- Visible-Light-Driven Selective Air-Oxygenation of C?H Bond via CeCl3 Catalysis in Water
-
Visible-light-induced C?H aerobic oxidation is an important chemical transformation that can be applied for the synthesis of aromatic ketones. High-cost catalysts and toxic solvents were generally needed in the present methodologies. Here, an efficient aqueous C?H aerobic oxidation protocol was reported. Through CeCl3-mediated photocatalysis, a series of aromatic ketones were produced in moderate to excellent yields. With air as the oxidant, this reaction could be performed under mild conditions in water and demonstrated high activity and functional group tolerance. This method is economical, highly efficient, and environmentally friendly, and it will provide inspiration for the development of aqueous photochemical synthesis reactions.
- Xie, Pan,Xue, Cheng,Shi, Sanshan,Du, Dongdong
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p. 2689 - 2693
(2021/05/07)
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- Nickel Hydride Catalyzed Cleavage of Allyl Ethers Induced by Isomerization
-
This report discloses the deallylation of O - and N -allyl functional groups by using a combination of a Ni-H precatalyst and excess Bronsted acid. Key steps are the isomerization of the O - or N -allyl group through Ni-catalyzed double-bond migration followed by Bronsted acid induced O/N-C bond hydrolysis. A variety of functional groups are tolerated in this protocol, highlighting its synthetic value.
- Kathe, Prasad M.,Berkefeld, Andreas,Fleischer, Ivana
-
supporting information
p. 1629 - 1632
(2021/02/09)
-
- Hydration of Alkynes to Ketones with an Efficient and Practical Polyoxomolybdate-based Cobalt Catalyst
-
Hydration of alkynes to ketones is one of the most atom economical and universal methods for the synthesis of carbonyl compounds. However, the basic reaction usually requires organic ligand catalysts or harsh reaction conditions to insert oxygen into the C≡C bond. Here, we report an inorganic ligand supported cobalt (III) catalyst, (NH4)3[CoMo6O18(OH)6], which is supported by a central cobalt (III) mononucleus and a ring-shaped pure inorganic ligand composed of six MoVIO6 octahedrons to avoid the disadvantages of expensive and unrecyclable organic ligand catalysts or noble metal catalysts. Under mild conditions, the cobalt (III) catalyst can be used for the hydration of alkynes to ketones. The catalyst is non-toxic, green, and environment friendly. The catalyst can be recycled at least six times with high activity. According to control experiments, a reasonable mechanism is provided.
- Xie, Ya,Wang, Jingjing,Wang, Yunyun,Han, Sheng,Yu, Han
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p. 4985 - 4989
(2021/10/12)
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- Catalyst- and acid-free Markovnikov hydration of alkynes in a sustainable H2O/ethyl lactate system
-
An efficient and sustainable protocol for the hydration of alkynes has been developed under metal/acid/catalyst/ligand-free conditions in a water/ethyl lactate mixture. The hydrogen-bond network in the ethyl lactate and water mixture plays a crucial and decisive role in activating the alkynes for hydration to afford the corresponding methyl ketones. This strategy gives the Markovnikov (ketone) addition product selectively over other possible products. The essential role of hydrogen bonding has been confirmed by experimental and theoretical techniques. A probable mechanism has been suggested by various control tests. The efficacy of the method has been further explored for the competent production of value-added α,β-unsaturated carbonyl compounds through the reaction of aldehydes with alkynes as ketonic surrogates. The environmentally benign hydration method takes place under mild conditions, has broad functional-group compatibility, and uses the ethyl lactate/water (1:3) medium as a “green alternative” in the absence of any hazardous, harmful, or expensive substances.
- Dandia, Anshu,Saini, Pratibha,Chithra,Vennapusa, Sivaranjana Reddy,Parewa, Vijay
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- Preparation method of O-methoxyacetophenone
-
The invention relates to a preparation method of o-methoxyacetophenone. A composite catalyst containing heteropolyacid and Lewis acid is adopted and can effectively catalyze the reaction of dimethyl ether and o-hydroxyacetophenone so that the use of dimethyl sulfate and other highly toxic substances as reaction reagents is avoided, the production cost is lowered, the discharge of highly toxic substances is reduced, and the process is enabled to be greener and more environment-friendly.
- -
-
Paragraph 0027; 0029
(2021/02/10)
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- Method for preparing o-methoxyacetophenone through catalytic distillation
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The invention relates to a method for preparing o-methoxyacetophenone by catalytic distillation. A composite dehydration catalyst containing heteropoly acid and Lewis acid is adopted and can effectively catalyze the reaction of methanol and o-hydroxyacetophenone so that the use of dimethyl sulfate and other highly toxic substances as reaction reagents is avoided, the production cost is reduced, and the emission of highly toxic substances is reduced and thus the process is more environment-friendly.
- -
-
Paragraph 0026; 0028
(2021/02/10)
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- Bioactivity study of thiophene and pyrazole containing heterocycles
-
Chalcones 3a-f were prepared by reacting thiophene containing pyrazolyl aldehyde (2) with different 2-hydroxy acetophenones 1a-f. The compounds 3a-f were transformed into different Pyrazolines 4a-f. The formation of chromene derivatives 5a-f occurred from the cyclization of 3a-f, which were then transformed into pyrazole derivatives 6a-f. Newly synthesized compounds have promising antibacterial activity against S. typhii and S. aureus, while weak activity against B. subtilis and E. coli. Compounds 5d and 6d had significant antifungal action towards A. niger, while most of the compounds were moderately active towards T. viride. Some of the synthesized compounds showed promising α-amylase inhibitory activity at 1 mg/mL concentration.
- Athare, Anil E.,Dare, Sushama B.,Kale, Nitin V.,Karale, Bhausaheb K.,Mhaske, Sadhana D.,Salve, Supriya P.,Takate, Sushama J.
