39903-97-4Relevant articles and documents
Practical epoxidation of α,β-unsaturated ketones with tetra-n-butylammonium peroxydisulfate
Kim, Yong Hae,Hwang, Je Pil,Yang, Seung Gak
, p. 3009 - 3012 (1997)
α,β-Unsaturated ketones reacted with tetra-n-butylammonium peroxydisulfate in the presence of hydrogen peroxide and base in acetonitrile at 25 °C to give the corresponding epoxides in excellent yields.
Catalytic Performance of Zr-Based Metal–Organic Frameworks Zr-abtc and MIP-200 in Selective Oxidations with H2O2
Maksimchuk, Nataliya V.,Ivanchikova, Irina D.,Cho, Kyung Ho,Zalomaeva, Olga V.,Evtushok, Vasiliy Yu.,Larionov, Kirill P.,Glazneva, Tatiana S.,Chang, Jong-San,Kholdeeva, Oxana A.
, p. 6985 - 6992 (2021/03/17)
The catalytic performance of Zr-abtc and MIP-200 metal–organic frameworks consisting of 8-connected Zr6 clusters and tetratopic linkers was investigated in H2O2-based selective oxidations and compared with that of 12-coordinated UiO-66 and UiO-67. Zr-abtc demonstrated advantages in both substrate conversion and product selectivity for epoxidation of electron-deficient C=C bonds in α,β-unsaturated ketones. The significant predominance of 1,2-epoxide in carvone epoxidation, coupled with high sulfone selectivity in thioether oxidation, points to a nucleophilic oxidation mechanism over Zr-abtc. The superior catalytic performance in the epoxidation of unsaturated ketones correlates with a larger amount of weak basic sites in Zr-abtc. Electrophilic activation of H2O2 can also be realized, as evidenced by the high activity of Zr-abtc in epoxidation of the electron-rich C=C bond in caryophyllene. XRD and FTIR studies confirmed the retention of the Zr-abtc structure after the catalysis. The low activity of MIP-200 in H2O2-based oxidations is most likely related to its specific hydrophilicity, which disfavors adsorption of organic substrates and H2O2.
Activation of H2O2over Zr(IV). Insights from Model Studies on Zr-Monosubstituted Lindqvist Tungstates
Abramov, Pavel A.,Carbó, Jorge J.,Chesalov, Yuriy A.,Eltsov, Ilia V.,Errington, R. John,Evtushok, Vasilii Yu.,Glazneva, Tatyana S.,Ivanchikova, Irina D.,Kholdeeva, Oxana A.,Maksimchuk, Nataliya V.,Maksimov, Gennadii M.,Poblet, Josep M.,Solé-Daura, Albert,Yanshole, Vadim V.,Zalomaeva, Olga V.
, p. 10589 - 10603 (2021/09/02)
Zr-monosubstituted Lindqvist-type polyoxometalates (Zr-POMs), (Bu4N)2[W5O18Zr(H2O)3] (1) and (Bu4N)6[{W5O18Zr(μ-OH)}2] (2), have been employed as molecular models to unravel the mechanism of hydrogen peroxide activation over Zr(IV) sites. Compounds 1 and 2 are hydrolytically stable and catalyze the epoxidation of C?C bonds in unfunctionalized alkenes and α,β-unsaturated ketones, as well as sulfoxidation of thioethers. Monomer 1 is more active than dimer 2. Acid additives greatly accelerate the oxygenation reactions and increase oxidant utilization efficiency up to >99%. Product distributions are indicative of a heterolytic oxygen transfer mechanism that involves electrophilic oxidizing species formed upon the interaction of Zr-POM and H2O2. The interaction of 1 and 2 with H2O2 and the resulting peroxo derivatives have been investigated by UV-vis, FTIR, Raman spectroscopy, HR-ESI-MS, and combined HPLC-ICP-atomic emission spectroscopy techniques. The interaction between an 17O-enriched dimer, (Bu4N)6[{W5O18Zr(μ-OCH3)}2] (2′), and H2O2 was also analyzed by 17O NMR spectroscopy. Combining these experimental studies with DFT calculations suggested the existence of dimeric peroxo species [(μ-?2:?2-O2){ZrW5O18}2]6- as well as monomeric Zr-hydroperoxo [W5O18Zr(?2-OOH)]3- and Zr-peroxo [HW5O18Zr(?2-O2)]3- species. Reactivity studies revealed that the dimeric peroxo is inert toward alkenes but is able to transfer oxygen atoms to thioethers, while the monomeric peroxo intermediate is capable of epoxidizing C?C bonds. DFT analysis of the reaction mechanism identifies the monomeric Zr-hydroperoxo intermediate as the real epoxidizing species and the corresponding α-oxygen transfer to the substrate as the rate-determining step. The calculations also showed that protonation of Zr-POM significantly reduces the free-energy barrier of the key oxygen-transfer step because of the greater electrophilicity of the catalyst and that dimeric species hampers the approach of alkene substrates due to steric repulsions reducing its reactivity. The improved performance of the Zr(IV) catalyst relative to Ti(IV) and Nb(V) catalysts is respectively due to a flexible coordination environment and a low tendency to form energy deep-well and low-reactive Zr-peroxo intermediates.
