140-39-6Relevant articles and documents
Fabrication of Fe3O4- l -dopa-CuII/SnIV@Micro-Mesoporous-SiO2 Catalyst Applied to Baeyer-Villiger Oxidation Reaction
Huo, Hongfei,Wu, Li,Ma, Jianxin,Yang, Honglei,Zhang, Le,Yang, Yuanyuan,Li, Shuwen,Li, Rong
, p. 779 - 786 (2016)
A Magnetic mFe3O4-l-dopa-CuII/SnIV@micro-mesoporous-SiO2 catalyst was successfully prepared. The catalyst exhibits high and stable catalytic activity for the Baeyer-Villiger oxidation reaction with air as oxidant. Furthermore, the selectivity can reach nearly 100 %. Meanwhile the catalyst can be easily separated by an external magnet and reused at least up to five cycles without any notable loss in catalytic activity. In addition, the effect of Sn and Cu on the oxidation of cyclohexanone is discussed.
Oxidation of p-cresol with ozone in acetic anhydride
Sedykh,Galstyan
, p. 123 - 126 (2006)
Preparation of aromatic alcohols and aldehydes by oxidation of p-cresol with ozone in acetic anhydride in the presence of sulfuric acid, manganese acetate, and potassium bromide was studied. The optimal oxidation conditions were determined. Pleiades Publishing, Inc., 2006.
Catalysis of reaction between ozone and 4-hydroxytoluene in acetic anhydride
Galstyan, A. G.,Sedykh, A. A.,Galstyan, G. A.
, p. 1510 - 1514 (2014)
Kinetics and products of 4-hydroxytoluene oxidation with ozone-air mixture in the presence of transition metal acetates as catalysts have been studied. Main steps of the catalytic series have been considered, and a mechanism of redox catalysis has been proposed which conforms to the experimental data and enables control over the direction, depth, and selectivity of the oxidation. Only manganese(II) acetate has been found to exhibit high catalytic activity in the presence of catalytic amounts of mineral acids. Manganese(II) acetate largely suppresses electrophilic reaction of ozone with the aromatic ring, so that the main reaction direction is oxidation of the methyl group with formation of 4-acetoxybenzyl acetate as the major product (62.6%) and 4-acetoxybenzylidene diacetate as a minor one (10.2%).
Oxidation of 4-hydroxytoluene with an ozone-oxygen mixture in acetic acid
Galstyan,Tarasenko,Shumilova
, p. 1865 - 1867 (2008)
Liquid-phase oxidation of 4-hydroxytoluene by ozone to 4-hydroxybenzoic acid in the presence of cobalt(II) acetate as a catalyst was studied. The optimal oxidation conditions were found.
New synthesis of 4-methoxyisophthalic acid
Liu,Yan,Wang,Li,Liu
, p. 459 - 461 (2017)
A new synthetic route to 4-methoxyisophthalic acid, the key intermediate in the synthesis of Picotamide, is reported. The new protocol starts from commercially available and cheap 4-methylphenol and includes four steps: esterification, Fries rearrangement, methylation, and oxidation; the overall yield is 49%. Unlike the traditional Blanc chloromethylation/oxidation scheme, the proposed procedure avoids using volatile and corrosive hydrochloric acid.
A simple, two-step conversion of various iodoarenes to (diacetoxyiodo)arenes with chromium(VI) oxide as the oxidant
Kazmierczak, Pawel,Skulski, Lech
, p. 1721 - 1723 (1998)
Chromium(VI) oxide, an inexpensive and easily handled oxidant, dissolved in the anhydrous acetic acid/acetic anhydride/concentrated H2SO4 liquid system effectively oxidizes various iodoarenes ArI to the respective iodine(III) intermediates AxISO4 and/or ArI(OSO3H)2. The resulting solutions were mixed with excess 20% aqueous ammonium acetate solution to give, after filtration and purification, (diacetoxyiodo)arenes ArI(OAc)2 in 58-82% yields.
