Environmentally benign chlorination and bromination of aromatic amines, hydrocarbons and naphthols

Vyas, Punita V.; Bhatt, Anjani K.; Ramachandraiah, G.; Bedekar, Ashutosh V.

doi:10.1016/s0040-4039(03)00834-7

Cited by 141 publications

(66 citation statements)

References 17 publications

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“…In the case of 30% H 2 O 2 with bromine, the substrate β-naphthol does react but the product is 1-bromo-2-naphthol. 38 In conclusion, we have shown that several different oxidants, easily and cheaply available, can oxidize mono- (24) [Co II (salpn)] (25) [Co II (dmsalpn)] (26) [Ni II (salen)] (27) [Cu II (salen)] (28) [VO IV (salen)] (29) Figure 3. The metal-ligand catalysts.…”

Section: Resultsmentioning

confidence: 97%

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Oxidation of mono-phenols to para-benzoquinones: a comparative study

Uliana¹,

Vieira²,

Donatoni³

et al. 2008

J. Braz. Chem. Soc.

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A oxidação de mono-fenóis à para-benzoquinonas é assunto de interesse contínuo devido à existência de inúmeros produtos naturais contendo esta unidade estrutural. As para-benzoquinonas possuem reatividade química importante como agentes oxidantes e como dienófilos na reação de Diels-Alder. Usualmente nós preparamos as para-benzoquinonas pela reação de oxidação dos respectivos mono-fenóis com oxigênio molecular e catalisada por [Co II (salen)]. Porém, foi necessário estudar estas oxidações utilizando-se outros oxidantes. Nós apresentamos aqui nossos resultados sobre esta importante reação de oxidação com uma variedade de oxidantes, utilizando onze mono-fenóis como substratos. Os oxidantes utilizados foram cobalto, níquel, cobre e vanádio derivados com alguns ligantes do tipo salen. Também foram estudados peróxido de hidrogênio, OXONE®, dimetil dioxirano e ácido iodoxibenzóico.The oxidation of mono-phenols to para-benzoquinones is of continuing interest due to the existence of numerous natural products containing this structural unit. The chemical reactivity of para-benzoquinones is also noteworthy, as oxidants and dienophiles in the Diels-Alder reaction. We have used for quite some time now, molecular oxygen and catalysis with [Co II (salen)] as the oxidation procedure, but felt the need for other oxidants and conditions to be of use with different phenol substrates. We now present our results on this important oxidation with a variety of oxidants, using eleven mono-phenols as substrates. The oxidants tested are cobalt, nickel, copper and vanadyl metals, with a selection of different salen type ligands. Completing this study we also investigated the use of hydrogen peroxide, OXONE®, dimethyl dioxirane and iodoxybenzoic acid. Keywords: oxidation, alkyl-substituted phenols, para-benzoquinones IntroductionNatural products frequently occur containing the parabenzoquinone sub-structural unit within the global structure, as can be exemplified by vitamins K 1 and K 2 , co-enzyme Q (ubiquinone), 1 and in many terpenes and alkaloids. 2 These natural products 3-13 are associated with important biological properties, such as cardiovascular, anti-tumour, antibacterial, anti-germination and anti-protozoan among others. There is no doubt that the para-benzoquinone nucleus is an important charge transfer receptor and easily undergoes nucleophilic addition reactions. 1 The redox relation with para-hydroquinones (para-quinols) is of importance in biological activity, and also makes many simple para-benzoquinones excellent oxidizing agents. 1 Synthetically, the para-benzoquinone structural unit is an excellent dienophile for the Diels-Alder reaction, among other relevant reactions. 1 The usual and obvious manner to prepare parabenzoquinones 1,14,15 is from the corresponding parahydroquinones, which is however rather limited due to the lack of a wide range of commercially or synthetically available substrates. As a second choice, the simple monophenol is an ideal substrate due to the ready availability of an extremely wide range of...

