- Solvent and temperature effects in the free radical aerobic oxidation of alkyl and acyl aromatics catalysed by transition metal salts and N-hydroxyphthalimide: New processes for the synthesis of p-hydroxybenzoic acid, diphenols, and dienes for liquid crystals and cross-linked polymers
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The aerobic oxidation of 4,4′-diisopropyldiphenyl and 2,6-diisopropylnaphthalene, catalysed by N-hydroxyphthalimide and Co(II) salts, leads to the corresponding tertiary benzyl alcohols with high conversion and selectivity under mild conditions (temperature 30-60°C and atmospheric pressure). Solvent and temperature effects, as resulting from the pioneering work of C. Walling, and more recently from the conclusive resolution of K. U. Ingold and co-workers on a quantitative kinetic basis, strongly affect the selectivity of the aerobic oxidation. This is related to the ratio between the rate of β-scission of the alkoxyl radical, which leads to acetophenone derivatives, and the rate of hydrogen atom abstraction, leading to tertiary benzyl alcohols. These latter are efficiently converted either to diphenols for the production of liquid crystals, by reaction with H2O2, or to dienes, useful as cross-linking agents, by dehydration. The aerobic oxidation of p-hydroxyacetophenone catalysed by Mn(NO3)2 and Co(NO3)2 leads with high selectivity to p-hydroxybenzoic acid, a useful monomer for liquid crystals.
- Minisci, Francesco,Recupero, Francesco,Cecchetto, Andrea,Gambarotti, Cristian,Punta, Carlo,Paganelli, Roberto,Pedulli, Gian Franco,Fontana, Francesca
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Read Online
- Electrochemical Aerobic Oxidative Cleavage of (sp3)C-C(sp3)/H Bonds in Alkylarenes
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An electrochemistry-promoted oxidative cleavage of (sp3)C-C(sp3)/H bonds in alkylarenes was developed. Various aryl alkanes can be smoothly converted into ketones/aldehydes under aerobic conditions using a user-friendly undivided cell setup. The features of air as oxidant, scalability, and mild conditions make them attractive in synthetic organic chemistry.
- Liu, Shuai,Liu, Zhong-Quan,Shen, Tong,Shen, Xu,Wang, Nengyong,Wu, Jintao,Yang, Le,Zhao, Jianyou
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p. 3286 - 3295
(2022/03/14)
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- Synthesis method of p-acetoxystyrene
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The invention discloses a synthesis method of p-acetoxystyrene, which relates to the field of organic synthesis. The synthesis route of the synthesis method is as follows: 1, adding p-hydroxyacetophenone and an acetylation reagent into a first solvent, and carrying out esterification reaction under an alkaline condition to generate p-acetoxyacetophenone, 2, adding p-acetoxyacetophenone into a second solvent, and reducing the p-acetoxyacetophenone into 4-acetoxyphenyl methyl methanol under the catalysis of a catalyst in a hydrogen atmosphere, and 3, dehydrating the 4-acetoxyphenyl methyl methanol in an alkaline ionic liquid to obtain the p-acetoxystyrene. The method is high in yield, low in three wastes, green and clean, and the recovery cost and the equipment cost are reduced.
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Paragraph 0033-0034
(2021/04/26)
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- An efficient and practical aerobic oxidation of benzylic methylenes by recyclable: N -hydroxyimide
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An efficient and practical benzylic aerobic oxidation catalyzed by cheap and simple N-hydroxyimide organocatalyst has been achieved with high yields and broad substrate scope. The organocatalyst used can be recycled and reused by simple workup and only minute amount (1 mol% in most cases) of simple iron salt is used as promoter. Phenyl substrates with mild and strong electron-withdrawing group could also be oxygenated in high yields as well as other benzylic methylenes. Influence of substituents, gram-scale application, catalysts decay and general mechanism of this methodology has also been discussed. This journal is
- Wang, Jian,Zhang, Cheng,Ye, Xiao-Qing,Du, Wenting,Zeng, Shenxin,Xu, Jian-Hong,Yin, Hong
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p. 3003 - 3011
(2021/01/28)
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- Method for oxidative cracking of compound containing unsaturated double bonds
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The invention relates to a method for oxidative cracking of a compound containing unsaturated double bonds. The method comprises the following steps: (A) providing a compound (I) containing unsaturated double bonds, a trifluoromethyl-containing reagent and a catalyst, wherein the catalyst is shown as a formula (II): M(O)mL1yL2z (II), M, L1, L2, m, y, z, R1, R2 and R3 being defined in the specification; and (B) mixing the compound containing the unsaturated double bonds and the trifluoromethyl-containing reagent, and performing an oxidative cracking reaction on the compound containing the unsaturated double bonds in the presence of air or oxygen by using the catalyst to obtain a compound represented by formula (III),.
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Paragraph 0108-0114; 0152-0154
(2021/07/09)
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- METHOD FOR OXIDATIVE CLEAVAGE OF COMPOUNDS WITH UNSATURATED DOUBLE BOND
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A method for oxidative cleavage of a compound with an unsaturated double bond is provided. The method includes the steps of: (A) providing a compound (I) with an unsaturated double bond, a trifluoromethyl-containing reagent, and a catalyst; wherein, the catalyst is represented by Formula (II): M(O)mL1yL2z??(II);wherein, M, L1, L2, m, y, z, R1, R2 and R3 are defined in the specification; and(B) mixing the compound with an unsaturated double bond and the trifluoromethyl-containing reagent to perform an oxidative cleavage of the compound with the unsaturated double bond by using the catalyst in air or under oxygen atmosphere condition to obtain a compound represented by Formula (III):
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Paragraph 0071
(2021/07/10)
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- Site-Specific Oxidation of (sp3)C-C(sp3)/H Bonds by NaNO2/HCl
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A site-specific oxidation of (sp3)C-C(sp3) and (sp3)C-H bonds in aryl alkanes by the use of NaNO2/HCl was explored. The method is chemical-oxidant-free, transition-metal-free, uses water as the solvent, and proceeds under mild conditions, making it valuable and attractive to synthetic organic chemistry.
