N-bromosuccinimide Research Articles

Selective recovery of Au from waste printed circuit board by water-soluble organic leaching: The key role of in situ bromine mediation and identificationof pathway

A large amount of gold in electronic waste (E-waste) is not properly recovered owing to the absence of efficient and safe leaching methods. Herein, we proposed the concept of ‘water-soluble organic Au leaching’ and created a new water-soluble organic leaching agent, WS NBS–DMF, by dissolving millimolar amounts of N-bromosuccinimide (NBS) and dimethylformamide (DMF) in water. Under mild conditions (25 ℃, pH 7.0), WS NBS–DMF achieved a 94.9 % leaching efficiency of Au for waste printed circuit board (WPCB) with limited leaching of base metals. The potent bromine radical (Br•) and ligands significantly contributed to Au complexation and oxidization via in situ bromine generation and radical initiation from WS NBS–DMF. The bidirectional hydrogen-bond effect of DMF facilitated the in situ bromine generation. Two Au(I) complexes ([AuBr2]- and [(NHS)AuBr]-) and an Au(III) complex ([(NHS)AuBr3]-) were confirmed as the Au leaching products by spectroscopy and mass spectrometry. Furthermore, reciprocal σ-donations between the Au center and ligands in the bonding orbitals enhanced the stability of the Au complexes, thereby promoting efficient Au leaching. Comparing with other leaching methods, this study of WS NBS–DMF provides a safe, economic and eco-friendly technique for efficient and selective gold recovery from e-waste.

Photoinduced Vitamin-B12-Catalyzed meta-C-H Bromination/Chlorination of Phenol Derivatives Assisted by a U-Shaped Nitrile Template.

A photoinduced vitamin-B12-catalyzed meta-C-H bromination/chlorination of phenol derivatives was established using a nitrile directing template and N-bromosuccinimide (NBS)/N-chlorosuccinimide (NCS) as halogenated reagents, and a series of meta-bromination/chlorination products were obtained in yields of 51 to 80%. This strategy overcame the selectivity problem of phenols, which have difficulty obtaining meta-products through conventional electrophilic reactions. Furthermore, natural product resveratrol and an intermediate of the γ-secretase inhibitor were successfully synthesized, which demonstrates the practicability of this method.

The Crystal Structures of Some Bromo-Derivatives of the DPPH Stable Free Radical

Bromination of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical with bromine or N-bromo-succinimide (NBS) affords a complex mixture of bromo- and nitro-derivatives of the starting material. In this study, by chromatographic separation, most of the reaction products were isolated. Suitable crystals for X-ray measurements were obtained and characterized for the compounds 2-p-bromophenyl-2-phenyl-1-picrylhydrazyl free radical (Br-DPPH), 2-p-bromophenyl-2-phenyl-1-picrylhydrazine (Br-DPPH-H), and 2,2-(p-bromophenyl)-1-(2-bromo-4,6-dinitrophenyl)hydrazine (Br2-DPPBr-H).

Etched-suppressed gold nanorods providing highly distinctive plasmonic patterns: Towards multiplex analysis of neuroblastoma biomarkers

