36776-51-9Relevant academic research and scientific papers
A new fluorogenic transformation: Development of an optical probe for coenzyme Q
Tremblay, Matthew S.,Sames, Dalibor
, p. 2417 - 2420 (2007/10/03)
(Chemical Equation Presented) A new fluorogenic transformation based on a quinone reduction/lactonization sequence has been developed and evaluated as a tool for probing redox phenomena in a biochemical context. The probe presented herein is an irreversible redox probe and is reduced selectively by biologically relevant quinols such as ubiquinol but is inert to reduced nicotinamides (e.g., NADH). The ensuing cyclization is fast and quantitative and provides a measurable optical response.
Total Synthesis of Linear Polyprenoids. 2. Improved preparation of the Aromatic Nucleus of Ubiquinone
Keinan, Ehud,Eren, Doron
, p. 3872 - 3875 (2007/10/02)
Highly efficient copper-catalyzed polymethoxylation of tribromocresol is the key process in a three-step, practical approach to obtain ubiquinone 0 from p-cresol.Short syntheses of several ubiquinones were achieved via direct, copper-mediated coupling of 2-lithio-3,4,5,6-tetramethoxytoluene to the appropriate polyprenyl bromide.
ipso Halogenation. II. Bromination of phenols, isomerisation and disproportionation of bromophenols, and dione-phenol rearrangement of bromodienones
Fischer, Alfred,Henderson, George Narayanan
, p. 1045 - 1052 (2007/10/02)
Bromination of p-cresol, bromo-p-cresol, 3,4-dimethylphenol, and mesitol in trifluoromethanesulfonic acid gices as the main product the bromo derivative with bromine meta to hydroxyl, a result attributed to the intermediate formation of a bromodienone and its rearrangement.Phenols does not give m-bromophenol in trifluoromethanesulfonic acid. 4-Bromo-2,4,6-trimethylcyclohexa-2,5-dienone rearranges to 3-bromomesitol in trifluoromethanesulfonic acid and, similarly, 2,4,6-tribromo-4-methylcyclohexa-2,5-dienone rearranges to 3-bromomesitol in trifluoromethanesulfonic acid and, similarly, 2,4,6-tribromo-4-methylcyclohexa-2,5-dienone rearranges to 2,3,6-tribromo-4-methylphenol.Under appropriate conditions debromination of bromodienones is competitive with rearrangement.Tetramethylammonium bromide in trifluoromethanesulfonic acid is an effective reagent for isomerization and disproportionation of bromophenols.Tetramethylammonium iodide in trifluoromethanesulfonic acid is an effective reagent for selective debromination of bromophenols at the ortho and para position.
Electrophilic Substitution with Rearrangement. Part 9. Dienones derived from Brominations of o-, m-, and p-Cresol
Brittain, Judith M.,Mare, Peter B. D. de la,Newman, Paul A.
, p. 32 - 41 (2007/10/02)
Regiospecific protodebromination of ring-substituted bromophenols derived from 2-, 3-, or 4-methylphenol can be effected by heating them with aqueous hydrogen iodide; the synthetic scope of this reaction has been explored.These di- and poly-bromophenols can generally be converted by further bromination in aqueous acetic acid into dienones , which have now been shown to have the 4-bromo-2,5-dienone rather than the 2-bromo-3,5-dienone structure.The rearrangemens of these dienones to ring-substituted polybromophenols by treatment with sulfuric acid have been investigated; where more than one product is formed, the regioselectivity differs from that prevailing in the corresponding direct bromination of the phenol with liquid bromine.The alternative rearrangements of these dienones in aprotic solvents with and without illumination have been compared with results obtained by reaction of methylphenols with bromine under the same conditions.Characteristic differences between the behaviours of 2-, 3-, and 4-methyl-substituted compounds reflect the specific reactions available to the particular dienones.
