Bromoethylsulfonium SaltA More Effective Annulation Agent for the Synthesis of 6- and 7-Membered 1,4-Heterocyclic Compounds

Reaction of bromoethylsulfonium salt with 1,2-/1,3-aminoalcohols gave six- and seven-membered rings in good-to-excellent yields. The reactions proceed through generation of a vinyl sulfonium salt followed by annulation to give 1,4-heterocyclic compounds such as morpholines and benzoxazepines in a simple procedure. The method accommodates a range of nitrogen substituents and the amino alcohol can be substituted by amino thiols and diamines to give thiomorpholines, piperazines and benzodiazepines

The Concise Synthesis of Unsymmetric Triaryl­acetonitriles via Pd‑Catalyzed Sequential Arylation: A New Synthetic Approach to Tri- and Tetraarylmethanes

The selective synthesis of multiarylated acetonitriles via sequential palladium-catalyzed arylations of chloroacetonitrile is reported. The three aryl groups are installed via a Pd-catalyzed Suzuki–Miyaura cross coupling reaction followed by back-to-back C–H arylations to afford triarylacetonitriles in three steps with no over-arylation at any step. The triarylacetonitrile products can be converted into highly functionalized species including tetraarylmethanes. This new strategy provides rapid access to a variety of unsymmetrical tri- and tetraarylmethane derivatives from simple, readily available starting materials

Transition Metal-Doped C₂₀ Fullerene-Based Single-Atom Catalysts with High Catalytic Activity for Hydrogen Dissociation Reaction

Hydrogen dissociation is a key step in almost all hydrogenation reactions; therefore, an efficient and cost-effective catalyst with a favorable band structure for this step is highly desirable. In the current work, transition metal-based C20 (M@C20) complexes are designed and evaluated as single-atom catalysts (SACs) for hydrogen dissociation reaction (HDR). Interaction energy (Eint) analysis reveals that all the M@C20 complexes are thermodynamically stable, whereas the highest stability is observed for the Ni@C20 complex (Eint = −6.14 eV). Moreover, the best catalytic performance for H2 dissociation reaction is computed for the Zn@C20 catalyst (Eads = 0.53 eV) followed by Ti@C20 (Eads = 0.65 eV) and Sc@C20 (Eads = 0.76 eV) among all considered catalysts. QTAIM analyses reveal covalent or shared shell interactions in H2* + M@C20 systems, which promote the process of H2 dissociation over M@C20 complexes. NBO and EDD analyses declare that transfer of charge from the metal atom to the antibonding orbital of H2 causes dissociation of the H–H bond. Overall outcomes of this study reveal that the Zn@C20 catalyst can act as a highly efficient, low-cost, abundant, and precious metal-free SAC to effectively catalyze HDR

Experimental and Theoretical Charge Density Analysis of a Bromoethyl Sulfonium Salt

Bromoethyl sulfonium trifluoromethanesulfonate is a salt complex in which a sulfur atom makes three covalent bonds. This molecule has been proved to act as an efficient annulation reagent which results in formation of synthetically challenging and pharmaceutically important 4-, 5-, 6-, and 7-membered heterocycles in excellent yields. The charge density of the molecule was determined from both experimentally and theoretically derived diffraction data. The stereochemistry and electron density topology of the sulfonium group was analyzed. To understand the chemical reactivity of the molecule, the electrostatic potential difference between the two carbon atoms of the bromoethyl group was investigated. It has been considered that the hydrogen atoms on the carbon atom bound to sulfur are more acidic in character due to their vicinity with the triply covalently bonded positively charged sulfur atom. The electropositivity of the S-attached and Br-attached methylene groups are compared in the experimental and theoretical charge densities using topological atomic charges and electrostatic potential at the molecular surface

Metal-Free Supramolecular Reduction of Nitro Compounds into the Cucurbit[7]uril Cavity: Testing the Enabling Technique in Aqueous Media

A metal-free strategy for the supramolecular reduction of nitroarenes in a cucurbit[7]uril (CB[7]) cavity has been developed under blue light (390 nm) irradiation using a mixture of aqueous sodium chloride/dichloromethane as the reaction media. The protocol was found to be simple, efficient, and environmentally benign to obtain diversely substituted anilines, including heterocyclic and aliphatic amines with excellent yields. This is the first ever report describing the blue light-driven supramolecular reduction of nitroarenes into a CB[7] cavity. The mechanism of this transformation was simulated by the DFT method

An Efficient Synthesis of Imidazolinium Salts Using Vinyl Sulfonium Salts

The synthesis of imidazolinium salts from the reaction of formamidines and (2-bromoethyl)diphenylsulfonium triflate is described. A variety of symmetrical and unsymmetrical imidazolinium triflate salts were synthesized in high yield in short reaction times under mild conditions. Aromatic and aliphatic N-substituents work well. The reaction is proposed to proceed via generation of a vinyl sulfonium salt intermediate from the bromoethylsulfonium triflate