- Zhao, Jianyou,Shen, Tong,Sun, Zhihui,Wang, Nengyong,Yang, Le,Wu, Jintao,You, Huichao,Liu, Zhong-Quan
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p. 4057 - 4061
(2021/05/26)
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- Synthesis method of aromatic benzyl ketone
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The invention discloses a synthesis method of aromatic benzyl ketone, which comprises the following step: by using oxygen and/or air as an oxidant, oxidizing an aromatic benzyl compound shown in a formula (I) under the action of a catalytic system to obtain aromatic benzyl ketone shown in a formula (II). The catalytic system is formed by combining ferric ions, nitrate radicals and N-hydroxyimide derivatives and does not contain heavy metal ions harmful to human bodies, wherein the molar ratio of the ferric ions to the nitrate radicals is 1: (0.5-5), and the molar ratio of the ferric ions to the N-hydroxyimide derivatives is (0.01-0.1): (0.03-0.2). The method disclosed by the invention is wide in substrate applicability and high in atom utilization rate, avoids the use of harmful heavy metals such as copper and cobalt, and has the characteristics of high efficiency, economy and environmental protection. The formulas are as follows: Ar-CH2-R (I) and Ar-CO-R (II).
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Paragraph 0122-0122
(2020/09/12)
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- Substrate substitution effects in the Fries rearrangement of aryl esters over zeolite catalysts
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The catalytic transformation of aryl esters to hydroxyacetophenones via Fries rearrangement over solid acids is of interest to avoid the use of corrosive and toxic Lewis and Br?nsted acids traditionally applied. Microporous zeolites are known to catalyze the reaction of simple substrates such as phenyl acetate, but their application to substituted derivatives has received limited attention. To refine structure-activity relationships, here we examine the impact of various parameters including the solvent polarity, water content, acidic properties, and framework type on the reaction scheme in the Fries rearrangement of p-tolyl acetate over common solid acids. The results confirm the importance of providing a high concentration of accessible Br?nsted acid sites, with beta zeolites exhibiting the best performance. Extension of the substrate scope by substituting methyl groups in multiple positions identifies a framework-dependent effect on the rearrangement chemistry and highlights the potential for the transformation of dimethylphenyl acetates. Kinetic studies show that the major competitive path of cleavage of the ester C-O bond usually occurs in parallel to the Fries rearrangement. The possibility of sequentially acylating the resulting phenol depends on the substrate and reaction conditions.
- Bonrath, Werner,Létinois, Ulla,Lin, Ronghe,Medlock, Jonathan,Mitchell, Sharon,Netscher, Thomas,Pérez-Ramírez, Javier,Stemmler, René T.
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p. 4282 - 4292
(2020/07/30)
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- Preparation method of p-acetoxystyrene
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The invention relates to the field of organic chemistry, and in particular, relates to a preparation method of p-acetoxystyrene. The preparation method of p-acetoxystyrene provided by the invention comprises the steps: carrying out a reaction of p-hydroxyacetophenone with an acetylation reagent to prepare p-acetoxyacetophenone; carrying out hydrogenation reduction on p-acetoxyacetophenone to prepare 1-(4-acetoxyphenyl)ethanol; and carrying out an elimination reaction on 1-(4-acetoxyphenyl)ethanol to prepare p-acetoxystyrene. According to the preparation method of p-acetoxystyrene, starting from the most basic raw materials, three steps of reactions are carried out, especially in the third step of alkene formation reaction, alkaline elimination is creatively adopted, the defects that in traditional acid catalysis alkene formation elimination reaction, double-bond acid catalysis sudden side reactions are likely to happen, the reaction is likely to be out of control, and consequently theyield is low are overcome, and generated double bonds can stably exist for a long time in a reaction system.
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Paragraph 0076-0081
(2020/01/14)
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- Copper-Catalyzed Late-Stage Benzylic C(sp3)–H Trifluoromethylation
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Direct trifluoromethylation of C(sp3)–H bonds, especially in late stages, remains a formidable challenge. Herein, we describe the copper-catalyzed benzylic C(sp3)–H trifluoromethylation. With Cu(I) or Cu(II) as the catalyst, (bpy)Zn(CF3)2 (bpy = 2,2′-bipyridine) as the CF3 source, and NFSI (or Selectfluor) as the oxidant, site-selective benzylic C(sp3)–H trifluoromethylation is successfully implemented in high efficiency under mild conditions. The protocol not only exhibits broad substrate scope and wide functional-group compatibility but also allows efficient late-stage C(sp3)–H trifluoromethylation of natural products or drug derivatives. The introduction of trifluoromethyl groups into organic molecules is of paramount importance in pharmaceuticals and agrochemicals because of their profound effect on properties such as lipophilicity, permeability, and metabolic stability. However, direct C(sp3)–H trifluoromethylation, which is most atom economical, remains a formidable challenge, and only a few examples with limited substrate scope and low to moderate efficiency have been reported to date. In this article, we introduce the copper-catalyzed benzylic C(sp3)–H trifluoromethylation with the easily available (bpy)Zn(CF3)2 complex as the CF3 source. This unprecedented protocol not only exhibits a high efficiency and broad substrate scope but also allows the late-stage trifluoromethylation of bioactive molecules or natural product derivatives. Because the procedure is operationally simple and the conditions are mild, the method should find immediate application in the synthesis of important trifluoromethylated molecules. Trifluoromethylated molecules are of paramount importance in pharmaceuticals and agrochemicals, but methods of making them by direct C(sp3)–H trifluoromethylation are extremely rare. In this issue of Chem, Li and coworkers describe a copper-catalyzed late-stage benzylic C–H trifluoromethylation with broad substrate scope and functional-group tolerance. The reaction may serve the late-stage modification of drug candidates.
