Ultrasonic and microwave effects in polyethylene glycol-bound metal nitrate initiated nitration of aromatic compounds under acid free conditions

Rajanna, K. C.; Chary, V. Sudhakar; Kumar, M. Satish; Krishnaiah, G.; Srinivas, P.; Venkanna, P.; Venkateswarlu, M.; Ramesh, K.; Reddy, K. Rajendar; Suresh, B.

doi:10.1080/17518253.2015.1105309

Cited by 4 publications

(3 citation statements)

References 19 publications

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“…These experiments suggest that the presence of PEG can promote nitration in RNase A more effectively both at pH 6.0 and 7.4. Although the mechanism of PEG mediated nitration in proteins is still unclear, previous experiments support the enhancement of nitration in organic compounds when reactions are carried out in a PEG medium …”

Section: Resultsmentioning

confidence: 99%

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pH‐Dependent Nitrotyrosine Formation in Ribonuclease A is Enhanced in the Presence of Polyethylene Glycol (PEG)

Roy

Panda

Hati

et al. 2019

Chemistry An Asian Journal

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Protein nitration can occur as ar esult of peroxynitrite-mediated oxidative stress. Excess production of peroxynitrite (PN) within the cellular mediumc an cause oxidative damage to biomolecules.T he in vitro nitration of Ribonuclease A( RNase A) resultsi nn itrotyrosine (NT) formation with as trong dependence on the pH of the medium. In order to mimic the cellular environment in this study,P Nmediated RNase An itration has been carried out in ac rowd-ed medium. The degree of nitration is higher at pH 7.4 (physiological pH) compared to pH 6.0 (tumorc ell pH). The extent of nitration increases significantly when PN is added to RNase Ai nt he presence of crowding agentsP EG 400 and PEG 6000. PEG has been found to stabilize PN overaprolonged period,t hereby increasing the degree of nitration. NT formation in RNase Aa lso results in as ignificant loss in enzymatic activity.Scheme1.Generation of peroxynitrite and subsequent formation of nitrating species.

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Section: Resultsmentioning

confidence: 99%

“…Althought he mechanism of PEG mediated nitration in proteins is still unclear,p revious experimentss upport the enhancement of nitration in organic compounds when reactions are carriedo ut in aP EG medium. [58,59]…”

Section: Fluorescence Quenching Studiesmentioning

confidence: 99%

pH‐Dependent Nitrotyrosine Formation in Ribonuclease A is Enhanced in the Presence of Polyethylene Glycol (PEG)

Roy

Panda

Hati

et al. 2019

Chemistry An Asian Journal

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“…In the cases of p-cresol (1f) and 2-naphthol (1j), the nitration occurred at the hydroxyl group to give 4-tolyl nitrate (4f) and 2-naphthyl nitrate (4j), respectively. Usual nitration of 4f and 4j in solution occurred at aromatic ring [25]. Recently it was reported that the efficient nitration of phenol and phenol derivatives with Al(NO 3 ) 3 ·9H 2 O [12] [13] and Bi(NO 3 ) 3 ·5H 2 O [26] on silica gel occurred at aro-matic ring.…”

Section: Solid-phase Nitration Of Aromatic Hydrocarbons (1) With Mg(nmentioning

confidence: 99%

Solid-Phase Aromatic Nitration with Mg(NO<sub>3</sub>)<sub>2</sub> on Silica Gel

Matsumoto¹,

Yamauchi²,

Ishikawa³

et al. 2017

IJOC

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Nitroaromatics are usually prepared using a mixed acid of nitric acid with strong acids. However, the use of strong acids caused dangerous work-up and the disposal of large amounts of acid-waste. Therefore, much effort has been made on the improvement of nitration process without strong acids. We examined solid-phase aromatic nitration with Mg(NO 3 ) 2 on silica gel in order to establish the nitration process without strong acids. The nitration of 1,2-and 1,3-, 1,4-dimethoxybenzenes and 4-methylanisole with Mg(NO 3 ) 2 proceeded by heating on silica gel at 150˚C for 4 -5 h to produce the nitroaromatics. The nitration of 1,3,5-trimethoxybenzene produced the nitrated dimer, 2,4,6,2', 4',6'-hexamethoxy-3-nitrobiphenyl, which was not isolated in other solid-phase nitration. In the cases of naphthalene derivatives, the α-nitrated compounds were obtained. In the cases of p-cresol and 2-naphthol, the esterification occurred at the hydroxyl group to give 4-tolyl nitrate and 2-naphthyl nitrate, respectively. It is synthetic interest to note that nitrate esters were isolated in solid phase. Thus Mg(NO 3 ) 2 -SiO 2 composite was mild reagent for solid-phase nitration. Acidity of Mg(NO 3 ) 2 -SiO 2 composite was determined to be pH 0.96 by the measurement of absorption spectra on a micro spectrophotometer using meso-tetra(p-cyanophenyl)porphyrin as a pH-indicator. Mg(NO 3 ) 2 -SiO 2 composite made acidic conditions. Therefore, it was suggested that Mg(NO 3 ) 2 reacted with proton on silica gel to form the 2 NO + . Thus, electron-rich aromatic hydrocarbons led the efficient nitration through electrophilic attack of 2 NO + . After the nitration, acidic Mg(NO 3 ) 2 -SiO 2 composite could be turned into neutrality by exposing wet conditions and disposed safely since the composite did not involve harmful elements. Thus the solid-phase nitration using Mg(NO 3 ) 2 -SiO 2 composite will provide safety and environmentally conscious chemical process.

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Mechanochemical nitration of toluene with metal oxide catalysts

Vasudevan

Schoenitz

Dreizin

2020

Applied Catalysis A: General

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Ultrasonic and microwave effects in polyethylene glycol-bound metal nitrate initiated nitration of aromatic compounds under acid free conditions

Cited by 4 publications

References 19 publications

pH‐Dependent Nitrotyrosine Formation in Ribonuclease A is Enhanced in the Presence of Polyethylene Glycol (PEG)

pH‐Dependent Nitrotyrosine Formation in Ribonuclease A is Enhanced in the Presence of Polyethylene Glycol (PEG)

Solid-Phase Aromatic Nitration with Mg(NO<sub>3</sub>)<sub>2</sub> on Silica Gel

Mechanochemical nitration of toluene with metal oxide catalysts

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Ultrasonic and microwave effects in polyethylene glycol-bound metal nitrate initiated nitration of aromatic compounds under acid free conditions

Cited by 4 publications

References 19 publications

pH‐Dependent Nitrotyrosine Formation in Ribonuclease A is Enhanced in the Presence of Polyethylene Glycol (PEG)

pH‐Dependent Nitrotyrosine Formation in Ribonuclease A is Enhanced in the Presence of Polyethylene Glycol (PEG)

Solid-Phase Aromatic Nitration with Mg(NO&lt;sub&gt;3&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt; on Silica Gel

Mechanochemical nitration of toluene with metal oxide catalysts

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Solid-Phase Aromatic Nitration with Mg(NO<sub>3</sub>)<sub>2</sub> on Silica Gel