Presence Of N-bromosuccinimide Research Articles

Oxidative Degradation of Paracetamol by N-Bromo Succinimide in Presence of Mercuric Acetate–A Computational Screening and Mechanistic Pathway

Oxidative Degradation of Paracetamol by N-Bromo Succinimide in Presence of Mercuric Acetate–A Computational Screening and Mechanistic Pathway

Synthesis and Structure of N-(1-(Bromomethyl)-7,7-dimethylbicyclo[2.2.1]heptan-2-yl)benzenesulfonamide

A new bicyclic sulfonamide derivative, N-(1-(bromomethyl)-7,7-dimethylbicyclo[2.2.1]heptan-2-yl)benzenesulfonamide, was synthesized in the reaction of benzenesulfonamide and camphene in the presence of N-bromosuccinimide in acetonitrile. The proposed mechanism of investigated reaction involves the Wagner–Meerwein rearrangement stage. 3-(Bromomethylene)-2,2-dimethylbicyclo[2.2.1]heptane was isolated as a minor product. The products were characterized by IR, NMR spectroscopy, X-ray diffraction analysis, HRMS and elemental analysis data.

Construction of pendant group functional HTPB and efficient light-harvesting carrier

The synthesis, characterization and application of the polymers with functional pendant groups have always been hot topics in the polymer field. A kind of functional polybutadiene (HTPB) derivative containing anthryl and azide groups was synthesized by anthracenic acid and HTPB in the presence of N-bromosuccinimide (NBS) and sodium azide via an electrophilic reaction. Furthermore, the HTPB derivative N3-HTPB-AN as a macromolecular main chain was reacted with alkynyl-terminated polytetrahydrofuran (Alk-PTHF) and maleimide-terminated polyethylene glycol (Mal-PEG) through "azide-alkyne" and "Diels-Alder" click reaction to obtain a bottle-brush polymer with the HTPB as the main chain and polytetrahydrofuran and polyethylene glycol as the side chains by one-pot. The bottle-brush polymer could self-assemble into uniform nanommicelles in aqueous solution. Meanwhile, the photoregulated fluorescence resonance energy transfer (FRET) exhibited by the interaction of the micelles assembled by the bottle-brush polymer in water with the dye was studied.

Indirect spectroscopic determination of esomeprazole using malachite green dye in the presence of N-bromosuccinimide

A simple, fast and sensitive spectrophotometric method has been developed for the determination of esomeprazole in its pure form and also in the form of a pharmaceutical preparation. The highest absorption was found at a wavelength of 618 nm and the limits of Beer were (2_24) µg/ml. The molar absorbance (2.1070 ˣ104) L.mol-1 .cm-1, Sandell sensitivity 0.016 µg.cm-2, and limits of detection LOD 0.0153 µg/ml, LOQ 0.0510 µg/ml were determined the method was also applied to pharmaceutical preparations, and the validity of the method was confirmed by standard addition.

Spectrophotometric Determination of Allopurinol by Oxidative Coupling Reaction Using 2-Nitrophenol Reagent in the Presence of N-Bromosuccinimide

This research included the development of a fast, easy and sensitive spectrophotometric method for the determination of quantities of allopurinol. The method depends on the oxidative coupling reaction between allopurinol and the reagent 2-nitrophenol in the presence of N-bromosuccinimide, so the product is a yellow color soluble in water that gives the highest absorption at the wavelength 420 nm and it follows Beer’s law In a range of concentrations ranged from 24-2.4 μg/ml and the molar absorbance value was 9282.02 liters. ml-1.cm-1, the value of the correlation coefficient is R = 0.9963 and the Sandell index value has 0.0146 µg/cm2, the relative standard deviation value is 1.273 RSD%, and the detection limit is 0.6635 µg/ml. The proposed method has been successfully applied in the determination of allopurinol in its preparation. Pharmacist keywords: Allopurinol, oxidative conjugation, 2-Nitrophenol

Mechanistic Details of Asymmetric Bromocyclization with BINAP Monoxide: Identification of Chiral Proton-Bridged Bisphosphine Oxide Complex and Its Application to Parallel Kinetic Resolution.

