Pyridinium Bromochromate: A New and Efficient Reagent for Bromination of Hydroxy Aromatics.

Abstract

Halogenation Halogenation O 0235 Pyridinium Bromochromate: A New and Efficient Reagent for Bromination of Hydroxy Aromatics. -The title compound, readily prepared from HBr, pyridine and CrO3 is described as a useful reagent for the regioselective high-yielding bromination of hydroxyarenes. -(PATWARI, S. B.; BASEER, M. A.; VIBHUTE*, Y. B.; BHUSARE, S. R.; Tetrahedron Lett. 44 (2003) 26, 4893-4894; Dep. Chem., Yeshwant Mahavidyalaya, Nanded 431 602, India; Eng.) -Mais 39-044

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

“…In 2003, Patwari et al reported this reagent as an efficient brominating agent for the bromination of hydroxy aromatics. 1183 PBC was used to brominate various substituted hydroxyacetophenones, hydroxy aldehydes, and hydroxyphenols for efficient and selective nuclear bromination. The hydroxy aromatics and PBC were dissolved in the minimum amount of glacial acetic acid, and the reaction mixtures were heated with constant stirring.…”

Modelling Phase Equilibria in Systems with Organic Solid Solutions

“…Reports on the formation of alloys, or solid solutions, of organic compounds, although still rare, have been appearing regularly in the last few years for aromatic compounds, such as substituted benzenes and naphtalenes [1][2][3], pyrene and anthracene [4][5][6], for carbohydrates [7], terpenes [8], neopentane derivatives [9-10] and fulerenes, besides solid solutions of C 60 with C 70 [11][12] solid solutions of C 60 in sulphur have been reported [13]. Nevertheless it is among the molecules with long n-alkyl chains such as n-alcohols Although the materials based on n-alkane alloys have been used for long as candles, waterproof coatings, pharmaceutical and cosmetics, and in spite of paraffin waxes being a valuable by-product of petroleum refining, the research on n-alkane solid solutions has been mainly prompted by its dark side: The damages and losses caused by wax precipitation from petroleum fluids.…”

“…Reports on the formation of alloys, or solid solutions, of organic compounds, although still rare, have been appearing regularly in the last few years for aromatic compounds, such as substituted benzenes and naphtalenes [1][2][3], pyrene and anthracene [4][5][6], for carbohydrates [7], terpenes [8], neopentane derivatives [9][10] and fulerenes, besides solid solutions of C 60 with C 70 [11][12] solid solutions of C 60 in sulphur have been reported [13]. Nevertheless it is among the molecules with long n-alkyl chains such as n-alcohols [14], fats [15], soaps [16] and alkanes [17][18][19][20] that solid solutions appear more frequently.…”

“…Although most of these alloys are still just interesting academic curiosities, these new materials seem quite promising and interesting applications for some of them have been identified. N-alkane blends have been patented for energy storage and preservation of food, medicine and cell tissues [21]; solutions of aromatics based on pyrene have interesting optical properties [4][5][6]. Surfactants of controlled properties [16] and the manipulation of the behaviour of fats to confer them new organoleptic characteristics [15] have been surfacing showing the exciting possibilities of these new materials.…”