Indole as a reagent for nitrite in aqueous solution

Rahim, S.A.; Fakhri, Neda; Bashir, Wadala A.

doi:10.1016/0026-265x(83)90004-8

Cited by 15 publications

(5 citation statements)

References 15 publications

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“…Communications incompatible with the in situ diazonium formation. [25] However,when pre-formed diazonium salt was added to N-Boc-l-Tr p-l-Cys-OMe,t he corresponding arylated derivative 10 a was obtained in 39 %yield. Finally, N-Boc-l-Phe-l-Cys-OMe afforded the corresponding arylated derivative 11 a in 55 % yield.…”

Section: Angewandte Chemiementioning

confidence: 99%

Visible‐Light‐Mediated Selective Arylation of Cysteine in Batch and Flow

et al. 2017

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A mild visible‐light‐mediated strategy for cysteine arylation is presented. The method relies on the use of eosin Y as a metal‐free photocatalyst and aryldiazonium salts as arylating agents. The reaction can be significantly accelerated in a microflow reactor, whilst allowing the in situ formation of the required diazonium salts. The batch and flow protocol described herein can be applied to obtain a broad series of arylated cysteine derivatives and arylated cysteine‐containing dipeptides. Moreover, the method was applied to the chemoselective arylation of a model peptide in biocompatible reaction conditions (room temperature, phosphate‐buffered saline (PBS) buffer) within a short reaction time.

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Section: Angewandte Chemiementioning

confidence: 99%

Visible‐Light‐Mediated Selective Arylation of Cysteine in Batch and Flow

et al. 2017

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“…For validation purposes, the nitrite content in sausage samples was also determined by UV–vis spectroscopy, according to the method reported in ref . First, a calibration curve was built with standard nitrite solutions at six different concentrations.…”

Section: Methodsmentioning

confidence: 99%

Iron Oxide, Reduced Graphene Oxide, and Electrodeposited Gold Nanoparticle-Based Electrodes for Nanomolar Detection of Nitrite in Food

Gross,

Paterno

2024

ACS Appl. Nano Mater.

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The nitrite ion (NO2 –) is used as a preservative of food and drink and has been widely used in the food industry. Nonetheless, it is a potential precursor of nitrosamines, which are known for their carcinogenic activity. Therefore, monitoring of nitrite in foods and drinks is of paramount importance for food safety. Herein, we report a very sensitive electroanalytical method for the determination of nitrite in food samples, capable of detecting nitrite at the nanomolar level. For that purpose, a nanocomposite electrode comprising a multilayered film of iron oxide nanoparticles and reduced graphene oxide (ION-RGO) was decorated with electrodeposited gold nanoparticles (AuNP) and operated by electrochemical impedance spectroscopy (EIS). It is observed a synergistic combination of the electrocatalytic activity of ION-RGO, the electrical conductivity of AuNP, and the interrogation of the electrode within the charge-transfer frequency range, which mitigates unwanted capacitive effects and enhances the nitrite electrooxidation. Consequently, nitrite has been detected within a wide linear range (r 2 > 0.999) of 0.58–3019 μM and with a limit of detection of 2.4 nM. Owing to the improved adhesion of AuNP to the ION-RGO framework, the electrode is highly stable and lasts for at least 30 consecutive runs without losing its sensitivity. Additionally, the proposed method enables the determination of nitrite in sausage and milk samples, when it performs identically to a reference method at the 95% confidence level.