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p. 891 - 899
(2021/09/08)
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- Chromone dioxadiazole compound as well as preparation method and application thereof
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The preparation method comprises the following steps: adding an intermediate F and bis (acetoxy) iodobenzene to dichloromethane for reaction to obtain the chromone compound. The invention provides a novel chromone dioxadiazole compound and a preparation method thereof, and overcomes the defects of large toxicity and high preparation cost of the traditional method.
- -
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Paragraph 0021-0023
(2021/10/30)
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- Decatungstate-mediated solar photooxidative cleavage of CC bonds using air as an oxidant in water
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With the increasing attention for green chemistry and sustainable development, there has been much interest in searching for greener methods and sources in organic synthesis. However, toxic additives or solvents are inevitably involved in most organic transformations. Herein, we first report the combination of direct utilization of solar energy, air as the oxidant and water as the solvent for the selective cleavage of CC double bonds in aryl olefins. Various α-methyl styrenes, diaryl alkenes as well as terminal styrenes are well tolerated in this green and sustainable strategy and furnished the desired carbonyl products in satisfactory yields. Like heterogeneous catalysis, this homogeneous catalytic system could also be reused and it retains good activity even after repeating three times. Mechanism investigations indicated that both O2- and 1O2 were involved in the reaction. Based on these results, two possible mechanisms, including the electron transfer pathway and the energy transfer pathway, were proposed.
- Du, Dongdong,Luo, Junfei,Shi, Sanshan,Xie, Pan,Xue, Cheng
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p. 5936 - 5943
(2021/08/23)
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- Revisiting the Structural Evolution of Hydrotalcite-Derived Mixed Metal Oxides upon Alkali Metal Doping and Its Impact on Base Catalysis
-
The structural evolution of classic coprecipitation-derived Mg?Al mixed oxide (MMO) upon doping of different alkali metals in a wide level (1–20 wt.%) was revisited. The pristine lateral MMO of aggregates into particulates, accompanied with the dramatic loss of the surface areas and the formation of aluminates. These phenomena become severer with the decrease of the atomic radius. The formation of NaAlO2 likely occurs via the gradual dealumination of the MMO, which is highly dependent on both the dopant content and the activation temperature. This leads to ultimately a new ensemble with MgO as the core decorated by NaAlO2 in the outer surfaces at high Na doping level and above 973 K. When evaluated in the base-catalyzed transesterification and acylation model reactions, the Na-doped MMO show enhanced performance and a plateau at increasing doping that might be explained by an interplay between the number and strength of strong basicity.
- Ding, Yunjie,Lin, Ronghe,Lv, Yali,Mou, Xiaoling,Yu, Qing
-
-
- Rhoda-Electrocatalyzed Bimetallic C?H Oxygenation by Weak O-Coordination
-
Rhodium-electrocatalyzed arene C?H oxygenation by weakly O-coordinating amides and ketones have been established by bimetallic electrocatalysis. Likewise, diverse dihydrooxazinones were selectively accessed by the judicious choice of current, enabling twofold C?H functionalization. Detailed mechanistic studies by experiment, mass spectroscopy and cyclovoltammetric analysis provided support for an unprecedented electrooxidation-induced C?H activation by a bimetallic rhodium catalysis manifold.
- Tan, Xuefeng,Massignan, Leonardo,Hou, Xiaoyan,Frey, Johanna,Oliveira, Jo?o C. A.,Hussain, Masoom Nasiha,Ackermann, Lutz
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supporting information
p. 13264 - 13270
(2021/05/06)
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- Direct Oxygenation of C-H Bonds through Photoredox and Palladium Catalysis
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This report presents the oxygenation of C-H bonds via the merger of photocatalysis and Pd catalysis. Herein, we describe the utilization of a photocatalyst to oxidize an organopalladium(II) intermediate to high-valent PdIII or PdIV intermediates, which promotes the formation of C-O bonds. The demonstrated method works efficiently with various directing groups, such as oxime ether and benzothiazole. The applicability of this direct C-O bond formation method is shown by synthesizing several metal complexes of 2-(benzo[d]thiazol-2-yl)phenol that can be used in organic light-emitting diodes and pharmaceuticals.
- Paul, Amrita,Shah, Sk. Sheriff,Shee, Maniklal,Singh, Amit Kumar,Singh, N. D. Pradeep
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p. 3426 - 3439
(2020/03/23)
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- Catalytic oxidation of alcohols and alkyl benzenes to carbonyls using Fe3O4?SiO2?(TEMPO)-: Co -(Chlorophyll-CoIII) as a bi-functional, self-co-oxidant nanocatalyst
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Chlorophyll b was extracted from heliotropium europaeum plant, demetalated, allylated and grafted to acrylated TEMPO through a copolymerization protocol. Then, the chlorophyll monomers were coordinated to Co ions, immobilized on magnetic nanoparticles and the resulting hybrid was used as a powerful catalyst for a variety of oxidation reactions. By using the present method, oxidation of benzylic alcohols and alkyl benzenes to carbonyls was accomplished in water under aerobic conditions. Moreover, direct oxidation of alcohols to carboxylic acids was performed by adding NaOCl to the mixture. All entries were oxidized to the corresponding desired product with high to excellent yields and up to 97% selectivity. The catalyst was thoroughly characterized by CV, TGA, VSM, XRD, XPS, DLS, FE-SEM, TEM, UV-Vis, EDX, and BET analyses. The activity of the catalyst was investigated by applying various components of the catalyst to the oxidation model separately. The reasonable mechanisms are suggested based on the cooperation between the TEMPO groups and cobalt(iii) (or Co(iv)) sites on the catalyst. The catalyst could be recovered and reused for at least 7 consecutive recycles without any considerable reactivity loss. This journal is
- Hamah-Ameen, Baram Ahmed,Kazemnejadi, Milad,Mahmoudi, Boshra,Rostami, Amin
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p. 6600 - 6613
(2020/11/16)
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- Acceptorless dehydrogenation of amines and alcohols using simple ruthenium chloride
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A highly efficient, economic and environmental friendly catalyst system has been developed for the dehydrogenation of alcohols and amines using simple RuCl3·nH2O and N-benzylhexamethylenetetramine. The in situ catalyst system efficiently oxidized the primary and secondary amines and secondary alcohols into nitrile, imine and ketone products, respectively in moderate to excellent yields. The developed catalyst system was also found to be efficient for the dehydrogenation of N-heterocyles. A detailed mechanism study revealed the first example of N-benzylhexamethylenetetramine (HMTA-Bz) being simultaneously acting as base, reducing agent and hydride source to generate the [Ru(II)(H)2] species as the active catalyst. The mechanism studies also revealed both the alcohol and amine oxidation involves dehydrogenative pathway with the evolution of hydrogen as the only by-product. The developed catalyst system also provides possible platform for the release of hydrogen from liquid organic hydrogen carriers (LOHCs).