Theoretical and experimental studies on selective oxidation of aromatic ketone by performic acid
Liu, Bo,Meng, Xiang-Guang,Li, Wei-Yi,Zhou, Liang-Chun,Hu, Chang-Wei
, p. 2920 - 2926 (2012)
The Baeyer-Villiger (B-V) reactions of 3,4-dimethoxy acetophenone (DMOAP), 4-methyl acetophenone (MAP), and acetophenone (AP) with performic acid (PFA) in formic acid (FA) solvent have been studied by density functional theory (DFT) method. The noncatalyzed and the formic acid-catalyzed reaction paths have been calculated at the MPWB1K/6-311++G(d,p)-IEF-PCM// MPWB1K/6-311G(d,p) level of theory. On the basis of the calculations, the attack of peracid to the carbonyl carbon is rate-determining in both the noncatalyzed and acid-catalyzed paths. The selective oxidation of 3,4-dimethoxy acetophenone and 4-methyl acetophenone by performic acid into aromatic esters have been experimentally investigated. The kinetic rate constants were obtained in the temperature range of 303 to 323 K. The selectivity of product was also explained by the NBO electric charge analysis. The calculated activation energy barriers of the B-V reaction of DMOAP and MAP were in good agreement with those of experiment.
Method for promoting acylation of amine or alcohol by carbon dioxide
-
Paragraph 0034-0035, (2021/05/29)
The invention relates to a method for promoting acylation of amine or alcohol by carbon dioxide, which comprises the following steps of: mixing an amine compound, carboxylate or thiocarboxylate compound and a reaction solvent under the action of carbon dioxide, and reacting to obtain an amide compound, or under the action of carbon dioxide, mixing the alcohol compound, the thiocarboxylate compound and the reaction solvent [gamma]-valerolactone, and reacting to obtain the ester compound. According to the invention, under the promotion action of carbon dioxide, carboxylate or thiocarboxylate is used as an acylation reagent, and amine and alcohol are converted into amide and ester compounds in the absence of a transition metal catalyst, so that acylation reagents such as acyl chloride or anhydride with irritation and corrosivity are avoided; and the method has the advantages of simple operation, mild reaction conditions, high tolerance of substrate functional groups, strong applicability and high yield, and provides an efficient, reliable and economical preparation method for synthesis of amide and ester compounds.
Steric effect of NHC ligands in Pd(II)–NHC-catalyzed non-directed C–H acetoxylation of simple arenes
Mandal, Tanmoy,Yadav, Sudha,Choudhury, Joyanta
, (2021/09/06)
Although there has been a lot of progress in oxidative arene C–H functionalization reactions catalyzed by Pd(II/IV) system, the non-directed, site-selective functionalization of arene molecules is still challenging. It has been established that ligands play a pivotal role in controlling rate- as well as selectivity-determining step in a catalytic cycle involving well-defined metal-ligand bonding. N-heterocyclic carbene (NHC) ligands have had a tremendous contribution in the recent extraordinary success of achieving high reactivity and excellent selectivity in many catalytic processes including cross-coupling and olefin-metathesis reactions. However, the immense potential of these NHC ligands in improving site-selectivity of non-directed catalytic C–H functionalization reactions of simple arenes is yet to be realized, where overriding the electronic bias on deciding selectivity is a burdensome task. The presented work demonstrated an initiative step in this regard. Herein, a series of well-defined discrete [Pd(NHCR′R)(py)I2] complexes with systematically varied degree of spatial congestion at the Pd centre, exerted through the R and R’ substituents on the NHC ligand, were explored in controlling the activity as well as the site-selectivity of non-directed acetoxylation of representative monosubstituted and disubstituted simple arenes (such as toluene, iodobenzene and bromobenzene, naphthalene and 1,2-dichlorobenzene). The resulting best yields were found to be 75% for toluene and 65% for bromobenzene with [Pd(NHCMePh)(py)I2], 75% for iodobenzene and 79% for naphthalene with [Pd(NHCMeMe)(py)I2], and 41% for 1,2-dichlorobenzene with [Pd(NHCCyCy)(py)I2]. Most importantly, with increasing the bulkiness of the NHC ligand in the complexes, the selectivity of the distal C-acetoxylated products in comparison to the proximal ones, was enhanced to a great extent in all cases. Considering the vast library of NHC ligands, this study underscores the future opportunity to develop more strategies to improve the activity and the crucial site-selectivity of C–H functionalization reactions in simple as well as complex organic molecules.
Direct Acetoxylation of Arenes
Hong Nguyen, Thi Anh,Hou, Duen-Ren
supporting information, p. 8127 - 8131 (2021/08/23)
Acetoxylation of arenes is an important reaction and an unmet need in chemistry. We report a metal-free, direct acetoxylation reaction using sodium nitrate under an anhydrous environment of trifluoroacetic acid, acetic acid, and acetic anhydride. Arenes (31 examples), with oxidation potentials (Eox, in V vs SCE) lower than benzene (2.48 V), were acetoxylated with good yields and regioselectivity. A stepwise, single electron-transfer mechanism is proposed.