BackgroundOn-site monitoring of vanillylmandelic acid (VMA), homovanillic acid (HVA), and dopamine (DA) as key diagnostic biomarkers for a wide range of neurological disorders holds utmost significance in clinical settings. Numerous colorimetric sensors with mechanistic approaches based on aggregation or silver metallization have been introduced for this purpose. However, these mechanisms have drawbacks, such as sensitivity to environmental factors and probe toxicity. Therefore, there is a great demand for a robust yet non-toxic colorimetric sensor that employs a novel route to monitor these biomarkers effectively. ResultsHere, we present a single-component multi-colorimetric probe based on the controllable etching suppression of gold nanorods (AuNRs) upon exposure to the mild etchant N-bromosuccinimide (NBS), designed to accurately detect and discriminate VMA, HVA, DA, and their corresponding mixtures, i.e., VMA:HVA, VMA:DA, HVA:DA, and VMA:HVA:DA. To enhance the sensitivity and automation capabilities of the designed multi-colorimetric sensor, two machine learning techniques were employed: linear discriminant analysis (LDA) for the qualitative classification and partial least-squares regression (PLSR) for the quantitative analysis of pure biomarkers and their mixtures. The outcomes revealed a high correlation between measured and predicted values, covering a linear range of 0.8–25, 1.2–25, and 2.7–100 μmol L−1, with remarkably low detection limits of 0.260, 0.397, and 0.913 μmol L−1 for VMA, HVA, and DA, respectively. Lastly, the performance of the probe was validated by successfully detecting the neuroblastoma biomarker VMA:HVA in human urine. SignificanceOur designed multi-colorimetric probe introduces a rapid, cost-effective, user-friendly, non-toxic, and non-invasive approach to detecting and discriminating not only the pure biomarkers but also their corresponding binary and ternary mixtures. The distinctive response profiles produced by the probe in the presence of different mixture ratios can indicate various disease states in patients, which is highly crucial in clinical diagnostics.

M-Pyripentaphyrins(1.0.0.0.0): BIII Complexes and β-β Directly Linked Dimers.

m-Pyripentaphyrins(1.0.0.0.0) were synthesized by Suzuki-Miyaura coupling of 3,5-bis(5-borylpyrrol-2-yl)-BODIPY with 2,6-dibromopyridine. Upon treatment with PhBCl2, pyripentaphyrin 1 provided mono- and bis-BIII complexes sequentially. The Mono-BIII complex shows a distorted tetrahedral coordinated BIII with a σ-phenyl ligand on the BIII and the bis-BIII complex shows an additional distorted tetrahedral coordinated BIII with a B-H bond. Bromination of the pyripentaphyrins with N-bromosuccinimide (NBS) resulted in regioselective formation of 8-bromopyripentaphyrins, which were dimerized to 8,8'-linked dimers by reductive coupling with Ni(cod)2. While all these pyripentaphyrins are nonaromatic, they exhibit characteristic broad absorption bands at long wavelength near the NIR region, indicating the presence of effective macrocyclic conjugation.

Amidation of β‐Keto Sulfonyl Fluorides via C−C Bond Cleavage

AbstractA simple protocol for amide bond construction using β‐keto sulfonyl fluorides (BKSFs) as the acyl surrogates has been achieved. The reaction of BKSFs with a range of amines could be performed in presence of N‐bromosuccinimide (NBS), affording various amides with diverse functionalities. Preliminary mechanistic studies revealed that the dibromo‐substituted sulfonyl fluorides could be the key intermediate in this amidation process.

Indirect Spectrophotometric Determination of Antidepressant Drugs by Oxidation Using Ponceau 4R Dye

A simple and sensitive indirect spectrophotometric method is developed for the assay of Adrenaline, Dopamine hydrochloride, and Methyldopa in their pure and pharmaceutical preparations. The method is based on the principle of oxidation of the above drugs with a known amount of the oxidizing agent, N-bromosuccinimide (NBS), in hydrochloric acid. The unreacted oxidant bleaches Ponceau 4R dye, then the absorbance of the remaining dye (ΔA) is measured at 507 nm. The method obeyed Beer’s law within the concentration range of 3.5-10, 4-15, and 5-20 μg/mL, with molar absorptivity values of 8.01×104, 5.32×104, and 4.93×104 L. mol-1cm-1 for Adrenaline, Dopamine hydrochloride and Methyldopa, respectively. The recovery ranged between 99.15 to 100.61%, and the relative standard deviation (RSD) was less than 1.42 % for all drug compounds. The method was applied successfully to pharmaceutical preparations for the studied medicinal compounds from different origins, as its results were in good agreement with the original content of the drugs in their pharmaceutical formulations and with the standard addition procedure, which proved that there was no interference by the excipients.