- Barteja, Parul,Devi, Preeti,Kannan, Muthukumar,Muthaiah, Senthilkumar
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- A Remote ‘Imidazole’-Based Ruthenium(II) Para-Cymene Pre-catalyst for the Selective Oxidation Reaction of Alkyl Arenes and Alcohols
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Herein we disclosed the use of a remote ‘imidazole’-based precatalyst [(para-cymene)RuII(L)Cl]+, C-1 where L=2-(4-substituted-phenyl)-1H-imidazo[4,5-f][1,10] phenanthroline) for the selective oxidation of a variety of alkyl arenes/heteroarenes and alcohols to their corresponding aldehydes or ketones in presence of tert-butyl hydroperoxide (TBHP). The remote ‘imidazole’ moiety present in the complex facilitates the activation of oxidant and subsequent generation of active species via the release of para-cymene from C-1, which in-turn was less effective without the ‘imidazole’ moiety. The mechanistic features of C-1 promoted oxidation of alkyl arenes were also assessed from spectroscopic, kinetic, and few control experiments. The substrate scope for C-1 promoted oxidation reaction was assessed based on the selective oxidation of 27-different alkyl arenes/heteroarenes and 25 different alcohols to their corresponding aldehydes/ketones in moderate to good yields.
- Dutta, Manali,Bania, Kusum K.,Pratihar, Sanjay
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p. 926 - 932
(2020/03/05)
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- Synthesis and anti-inflammatory activity of 2-oxo-2H-chromenyl and 2H-chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates
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Cycloaddition reaction of 4-chloro-2-oxo-2H-chromene-3-carbaldehydes (3a-g) and 4-chloro-2H-chromene-3-carbaldehydes (7a-h) with activated alkynes (4a-b) provided the 2-oxo-2H-chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates (5a-n) and 2H-chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates (8a-p). All the prepared compounds were screened for anti-inflammatory activity. In vitro anti-inflammatory activity data demonstrated that the compounds 5g, 5i, 5k-l and 8f are effective among the tested compounds against TNF-α (1.108 ± 0.002, 0.423 ± 0.022, 0.047 ± 0.001, 0.070 ± 0.002 and 0.142 ± 0.001 μM) in comparison with standard compound Prednisolone (0.033 ± 0.002 μM). Based on in vitro results, three compounds (5i, 5k and 8f) have been selected for in vivo experiments and these compounds are identified as better compounds with respect to anti-inflammatory activity in LPS induced mice model. Compound 5i was identified as potent and showed significant reduction in TNF-α and IL-6.
- Bhimapaka, China Raju,Karri, Shailaja,Kuncha, Madhusudana,Kurma, Siva Hariprasad,Sistla, Ramakrishna
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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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- Cu(I)/sucrose-catalyzed hydroxylation of arenes in water: The dual role of sucrose
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A protocol for the hydroxylation of aryl halides catalyzed by copper(I) and sucrose in neat water has been developed. The dual role of sucrose, the reaction pathway, and the high selectivity for hydroxylation were investigated using a combination of experimental and theoretical techniques. This journal is
- Murata, Shigeo,Takagi, Mio,Takita, Ryo,Watanabe, Ayako,Watanabe, Kohei
-
supporting information
p. 7827 - 7831
(2020/11/02)
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- C?H Oxygenation Reactions Enabled by Dual Catalysis with Electrogenerated Hypervalent Iodine Species and Ruthenium Complexes
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The catalytic generation of hypervalent iodine(III) reagents by anodic electrooxidation was orchestrated towards an unprecedented electrocatalytic C?H oxygenation of weakly coordinating aromatic amides and ketones. Thus, catalytic quantities of iodoarenes in concert with catalytic amounts of ruthenium(II) complexes set the stage for versatile C?H activations with ample scope and high functional group tolerance. Detailed mechanistic studies by experiment and computation substantiate the role of the iodoarene as the electrochemically relevant species towards C?H oxygenations with electricity as a sustainable oxidant and molecular hydrogen as the sole by-product. para-Selective C?H oxygenations likewise proved viable in the absence of directing groups.
- Massignan, Leonardo,Tan, Xuefeng,Meyer, Tjark H.,Kuniyil, Rositha,Messinis, Antonis M.,Ackermann, Lutz
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supporting information
p. 3184 - 3189
(2020/01/24)
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- Method for hydrogenolysis of halides
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The invention discloses a method for hydrogenolysis of halides. The invention discloses a preparation method of a compound represented by a formula I. The preparation method comprises the following step: in a polar aprotic solvent, zinc, H2O and a compound represented by a formula II are subjected to a reaction as shown in the specification, wherein X is halogen; Y is -CHRR or R; hydrogenin H2O exists in the form of natural abundance or non-natural abundance. According to the preparation method, halide hydrogenolysis can be simply, conveniently and efficiently achieved through a simple and mild reaction system, and good functional group compatibility and substrate universality are achieved.