- Xiao, Haiwen,Liu, Zhonglin,Shen, Haigen,Zhang, Benxiang,Zhu, Lin,Li, Chaozhong
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supporting information
p. 940 - 949
(2019/04/10)
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- Semi-heterogeneous Dual Nickel/Photocatalysis using Carbon Nitrides: Esterification of Carboxylic Acids with Aryl Halides
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Cross-coupling reactions mediated by dual nickel/photocatalysis are synthetically attractive but rely mainly on expensive, non-recyclable noble-metal complexes as photocatalysts. Heterogeneous semiconductors, which are commonly used for artificial photosynthesis and wastewater treatment, are a sustainable alternative. Graphitic carbon nitrides, a class of metal-free polymers that can be easily prepared from bulk chemicals, are heterogeneous semiconductors with high potential for photocatalytic organic transformations. Here, we demonstrate that graphitic carbon nitrides in combination with nickel catalysis can induce selective C?O cross-couplings of carboxylic acids with aryl halides, yielding the respective aryl esters in excellent yield and selectivity. The heterogeneous organic photocatalyst exhibits a broad substrate scope, is able to harvest green light, and can be recycled multiple times. In situ FTIR was used to track the reaction progress to study this transformation at different irradiation wavelengths and reaction scales.
- Pieber, Bartholom?us,Malik, Jamal A.,Cavedon, Cristian,Gisbertz, Sebastian,Savateev, Aleksandr,Cruz, Daniel,Heil, Tobias,Zhang, Guigang,Seeberger, Peter H.
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supporting information
p. 9575 - 9580
(2019/06/25)
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- Ag2CO3-mediated direct functionalization of alkyl nitriles: Facile synthesis of γ-ketonitriles through nitrile alkylation of enol acetates
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Direct C(sp3)-H functionalization of alkyl nitriles is a low toxic and facile route to nitrile-containing compounds. In this research, the Ag2CO3-mediated nitrile methylenation of enol acetates is developed to prepare γ-ketonitriles through the direct C(sp3)-H oxidative functionalization of acetonitrile. A radical pathway is proposed, and acetonitrile serves both as solvent and CN-containing radical source.
- Cheng, Pi,Wang, Wei,Wang, Lin,Zeng, Jianguo,Reiser, Oliver,Liang, Yun
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p. 1408 - 1412
(2019/05/06)
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- Na 2 CO 3-Catalyzed O-Acylation of Phenols for the Synthesis of Aryl Carboxylates with Use of Alkenyl Carboxylates
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Inorganic base-catalyzed O-acylation of phenol and its derivatives has been developed. The procedure provides an efficient catalysis system for the preparation of aryl carboxylates with alkenyl carboxylates as acyl reagents. The reaction proceeded smoothly by using ?-Na 2 CO 3 as the catalyst in MeCN to produce the corresponding aryl carboxylates in good to excellent yields.
- Zhou, Xiao-Yu,Chen, Xia
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supporting information
p. 2321 - 2325
(2018/10/20)
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- Copper-Catalyzed C-S Bond Formation via the Cleavage of C-O Bonds in the Presence of S8 as the Sulfur Source
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Useful and applicable methods for one-pot and odorless synthesis of unsymmetrical and symmetrical diaryl sulfides via C-O bond activation are presented. First, a new efficient procedure for the synthesis of unsymmetrical sulfides using the cross-coupling reaction of phenolic esters such as acetates, tosylates, and triflates and with arylboronic acid or triphenyltin chloride as the coupling partners is reported. Depending on the reaction, S 8 /KF or S 8 /NaO t -Bu system is found to be an effective source of sulfur in the presence of copper salts and in poly(ethylene glycol) as a green solvent. Then, the synthesis of symmetrical diaryl sulfides from phenolic compounds by using S 8 as the sulfur source and NaO t -Bu in anhydrous DMF at 120 °C under N 2 is described. By these protocols, the synthesis of a variety of unsymmetrical and symmetrical sulfides become easier than the available protocols in which thiols and aryl halides are directly used for the preparation of the sulfides.
- Rostami, Abed,Rostami, Amin,Ghaderi, Arash,Gholinejad, Mohammad,Gheisarzadeh, Sajedeh
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p. 5025 - 5038
(2017/10/06)
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- Wacker-Type Oxidation Using an Iron Catalyst and Ambient Air: Application to Late-Stage Oxidation of Complex Molecules
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A practical and general iron-catalyzed Wacker-type oxidation of olefins to ketones is presented, and it uses ambient air as the sole oxidant. The mild oxidation conditions enable exceptional functional-group tolerance, which has not been demonstrated for any other Wacker-type reaction to date. The inexpensive and nontoxic reagents [iron(II) chloride, polymethylhydrosiloxane, and air] can, therefore, also be employed to oxidize complex natural-product-derived and polyfunctionalized molecules.