The mechanism of our previously reported catalytic asymmetric bromocyclization reactions using 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP) monoxide was examined in detail by the means of control experiments, NMR studies, X-ray structure analysis, and CryoSpray electrospray ionization mass spectrometry (ESI-MS) analysis. The chiral BINAP monoxide was transformed to a key catalyst precursor, proton-bridged bisphosphine oxide complex (POHOP·Br), in the presence of N-bromosuccinimide (NBS) and contaminating water. The thus-formed POHOP further reacts with NBS to afford BINAP dioxide and molecular bromine (Br2) simultaneously in equimolar amounts. While the resulting Br2 is activated by NBS to form a more reactive brominating reagent (Br2─NBS), BINAP dioxide serves as a bifunctional catalyst, acting as both a Lewis base that reacts with Br2─NBS to form a chiral brominating agent (P═O+─Br) and also as a Brønsted base for the activation of the substrate. By taking advantage of this novel concerted Lewis/Brønsted base catalysis by BINAP dioxide, we achieved the first regio- and chemodivergent parallel kinetic resolutions (PKRs) of racemic unsymmetrical bisallylic amides via bromocyclization.

1,3-Dimethyl-3′,5-diphenyl-1,5-dihydro-2H,5′H-spiro[furo[2,3-d]pyrimidine-6,4′-isoxazole]-2,4,5′(3H)-trione

Michael addition–halogenation–intramolecular ring-closing (MHIRC) reactions are processes in which a halogen atom as a leaving group can attach to substrates or reactants during the reaction, which then undergoes intramolecular ring closure. In this communication the MHIRC transformation of 4-benzylidene-3-phenylisoxazol-5(4H)-one and 1,3-dimethylbarbituric acid in the presence of N-bromosuccinimide and sodium acetate in EtOH at room temperature was carefully investigated to give novel 1,3-dimethyl-3′,5-diphenyl-1,5-dihydro-2H,5′H-spiro[furo[2,3-d]pyrimi- dine-6,4′-isoxazole]-2,4,5′(3H)-trione in a good yield. The structure of the new compound was confirmed by the results of elemental analysis as well as mass, nuclear magnetic resonance, and infrared spectroscopy.

Surface-initiated atom-transfer radical polymerization (SI-ATRP) of bactericidal polymer brushes on poly(lactic acid) surfaces

We have modified the surface of poly(lactic acid) (PLA) by bromination in the presence of N-bromosuccinimide (NBS) under UV irradiation. This new approach to impart functionality to the surface does not effect the bulk of the material. Brominated PLA surfaces served as initiators for atom-transfer radical polymerization (SI-ATRP) of 2-(methacryloyloxy)ethyl]trimethylammonium chloride, a quaternary ammonium methacrylate (QMA). Grafting of poly(QMA) brushes rendered PLA films hydrophilic and these films displayed a three-order of magnitude increase in antimicrobial efficacy against Gram-negative bacteria such as Escherichia coli as compared to unmodified PLA. The two-step strategy described here to modify PLA surface represents a useful route to modified PLA materials for biomedical and antimicrobial packaging applications.

A convenient and mild protocol for preparation of α –trimethylsilyloxyphosphonates using sulfamic acid and their oxidation to α – ketophosphonates in the presence of N-bromosuccinimide

A convenient and mild protocol for preparation of α –trimethylsilyloxyphosphonates using sulfamic acid and their oxidation to α – ketophosphonates in the presence of N-bromosuccinimide

Synthesis of Fused Diaziridine Derivatives from Cyclic Secondary Amines by Utilizing N-Bromosulfonamides as an Aminating Reagent

AbstractThe synthesis of a series of fused diaziridines, which are difficult to access by existing methods, was achieved by the reaction of cyclic secondary amines with p-toluenesulfonamide in the presence of N-bromosuccinimide (NBS) and a suitable base. This oxidation system enables the efficient in situ formation of the key intermediates, which are N-bromoamines (a precursor of cyclic imines) and N-bromosulfonamides. In addition, an alternative method using N-bromo-N-sodio-p-toluenesulfonamide (bromamine-T) in the presence of a catalytic amount of CF3CO2H for the synthesis of fused diaziridines is also reported.

