14035-36-0Relevant academic research and scientific papers
Redox potentials, laccase oxidation, and antilarval activities of substituted phenols
Prasain, Keshar,Nguyen, Thi D.T.,Gorman, Maureen J.,Barrigan, Lydia M.,Peng, Zeyu,Kanost, Michael R.,Syed, Lateef U.,Li, Jun,Zhu, Kun Yan,Hua, Duy H.
body text, p. 1679 - 1689 (2012/04/23)
Laccases are copper-containing oxidases that are involved in sclerotization of the cuticle of mosquitoes and other insects. Oxidation of exogenous compounds by insect laccases may have the potential to produce reactive species toxic to insects. We investigated two classes of substituted phenolic compounds, halogenated di- and trihydroxybenzenes and substituted di-tert-butylphenols, on redox potential, oxidation by laccase and effects on mosquito larval growth. An inverse correlation between the oxidation potentials and laccase activity of halogenated hydroxybenzenes was found. Substituted di-tert-butylphenols however were found to impact mosquito larval growth and survival. In particular, 2,4-di-tert-butyl-6-(3-methyl-2-butenyl)phenol (15) caused greater than 98% mortality of Anopheles gambiae larvae in a concentration of 180 nM, whereas 2-(3,5-di-tert-butyl-4-hydroxyphenyl)-2-methylpropanal oxime (13) and 6,8-di-tert-butyl-2,2-dimethyl-3,4-dihydro-2H-chromene (33) caused 93% and 92% mortalities in concentrations of 3.4 and 3.7 μM, respectively. Larvae treated with di-tert-butylphenolic compounds died just before pupation.
Oxygenation of tert-Butylphenols with an Unsaturated Side Chain
Nishinaga, Akira,Iwasaki, Hitoshi,Shimizu, Tadashi,Toyoda, Yasushi,Matsuura, Teru
, p. 2257 - 2266 (2007/10/02)
Base- and Co(Salpr)-promoted oxygenations of title compounds have been investigated with a view to obtaining further details concerning controlling factors in regioselective O2 incorporation into phenols.In the oxygenation of 4-alkenyl-2,6-di-tert-butyl- and 2-alkenyl-4,6-di-tert-butylphenols (1 and 12), the reactivity of the substrates and regioselectivity in the O2 incorporation may be interpreted in terms of electronic and steric effects of the alkenyl group as well as association effect of the countercation K+ on the transition-state 26 involving a charge transfer from the substrate anion to O2.With 4-alkynyl-2,6-di-tert-butylphenols (21), dioxygen was incorporated exclusively into the ortho position only when the phenolate anion was associated with K+.On the contrary, in the oxygenation of 1 and 12 with Co(Salpr), O2 was incorporated exclusively into the alkynyl side chain, regardless of the nature of the substituent, whereas with 21, O2 incorporation was distributed to both the ortho and the alkenyl side chain.The substituent-dependent regioselectivity in the oxygenation of phenols with Co(Salpr) is because the reactive phenolate-COIII species undergo homolysis to form phenoxy radical-CoII species reversibly, whose oxygenations compete with each other.When the oxygenation of the anionic species predominates, O2 is incorporated into the ortho position, whereas with the radical species the para and side chain oxydations predominate.
Oxygenation of 2,6-Di-tert-butylphenols Bearing an Electron-Withdrawing Group in the 4-Position
Nishinaga, Akira,Shimizu, Tadashi,Toyoda, Yasushi,Matsuura, Teruo,Hirotsu, Ken
, p. 2278 - 2285 (2007/10/02)
Co(Salpr), a five-coordinate cobalt (II) Schiff base complex, has been found to promote oxygenation of 2,6-di-tert-butylphenols bearing an electron-withdrawing group in the 4-position, leading to dioxygen incorporation exclusively into the ortho position of the phenols. 4-Acyl-2,6-di-tert-butylphenols (1) and their oxime O-methyl ethers (2) gave the corresponding 6-hydroperoxy-2,4-cyclohexadienone derivatives 3 and 4 quantitatively.Schiff bases 10 derived from 3,5-di-tert-butyl-4-hydroxybenzaldehyde, on the other hand, gave unexpected products, 1,2-dihydropyridine derivatives 11, cyclopentadienone 12, and epoxy-o-quinol 13.The structure of dihydropyridine 11a was determined by X-ray analysis. 2,6-Di-tert-butyl-4-cyanophenol gave 2,5-di-tert-butyl-3-cyano-2,4-cyclopentadienone in good yield.The formation of these products can be understood to result from intramolecular decomposition of the corresponding o-peroxidic intermediate.Phenols 2 were readily oxygenated in t-BuOH containing t-BuOK to give epoxy-o-quinols 7 in excellent yield, although the other phenols examined were unsusceptible to oxygenation under various basic conditions.
OXYGENATION OF 2,6-DI-t-BUTYLPHENOLS BEARING ELECTRON-WITHDRAWING GROUP AT 4-POSITION MEDIATED BY CO(II)-SCHIFF BASE COMPLEX
Nishinaga, A.,Shimizu, T.,Matsuura, T.
, p. 5293 - 5296 (2007/10/02)
4-Acyl-2,6-di-t-butylphenols except 3,5-di-t-butyl-4-hydroxybenzaldehyde were oxygenated in the presence of Co(Salpr) exclusively at the ortho position to give the corresponding 3,5-di-t-butyl-6-hydroperoxy-2,4-cyclohexadienone derivatives in quantitative
Oxidation of Bisphenols. II. Some Compounds Related to Galvinoxyl
Colegate, Steven M.,Hewgill, F. Richmond
, p. 351 - 369 (2007/10/02)
The oxidation of a series of 4,4'-alkylidenebis(2,6-di-t-butylphenols) having increasing substitution of the central methylene carbon by alkyl groups is examined.In the monosubstituted compounds the stability of the monophenoxy radical increases with increase in the size of the substituent, while the stability of the galvinoxyl type radical decreases. β-Coupled products are only obtained from the ethylidene bisphenol, a result that can be correlated with e.s.r. hyperfine splitting constants.With increasing mono- or di-substitution bisspiroperoxides become the preferred oxidation products.The e.s.r. spectrum of an ethylenebisgalvinoxyl biradical is described