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

A Versatile Approach for the Synthesis of Antimicrobial Polymer Brushes on Natural Rubber/Graphene Oxide Composite Films via Surface-Initiated Atom-Transfer Radical Polymerization.

A simple strategy was adopted for the preparation of an antimicrobial natural rubber/graphene oxide (NR/GO) composite film modified through the use of zwitterionic polymer brushes. An NR/GO composite film with antibacterial properties was prepared using a water-based solution-casting method. The composited GO was dispersed uniformly in the NR matrix and compensated for mechanical loss in the process of modification. Based on the high bromination activity of α-H in the structure of cis-polyisoprene, the composite films were brominated on the surface through the use of N-bromosuccinimide (NBS) under the irradiation of a 40 W tungsten lamp. Polymerization was carried out on the brominated films using sulfobetaine methacrylate (SBMA) as a monomer via surface-initiated atom transfer radical polymerization (SI-ATRP). The NR/GO composite films modified using polymer brushes (PSBMAs) exhibited 99.99% antimicrobial activity for resistance to Escherichia coli and Staphylococcus aureus. A novel polymer modification strategy for NR composite materials was established effectively, and the enhanced antimicrobial properties expand the application prospects in the medical field.

Butadiene Sulfone-catalyzed Monobromination of Arenes with NBS as the Bromination Source: A Simple, Mild, Efficient, and Chemoselective Protocol

Abstract: In literature, dimethyl sulfoxide (DMSO) catalyzed bromination of arenes and heteroarenes is reported. In this study, simple, mild, and chemoselective N-bromosuccinimide (NBS) mediated monobromination of arenes and heteroarenes using butadiene sulfone as a catalyst is reported. : Butadiene sulfone is a good substitute for DMSO as it is volatile, easy to recover and recycle, and environment- friendly. The method has been demonstrated to give high-yield brominated products for an extensive range of activated and deactivated arenes.

Purification and characterization of L-arginine deiminase from Penicillium chrysogenum

L-arginine deiminase (ADI, EC 3.5.3.6) hydrolyzes arginine to ammonia and citrulline which is a natural supplement in health care. ADI was purified from Penicillium chrysogenum using 85% ammonium sulfate, DEAE-cellulose and Sephadex G200. ADI was purified 17.2-fold and 4.6% yield with a specific activity of 50 Umg− 1 protein. The molecular weight was 49 kDa. ADI expressed maximum activity at 40oC and an optimum pH of 6.0. ADI thermostability was investigated and the values of both t0.5 and D were determined. Kd increased by temperature and the Z value was 38oC. ATP, ADP and AMP activated ADI up to 0.6 mM. Cysteine and dithiothreitol activated ADI up to 60 µmol whereas the activation by thioglycolate and reduced glutathione (GSH) prolonged to 80 µmol. EDTA, α,α-dipyridyl, and o-phenanthroline inactivated ADI indicating that ADI is a metalloenzyme. N-ethylmaleimide (NEM), N-bromosuccinimide (NBS), butanedione (BD), dansyl chloride (DC), diethylpyrocarbonate (DEPC) and N-acetyl-imidazole (NAI) inhibited ADI activity indicating the necessity of sulfhydryl, tryptophanyl, arginyl, lysyl, histidyl and tyrosyl groups, respectively for ADI catalysis. The obtained results show that ADI from P. chrysogenum could be a potential candidate for industrial and biotechnological applications.

Construction and Preclinical Evaluation of 124I/125I-Labeled Antibody Targeting T Cell Immunoglobulin and Mucin Domain-3.