Synthesis of 1-(2-bromo-1-arylethyl)-1H-benzotriazoles via NBS promoted addition of 1H-benzotriazole to alkene: Relevance in benzotriazole ring cleavage

A cost-effective and expeditious one-pot synthesis of 1-(2-bromo-1-arylethyl)-1H-benzotriazoles has been devised by reacting styrene and their derivatives with 1H-benzotriazole in presence of N-bromosuccinimide in anhydrous CH2Cl2 at room temperature. Further, the resulted compounds undergo E2-ellimination to afford the respective 1-(1-aryl-vinyl)-1H-benzotriazoles. At the end, 1-(1-phenylvinyl)-1H-benzotriazoles underwent benzotriazole ring cleavage (BtRC) under free radical condition to produce phenanthridine as the final product.

Microwave-Accelerated N-Acylation of Sulfoximines with Aldehydes under Catalyst-Free Conditions

An efficient catalyst-free radical cross-coupling reaction between aromatic aldehydes and sulfoximines was developed. The reaction took place in the presence of N-bromosuccinimide as the radical initiator under microwave irradiation to afford the corresponding acylated sulfoximines in moderate to excellent yields (27 examples). This protocol proved to be rapid, easy to handle, and applicable to a broad scope of substrates.

NBS-activated cross-dehydrogenative esterification of carboxylic acids with DMSO

A convenient and versatile cross-dehydrogenative esterification of carboxylic acids with DMSO for preparing (methylsulfinyl)methyl esters has been developed in the presence of N-bromosuccinimide.

Spectrophotometric Method for Estimation of Promethazine- HCl in Pharmaceutical Formulation Based on Oxidative Coupling with the Reagent m-Amino Benzoic Acid in Presence of N-Bromosuccinimide.

Spectrophotometric Method for Estimation of Promethazine- HCl in Pharmaceutical Formulation Based on Oxidative Coupling with the Reagent m-Amino Benzoic Acid in Presence of N-Bromosuccinimide.

Cyanide-Mediated Synthesis of Sulfones and Sulfonamides from Vinyl Sulfones

We report a facile synthesis of sulfones, β-keto sulfones, and sulfonamides from vinyl sulfones via an addition–elimination sequence where in situ generation of nucleophilic sulfinate ion is mediated by cyanide. The use vinyl sulfones renders high selectivity for S-alkylation to produce sulfones in high yields. In the presence of N-bromosuccinimide, primary and secondary amines underwent sulfonamide formation. A preliminary mechanistic study showed the formation of acrylonitrile as an innocent byproduct, without interfering with the desired reaction pathway while generating a sulfinate nucleophile.

Heterocyclization of 5-(Arylmethylidene)pyrimidine-2,4,6(1H,3H,5H)-triones with Arenecarbaldehyde Oximes in the Presence of N-Bromosuccinimide and Triethylamine

5-(Arylmethylidene)pyrimidine-2,4,6(1H,3H,5H)-triones reacted with substituted benzaldehyde oximes in the presence of N-bromosuccinimide and triethylamine to give 1,4-diaryl-2-oxa-3,7,9-triazaspiro-[4.5]dec-3-ene-6,8,10-triones and 3,4-diaryl-1,2,5-oxadiazole N-oxides.

Solvent interception, heterocyclization and desilylation upon NBS-induced sulfamidation of trimethyl(vinyl)silane.

The reaction of trimethyl(vinyl)silane with sulfonamides in the presence of N-bromosuccinimide was shown to proceed regioselectively in methylene chloride under mild conditions and led to the products of bromosulfamidation in up to 88% yield. The obtained adducts undergo base-promoted dehydrobromination to give 2-trimethylsilyl-N-sulfonyl aziridines in a close to quantitative yield. In the reaction with trifluoromethanesulfonamide in acetonitrile or tetrahydrofuran, the Ritter-type (solvent-interception) products were obtained and converted to 1-triflyl-2-methyl-5-(trimethylsilyl)-2-imidazoline or 4-triflyl-3-(trimethylsilyl)-1,4-oxazocane in almost quantitative yield.