- Liu, Binbin,Jin, Fengli,Wang, Tianjiao,Yuan, Xiaorong,Han, Wei
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supporting information
p. 12712 - 12717
(2017/09/11)
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- Wacker Oxidation of Terminal Alkenes Over ZrO2-Supported Pd Nanoparticles Under Acid- and Cocatalyst-Free Conditions
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Highly efficient Wacker oxidation of aromatic or aliphatic terminal alkenes into methyl ketones and benzofurans is developed by using reusable Pd0 nanoparticles (NPs) supported on ZrO2 under acid- and cocatalyst-free conditions. Molecular oxygen or air can be utilized as the terminal oxidant, which results in the formation of H2O as the only theoretical byproduct. The activation of the Pd NPs by O2 plays an important role in promoting this reaction. Interestingly, PdO supported on ZrO2 showed no activity. Additionally, the Pd particle size significantly affects the catalytic activity, with an apparent optimal diameter of 4–12 nm. In addition to the heterogeneous catalyst forms, the Pd NPs can be generated from a Pd0 complex during the reaction, and these particles are even recyclable.
- Zhang, Zhenzhong,Kumamoto, Yuhya,Hashiguchi, Taishin,Mamba, Tetsuya,Murayama, Haruno,Yamamoto, Eiji,Ishida, Tamao,Honma, Tetsuo,Tokunaga, Makoto
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p. 3482 - 3489
(2017/09/15)
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- Mechanism of Catalytic Oxidation of Styrenes with Hydrogen Peroxide in the Presence of Cationic Palladium(II) Complexes
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Kinetic studies, isotope labeling, and in situ high-resolution mass spectrometry are used to elucidate the mechanism for the catalytic oxidation of styrenes using aqueous hydrogen peroxide (H2O2) and the cationic palladium(II) compound, [(PBO)Pd(NCMe)2][OTf]2 (PBO = 2-(pyridin-2-yl)benzoxazole). Previous studies have shown that this reaction yields acetophenones with high selectivity. We find that H2O2 binds to Pd(II) followed by styrene binding to generate a Pd-alkylperoxide that liberates acetophenone by at least two competitive processes, one of which involves a palladium enolate intermediate that has not been previously observed in olefin oxidation reactions. We suggest that acetophenone is formed from the palladium enolate intermediate by protonation from H2O2. We replaced hydrogen peroxide with t-butyl hydroperoxide and found that, although the palladium enolate intermediate was observed, it was not on the major product-generating pathway, indicating that the form of the oxidant plays a key role in the reaction mechanism.
- Walker, Katherine L.,Dornan, Laura M.,Zare, Richard N.,Waymouth, Robert M.,Muldoon, Mark J.
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supporting information
p. 12495 - 12503
(2017/09/23)
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- Cationic Palladium(II) Complexes for Catalytic Wacker-Type Oxidation of Styrenes to Ketones Using O2 as the Sole Oxidant
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A series of new cationic palladium(II) complexes were prepared and studied for their ability to catalyze the Wacker-type oxidation of styrenes to their corresponding acetophenones using O2 as the sole oxidant. Catalysts are active at room temperature and the study highlights the importance of solvent choice and the need for ligand development in improving catalyst performance.
- Chai, Hongxin,Cao, Qun,Dornan, Laura M.,Hughes, N. Louise,Brown, Clare L.,Nockemann, Peter,Li, Jiarong,Muldoon, Mark J.
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p. 5604 - 5608
(2017/12/26)
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- Method for directly oxidizing benzyl-position C-H bond into ketone
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The invention discloses a method for directly oxidizing a benzyl-position C-H bond into ketone, wherein aryl ethyl compounds are catalyzed and oxidized by nitrite ester; a synergistic catalytic system of free radical initiator and nitrite ester is adopted, and a catalytic system of non-metallic catalyst and oxygen is adopted, the oxidization of the C-H bond of a free radical-activated aryl side chain is simple in operation; after completing the reaction, petroleum ether/ethyl acetate at a volume ratio of (50-1):1 is used as an eluent; column chromatography separation is performed to obtain a target product. The catalytic system in the invention uses oxygen as an oxygen source and has high atomic economy; the invention is a non-metallic catalytic system and provides a novel method for avoid metal residues in synthetic drugs; for diethyl aromatic hydrocarbon, the method provided by the invention can be adopted to selectively oxidize diethyl aromatic hydrocarbon into monoketone and diketone; the method of the invention can be adopted to efficiently synthesize tranquillizer lenperone, so that a novel method for synthesizing lenperone is provided.
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Paragraph 0022-0024
(2017/08/29)
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- Transition-Metal- and Halogen-Free Oxidation of Benzylic sp 3 C-H Bonds to Carbonyl Groups Using Potassium Persulfate
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Aryl carbonyl compounds including acetophenones, benzophenones, imides, and benzoic acids are prepared from benzyl substrates using potassium persulfate as oxidant with catalytic pyridine in acetonitrile under mild conditions. Neither transition metals nor halogens are involved in the reactions.
- Hu, Yixin,Zhou, Lihong,Lu, Wenjun
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supporting information
p. 4007 - 4016
(2017/08/29)
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- Graphite oxide-catalyzed acetylation of alcohols and phenols
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Graphite oxide (GO) was used as a catalyst for the reactions of alcohols and phenols with acetic anhydride. The acetates of primary and secondary alcohols were prepared in good to excellent yields in short reaction time under mild conditions. Electron deficient phenols could be converted to the corresponding acetates steadily. As an efficient catalyst, GO is easily available, cheap, moderately toxic and weakly acidic.