- -
-
Paragraph 0230-0232; 0293-0295
(2021/01/11)
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- Pd(OAc)2-catalyzed orthogonal synthesis of 2-hydroxybenzoates and substituted cyclohexanones from acyclic unsaturated 1,3-carbonyl compounds
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A Pd-catalyzed orthogonal synthesis of substituted 2-hydroxybenzoates and substituted cyclohexanones was developed for the first time. The substituted 2-hydroxybenzoates were obtained from acyclic unsaturated 1,3-carbonyl compounds using a combination of catalytic Pd(OAc)2 and Cu(OAc)2. On the other hand, the substituted cyclohexanones were produced from similar substrates via catalytic Pd(OAc)2 and hydrogen chloride. Each transformation was clean, easy to work up, provided the desired compounds in good purities, and did not require column chromatography purification.
- Miyagi, Toshinori,Okada, Sho,Tada, Naoya,Sugihara, Masahiro,Kagawa, Natsuko,Takabatake, Tetsuhiko,Toyota, Masahiro
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supporting information
p. 1653 - 1657
(2019/05/29)
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- Efficient preparation method of 2'-hydroxyacetophenone compounds
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The invention discloses an efficient preparation method of 2'-hydroxyacetophenone compounds. The method comprises the following steps: substituted phenol and acetic anhydride in a molar ratio of 1:(1-1.1) is subjected to a reaction at 130-150 DEG C in the absent of a solvent, acetic acid substituted phenyl ester as shown in the formula is generated, and acetic acid and acetic acid substituted phenyl ester are separated by rectification; prepared acetic acid substituted phenyl ester is subjected to a transposition reaction under the action of a catalyst in an organic solvent at the temperatureof 50-120 DEG C, and 2'-hydroxyacetophenone compounds as shown in the formula are generated; filtering is performed to remove the catalyst after the reaction is finished, the solvent is removed by evaporation, and the 2'-hydroxyacetophenone compounds are prepared by rectification under vacuum, wherein the catalyst is phosphomolybdic acid, phosphotungstic acid, silicotungstic acid or a mixture of the acid. The preparation method has mild conditions and simple flow, and is environmentally friendly and suitable for industrial production, selectivity is high, and ortho-position selectivity is as high as 99.5%.
- -
-
Paragraph 0024; 0025; 0027; 0028
(2019/05/08)
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- Visible light induced redox neutral fragmentation of 1,2-diol derivatives
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A homogeneous, redox-neutral photo fragmentation of diol derivatives was developed. Under photo/hydrogen atom transfer (HAT) dual catalysis, diol derivatives such as lignin model compounds and diol monoesters undergo selective β C(sp3)-O bond cleavage to afford ketones, phenols and acids effectively.
- Chen, Kang,Schwarz, Johanna,Karl, Tobias A.,Chatterjee, Anamitra,K?nig, Burkhard
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p. 13144 - 13147
(2019/11/11)
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- Dehalogenative Deuteration of Unactivated Alkyl Halides Using D2O as the Deuterium Source
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The general dehalogenation of alkyl halides with zinc using D2O or H2O as a deuterium or hydrogen donor has been developed. The method provides an efficient and economic protocol for deuterium-labeled derivatives with a wide substrate scope under mild reaction conditions. Mechanistic studies indicated that a radical process is involved for the formation of organozinc intermediates. The facile hydrolysis of the organozinc intermediates provides the driving force for this transformation.
- Xia, Aiyou,Xie, Xin,Hu, Xiaoping,Xu, Wei,Liu, Yuanhong
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p. 13841 - 13857
(2019/10/17)
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- Directed Hydroxylation of sp2 and sp3 C-H Bonds Using Stoichiometric Amounts of Cu and H2O2
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The use of copper for C-H bond functionalization, compared to other metals, is relatively unexplored. Herein, we report a synthetic protocol for the regioselective hydroxylation of sp2 and sp3 C-H bonds using a directing group, stoichiometric amounts of Cu and H2O2. A wide array of aromatic ketones and aldehydes are oxidized in the carbonyl γ-position with remarkable yields. We also expanded this methodology to hydroxylate the β-position of alkylic ketones. Spectroscopic characterization, kinetics, and density functional theory calculations point toward the involvement of a mononuclear LCuII(OOH) species, which oxidizes the aromatic sp2 C-H bonds via a concerted heterolytic O-O bond cleavage with concomitant electrophilic attack on the arene system.
- Trammell, Rachel,D'Amore, Lorenzo,Cordova, Alexandra,Polunin, Pavel,Xie, Nan,Siegler, Maxime A.,Belanzoni, Paola,Swart, Marcel,Garcia-Bosch, Isaac
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p. 7584 - 7592
(2019/06/11)
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- CuCl/bpy-promoted unusual Z-stereoselective synthesis of trichloroacetic acid phenyl ester for Hirshfeld surface analysis and DFT study
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A trichloromethyl ester devoid of suitably substituted C[dbnd]C bond, any leaving group or a H-atom at the β-position to the radical, which are otherwise known for ATRA/ATRC, 1,2-rearrangement/fragmentation or simple 1,2-H shift respectively, in a reaction of trichloro-acetic acid phenyl ester with 2 mol equiv CuCl/bpy in reflux DCE or benzene under inert N2 condition resulted to stereoselective synthesis of Z-2,3-dichloro-but-2-enedioic acid diphenyl ester and/or formation of reductive de-chlorination side product. The Z-stereochemistry of the product was confirmed by X-ray diffraction spectroscopy of Z-2,3-dichloro-but-2-enedioic acid dinaphthalen-1-yl ester which crystalizes in monoclinic system of P21/c symmetry elements. Hirshfeld surface analysis of experimentally established structure of Z-2,3-dichloro-but-2-enedioic acid diphenyl ester unrevealed the intermolecular interactions showing both H-bonding and short contacts. The stereochemistry was also interpreted computationally using Density Functional Theory at B3LYP/6-311G(d,p) level of theory. The calculated energies, energy gap and balance between the electrostatic potential on the molecular surface were computed which revealed unusual formation of less stable Z-isomer.