Experimental and Theoretical Charge Density Analysis of a Bromoethyl Sulfonium Salt

Bromoethyl sulfonium trifluoromethanesulfonate is a salt complex in which a sulfur atom makes three covalent bonds. This molecule has been proved to act as an efficient annulation reagent which results in formation of synthetically challenging and pharmaceutically important 4-, 5-, 6-, and 7-membered heterocycles in excellent yields. The charge density of the molecule was determined from both experimentally and theoretically derived diffraction data. The stereochemistry and electron density topology of the sulfonium group was analyzed. To understand the chemical reactivity of the molecule, the electrostatic potential difference between the two carbon atoms of the bromoethyl group was investigated. It has been considered that the hydrogen atoms on the carbon atom bound to sulfur are more acidic in character due to their vicinity with the triply covalently bonded positively charged sulfur atom. The electropositivity of the S-attached and Br-attached methylene groups are compared in the experimental and theoretical charge densities using topological atomic charges and electrostatic potential at the molecular surface

Synthesis and DPPH scavenging assay of reserpine analogues, computational studies and in silico docking studies in AChE and BChE responsible for Alzheimer's disease

Alzheimer's disease (AD) is a fast growing neurodegenerative disorder of the central nervous system and anti-oxidants can be used to help suppress the oxidative stress caused by the free radicals that are responsible for AD. A series of selected synthetic indole derivatives were biologically evaluated to identify potent new antioxidants. Most of the evaluated compounds showed significant to modest antioxidant properties (IC50 value 399.07 140.0±50 µM). Density Functional Theory (DFT) studies were carried out on the compounds and their corresponding free radicals. Differences in the energy of the parent compounds and their corresponding free radicals provided a good justification for the trend found in their IC50 values. In silico, docking of compounds into the proteins acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), which are well known for contributing in AD disease, was also performed to predict anti-AD potential.</div

Synthesis, characterization, antimicrobial, cytotoxic, DNA-interaction, molecular docking and DFT studies of novel di- and tri-organotin(IV) carboxylates using 3-(3-nitrophenyl)2-methylpropenoic acid

One diorganotin(IV) [n-Bu2SnL2] (1) and two triorganotin(IV) carboxylates [n-Bu3SnL] (2) and [Ph3SnL] (3) [L = 3-(3-nitrophenyl) 2-methylpropenoic acid] were synthesized and characterized by elemental analysis, FT-IR and NMR (1H, 13C) spectroscopies. The geometry of complexes and binding mode of ligand were worked out through FT-IR and NMR spectroscopies. The ligand coordinate with Sn via carboxylato oxygen in monodentate fashion leading to four coordinated geometries around Sn center. The effectiveness of complexes towards their antimicrobial and cytotoxic potential was evaluated and a significant extent of antimicrobial potential was observed with a few exceptions. Molecular docking studies were performed for these complexes to check their interaction with DNA. Results from this study revealed that these compounds can bind favorably with cisplatin binding site and targeting the major groove of DNA. The complex-DNA interaction study was also performed through UV-Vis spectroscopic technique and viscosity measurement, and the observed experimental results were well matched with theoretical results. Computational vibrational analysis, frontier molecular orbital (FMO), natural bond orbitals (NBOs), linear and non-linear optical (NLO) properties of ligand and complexes 1-3 were calculated by density functional theory (DFT) and time-dependent DFT (TDDFT) using CAM-B3LYP/6-31G (d,p) level of theory to evaluate spectroscopic, structural parameters and reactivity patterns. </p

Metallofullerenes as Robust Single-Atom Catalysts for Adsorption and Dissociation of Hydrogen Molecules: A Density Functional Study

Hydrogen is currently considered as the best alternative for traditional fuels due to its sustainable and ecofriendly nature. Additionally, hydrogen dissociation is a critical step in almost all hydrogenation reactions, which is crucial in industrial chemical production. A cost-effective and efficient catalyst with favorable activity for this step is highly desirable. Herein, transition-metal-doped fullerene (TM@C60) complexes are designed and investigated as single-atom catalysts for the hydrogen splitting process. Interaction energy analysis (Eint) is also carried out to demonstrate the stability of designed TM@C60 metallofullerenes, which reveals that all the designed complexes have higher thermodynamic stability. Furthermore, among all the studied metallofullerenes, the best catalytic efficiency for hydrogen dissociation is seen for the Sc@C60 catalyst Ea = 0.13 eV followed by the V@C60 catalyst Ea = 0.19 eV. The hydrogen activation and dissociation processes over TM@C60 metallofullerenes is further elaborated by analyzing charge transfer via the natural bond orbital and electron density difference analyses. Additionally, quantum theory of atoms in molecule analysis is carried out to investigate the nature of interatomic interactions between hydrogen molecules and TMs@C60 metallofullerenes. Overall, results of the current study declare that the Sc@C60 catalyst can act as a low cost, highly efficient, and noble metal-free single-atom catalyst to efficiently catalyze hydrogen dissociation reaction