- Liu, Yuan-Yuan,Qi, Jun-Mei,Bai, Li-Sha,Xu, Yue-Long,Ma, Ning,Sun, Fei-Fei
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supporting information
p. 726 - 730
(2016/05/19)
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- Synthesis and characterization of novel oxime derivatives
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Background: The synthesis of effective drugs are very important for the scientist. The various biological effects of the thiazole, oxime and ether functional groups are well known properties by the drug developers. So we have synthesised new molecules which contains three of them on the same molecules. Methods: The acetophenone derivatives have been used for synthesis new oximes. The synthetic pathway includes mainly four steps. s1. α-Bromination of acetophenone derivatives, s2. Synthesis of thiazole ring using brominated acetophenones, s3. Synthesis of ethers using synthesised thiazole, s4. Synthesis of oximes. Results: The synthesised molecules characterised using IR,1H-NMR, 13C-NMR and elementel analysis methods. Conclusion: The new oximes which include thiazole and ether groups have been synthesised using acetophenone derivatives.
- Arslan, Taner,Keskin, Serhat,Demirayak, Seref
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p. 672 - 677
(2017/01/13)
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- Zn(II) porphyrin based nano-/microscale metal-organic frameworks: Morphology dependent sensitization and photocatalytic oxathiolane deprotection
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With Zn(ii) porphyrin as a building block, nano-/microscale MOFs with different morphologies were synthesized as sensitizers for O2 (forming 1O2). The sensitization efficiency was observed to enhance remarkably with the decrease of morphological dimension of the sample. With high sensitization ability, the one-dimensional MOF could selectively photocatalyze the deprotection of oxathiolanes to ketones.
- Zhao, Fang-Yao,Li, Wen-Juan,Guo, An,Chang, Lan,Li, Yue,Ruan, Wen-Juan
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p. 26199 - 26202
(2016/03/25)
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- Rh-Catalyzed Synthesis of Coumarin Derivatives from Phenolic Acetates and Acrylates via C-H Bond Activation
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An efficient annulation strategy involving the reaction of phenolic acetates with acrylates in the presence of [Rh2(OAc)4] as catalyst and formic acid as reducing agent, leading to the high yield synthesis of coumarin derivatives, has been developed. The addition of NaOAc as a base increased the yield of the products. The reaction is quite successful for both electron-rich as well as electron-deficient phenolic acetates, affording coumarins with excellent regioselectivity, and proceeds via C-H bond activation proven by deuterium incorporation studies.
- Gadakh, Sunita K.,Dey, Soumen,Sudalai, Arumugam
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p. 11544 - 11550
(2015/12/04)
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- Cationic palladium(II) complexes as catalysts for the oxidation of terminal olefins to methyl ketones using hydrogen peroxide
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Ligated Pd(II) complexes have been studied for the catalytic oxidation of terminal olefins to their corresponding methyl ketones. The method uses aqueous hydrogen peroxide as the terminal oxidant; a sustainable and readily accessible oxidant. The choice of ligand, counterion and solvent all have a significant effect on catalytic performance and we were able to develop systems which perform well for these challenging oxidations.
- Cao, Qun,Bailie, David S.,Fu, Runzhong,Muldoon, Mark J.
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supporting information
p. 2750 - 2757
(2015/05/27)
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- Insights into the binding of thiosemicarbazone derivatives with human serum albumin: Spectroscopy and molecular modelling studies
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4-[(1Z)-1-(2-carbamothioylhydrazinylidene)ethyl]phenyl acetate [Ace semi],4-[(1Z)-1-(2-carbamothioylhydrazinylidene) ethyl]phenyl propanoate [Pro semi] from the family of thiosemicarbazones derivative has been newly synthesized. It has good anticancer activity as well as antibacterial and it is also less toxic in nature, its binding characteristics are therefore of huge interest for understanding pharmacokinetic mechanism of the drug. The binding of thiosemicarbazone derivative to human serum albumin (HSA) has been investigated by studying its quenching mechanism, binding kinetics and the molecular distance (r) between donor (HSA) and acceptor (thiosemicarbazone derivative) was estimated according to Forster’s theory of non-radiative energy transfer using fluorescence spectroscopy. The binding dynamics has been elaborated using synchronous fluorescence spectroscopy, and the feature of thiosemicarbazone derivative induced structural changes of HSA has been studied by circular dichorism, Fourier transform infrared spectroscopy. Molecular modelling simulations explore the hydrophobic interaction and hydrogen bonding which stabilizes the interaction.
- Karthikeyan, Subramani,Bharanidharan, Ganesan,Kesherwani, Manish,Mani, Karthikananth,Srinivasan, Narasimhan,Velmurugan, Devadasan,Aruna, Prakasarao,Ganesan, Singaravelu
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p. 1264 - 1281
(2016/09/09)
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- Reactivity switch enabled by counterion: Highly chemoselective dimerization and hydration of terminal alkynes
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A counterion-controlled reactivity tuning in Pd-catalyzed highly chemoselective and regioselective dimerization and hydration of terminal alkynes is reported. The use of acetate as counterion favors the formation of an alkenyl alkynyl palladium intermediate which forms hitherto less reported 1,3-diaryl-substituted conjugated enynes after reductive elimination. Using chloride, which is a better leaving group, leads to anion exchange on the alkenylpalladium intermediate with hydroxide which after reductive elimination and tautomerization delivered the hydration products.