- Tittal, Ram Kumar,Ram, Ram Nath,Nirwan, Ayushi,Ghule, Vikas D.,Kumar, Satish
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p. 300 - 309
(2019/03/12)
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- Fe(NO3)3·9H2O-catalyzed aerobic oxidative deoximation of ketoximes and aldoximes under mild conditions
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A mild, simple process for the effective aerobic oxidative deoximation of a wide range of ketoximes and aldoximes has been developed that utilizes Fe(NO3)3·9H2O as the single catalyst and molecular oxygen as the green oxidant. The environmentally benign protocol provides moderate to excellent yield and broad functional groups tolerance and is a valuable synthetic method for practical applications. According the relevant verification experiment, a plausible mechanism has been proposed.
- Li, Yongshu,Xu, Nizhou,Mei, Guangyao,Zhao, Yun,Zhao, Yiyong,Lyu, Jinghui,Zhang, Guofu,Ding, Chengrong
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supporting information
p. 810 - 814
(2018/08/09)
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- Practical and efficient synthesis of hydroxyaryl ketones catalyzed by HF@SiO2 under solvent-free condition
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A wide variety of hydroxyaryl ketones bearing different motifs was successfully synthesized with good yields and excellent selectivities in the presence of HF@SiO2 as an environmental friendly acid under solvent-free condition. Mild and green reaction conditions and excellent yields (50-91%) make this method an attractive method for the efficient synthesis of hydroxyaryl ketones. Fries rearrangement of phenyl benzoate in the presence of HF@SiO2 led to p-hydroxybenzophenone, while phenyl acetate in the same conditions produced o-hydroxyacetophenone as a single isomer.
- Paghandeh, Hossein,Saeidian, Hamid,Ghaffarzadeh, Mohammad
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p. 809 - 814
(2018/09/26)
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- Ultrasound-assisted synthesis and antimicrobial activity of tetrazole-based pyrazole and pyrimidine derivatives
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New tetrazole-based pyrazole and pyrimidine derivatives were synthesized by an ultrasound irradiation method. All compounds were characterized by infrared spectroscopy (IR), 1H nuclear magnetic resonance (NMR), 13C NMR, mass spectrometry (MS) and elemental analysis and assessed in vitro for their efficacy as antimicrobial agents against four bacteria (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa) and two fungi (Candida albicans, Aspergillus Niger). Compounds 8a, 8e, 9a, 9b and 9e show potent activity against the tested strains compared to the reference drugs chloramphenicol and clotrimazole.
- Dofe, Vidya S.,Sarkate, Aniket P.,Shaikh, Zarina M.,Gill, Charansingh H.
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- Deprotection of durable benzenesulfonyl protection for phenols — efficient synthesis of polyphenols
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A robust protection method for phenol was demonstrated by the use of durable benzenesulfonyl group, which survives various harsh reaction conditions using Grignard reagent, organolithium reagent, metal alkoxide, phosgene, mineral, and Lewis acids. A facile deprotection condition utilizing pulverized KOH (5 equiv) and t-BuOH (10 equiv) in hot toluene makes this protocol as a practical method, which can be applied to the multistep synthesis of biologically and medicinally important polyphenol compounds.
- Alam, Mohammad Shariful,Koo, Sangho
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supporting information
p. 247 - 254
(2018/01/08)
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- Acid-Functionalised Magnetic Ionic Liquid [AcMIm]FeCl4 as Catalyst for Oxidative Hydroxylation of Arylboronic Acids and Regioselective Friedel–Crafts Acylation
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An acid-functionalised, magnetic, room-temperature ionic liquid, 1-acyl-3-methylimidazolium tetrachloroferrate ([AcMIm]FeCl4), was synthesised and its optical, magnetic, and thermal properties were investigated. The magnetic moment (0.05402 emu in 2 T magnetic fields) showed strong paramagnetic behaviour, and thermogravimetric analysis indicated very good thermal stability with a decomposition temperature higher than 230 °C. Additionally, [AcMIm]FeCl4 efficiently catalysed the oxidative ipso-hydroxylation of arylboronic acids and regioselective Friedel–Crafts acylation without external organic solvent or additives, such as acids, base, and ligands. This functionalised ionic liquid, [AcMIm]FeCl4, was recycled and reused at least six times without significant loss of its catalytic properties and stability.
- Saha, Arijit,Payra, Soumen,Dutta, Dipa,Banerjee, Subhash
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p. 1129 - 1134
(2017/08/18)
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- Synthesis, antimicrobial activity and anti-biofilm activity of novel tetrazole derivatives
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In the development of antimicrobial agents, we designed and synthesized novel tetrazole derivatives. The structures of compounds 6a-f and 7a-f were characterized by IR, 1H NMR, 13C NMR, MS and elemental analysis. These compounds were tested for their antimicrobial activity against a series of strains Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa and for antifungal activity against the strains Candida albicans, Candida glabrata, and Candida tropicalis. Compounds 6e, 6f, 7a, and 7f exhibit potent antimicrobial activities compared to the reference drugs streptomycin and miconazole. Tetrazole derivatives 7a-f also inhibit biofilm formation and compound 7f exhibits best anti-biofilm activity with a biofilm inhibitory concentration (BIC) as low as 0.9 μm.