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Section: Resultsmentioning

confidence: 97%

“…In the case of 30% H 2 O 2 with bromine, the substrate β-naphthol does react but the product is 1-bromo-2-naphthol. 38 In conclusion, we have shown that several different oxidants, easily and cheaply available, can oxidize mono- Oxidation of Mono-Phenols to para-Benzoquinones J. Braz. Chem.…”

mentioning

confidence: 85%

Oxidation of mono-phenols to para-benzoquinones: a comparative study

Uliana¹,

Vieira²,

Donatoni³

et al. 2008

J. Braz. Chem. Soc.

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“…have been extensively developed for use in organic synthesis, which includes N-haloamines, N-haloamides, N- N-haloureas, N-halosaccharins, N-halosulfonamides, N-halosulfonimides in general, and Nhalosuccinimides (>N-X, Where X= Cl, Br, I etc.) in particular [31][32][33][34][35][36][37] . This is supported by the fact that Nhalocompounds are good sources of halonium cations (X + ), hypohalite species (HOX) and nitrogen anions.…”

Section: -30mentioning

confidence: 99%

Ultrasonically Assisted Substitution and Oxidation Reactions With Camphor

2017

Rasayan J Chem

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Substitution (bromination, thiocyanation, and nitration) reactions of camphor (CAMP) were carried out using a variety of oxidizing catalysts such as N-Bromosuccinimide (NBS), N-Bromophthalimide (NBP), N-Bromo acetamide (NBA), trichloroisocyanuric acid (TCICA), ceric ammonium nitrate (CAN), and ammonium metavanadate (AMV) in presence suitable salt as additive. Bromination is conducted with the reagent in presence of KBr, while thiocyanation is done in presence of NH4SCN under acid free conditions. However, nitration is carried out in presence of NaNO2 and KHSO4. Noteworthy rate accelerations are recorded in ultrasonically assisted reactions, which were attributed to cavitation effects. On the other hand, the sluggish CAN oxidation of camphor underwent substantial rate acceleration in presence of PEGs and micelles. Present protocols have depicted several greenery features such as simple work-up, fast reaction times, high product yield, eco-friendly and readily available additives as catalysts.

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“…The synthesis of 1-bromopyrene was carried out after a known literature procedure [43] To a stirred solution of pyrene (2.02 g, 10.0 mmol) and hydrobromic acid (1.24 mL, 48 %, 11.0 mmol) in methanol-ether (20 mL, 1 : 1) was slowly added hydrogen peroxide (0.34 g; 0.86 mL of a 35 % aqueous solution; 10 mmol) over a period of 15 min at 10 -15 • C. The reaction was left at room temperature for 14 h while its progress was monitored by TLC. After the completion of monobromination, the solvent was removed under reduced pressure and the crude product was taken up in ethyl acetate and washed with water and brine and dried over anhydrous sodium sulfate.…”

Section: Synthesis Of 1-bromopyrene (1)mentioning

confidence: 99%

3-Pyrenylacrylates: Synthetic, Photophysical, Theoretical and Electrochemical Investigations

Reimann

Sharif

Wittler

et al. 2013

Zeitschrift Für Naturforschung B

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The Mizoroki-Heck coupling of 1-bromopyrene with acrylates provides a convenient access to a variety of 3-pyrenylacrylates in very good yields (up to 93 %). Their photophysical properties combined with solvatochromic effects were studied. In addition, electrochemical oxidation potentials were determined by DPV (differential pulse voltammetry) measurements. The fine structure of the absorbance spectra obtained from photophysical measurements are compared with the results of theoretical calculations performed by time dependent TD-B3LYP methods using the 6-31G* basis set.

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Environmentally benign chlorination and bromination of aromatic amines, hydrocarbons and naphthols

Cited by 141 publications

References 17 publications

Oxidation of mono-phenols to para-benzoquinones: a comparative study

Oxidation of mono-phenols to para-benzoquinones: a comparative study

Ultrasonically Assisted Substitution and Oxidation Reactions With Camphor

3-Pyrenylacrylates: Synthetic, Photophysical, Theoretical and Electrochemical Investigations

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