- Xu, Caixia,Du, Weiyuan,Zeng, Yi,Dai, Bin,Guo, Hao
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p. 948 - 951
(2014/03/21)
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- Trifluoroacetic acid-catalyzed synthesis of N -(1-(3-chlorophenyl)-3-aryl- 3-oxopropyl)-2-(4-nitrophenyl)acetamides via Dakin-west reaction
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A series of novel N-(1-(3-chlorophenyl)-3-aryl-3-oxopropyl)-2-(4- nitrophenyl) acetamides were synthesized using p-nitrophenylacetonitrile, m-chlorobenzaldehyde, and aryl methyl ketones as starting materials and trifluoroacetic acid (TFA) as catalyst. This realized an improved Dakin-West reaction in which p-nitrophenylacetonitrile was involved. The chemical structures of up to 15 target molecules were characterized by 1H NMR, 13C NMR, and high-resolution mass spectrometry. This method provides a facile synthetic protocol under more moderate reaction conditions, smaller dosage (0.40 mol%) and hence lower cost of catalyst, and simpler posttreatment in comparison to other known methods. A reaction mechanism is proposed in which hydroxyacetophenone is first catalytically converted into the corresponding acetoxyacetophenone prior to be involved in the subsequent Dakin-West reaction that eventually leads to hydroxyl-acetylated target compounds. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
- Tian, Hui-Hui,Fan, Li,Zhang, Xing-Hua,Zhou, Cheng-He,Zhou, Guang-Ming,Yang, Da-Cheng
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p. 170 - 180
(2013/12/04)
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- Highly selective Wacker reaction of styrene derivatives: A green and efficient aerobic oxidative process promoted by benzoquinone/NaNO 2/HClO4 under mild conditions
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A green and efficient catalytic redox system for the aerobic oxidative Wacker oxidation of styrene derivatives at room temperature using molecular oxygen as the terminal oxidant without copper chloride has been developed. The newly developed system exhibited excellent catalytic activity for the smooth transformation of terminal styrene derivatives to the desired methyl ketones with up to 96% yield and >99% selectivity. The Royal Society of Chemistry 2013.
- Zhang, Guofu,Xie, Xiaoqiang,Wang, Yong,Wen, Xin,Zhao, Yun,Ding, Chengrong
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supporting information
p. 2947 - 2950
(2013/07/25)
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- Environmentally benign deprotection of dithioacetals using 30% hydrogen peroxide catalyzed by Fe(acac)3 and sodium iodide
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The reaction of dithioacetals with 30% hydrogen peroxide in the presence of catalytic amounts of iron(III) acetylacetonate and sodium iodide efficiently produced the corresponding carbonyl compounds in high yields.
- Kirihara, Masayuki,Suzuki, Satoshi,Ishizuka, Yuki,Yamazaki, Kento,Matsushima, Ryoji,Suzuki, Takaya,Iwai, Toshiaki
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p. 5477 - 5480
(2013/09/23)
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- Direct and selective benzylic oxidation of alkylarenes via C-H abstraction using alkali metal bromides
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A direct benzylic oxidation of alkylarenes via C-H bond abstraction was developed using alkali metal bromides and oxidants under mild conditions. This reaction proceeded with excellent selectivity by thermal oxidation or photooxidation to provide a broad range of carbonyl compounds containing electron-deficient aryl carbonyl compounds in high yields.
- Moriyama, Katsuhiko,Takemura, Misato,Togo, Hideo
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supporting information; experimental part
p. 2414 - 2417
(2012/06/18)
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- Deprotection of dithioacetals with 30% hydrogen peroxide catalyzed by tantalum(V) chloride-sodium iodide or niobium(V) chloride-sodium iodide
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The reaction of dithioacetals with 30% hydrogen peroxide in the presence of catalytic amounts of tantalum(V) and iodide ion effectively produced carbonyl compounds in high yields. Dithioacetals also can be deprotected using the niobium(V) catalyzed oxidation of iodide ion by hydrogen peroxide under mild conditions.
- Kirihara, Masayuki,Noguchi, Takuya,Okajima, Nobuhiro,Naito, Sayuri,Ishizuka, Yuki,Harano, Aiko,Tsukiji, Hiroyuki,Takizawa, Ryu
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experimental part
p. 1515 - 1520
(2012/03/07)
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- Candida tenuis xylose reductase catalysed reduction of acetophenones: The effect of ring-substituents on catalytic efficiency
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The catalytic efficiencies of Candida tenuis xylose reductase catalysed reductions of mono-substituted acetophenones are in reasonable correlation with the σ-Hammett coefficients of the substituted phenyl groups. Variations of the substrate transformation rates are hence mainly caused by mesomeric and inductive effects of the substituents, while differences in substrate binding have a secondary relevance. Some substrate 1H NMR chemical shifts and carbonyl IR absorption bands are in reasonable accordance with the catalytic activities and allow the estimation of the transformation rates with good accuracy. The resulting substituted (S)-1-phenyl ethanols are generated in very high enantiomeric excess.
- Vogl, Michael,Kratzer, Regina,Nidetzky, Bernd,Brecker, Lothar
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experimental part
p. 5863 - 5870
(2011/09/30)
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- An atom-efficient and powerful method for direct esterification of silyl ethers catalyzed by HClO4-SiO2
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An efficient and convenient procedure for direct esterification of alkyl and aryl silyl ethers with Ac2O and a catalyst system of perchloric acid immobilized on a silica gel (HClO4-SiO2) has been developed. The silyl protecting groups are directly replaced by acetyls and the protecting groups themselves are transformed into acetates as the sole byproducts, which can be readily recovered and converted back to silylchlorides, the original protecting agents, thus minimizing wastes.