T cell immunoglobulin and mucin domain-3 (TIM3; HAVCR2) is a transmembrane protein that exerts negative regulatory control over T cell responses. Studies have demonstrated an upregulation of TIM3 expression in tumor-infiltrating lymphocytes (TILs) in cancer patients. In this investigation, a series of monoclonal antibodies targeting TIM3 were produced by hybridoma technology. Among them, C23 exhibited favorable biological properties. To enable specific binding, we developed a 124I/125I-C23 radio-tracer via N-bromosuccinimide (NBS)-mediated labeling of the monoclonal antibody C23. Binding affinity and specificity were assessed using the 293T-TIM3 cell line, which overexpresses TIM3, and the parent 293T cells. Furthermore, biodistribution and in vivo imaging of 124I/125I-C23 were examined in HEK293TIM3 xenograft models and allograft models of 4T1 (mouse breast cancer cells) and CT26 (mouse colon cancer cells). Micro-PET/CT imaging was conducted at intervals of 4, 24, 48, 72, and/or 96 h post intravenous administration of 3.7-7.4 MBq 124I-C23 in the respective model mice. Additionally, immunohistochemistry (IHC) staining of TIM3 expression in dissected tumor organs was performed, along with an assessment of the corresponding expression of Programmed Death 1 (PD1), CD3, and CD8 in the tumors. The C23 monoclonal antibody (mAb) specifically binds to TIM3 protein with a dissociation constant of 23.28 nM. The 124I-C23 and 125I-C23 radio-tracer were successfully prepared with a labeling yield of 83.59 ± 0.35% and 92.35 ± 0.20%, respectively, and over 95.00% radiochemical purity. Stability results indicated that the radiochemical purity of 124I/125I-C23 in phosphate-buffered saline (PBS) and 5% human serum albumin (HSA) was still >80% after 96 h. 125I-C23 uptake in 293T-TIM3 cells was 2.80 ± 0.12%, which was significantly higher than that in 293T cells (1.08 ± 0.08%), and 125I-C23 uptake by 293T-TIM3 cells was significantly blocked at 60 and 120 min in the blocking groups. Pharmacokinetics analysis in vivo revealed an elimination time of 14.62 h and a distribution time of 0.4672 h for 125I-C23. Micro-PET/CT imaging showed that the 124I-C23 probe uptake in the 293T-TIM3 model significantly differed from that of the negative control group and blocking group. In the humanized mouse model, the 124I-C23 probe had obvious specific uptake in the 4T1 and CT26 models and maximum uptake at 24 h in tumor tissues (SUVmax (the maximum standardized uptake value) in 4T1 and CT26 humanized TIM3 murine tumor models: 0.59 ± 0.01 and 0.76 ± 0.02, respectively). Immunohistochemistry of tumor tissues from these mouse models showed comparable TIM3 expression. CD3 and CD8 cells and PD-1 expression were also observed in TIM3-expressing tumor tissues. The TIM3-targeting antibody C23 showed good affinity and specificity. The 124I/125I-C23 probe has obvious targeting specificity for TIM3 in vitro and in vivo. Our results suggest that 124I/125I-C23 is a promising tracer for TIM3 imaging and may have great potential in monitoring immune checkpoint drug efficacy.

Design, synthesis and anticholinergic properties of novel α-benzyl dopamine, tyramine, and phenethylamine derivatives