Design and synthesis of simple, yet potent and selective non-ring-A pyripyropene A-based inhibitors of acyl-coenzyme A: Cholesterol acyltransferase 2 (ACAT2)
Zhan, Yang,Zhang, Xiao-Wei,Xiong, Ying,Li, Bo-Liang,Nan, Fa-Jun
supporting information, p. 747 - 751 (2016/01/12)
A series of pyripyropene A-based compounds were designed and synthesized by opening the upper section of the A-ring, which significantly simplifies the structure and synthesis from commercially available starting materials. Representative compound (-)-3 exhibited potent activity against ACAT2 and greater selectivity for ACAT2 than for ACAT1.
Unique salt effect on highly selective synthesis of acid-labile terpene and styrene oxides with a tungsten/Hcatalytic system under acidic aqueous conditions
Hachiya, Houjin,Kon, Yoshihiro,Ono, Yutaka,Takumi, Kiyoshi,Sasagawa, Naoki,Ezaki, Yoichiro,Sato, Kazuhiko
experimental part, p. 1672 - 1678 (2012/07/16)
Acid-labile epoxides such as terpene and styrene oxides are effectively synthesized in high yields with good selectivities using tungsten-catalyzed hydrogen peroxide epoxidation in the presence of NaO The salt effect is thought to originate with the addition of a saturated amount of NaOto aqueous H this addition strongly inhibited the undesired hydrolysis of the acid-labile epoxy products, despite the biphasic conditions of substrate as oil phase and Has acidic aqueous phase.
An effective synthesis of acid-sensitive epoxides via oxidation of terpenes and styrenes using hydrogen peroxide under organic solvent-free conditions
Kon, Yoshihiro,Hachiya, Houjin,Ono, Yutaka,Matsumoto, Tomohiro,Sato, Kazuhiko
experimental part, p. 1092 - 1098 (2011/05/14)
An efficient epoxidation process for various terpenes and styrenes using a hydrogen peroxide-tungsten catalytic system with organic solvent-and halide-free conditions was developed. In the presence of the catalytic system, Na 2WO4, PhP(O)(OH)2, and [Me(n-C 8H17)3N]HSO4, and under weak acidic conditions, hydrogen peroxide successfully epoxidized -pinene to -pinene oxide in 95% selectivity at 91% conversion, while the previously published conditions utilizing NH2CH2P(O)(OH)2 as a promoter provided no epoxide. Georg Thieme Verlag Stuttgart.
Unique salt effect on the high yield synthesis of acid-labile terpene oxides using hydrogen peroxide under acidic aqueous conditions
Hachiya, Houjin,Kon, Yoshihiro,Ono, Yutaka,Takumi, Kiyoshi,Sasagawa, Naoki,Ezaki, Yoichiro,Sato, Kazuhiko
scheme or table, p. 2819 - 2822 (2012/01/02)
Acid-labile epoxides such as -pinene oxide are (effectively) synthesized in high yield from the epoxidation of terpenes with aqueous H2O 2 catalyzed by Na2WO4, [Me(n-C 8H17)3N]HSO4, and PhP(O)(OH) 2 in the presence of Na2SO4 as an auxiliary additive under organic solvent-free conditions at ambient temperature. Origin of the salt effect is considered that the addition of a saturated amount of Na2SO4 to aqueous H2O2 strongly inhibited the undesired hydrolysis of the acid-labile epoxide products, despite the highly acidic reaction conditions. Georg Thieme Verlag Stuttgart · New York.
Inverse phase transfer catalysis. III.- Optimization of the epoxidation reaction of α,β-unsaturated ketones by hydrogen peroxide
Boyer, Bernard,Hambardzoumian, Araik,Roque, Jean-Pierre,Beylerian, Norair
, p. 6147 - 6152 (2007/10/03)
The epoxidation of chalcone using hydrogen peroxide in the presence of a base in a two-phase medium system following the so-called Inverse Phase Transfer Catalysis (IPTC) process was investigated. Careful examination of various parameters including surfactant concentration, pH, H2O2 decomposition side-reactions and epoxide ring-opening, allowed us to determine optimal experimental conditions.
A versatile cobalt(II)-Schiff base catalyzed oxidation of organic substrates with dioxygen: Scope and mechanism
Punniyamurthy,Bhatia, Beena,Reddy, M. Madhava,Maikap, Golak C.,Iqbal, Javed
, p. 7649 - 7670 (2007/10/03)
Cobalt(II) complex 1a-f derived from Schiff bases act as efficient catalysts during the oxidation of wide range of organic substrates(e.g. alkenes, alcohols, benzylic compounds and aliphatic hydrocarbons) with dioxygen in the presence of aliphatic aldehydes or ketones or ketoesters. EPR studies on 1a-f complexes suggest that the aliphatic carbonyl compounds promote the formation of a cobalt(II)-superoxo species responsible for the oxidation of organic compounds. These studies also demonstrate the role of ligands on cobalt in controlling the chemoselectivity of these oxidations. A plausible mechanistic rational is also provided for these oxidations.
Hydrotalcite-Promoted Epoxidation of Electron-Deficient Alkenes with Hydrogen Peroxide
Cativiela, Carlos,Figueras, Francois,Fraile, Jose M.,Garcia, Jose I.,Mayoral, Jose A.
, p. 4125 - 4128 (2007/10/02)
A synthetic anionic clay, hydrotalcite (Mg/Al=2.8), promotes the epoxidation of electrondeficient alkenes with H2O2.With open-chain, α,β-unsaturated carbonyl compounds 3-hydroxy-1,2-dioxolanes are also obtained.
