3377-89-7Relevant academic research and scientific papers
New synthesis of tert-butyl peroxycarboxylates
Donchak,Voronov,Yur'ev
, p. 487 - 490 (2007/10/03)
tert-Butyl peroxyacetate, tert-butyl peroxybutyrate, tert-butyl phenylperoxyacetate, and tert-butyl peroxyundecanoate were obtained in nearly quantitative yields by the esterification of the corresponding carboxylic acids with tert-butyl hydroperoxide in the presence of trifluoroacetic anhydride and pyridine in nonaqueous medium at 0-5°C. No tert-butyl peroxytrifluoroacetate was formed as a by-product during the process. A possible reaction mechanism is discussed. Pleiades Publishing, Inc., 2006.
Secondary α-Deuterium Kinetic Isotope Effects Signifying a Polar Transition State in the Thermolysis of Ring-Substituted tert-Butyl Phenylperacetates
Kim, Sung Soo,Tuchkin, Alexey
, p. 3821 - 3824 (2007/10/03)
Several ring-substituted tert-butyl phenylperacetates (YC6H4CH2CO3But) and their deuterated versions (YC6H4CD2CO3But) were prepared (Y: p-OCH3, p-CH3, p-H, and p-NO2). Thermolyses at 80°C in CDCl3 showed excellent first-order kinetics. The rates have been measured as kYH × 104 and kYD × 104 s-1: 11.9 and 9.20 (p-OCH3), 2.64 and 2.22 (p-CH3), 1.06 and 0.93 (p-H), 0.164 and 0.156 (p-NO2). Hammett correlations were derived to yield ρYH+ = -1.17 and ρYD+ = -1.12. However, better Hammett plots were obtained with three points (p-OCH3, p-CH3, and p-H) showing ρYH+ = -1.35 and ρYD+ = -1.28. SDKIE was calculated as 1.293 (p-OCH3), 1.189 (p-CH3), 1.140 (p-H), and 1.051 (p-NO2), showing substantial substituent effects. Values of kYH/kYD for p-NO2 showed little temperature dependence. Hammett correlations and SDKIE were derived from the same kinetic entity that is the bond cleavage.
Reactions of Ketones with the Oxidizing System Aluminum Tri-tert-butylate-tert-Butyl Hydroperoxide
Stepovik,Zaburdaeva,Dodonov
, p. 264 - 269 (2007/10/03)
Oxidation of ketones containing primary, secondary, and tertiary carbon atoms at the α-position [dialkyl ketones, alkyl aryl ketones, and alkyl (aryl) benzyl ketones] with the system aluminum tri-tert-butylale-tert-butyl hydroperoxide is accompanied by cleavage of the carbon skeleton of the substrate via formation of α-hydroxy carbonyl and α-dicarbonyl compounds. The qualitative and quantitative composition of the reaction products indicates that the oxidation involves free radicals. Simultaneously, the oxidizing system adds across the carbonyl group of the substrate, which is followed by decomposition of aluminum-containing peroxides.
Mass Spectral Fragmentations and Gas Phase Reactions of t-Butyl Peresters
Madhusudanan, K. P.,Misra, Dharmendra,Singh, Chandan
, p. 398 - 401 (2007/10/02)
The mass spectral behaviour of a few aliphatic and aromatic peresters has been studied under electron impact (EI) and chemical ionization (CI) conditions.Under EI, fragmentation of the molecules occurs mainly by C-C cleavage at either side of the carbonyl group.The C4H9O+ ion generated by the attack of the CI reagent on the sample molecule adds on to the molecule leading to (M + 73)+ ion in the CI (i-C4H10) spectra while with the more basic reagent, NH3, clustering of the molecule around NH4+ ion is the predominant pathway for ion formation.
Extent of Charge Transfer in the Photoreduction of Phenyl Ketones by Alkylbenzenes
Wagner, Peter J.,Truman, Royal J.,Puchalski, Alan E.,Wake, Ronald
, p. 7727 - 7738 (2007/10/02)
Rate constants for triplet-state reaction of various ring-substituted benzophenones (BPs), acetophenones (APs), and α,α,α-trifluoroacetophenones (TFAs) with toluene and p-xylene have been determined by a combination of flash kinetics, steady-state quenching, and quantum yield measurements.The relative amounts of primary and tertiary radicals formed by reaction of the same ketons with p-cymene have also been measured.For all three types of ketones, rate constants correlate well with triplet ketone reduction potentials.The magnitude of the kinetic isotope effects observed with toluene-d8 and p-xylene-d10 diminishes as the ketones become easier to reduce.All of the ketone triplets react with alkylbenzenes primarily by a charge-transfer mechanism, with the rate-determining step changing from complexation to hydrogen transfer as the ketones become harder to reduce.The least reactive AP triplets probably react significantly via simple hydrogen atom abstraction as well.Those ketones with n,?* lowest triplets (all BPs and some APs) react with p-cymene to give primary/tertiary radical ratios that vary no more than a factor of 2 from the 0.40 value displayed by tert-butoxy radicals; those with ?,?* lowest triplets (TFAs and some APs) give ratios that favor primary radicals and that vary by an order of magnitude with the triplet ketone reduction potential.The variation in cymene product ratios reflect different orientations for attack on cymene by n,?* and ?,?* triplets and differing degrees of partial electron transfer within the exciplexes, which are not tight radical ion pairs.The variation seen for ?,?* triplets represents a stereoelectronic effect within face-to-face exciples, as evidenced by the excerptional behavior of p-diacylbenzenes, which give the highest ratio of tertiary radicals from cymene.There is no set intrinsic ratio of reactivity for ?,?* triplets vs. n,?* triplets in these CT reactions.The two types of triplets show similar reactivity for the more easily reduced triplets, with the harder to reduce ?,?* triplets being only one-tenth as reactive as n,?* triplets of comparable triplet reduction potential.When the extent of electron transfer in the exciplex is small, hydogen transfer is rate determining and ?,?* reactivity drops.A study of two radical reactions which generate benzyl and α-hydroxy-α-methylbenzyl radicals indicates that radical disproportionation cannot explain the low quantum yields (0.10) of most ketone-toluene photoreductions, which apparently involve substantial radiation less decay by the exciplex intermediates.
Peroxy Esters. 8. Base-Catalyzed Rearrangement of Peroxy Esters: Formation of Alkoxyacetic Acid Derivatives
Nishinaga, Akira,Nakamura, Koichi,Matsuura, Teruo
, p. 3696 - 3700 (2007/10/02)
p-Peroxyquinol esters derived from base-catalyzed oxygenation of 4-alkyl-2,6-tert-butylphenols followed by Schotten-Baumann acylation undergo a novel base-catalyzed rearrangement with t-BuOK in N,N-dimethylformamide to give p-quinoxyacetic acid derivatives in excellent yield.The same base-catalyzed rearrangement was also observed with tert-butyl peroxy esters.The base-catalyzed reaction of peroxy esters depended strongly on the nature of the acyl group in the esters and the base used and is suggested to involve homolysis of the peroxy bond.