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“…A remarkable acceleration and increase in yield was observed when the arylation of N ‐Boc‐ l ‐Leu‐ l ‐Cys‐OMe was conducted in flow. When attempting the arylation of N ‐Boc‐ l ‐Trp‐ l ‐Cys‐OMe, we found the presence of indole to be incompatible with the in situ diazonium formation . However, when pre‐formed diazonium salt was added to N ‐Boc ‐ l ‐Trp‐ l ‐Cys‐OMe, the corresponding arylated derivative 10 a was obtained in 39 % yield.…”

Section: Optimization Of Reaction Conditions In Batch For Cysteine Armentioning

confidence: 99%

“…Zuschriften incompatible with the in situ diazonium formation. [25] However,when pre-formed diazonium salt was added to N-Boc-l-Tr p-l-Cys-OMe,t he corresponding arylated derivative 10 a was obtained in 39 %yield. Finally, N-Boc-l-Phe-l-Cys-OMe afforded the corresponding arylated derivative 11 a in 55 % yield.…”

Section: Angewandte Chemiementioning

confidence: 99%

Visible‐Light‐Mediated Selective Arylation of Cysteine in Batch and Flow

et al. 2017

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Am ild visible-light-mediated strategy for cysteine arylation is presented. The method relies on the use of eosin Y as am etal-free photocatalyst and aryldiazonium salts as arylating agents.T he reaction can be significantly accelerated in amicroflowreactor,whilst allowing the in situ formation of the required diazonium salts.T he batch and flowp rotocol described herein can be applied to obtain ab road series of arylated cysteine derivatives and arylated cysteine-containing dipeptides.M oreover,t he method was applied to the chemoselective arylation of am odel peptide in biocompatible reaction conditions (room temperature,p hosphate-buffered saline (PBS) buffer) within ashort reaction time.TheformationofC À Sbonds is of high interest in the fields of organic synthesis and drug discovery.[1] However,d ue to the undesired coordination between metal catalysts and sulfur atoms,t raditional cross-coupling methods are often inadequate strategies for C À Sb ond formation.[2] Despite the undesired coordination, some transition-metal-catalyzed cross-coupling methods for C À Sb ond formation have been reported.[3] However,t hese methods often rely on high reaction temperatures and/or require stoichiometric amounts of as trong base.Awell-known strategy largely applied in industry for C À Sb ond formation is the so-called StadlerZiegler reaction, in which adiazonium salt reacts with an aryl thiolate to afford the desired thioether derivative.[4] Starting from the original conditions reported by Stadler and Ziegler, ap lethora of methodologies have emerged, allowing milder reaction conditions.[5] Among them, our group reported am ild one-pot procedure for the synthesis of arylsulfides facilitated by photoredox catalysis. [6] In the interest of developing mild methodologies for chemical biology purposes, [7] we envisaged modifying our procedure to achieve av isible-light-induced protocol for cysteine arylation. Specifically,w ed irected our attention towards the development of ab iocompatible metal-free strategy involving inexpensive organic dyes as photoredox catalysts.Inaddition, due to the incompatibility of UV light to peptides and proteins,w er easoned that visible light photoredox catalysis would be perfectly suited to chemical biology applications owing to the milder reaction conditions (e.g. room temperature and visible light).Novel selective chemical modifications of peptides and proteins are of pivotal importance for the study of proteinprotein interactions and for the development of novel bioconjugates and drug candidates.[8] Compared to other amino acids commonly targeted for post-translational modifications,c ysteinee xhibits low natural abundancya nd ar elatively high nucleophilicity.[9] Together,t hese characteristics account for the generally higher selectivity and the broad reactivity profile typical for post-translational chemical modifications involving cysteine residues.S ome of the most widespread strategies for cysteine bioconjugation include disulfide formation, [10] thiol-maleimide reactions...

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Indole as a reagent for nitrite in aqueous solution

Cited by 15 publications

References 15 publications

Visible‐Light‐Mediated Selective Arylation of Cysteine in Batch and Flow

Visible‐Light‐Mediated Selective Arylation of Cysteine in Batch and Flow

Iron Oxide, Reduced Graphene Oxide, and Electrodeposited Gold Nanoparticle-Based Electrodes for Nanomolar Detection of Nitrite in Food

Visible‐Light‐Mediated Selective Arylation of Cysteine in Batch and Flow

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