Tandem synthesis of aromatic amides from styrenes in water

An expedient one-pot synthesis of aromatic amides has been reported from styrenes in the presence of N-bromosuccinimide and iodine by using aqueous ammonia in water. The reaction proceeds through the formation of α-bromoketone as an intermediate in the presence of NBS and water. α-Bromoketone on reaction with iodine forms bromodiiodoketone which on nucleophilic substitution with aqueous ammonia gives aromatic amide. Substituted aromatic amides were obtained in good yields with wide functional group compatibility.

Utility of thermo-alkali-stable γ-CA from polyextremophilic bacterium Aeribacillus pallidus TSHB1 in biomimetic sequestration of CO2 and as a virtual peroxidase.

Aeribacillus pallidus TSHB1 polyextremophilic bacterium produces a γ-carbonic anhydrase (ApCA), which is a homotrimeric biocatalyst with a subunit molecular mass of 32±2kDa. The enzyme is stable in the pH range between 8.0 and 11.0 and thus alkali-stable and moderately thermostable with T1/2 values of 40±1, 15±1, and 8±0.5min at 60, 70, and 80°C, respectively. Activation energy for irreversible inactivation "E d " of carbonic anhydrase is 67.119kJmol-1. The enzyme is stable in the presence of various flue gas contaminants such as SO32-,SO42-, and NO3- and cations Mg2+, Mn2+, Ca2+, and Ba2+. Fluorescence studies in the presence of N-bromosuccinimide and fluorescence quenching using KI and acrylamide revealed the importance of tryptophan residues in maintaining the structural integrity of the enzyme. ApCA is more efficient than the commercially available bovine carbonic anhydrase (BCA) in CO2 sequestration. The enzyme was successfully used in biomineralization of CO2 from flue gas. Replacement of active site Zn2+ with Mn2+ enabled ApCA to function as a peroxidase which exhibited alkali-stability and moderate thermostability like ApCA.

Heterologous expression of γ-glutamyl transpeptidase from Bacillus atrophaeus GS-16 and its application in the synthesis of γ-d-glutamyl-l-tryptophan, a known immunomodulatory peptide.

Gamma-glutamyl transpeptidase from a mesophilic bacterium Bacillus atrophaeus GS-16 (BaGGT) was expressed heterologously in E. coli using pET-51b vector. Maximum production of BaGGT was obtained at 16°C after 16h of IPTG induction and the protein, in its native conformation, was active as a heterooctamer which was composed of four heterodimeric units combined together. One heterodimeric unit constituted two subunits with molecular masses of 45kDa and 21kDa, respectively. The recombinant enzyme was purified by one step His-tag affinity purification protocol with a specific activity of 90U/mg and 5.2 fold purity. The purified enzyme had a pH optimum of 10.0 and temperature optimum of 50°C. It exhibited broad pH stability (6.0-12.0) and was thermostable (t1/2 of 54min at 50°C). The enzyme was completely inactivated by Pb2+ ions and strongly inhibited in presence of N-bromosuccinimide, azaserine and 6-diazo-5oxo-l-norleucine. Kinetic characterization of BaGGT using GpNA as a donor and glycylglycine as acceptor revealed that it had a Km of 0.15mM and 0.37mM and Vmax of 23.09μmol/mg/min and 121.95μmol/mg/min for hydrolysis and transpeptidation reactions, respectively. BaGGT also displayed broad substrate specificity for various amino acids. It was studied for its prospective use in the synthesis of an immunomodulatory peptide, γ-d-glutamyl-l-tryptophan. After optimization of various process parameters, a conversion rate of 50%, corresponding to 25mM product yield, was achieved within 6h of incubation using 50mM d-glutamine as donor and 50mM l-tryptophan as acceptor and 0.3U/mL of BaGGT in the reaction, performed at pH 10.0 and 37°C. The product was purified to homogeneity using Dowex 1×2 column and its purity was confirmed by HPLC and H1 NMR.