- Dofe, Vidya S.,Sarkate, Aniket P.,Kathwate, Santosh H.,Gill, Charansingh H.
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p. 325 - 330
(2017/08/18)
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- C-H Alkenylation of Heteroarenes: Mechanism, Rate, and Selectivity Changes Enabled by Thioether Ligands
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Thioether ancillary ligands have been identified that can greatly accelerate the C-H alkenylation of O-, S-, and N-heteroarenes. Kinetic data suggest thioether-Pd-catalyzed reactions can be as much as 800× faster than classic ligandless systems. Furthermore, mechanistic studies revealed C-H bond cleavage as the turnover-limiting step, and that rate acceleration upon thioether coordination is correlated to a change from a neutral to a cationic pathway for this key step. The formation of a cationic, low-coordinate catalytic intermediate in these reactions may also account for unusual catalyst-controlled site selectivity wherein C-H alkenylation of five-atom heteroarenes can occur under electronic control with thioether ligands even when this necessarily involves reaction at a more hindered C-H bond. The thioether effect also enables short reaction times under mild conditions for many O-, S-, and N-heteroarenes (55 examples), including examples of late-stage drug derivatization.
- Gorsline, Bradley J.,Wang, Long,Ren, Peng,Carrow, Brad P.
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supporting information
p. 9605 - 9614
(2017/07/24)
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- Photocatalytic benzene and benzene derivative direct hydroxylation or amination method
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The invention discloses a photocatalytic benzene and benzene derivative direct hydroxylation or amination method. The method is characterized by comprising the following steps: (1) adding a photo-sensitizer and a cobalt catalyst into a solvent to obtain a solution (A); (2) adding benzene (or benzene derivatives), water, ammonia gas, and amide derivatives (or sulfonamide derivatives) into the solution (A) to obtain a solution (B); and (3) in a N2 (or Ar) environment, radiating the solution (B) by a medium pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, or an LED lamp to obtain phenols or amines and H2. For the first time, a photo-sensitizer and a cobalt catalyst are combined and applied to photocatalytic hydroxylation and amination of benzene. The conditions of the method are mild, light is taken as the driving energy, no oxidant is added, the only byproduct is H2, and the whole process is green, concise, and efficient. High selective benzene one-step hydroxylation to generate phenol or high selective phenol/benzene one-step amination to generate aniline is realized, and the method can be applied to the production of phenol and aniline.
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Paragraph 0112-0113
(2017/11/29)
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- Palladium-catalyzed oxime ether directed regioselective C-H alkoxylation of arenes
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A palladium-catalyzed highly regioselective ortho-C(sp2)-H alkoxylation of oxime ethers with PhI(OAc)2as the oxidant and alcohols as the alkoxylation reagents has been developed. Mono-alkoxylated and acetoxylated products could be selectively obtained via tuning the reaction conditions. A series of oxime ethers were tolerated, affording the corresponding products in moderate to good yields. Both primary and secondary alcohols survived the reaction conditions. Moreover, the directing group can be easily removed, thereby providing a straightforward access to substituted aryl ketones.
- Pan, Liang,Wang, Liang,Chen, Qun,He, Mingyang
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supporting information
p. 1981 - 1988
(2016/12/09)
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- A Green, Solvent-Free, Microwave-Assisted, High-Yielding YbCl3Catalyzed Deprotection of THP/MOM/Ac/Ts Ethers of Chalcone Epoxide and 2′-Aminochalcone and Their Sequel Cyclization
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Under microwave and solvent-free conditions, YbCl3efficiently catalyzed the deprotection of tetrahydropyran-2-yl, methoxymethyl (MOM), acetyl, and tosyl groups and sequel cyclization of chalcone epoxide to 2-hydroxyindanone and 2′-aminochalcone to aza-flavanone. The reaction afforded the products in excellent yield (78–99%) at 850 W microwave heating within 1–5 min under eco-friendly conditions. The merits of the presented protocol include high yield, use of microwave irradiation, solvent-free condition, catalyst reusability, and no need for purification with column chromatography. The present method is very much milder but more advanced than those reported earlier.
- Kumar, Sumit,Verma, Nishant,Parveen, Iram,Ahmed, Naseem
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supporting information
p. 2111 - 2122
(2016/11/23)
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- β-Cyclodextrin/IBX in water: Highly facile biomimetic one pot deprotection of THP/MOM/Ac/Ts ethers and concomitant oxidative cleavage of chalcone epoxides and oxidative dehydrogenation of alcohols
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A mild and efficient one-pot deprotection of THP/MOM/Ac/Ts ethers, and concomitant oxidative cleavage of epoxides and oxidative dehydrogenation of alcohols to form β-hydroxy 1,2-diketones, 1,2,3-triketones and conjugated aromatic carbonyl systems (chalcones) using β-cyclodextrin/IBX in water has been developed. o-Iodoxybenzoic acid, a readily available hypervalent iodine(v) reagent, was found to be highly effective with β-cyclodextrin in carrying out the deprotection and subsequent transformations under an eco-friendly environment. The reaction gave moderate to excellent yields ranging from 50-99% at 60°C in 40 min to 6 h.