- Du, Ti-Jian,Wu, Qin-Pei,Liu, Hai-Xia,Chen, Xi,Shu, Yi-Nan,Xi, Xiao-Dong,Zhang, Qing-Shan,Li, Yun-Zheng
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experimental part
p. 1096 - 1101
(2011/04/16)
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- On the mechanism of the palladium-catalyzed tert-butylhydroperoxide- mediated wacker-type oxidation of alkenes using quinoline-2-oxazoline ligands
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The mechanism of the tert-butylhydroperoxide-mediated, Pd(Quinox)-catalyzed Wacker-type oxidation was investigated to evaluate the hypothesis that a selective catalyst-controlled oxidation could be achieved by rendering the palladium coordinatively saturated using a bidentate amine ligand. The unique role of the Quinox ligand framework was probed via systematic ligand modifications. The modified ligands were evaluated through quantitative Hammett analysis, which supports a push-pull relationship between the electronically asymmetric quinoline and oxazoline ligand modules.
- Michel, Brian W.,Steffens, Laura D.,Sigman, Matthew S.
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supporting information; experimental part
p. 8317 - 8325
(2011/07/08)
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- Air-stable titanocene bis(perfluorooctanesulfonate) as a new catalyst for acylation of alcohols, phenols, thiols, and amines under solvent-free condition
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Air-stable titanocene bis(perfluorooctanesulfonate) [Cp2Ti(OSO2C8F17)2] that shows high Lewis acidity was prepared from Cp2TiCl2 and AgOSO2C8F17. The compound was characterized by different techniques, and examined as a catalyst for acylation reactions. It was found that using equimolar acetic anhydride as acetylating agent and under solvent-free condition, Cp2Ti(OSO2C8F17)2 exhibits high activity and selectivity in the acetylation of various alcohols, phenols, thiols, and amines. Also, good catalytic efficiency is observed in the acylation of 2-phenylethanol across various acylating reagents. The catalyst can be reused without loss of activity in a test of ten cycles. The Cp2Ti(OSO2C8F17)2 catalyst affords a simple, efficient and general method for the acylation of alcohols, phenols, thiols, and amines.
- Qiu, Renhua,Zhang, Guoping,Ren, Xiaofang,Xu, Xinhua,Yang, Ronghua,Luo, Shenglian,Yin, Shuangfeng
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experimental part
p. 1182 - 1188
(2010/06/13)
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- Acetylation of alcohols and phenols with acetic anhydride under solvent-free conditions using an ionic liquid based on morpholine as a recoverable and reusable catalyst
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Rapid and efficient acetylation of alcohols and phenols with acetic anhydride is performed in the presence of economical Bronsted acidic ionic liquids that bear a propanesulfonic acid group on a morpholinium cation as catalysts under solvent-free conditions. [MMPPA][HSO4] (N-methylmorpholinium propanesulfonic acid ammonium hydrogensulfate) was proven to be the most active catalyst, and after removal of water, it could be recycled and reused for up to four times without a noticeable decrease in catalytic activity. Springer-Verlag 2010.
- Yue, Caibo,Liu, Qingqing,Yi, Tingfeng,Chen, Yun
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experimental part
p. 975 - 978
(2011/09/30)
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- Convenient, mild catalytic deprotection of oximes to carbonyl compounds with hydrogen peroxide and iodine catalyst in aqueous acetonitrile
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A clean, mild, and efficient catalytic deoximation procedure compatible with several common functional groups has been developed using 30% hydrogen peroxide activated by iodine catalyst in aqueous acetonitrile under essentially neutral conditions. The mechanistic features of an iodonium ion-driven nucleophilic cleavage of oximic C=N have been revealed.
- Ganguly, Nemai C.,Nayek, Subhasis,Barik, Sujoy Kumar
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experimental part
p. 4053 - 4061
(2009/12/24)
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- Counterattack mode differential acetylative deprotection of phenylmethyl ethers: Applications to solid phase organic reactions
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A counterattack protocol for differential acetylative cleavage of phenylmethyl ether has been developed. The phenylmethyl moiety is liberated as benzyl bromide that is isolated and reused providing advantages in terms of waste minimization/utilization and atom economy. The applicability of this methodology has been extended for solid phase organic reactions with the feasibility of reuse of the solid support.
- Chakraborti, Asit K.,Chankeshwara, Sunay V.
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experimental part
p. 1367 - 1370
(2009/07/04)
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- Samarium trifluoromethanesulfonate: An efficient moisture tolerant acylation catalyst under solvent-free condition
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Samarium trifluoromethanesulfonate catalyzed the acylation of phenols, alcohols, thiols, free reducing sugars, and glycosides in excellent yields at ambient temperature under solvent-free condition using stoichiometric amounts of various anhydrides. (Chemical Equation Presented). Copyright Taylor & Francis Group, LLC.
- Roy, Bimalendu,Dasgupta, Somnath,Kumar Rajput, Vishal,Mukhopadhyay, Balaram
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- Silica supported zinc chloride catalyzed acetylation of amines, alcohols and phenols
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Silica supported zinc chloride (SiO2-ZnCl2) has been prepared and found to efficiently catalyze the acetylation of amines, alcohols and phenols by stirring in acetonitrile at 80°C under heterogeneous conditions. The catalyst can be separated from the reaction medium simply by filtration and re-used up to four times.
