An efficient regioselective NBS aromatic bromination in the presence of an ionic liquid

Pingali, Subramanya R. K.; Madhav, Monika; Jursic, Branko S.

doi:10.1016/j.tetlet.2010.01.002

Cited by 43 publications

(20 citation statements)

References 23 publications

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“…Despite the enormous pharmacological [ 11 , 12 , 13 , 15 , 16 , 17 ] and chemical [ 19 , 20 , 21 , 22 , 23 , 24 ] interest in the N -unsubstituted 2-aminobenzamides, to our knowledge, the presence of intramolecular hydrogen bonding in these compounds has been less demonstrated in the literature [ 25 , 26 , 27 , 28 ]. This prompted us to study the structural properties of the known 5-bromo/iodo- and 3,5-dihalogenated 2-aminobezamides by means of spectroscopic (NMR, UV-Vis, IR, Raman) methods and single X-ray crystallography in combination with density functional theory methods.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic, DFT, and XRD Studies of Hydrogen Bonds in N-Unsubstituted 2-Aminobenzamides

et al. 2017

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The structures of the mono- and the dihalogenated N-unsubstituted 2-aminobenzamides were characterized by means of the spectroscopic (1H-NMR, UV-Vis, FT-IR, and FT-Raman) and X-ray crystallographic techniques complemented with a density functional theory (DFT) method. The hindered rotation of the C(O)–NH2 single bond resulted in non-equivalence of the amide protons and therefore two distinct resonances of different chemical shift values in the 1H-NMR spectra of these compounds were observed. 2-Amino-5-bromobenzamide (ABB) as a model confirmed the presence of strong intramolecular hydrogen bonds between oxygen and the amine hydrogen. However, intramolecular hydrogen bonding between the carbonyl oxygen and the amine protons was not observed in the solution phase due to a rapid exchange of these two protons with the solvent and fast rotation of the Ar–NH2 single bond. XRD also revealed the ability of the amide unit of these compounds to function as a hydrogen bond donor and acceptor simultaneously to form strong intermolecular hydrogen bonding between oxygen of one molecule and the NH moiety of the amine or amide group of the other molecule and between the amine nitrogen and the amide hydrogen of different molecules. DFT calculations using the B3LYP/6-311++G(d,p) basis set revealed that the conformer (A) with oxygen and 2-amine on the same side predominates possibly due to the formation of a six-membered intramolecular ring, which is assisted by hydrogen bonding as observed in the single crystal XRD structure.

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Section: Introductionmentioning

confidence: 99%

Spectroscopic, DFT, and XRD Studies of Hydrogen Bonds in N-Unsubstituted 2-Aminobenzamides

et al. 2017

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“…The applications of brominated aldehydes have been a matter of concern since they are promising targets to be utilized as precursors to yield natural products,, and also as salen‐type ligands in asymmetric catalysis . Aryl bromides can be obtained using a number of methodologies such as sandmeyer reaction, elemental bromination, and regioselective nuclear bromination applying NBS with tetrabutylammonium or dioxane dibromide. 18 Yet, harsh reaction conditions, solvent toxicity and auxiliary reagents requirement have led to further research to explore new synthetic pathways.…”

Section: Bromination Of Aniline and Phenol Derivatives (Scheme Entrmentioning

confidence: 99%

Urea‐2,2‐dihydroperoxypropane as a Novel and High Oxygen Content Alternative to Dihydroperoxypropane in Several Oxidation Reactions

Khosravi

Naserifar

2019

ChemistrySelect

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Urea‐2,2‐dihydroperoxypropane (UDHPP)‐ a white crystalline solid oxidant which is formed when urea is recrystallized from dihydroperoxypropane‐ was applied as the terminal oxidant in several oxidative procedures namely epoxidation of α, β‐unsaturated ketones and alkenes, oxidation of sulfides to sulfoxides and sulfones, bayer‐villeger reaction, bromination and iodation of aniline and phenol derivatives, oxidative esterification, oxidative amidation of aromatic aldehydes, thiocyanation of aromatic compounds, and oxidation of pyridines, oxidation of secondary, allylic and benzylic alcohols. All the approaches were carried out under mild conditions and short reaction times and afforded the corresponding products in high yields.

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“…The selections of new bromination methods have been used along with the conventional reagent-bromine to improve the efficiency and selectivity (Pingali et al, 2010). Few examples are Br2/SO2/Cl2 (Surine andMajewski, 1968, Hai andNelson, 1991), Br2/SbF3/HF (Bedekar et al, 2005), Br2/Ag2SO4 (De La Mare, 1976), Br2H2O2 (Encyclopedia of Chemicals, 1990), Br2/H2O2/LDH-WO4 (Adimurthy et al, 2006), Br2-silica (Zolfigol et al, 2007) etc.…”

Section: Introductionmentioning

confidence: 99%

Eco-friendly and fast bromination of industrially-important aromatic compounds in water using recyclable AlBr3-Br2 system

Sharma¹,

Consultant²

2019

Preprint

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A fast, efficient, simple, eco-friendly, regioselective, controllable and economical method for the bromination of aromatic compounds using AlBr3-Br2 system was invetigated. The direct bromination of anilines and phenols with molecular bromine in solution frequently results in polybromination, and when brominated in the existence of oxidants, they also get oxidized rather than experiencing substitutions and in some cases, require fortification of the amino (-NH2) group.

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An efficient regioselective NBS aromatic bromination in the presence of an ionic liquid

Cited by 43 publications

References 23 publications

Spectroscopic, DFT, and XRD Studies of Hydrogen Bonds in N-Unsubstituted 2-Aminobenzamides

Spectroscopic, DFT, and XRD Studies of Hydrogen Bonds in N-Unsubstituted 2-Aminobenzamides

Urea‐2,2‐dihydroperoxypropane as a Novel and High Oxygen Content Alternative to Dihydroperoxypropane in Several Oxidation Reactions

Eco-friendly and fast bromination of industrially-important aromatic compounds in water using recyclable AlBr3-Br2 system

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