- Kumar, Sumit,Ahmed, Naseem
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supporting information
p. 648 - 656
(2016/02/12)
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- Bi (NO3)3·5H2O and cellulose mediated Cu-NPs - A highly efficient and novel catalytic system for aerobic oxidation of alcohols to carbonyls and synthesis of DFF from HMF
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A highly efficient and versatile catalytic system for oxidation of primary and secondary aromatic alcohols to carbonyls has been developed. High efficiency, general synthetic applicability, broader functional group tolerance and versatility towards oxidation of both primary and secondary aromatic alcohols are the key features of this green and sustainable protocol. Selective oxidation of 5-hydroxymethyl furfural (HMF) to biofuel 2,5-diformylfuran (DFF) has been observed in excellent yields. Use of sustainable bio-polymer cellulose as a Cu-nanoparticle support makes the catalytic system environmentally benign.
- Baruah, Diganta,Hussain, Farhaz L.,Suri, Mrinaly,Saikia, Ujwal Pratim,Sengupta, Pinaki,Dutta, Dipak Kumar,Konwar, Dilip
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- 1,2,3-Triazole tethered acetophenones: Synthesis, bioevaluation and molecular docking study
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A small focused library of eighteen new 1,2,3-triazole tethered acetophenones has been efficiently prepared via click chemistry approach and evaluated for their antifungal and antioxidant activity. The antifungal activity was evaluated against five human pathogenic fungal strains: Candida albicans, Fusarium oxysporum, Aspergillus flavus, Aspergillus niger, and Cryptococcus neoformans. Among the synthesized compounds, 9c, 9i, and 9p found to be more potent antifungal agents that the reference standard. These 1,2,3-triazole based derivatives were also evaluated for antioxidant activity, and compound 9h was found to be the most potent antioxidant as compared to the standard drug. Furthermore, molecular docking study of the newly synthesized compounds was performed and results showed good binding mode in the active site of fungal C. albicans enzyme P450 cytochrome lanosterol 14α-demethylase. Moreover, the synthesized compounds were also analyzed for ADME properties and showed potential as good oral drug candidates.
- Shaikh, Mubarak H.,Subhedar, Dnyaneshwar D.,Khedkar, Vijay M.,Jha, Prakash C.,Khan, Firoz A. Kalam,Sangshetti, Jaiprakash N.,Shingate, Bapurao B.
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supporting information
p. 1058 - 1063
(2016/07/29)
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- A process for the preparation of ortho-hydroxy acetophenone
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The invention provides a preparation method of hydroxyacetophenone. The preparation method comprises the following steps: firstly weighing phenol and acetylchloride of which the mole ratio is 1:(1.2-1.5); metering an organic solvent; adding the phenol, the acetylchloride and the organic solvent into a reaction container; reacting at the temperature of 20-30 DEG C; after the reaction is finished, washing by using weak alkali; collecting an organic phase; concentrating and drying to obtain phenyl acetate; adding Lewis acid into the obtained phenyl acetate to react at the temperature of 120 to 160 DEG C; after the reaction is finished, dehydrating the obtained product by using a hydrochloric acid solution; extracting by using the organic solvent; concentrating an organic layer; adding the organic solvent into the organic layer; freezing and filtering the organic layer to obtain a filter cake; distilling the filter cake by using water steam to obtain a product hydroxyacetophenone. The raw materials adopted by the method disclosed by the invention are low in price, the experiment condition is mild, the yield is high, and the O/P ratio is as high as 3.55:1, so the method disclosed by the invention has a great application value in production.
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Paragraph 0045; 0046
(2017/02/24)
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- Photochemistry of aroyloxiranes: Substituent effect on oxepinones and hydroxyalkenones formation
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The photo-irradiation of some aroyloxiranes with Pyrex filtered UV-light from 125?W medium pressure Hg lamp has been described. These compounds furnished the 2-aryl-4,10-dihydrofuro[3,2-c][1]benzoxepin-10-ones and the hydroxyalkenones by the photochemical irradiation. The product(s) formation/distribution in terms of oxepinones and the hydroxyalkenones largely depended upon the nature of the substituent: the oxiranes having electron-donating groups in their benzoyl moiety gave the hydroxyalkenones while oxiranes having electron-withdrawing groups furnished the oxepinones as the major products. The formation of oxepinones has been envisaged to occur through the heterolytic [Formula presented] bond cleavage of epoxide to give carbonyl ylide intermediates followed by the furo-oxepinone ring formation via [3+2] cycloaddition and of hydroxyalkenones through the initial β-H abstraction followed by epoxide ring opening. The structures of all the compounds (substrates and photoproducts) have been determined on the basis of their spectral data (IR, NMR and Mass).
- Dalal, Aarti,Khanna, Radhika,Berar, Urmila,Kamboj, Ramesh C.
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p. 238 - 245
(2016/07/22)
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- Novel synthetic method for flavonoid compound
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A novel synthetic method for flavonoid compounds comprises the following steps: 1) fully mixing 21.4 g (0.21 mol) of acetic anhydride and 18.8 g (0.2 ml) of phenol; 2) placing the mixture in ice water bath, adding concentrated sulfuric acid by three drops to the mixture, shaking the mixture, performing fractionation to obtain acetic acid, and collecting the fraction at 194-196 DEG C to obtain liquid phenyl acetate which is colorless and transparent; 3) adding 1-o-hydroxyphenyl-3-phenyl-1,3-propanedione and 20 ml of glacial acetic acid into a 100 ml round-bottom flask, uniformly mixing the components, adding 0.8 ml of concentrated sulfuric acid to interior of the mixture, mounting a reflux condensing tube and heating the mixture for 1 h in boiled water; 4) weighing 100 g of crush ice by a beaker and pouring the mixture into the beaker with continuous stirring until ice is dissolved completely; and 5) performing suction filtration to solid and washing the solid in water continuously until acidity is eliminated, and finally weighing the dried product to obtain the flavonoid compound 2-phenyl benzopyrone.
