for viscosity reduction of the photopolymerizing mixtures because of their lower viscosity compared to the epoxy monomers comprising more than one epoxy group.

Metal-free Oxidations with m-CPBA: An Octennial Update

Abstract: meta-Chloroperbenzoic acid (mCPBA) is a readily available peroxide that is a powerful oxidizing agent utilized in a range of oxidative reactions. Metal-free oxidations mediated by mCPBA involving selective oxidation of aliphatic amines to oximes, selective oxidation of organosulphides/ aldehydes, synthesis of heterocyclic N-oxides, domino C[sp2] hydroxylation/ annulation of enaminones (heterocyclic ring formation), acid to phenol conversion, oxidation of exocyclic C=C bond, oxidative ring contraction, etc. have been comprehensively and critically examined in this mini-review from 2015 to date.

Fast, Efficient, Catalyst-Free Epoxidation of Butyl Rubber Using Oxone/Acetone for Improved Filler Dispersion.

Incorporation of a polar filler such as silica into a nonpolar rubber matrix is challenging and energy consuming due to their large difference in polarity. Epoxidation of carbon-carbon double bonds in unsaturated rubber, especially for rubber with low unsaturation such as butyl rubber, is an effective method to introduce polar functional groups to the rubber macromolecules for better filler dispersion. Although different epoxidation reagents including hydrogen peroxide (H2O2), peracid, and meta-chloroperoxybenzoic acid (mCPBA) have been previously reported, these reagents have different drawbacks. In this article, a metal-free epoxidation reagent, dimethyl dioxirane (DMDO), generated from acetone and Oxone is explored for efficient epoxidation of rubber with low unsaturation. The effects of the addition manner of the reactant Oxone and buffer sodium bicarbonate (NaHCO3) and reaction temperature on the epoxide formation are studied. Compared to peracid, a faster and more efficient epoxidation without the generation of a ring-opened product is achieved when DMDO is used as the epoxidation reagent. Furthermore, it is found that the epoxidation using DMDO is not sensitive to the water concentration in the rubber solution up to 20 wt %. The addition of quaternary ammonium salt as a phase transfer catalyst not only improves the conversion but also further increases the water tolerance to 25 wt %. The reaction conditions for preparation of epoxidized butyl rubber with different percentages of epoxide group are optimized by Design of Experiments (DoE). At the end, improved dispersion of silica in the matrix of epoxidized butyl rubber is achieved, as revealed by the rubber process analyzer (RPA) and atomic force microscopy (AFM).

Recent Advances in Hypervalent Iodine Reagents and m-CPBA Mediated Oxidative Transformations

Abstract: Among the several peroxides available, meta-chloroperbenzoic acid (mCPBA) plays an efficient role of oxidizing reagent and is used for many oxidative transformations, such as oxidation of various functional groups, carbon-carbon, carbon-hetero bond formation, heterocyclic ring formation, heteroarylation, oxidative cross-coupling, lactonization, oxidative dearomatization, α-oxytosylation or α-acetoxylation, oxidative C-C bond activation and in other miscellaneous reactions. The purpose of this review is to critically discuss the significant contributions of mCPBA along with hypervalent iodine/iodine reagents in organic synthesis from mid-2015 to date.

Improved Protocols for the Synthesis of Precursors of Thiazol-2-ylidene N-Heterocyclic Carbenes

AbstractWe report improved protocols for the synthesis of thiazolium precatalysts from primary amines, carbon disulfide, and α-halo ketones. For N-alkyl-substituted derivatives, yields of the corresponding thiazolethiones can be dramatically improved by isolating the intermediate dithiocarbamates. In most cases, meta-chloroperbenzoic acid can advantageously replace H2O2 in acetic acid for the oxidation of thiazolethiones into thiazoliums. This approach was applied to the synthesis of a thiazolium featuring a 2-adamantyl N-substituent, the corresponding persistent carbene, and its dimer.

Racemic total synthesis of oxomaritidine by iodobenzene-catalyzed oxidative phenolic coupling under mild reaction conditions

A hypervalent iodine-catalyzed phenolic coupling reaction of norbelladine derivatives was examined with a catalytic amount of iodobenzene and meta-chloroperbenzoic acid as the terminal oxidant. The addition of acetic acid dramatically accelerated the reaction rate even at room temperature, and the cyclized products were successfully obtained under mild reaction conditions. The methods were applicable to the racemic total synthesis of oxomaritidine.

2-Benzoyl-4-phenyl-1,2,5-thiadiazol-3(2H)-one 1,1-Dioxide

3,5-Diphenyl-4H-1,2,6-thiadiazin-4-one treated with meta-chloroperoxybenzoic acid undergoes an oxidative ring contraction to give 2-benzoyl-4-phenyl-1,2,5-thiadiazol-3(2H)-one 1,1-dioxide in a 29% yield, the structure of which is supported by single-crystal X-ray diffraction analysis and the available spectroscopic data.