- Gupta, Raman,Kumar, Vineet,Gupta, Monika,Paul, Satya,Gupta, Rajive
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experimental part
p. 1739 - 1743
(2009/06/28)
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- SbCl3 as a highly efficient catalyst for the acetylation of alcohols, phenols, and amines under solvent-free conditions
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Antimony trichloride has been found to be an efficient and expedient catalyst for the acylation of alcohols, phenols, amines, and sugars with acetic anhydride in high yields and in a short reaction time under solvent-free conditions at room temperature. Also, racemization of chiral alcohols and epimerization of sugars were not observed in any of the substrates. Copyright Taylor & Francis Group, LLC.
- Bhattacharya, Asish K.,Diallo, Mamadou A.,Ganesh, Krishna N.
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p. 1518 - 1526
(2008/09/20)
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- Al(OTf)3 as a highly efficient catalyst for the rapid acetylation of alcohols, phenols and thiophenols under solvent-free conditions
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Aluminium triflate (0.01-0.1 mol %) was found to be an efficient catalyst for the acylation of alcohols, phenols, thiols and sugars with acetic anhydride in high yields under solvent-free conditions in a short reaction time at room temperature. Racemization of optically active alcohols and epimerization of sugars were not observed. The acylation efficacy of various acyl donors was also investigated.
- Kamal, Ahmed,Khan, M. Naseer A.,Reddy, K. Srinivasa,Srikanth,Krishnaji
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p. 3813 - 3818
(2008/02/06)
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- A simple synthetic protocol for oxidation of alkyl-arenes into ketones using a combination of HBr-H2O2
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A wide variety of alkyl- and cycloalkyl-arenes undergo benzylic C-H oxidation by employing a combination of 48% hydrogen bromide and 30% hydrogen peroxide in dichloromethane at room temperature. In addition, a chemoselective oxidation at the benzylic position is feasible by deactivating the aromatic ring using the same combination.
- Khan, Abu T.,Parvin, Tasneem,Choudhury, Lokman H.,Ghosh, Subrata
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p. 2271 - 2274
(2007/10/03)
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- Magnesium bistrifluoromethanesulfonimide as a new and efficient acylation catalyst
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Magnesium bistrifluoromethanesulfonimide catalyzed the acetylation of phenols, alcohols, and thiols under solvent-free conditions at room temperature and in short times. Electron-deficient and sterically hindered phenols provided excellent yields. The catalyst was found to be general for acylation with other anhydrides, such as propionic, isobutyric, pivalic, chloroacetic, and benzoic anhydrides. The rate of acylation was influenced by the electronic and steric factors associated with the anhydride. The reaction with less electrophilic anhydrides (e.g., chloroacetic and benzoic anhydrides) required higher temperature (～80 °C). Chemoselective acetylation, pivalation, and benzoylation took place with acid-sensitive alcohols without any competitive dehydration/rearrangement.
- Chakraborti, Asit K.,Shivani
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p. 5785 - 5788
(2007/10/03)
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- A novel 3-nitrobenzeneboronic acid as an extremely mild and environmentally benign catalyst for the acetylation of alcohols under solvent-free conditions
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A novel 3-nitrobenzeneboronic acid is found to catalyse efficiently the acetylation of a wide range of alcohols as well as phenols with acetic anhydride in good to excellent yields at room temperature under solvent-free conditions. The reactions are clean and the catalyst is mild such that highly sensitive functional groups including oximes are stable to the reaction conditions.
- Tale,Adude
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p. 7263 - 7265
(2007/10/03)
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- Deprotection of dithioacetals using the tantalum(V) chloride catalyzed oxidation of iodide ion by hydrogen peroxide
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Dithioacetals can be deprotected to afford carbonyl groups using the tantalum(V) chloride catalyzed oxidation of iodide ion by hydrogen peroxide under mild conditions.
- Kirihara, Masayuki,Harano, Aiko,Tsukiji, Hiroyuki,Takizawa, Ryu,Uchiyama, Tomoyuki,Hatano, Akihiko
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p. 6377 - 6380
(2007/10/03)
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- Zirconiuni(IV) chloride as a new, highly efficient, and reusable catalyst for acetylation of phenols, thiols, amines, and alcohols under solvent-free conditions
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Zirconium(IV) chloride has been found to be a new, highly efficient, and reusable catalyst for acetylation of structurally diverse phenols, thiols, amines, and alcohols under solvent-free condtions. Acetylation of sterically hindered and electron deficient phenols is achieved in excellent yields with stoichiometric amounts of Ac2O at room temperature. Acid-sensitive alcohols undergo acetylation with excellent chemoselectivity without competitive side reactions such as dehydration or rearrangement. The mild Lewis acid property of the catalyst enables the acetylation to be carried out with optically active substrates without any detrimental effect on the optical purity.
- Chakraborti, Asit K.,Gulhane, Rajesh
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p. 627 - 630
(2007/10/03)
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- Copper(II) Tetrafluoroborate-Catalyzed Acetylation of Phenols, Thiols, Alcohols, and Amines
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Copper(II) tetrafluoroborate efficiently catalyzes acetylation of structurally diverse phenols, alcohols, thiols, and amines with stoichiometric amounts of Ac2O under solvent-free conditions at room temperature. Acid-sensitive alcohols are smoothly acetylated without competitive side reactions. The reaction is influenced by the steric and electronic factors associated with the substrate as well as the anhydride. Acetylation of a sterically hindered substrate requires excess of anhydride and longer time. Acylation with less electrophilic anhydrides affords poor to moderate yields.
- Chakraborti, Asit K.,Gulhane, Rajesh,Shivani
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p. 111 - 115
(2007/10/03)
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