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Paragraph 0016
(2016/11/28)
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- A New Route to Phenols: Palladium-Catalyzed Cyclization and Oxidation of γ,δ-Unsaturated Ketones
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We report a new strategy for the synthesis of phenols from acyclic unsaturated ketones in one pot. The reaction proceeds by palladium-catalyzed carbopalladation of an alkene with the enol form of the tethered ketone, generating a substituted cyclohexanone. Upon introduction of a terminal oxidant a palladium-catalyzed oxidation ensues to give the desired phenol. This approach allows the programming of phenol substituents on the acyclic substrate and therefore circumvents the limitations inherent in traditional syntheses of phenols.
- Samadi, Sadaf,Orellana, Arturo
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p. 2472 - 2475
(2016/08/25)
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- Acylation of Csp2-H bond with acyl sources derived from alkynes: Rh-Cu bimetallic catalyzed CC bond cleavage
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A Rh-Cu bimetallic catalyzed o-acylation of acyloxacetamide with alkynes has been described. This transformation provides a novel, concise way to synthesize ortho-acylphenols using functionalized alkynes as acylating reagents. Mechanistic studies revealed a Rh-Cu relay process, in which O2 plays a critical role for the formation of carbonyl compounds.
- Xie, Ying
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supporting information
p. 12372 - 12375
(2016/10/22)
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- A Mild Strategy for the Preparation of Phenols via the Ligand-Free Copper-Catalyzed O-Arylation of para -Toluenesulfonic Acid
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A facile and simple ligand-free copper-catalyzed reaction to synthesize substituted phenols is reported. The reaction presumably proceeds via an O-arylsulfonate intermediate that is hydrolyzed to afford good to excellent yields of up to 88%. This protocol provides an alternative to existing reports which use strong hydroxide salts as the direct hydroxylation partner. Demonstrating a wide substrate scope and functional group tolerance, this protocol can also be applied to inexpensive and commercially available carboxylic acids to yield phenols.
- Tan, Bryan Yong-Hao,Teo, Yong-Chua
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supporting information
p. 1814 - 1819
(2016/07/16)
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- Photocatalytic Hydrogen-Evolution Cross-Couplings: Benzene C-H Amination and Hydroxylation
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We present a blueprint for aromatic C-H functionalization via a combination of photocatalysis and cobalt catalysis and describe the utility of this strategy for benzene amination and hydroxylation. Without any sacrificial oxidant, we could use the dual catalyst system to produce aniline directly from benzene and ammonia, and phenol from benzene and water, both with evolution of hydrogen gas under unusually mild conditions in excellent yields and selectivities.
- Zheng, Yi-Wen,Chen, Bin,Ye, Pan,Feng, Ke,Wang, Wenguang,Meng, Qing-Yuan,Wu, Li-Zhu,Tung, Chen-Ho
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supporting information
p. 10080 - 10083
(2016/09/04)
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- β-Cyclodextrin in water: Highly facile biomimetic one pot deprotection of phenolic THP/MOM/Ac/Ts ethers and concomitant regioselective cyclization of chalcone epoxides and 2′-aminochalcones
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A mild and efficient one-pot deprotection of THP/MOM/Ac/Ts ethers and the concomitant cyclization of chalcone epoxides to 2-hydroxyindanones or 2′-aminochalcones to aza-flavanones using β-cyclodextrin in water has been developed. β-CD was found to be highly effective at carrying out the deprotection and sequential transformations in an eco-friendly environment affording moderate to excellent yields (59-99%) at 60 °C in 8-22 min. Water, an eco-friendly reaction medium, has been utilized for the first time in this reaction. The merits of the presented protocol include the high yields and catalyst reusability and the protocol precludes the use of metals and organic solvents. The present method is much milder but more advanced than those reported earlier.
- Kumar, Sumit,Verma, Nishant,Ahmed, Naseem
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p. 85128 - 85138
(2015/10/28)
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- Ligand-Promoted Pd-Catalyzed Oxime Ether Directed C-H Hydroxylation of Arenes
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An efficient Pd-catalyzed oxime ether directed ortho C-H hydroxylation of arenes under neutral conditions has been developed. The efficiency of this hydroxylation is significantly improved by a ligand. Oxone, an inexpensive, readily available, and safe reagent, was employed as terminal oxidant and oxygen source. The challenging electron-deficient substrates could also be monohydroxylated in high efficiency. Drug modification with this protocol was also successfully demonstrated.
- Liang, Yu-Feng,Wang, Xiaoyang,Yuan, Yizhi,Liang, Yujie,Li, Xinyao,Jiao, Ning
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p. 6148 - 6152
(2015/10/12)
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- Ruthenium Trichloride Catalyzed Highly Efficient Deoximation of Oximes to the Carbonyl Compounds and Nitriles without Acceptors
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An acceptor-free catalysis protocol for the deoximation of ketoximes and aldoximes using RuCl3 as the catalyst has been developed. Under the optimized conditions, various oximes were converted to ketones and nitriles with excellent isolated yields. An acceptor-free catalysis protocol for the deoximation of ketoximes and aldoximes using RuCl3 as the catalyst has been developed. Under the optimized conditions, various oximes were converted to ketones and nitriles with excellent isolated yields.
- Liu, Yuxiao,Yang, Na,Chu, Changhu,Liu, Renhua
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supporting information
p. 1011 - 1014
(2015/09/28)
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- In the cleaving org. compd. ether bond
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PROBLEM TO BE SOLVED: To provide a cleavage method of a methyl ether bond in an organic compound for cleaving the methyl ether bond in the organic compound which is usable as various synthesis methods for organic compounds without especially using a solvent or a post-treatment agent. SOLUTION: The method is characterized in that an organic compound having a methyl ether bond is contacted with hydrogen iodide gas at room temperature without dissolving a solvent so that the methyl ether bond is cleaved. COPYRIGHT: (C)2013,JPOandINPIT
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Paragraph 0072-0075
(2016/12/22)
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