Due to the important biological properties of dopamine, phenethylamine, and tyramine derivatives in the central nervous system, herein the synthesis of novel α-benzyl dopamine, phenethylamine, and tyramine derivatives is described. The title compounds were synthesized starting from 3-phenylpropanoic acids and methoxybenzenes in six or seven steps. Firstly, 3-(2,3-dimethoxyphenyl)propanoic acid (11) and 3-(3,4-dimethoxyphenyl)propanoic acid (12) were selectively brominated with N-bromosuccinimide (NBS). The Friedel–Crafts acylation of methoxylated benzenes with these brominated acids or commercially available 3-phenylpropanoic acid in polyphosphoric acid gave the desired dihydrochalcones. α-Carboxylation of dihydrochalcones, reduction of benzylic carbonyl groups, hydrolysis of esters to acid derivatives, and the Curtius rearrangement reaction of acids followed by in situ synthesis of carbamates from alkyl isocyanates and hydrogenolysis of the carbamates afforded the title compounds in good total yields. Alzheimer's disease (AD) and Parkinson's disease (PD) are chronic neurodegenerative diseases that become serious over time. However, the exact pathophysiology of both diseases has not been revealed yet. There have been many different approaches to the treatment of patients for many years, especially studies on the cholinergic system cover a wide area. Within the scope of this study, the inhibition effects of dopamine-derived carbamates and amine salts on the cholinergic enzymes AChE and BChE were examined. Dopamine-derived carbamate 24a-i showed inhibition in the micro-nanomolar range; compound 24d showed a Ki value of 26.79 nM against AChE and 3.33 nM against BChE, while another molecule, 24i, showed a Ki range of 27.24 nM and 0.92 nM against AChE and BChE, respectively. AChE and BChE were effectively inhibited by dopamine-derived amine salts 25j-s, with Ki values in the range of 17.70 to 468.57 µM and 0.76–211.23 µM, respectively. Additionally, 24c, 24e and 25m were determined to be 60, 276 and 90 times more selective against BChE than AChE, respectively.

Indium(III)‐Catalyzed Three Component Reaction of N‐Bromosuccinimide, Alkenes and N‐Tosylhydrazones

AbstractA three‐component reaction involving alkenes, N‐sulfonylhydrazones, and N‐bromosuccinimide (NBS) is described that uses Indium(III) triflate for the synthesis of bromoethyl sulfonyl hydrazones. Using N‐tosylhydrazones as a nitrogen source and NBS as a bromine source, this intermolecular aminobromination of alkenes is carried out under air in mild conditions. A mechanism of electrophilic addition is proposed based on the GC‐MS analytical result.

Zinc‐bis(imino)pyridine Complexes as Catalysts for Intermolecular Amidation of Benzylic C(sp3)−HBond

AbstractEfficient NNN‐pincer type bis(imino)pyridine ligand based zinc(II) catalyzed intermolecular amidation of benzylic hydrocarbons with sulfonamides has been developed. The zinc complexes were synthesized by the reaction of bis(imino)pyridine ligand with zinc(II) precursors such as Zn(OAc)2 ⋅ 2H2Oand ZnBr2. The structure of the bis(imino)pyridine‐Zn(OAc)2 complex was characterized by single crystal X‐ray diffraction. The zinc(II)‐bis(imino)pyridine complexes were utilized as catalysts for the intermolecular amidation of benzylic C(sp3)−H bond in the presence of N‐bromosuccinimide (NBS) as an oxidant. A broad range of substrates delivered the products in moderate to good yields. This protocol provides the synthesis of various amides viaC−H activation.

Visible Light-Assisted Ring-Opening of Cyclic Ethers with Carboxylic Acids Mediated by Triphenylphosphine and N-Halosuccinimides.

The ring-opening of cyclic ethers (epoxide, oxetane, THF, and THP) by carboxylic acids was achieved by using N-iodosuccinimide (NIS) or N-bromosuccinimide (NBS) and triphenylphosphine under blue light. The corresponding ω-haloalkyl carboxylates were obtained under mild reaction conditions. The reaction is believed to work through a halogen bond complex between NIS (or NBS) and triphenylphosphine, which, upon irradiation with blue light, produces the key phosphine radical cation intermediate that initiates the ring-opening reactions.

Visible-light-induced C-S bond formation in the synthesis of 2,4-disubstituted thiazoles through cascade difunctionalization of acetophenone: a greener approach.

A groundbreaking approach has been developed for synthesizing 2,4-disubstituted thiazoles using an eco-friendly and metal-free approach. This novel method utilizes methyl aryl ketones, N-bromo-succinimide (NBS), and thioamides in water as a green reaction medium under visible light irradiation. Using NBS as a bromine source, the reaction takes place through an in situ α-bromination method. This approach does not require any catalyst, which makes it exceptionally beneficial for the environment. The advantages of this efficient approach are manifold and include the use of greener conditions, absence of metals, easy isolation of products, cost-effectiveness, non-toxicity, and reliance on renewable energy sources like visible light. Moreover, this technique offers higher product purity and excellent yield, enhancing itsappeal.

