Synthesis description for preparation of PYRIDINIUM TRIBROMIDE

Pyridine hydrobromide perbromide is used as a brominating reagent in alfa-bromination and alfa-thiocyanation of ketones, phenols, unsaturated and aromatic ethers. It is used as a raw material in the preparation of beta-adrenergic blocking agents. Furthermore, it is used as an analytical reagent.

Pyridinium bromide-perbromide for synthesis | VWR

Pyridinium perbromide was then added in small portions to the vigorously stirred suspension.

Pyridinium tribromide technical grade, 90% | Sigma-Aldrich

Stable, crystalline, readily-handled source of bromine, useful for a wide range of brominations, including ɑ-bromination of ketones: J. Am. Chem. Soc., 70, 417 (1948), and conversion of alkenes to vic-dibromides. See, for example: Org. Synth. Coll., 5, 604 (1973), Note 2. The rate of addition to alkenes increases markedly on increased substitution, so that selective bromination of the more substituted of two double bonds can be achieved: Synthesis, 966 (1979). In pyridine, cyclopentenones are converted directly to their ɑ-bromo derivatives (addition-elimination): Synth. Commun., 18, 1323 (1988). Selective monobromination of anilines, predominantly at the para-position, can be effected in THF: Synth. Commun., 23, 855 (1993). In aqueous AcOH, alkyl aryl ethers are p-brominated in high yield: Synth. Commun., 28, 499 (1998), whereas aryl methyl ethers are demethylated on heating in xylene: Indian J. Chem., 33B, 288 (1994). Cleaves thioacetals in the presence of TBAB: J. Org. Chem., 46, 1745 (1981). Hu, Y.; Ju, L.; Lu, L.; Ma, H.; Yu, X. Stereoselective alpha-indolylation of enals via an organocatalytic formal cross-coupling with indoles. Org. Biomol. Chem. 2015, 13 (33), 8869-8874.Amaya, T.; Hirao, T. Chemistry of Sumanene. Chem Rec 2015, 15 (1), 310-321.

Pyridinium Hydrobromide Perbromide

In pyridine, cyclopentenones are converted directly to their ɑ-bromo derivatives (addition-elimination): Synth. Commun., 18, 1323 (1988).

Preparative Method: from pyridine, 48% hydrobromic acid, and . The  content varies depending on the method of preparation.

A15684 Pyridine hydrobromide perbromide, tech

Pentyl- pyridiniumtribromide: A vapor-pressure-free, room-temperature, ionic...A new method for stereoselective bromination of stilbene and chalcone in...

CAS No.39416-48-3,Pyridinium tribromide …

such as pyridinium bromide, pyridinium chloride, pyridiniumtribromide, and pyridinium-p-toluenesulfonate (e.g., from ...[Note: 10-methoxy-5H-dibenz[b,f]azepine may be obtained from iminostilbene according to the process disclosed ...

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Search results for Pyridinium tribromide at Sigma-Aldrich

In this experiment, a safer, solid bromination reagent (pyridinium tribromide) and a more benign solvent (ethanol) are employed to green the reaction and provide an effective bromination of an alkene, stilbene. Although bromination of alkenes is an important reaction in organic chemistry, the standard procedures involve the use of liquid bromine and chlorinated solvents. The traditional reagent and solvent present serious safety concerns, health risks and environmental impact. The solid reagent and ethanol solvent significantly decrease the hazards associated with the exercise. On the other hand, the use of the pyridinium tribromide decreases the atom economy of the reaction. This compromise spurred the development of a (yet) greener bromination experiment involving hydrobromic acid and hydrogen peroxide. The link to the laboratory procedure includes post-lab questions.

Pyridinium tribromide supplier | CasNO.39416-48-3

Pyridinium tribromide catalyzed condensation of indoles ..

of the N,N‘-Dibenzyl Viologen and the 4-Benzoyl-N-benzylpyridinium ...(2) with benzyltrimethylammonium tribromide or bromine exclusively gave the ...In α-methylstilbene bromination and in any reaction where substituent effects...

8-Bromination of 2,6,9-trisubstituted purines with pyridinium tribromide

bromination with pyridinium tribromide, ..

Abstract An efficient bromination of trans-stilbene using a domestic microwave oven is described. This microwave-promoted, water mediated bromination uses pyridiniumtribromide as an alternative brominating agent avoiding the chemical...