Halogenation of aromatic compounds with N-halosuccinimides (NXS) catalysed by D-camphorsulfonic acid-BiCl3.

Aromatic bromination catalysed by 0.5-10 mol% of D-camphorsulfonic acid-BiCl3 with N-bromosuccinimides (NBS) was carried out in MeCN under air conditions, and the procedure was extended to the reactions with N-chlorosuccinimides (NCS) and N-iodosuccinimides (NIS). The halogenation of some drugs and natural products was also attempted. One-pot bromination/Suzuki-Miyaura cross-coupling and bromination/Sonogashira coupling reactions were achieved without the removal of the solvent.

Indirect Spectrophotometric Determination of Mefenamic Acid using Safranin Dye

A simple, accurate, and rapid indirect spectrophotometric method has been developed for the determination of mefenamic acid in its pure form and in pharmaceutical preparations. The method is based on the oxidation of the mefenamic acid by N-bromosuccinimide (NBS) (excess) and estimating the amount of unconsumed NBS by safranin dye in the presence of the acid and the surfactant SDS in the aqueous medium at λmax = 527 nm. Regression analysis of Beer–Lambert's plot proves excellent correlation in the concentration ranges 0.025 – 5 μg mL-1 with a correlation coefficient 0.993. A molar absorptivity, Sandell sensitivity, and limits of detection (LOD) and quantification (LOQ) were calculated to be 2.05×104 L mol-1 cm-1, 0.0117 μg cm-2, 0.254 μg mL-1 and 0.847 μg mL-1, respectively. The possibility of quantitative determination of mefenamic acid in pure form and in pharmaceutical preparations in the form of syrup and capsules with average recoveries 102.57 %, 100.88 %, and 100.57 %, and RSD ≤ 1.69 %, ≤1.42 % and ≤1.89 % also, respectively, are shown.

Synthesis of methyl 3,4-anhydro-6-bromo-2-o-tert-butyldimethylsilyl-6-deoxy-α-d-allopyranoside from α-d-glucose

Some of simple carbohydrates and their derivatives are used clinically for the treatment of various diseases. Epoxide derivatives, which can be obtained by the intramolecular elimination of water from two vicinal hydroxyl groups, are stable, but sufficiently reactive compounds very often used as intermediaries in various syntheses. Synthesis of epoxide derivative, methyl 3,4-anhydro-6- bromo-2-O-tert-butyldimethylsilyl-6-deoxy-?-D-allopyranoside from ?-D-glucose was achieved in high yields in the minimal number of synthetic steps. Anhydrous glucose was used as a starting material which was transformed into methyl ?-D-glucopyranoside using dry, gaseous hydrogen chloride. Thus obtained derivative was treated with benzaldehyde in the presence of zinc chloride as Lewis acid giving methyl (R)-4,6-O-benzylidene-?-D-glucopyranoside. Obtained compound was treated with NBS (N-bromosuccinimide) in dichloromethane in the presence of barium carbonate giving methyl 4-O-benzoyl-6-bromo-6-deoxy-?-D-glucopyranoside. In the next step obtained compound was treated with TBDMSCl (tert-butyldimethylsilyl chloride) in pyridine, and methyl 4-O-benzoyl-6-bromo-2-O-tert-butyldimethylsilyl-6-deoxy-?-D-glucopyranoside was further mesylated, and obtained methyl 4-O-benzoyl-6-bromo-2-O-tert-butyldimethylsilyl-6-deoxy-3- O-mesyl-?-D-glucopyranoside was treated at the end with KOH to give methyl 3,4-anhydro-6-bromo-2-O-tert-butyldimethylsilyl-6-deoxy-?-D-allopyranoside (yield 78 %).