- Simultaneous multistep synthesis using polymeric reagents
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A synthesis was accomplished involving three transformations using three different polymeric reagents simultaneously in one reaction vessel to afford 2-[[4-chloro-1-methyl-5-(trifluoromethyl)-1H-pyrazol-3-yl]oxy]-1-pheny lethanone (4).
- Parlow, John J.
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Read Online
- Visible light-mediated, high-efficiency oxidation of benzyl to acetophenone catalyzed by fluorescein
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An environmentally friendly aerobic oxidation of benzyl C(sp3)-H bonds to ketones via selective oxidation catalysis was developed. Fluorescein is an efficient photocatalyst with excellent chemical selectivity. The reaction has a wide substrate scope, and a successful gram-scale experiment demonstrated its potential industrial utility.
- Geng, Haoxing,Liu, Xin,Zhu, Qing
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supporting information
(2021/12/20)
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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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- HCl-Catalyzed Aerobic Oxidation of Alkylarenes to Carbonyls
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The construction of C?O bonds through C?H bond functionalization remains fundamentally challenging. Here, a practical chlorine radical-mediated aerobic oxidation of alkylarenes to carbonyls was developed. This protocol employed commercially available HCl as a hydrogen atom transfer (HAT) reagent and air as a sustainable oxidant. In addition, this process exhibited excellent functional group tolerance and a broad substrate scope without the requirement for external metal and oxidants. The mechanistic hypothesis was supported by radical trapping, 18O labeling, and control experiments.
- Ding, Ling,Liu, Yuxiu,Niu, Kaikai,Shi, Xiaodi,Song, Hongjian,Wang, Qingmin
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- Visible-light photocatalytic selective oxidation of C(sp3)-H bonds by anion-cation dual-metal-site nanoscale localized carbon nitride
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Selective oxidation of C(sp3)-H bonds to carbonyl groups by abstracting H with a photoinduced highly active oxygen radical is an effective method used to give high value products. Here, we report a heterogeneous photocatalytic alkanes C-H bonds oxidation method under the irradiation of visible light (λ= 425 nm) at ambient temperature using an anion-cation dual-metal-site modulated carbon nitride. The optimized cation (C) of Fe3+or Ni2+, with an anion (A) of phosphotungstate (PW123?) constitutes the nanoscale dual-metal-site (DMS). With a Fe-PW12dual-metal-site as a model (FePW), we demonstrate a A-C DMS nanoscale localized carbon nitride (A-C/g-C3N4) exhibiting a highly enhanced photocatalytic activity with a high product yield (86% conversion), selectivity (up to 99%), and a wide functional group tolerance (52 examples). The carbon nitride performs the roles of both the visible light response, and improves the selectivity for the oxidation of C(sp3)-H bonds to carbonyl groups, along with the function of A-C DMS in promoting product yield. Mechanistic studies indicate that this reaction follows a radical pathway catalyzed by a photogenerated electron and hole on A-C/g-C3N4that is mediated by thetBuO˙ andtBuOO˙ radicals. Notably, a 10 g scale reaction was successfully achieved for alkane photocatalytic oxidation to the corresponding product with a good yield (80% conversion), and high selectivity (95%) under natural sunlight at ambient temperature. In addition, this A-C/g-C3N4photocatalyst is highly robust and can be reused at least six times and the activity is maintained.
- Duan, Limei,Li, Peihe,Li, Wanfei,Liu, Jinghai,Liu, Ying,Liu, Zhifei,Lu, Ye,Sarina, Sarina,Wang, Jinghui,Wang, Yin,Wang, Yingying,Zhu, Huaiyong
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p. 4429 - 4438
(2021/07/12)
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- Thiazole ring-containing amide compounds as well as preparation method and application thereof
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The invention discloses thiazole ring-containing amide compounds as well as a preparation method and application thereof, and belongs to the field of chemical technologies and pesticides. According to the present invention, p-phenylenediamine is adopted as a raw material to synthesize a series of the thiazole ring-containing amide compounds, and the synthesized thiazole ring-containing amide compounds have good inhibition effects on Xanthomonas oryzae pv.Oryza (Xoo), Xanthomonas oryzae pv.Oryzcola (Xoc) and Xanthomonas axonophora pv.Citri (Xac) in agricultural diseases and insect pests, and can be used for preparing the anti-plant bacterium agent.
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Paragraph 0044; 0051; 0103; 0106; 0185; 0190; 0255; 0260
(2021/06/23)
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- Flexible on-site halogenation paired with hydrogenation using halide electrolysis
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Direct electrochemical halogenation has appeared as an appealing approach in synthesizing organic halides in which inexpensive inorganic halide sources are employed and electrical power is the sole driving force. However, the intrinsic characteristics of direct electrochemical halogenation limit its reaction scope. Herein, we report an on-site halogenation strategy utilizing halogen gas produced from halide electrolysis while the halogenation reaction takes place in a reactor spatially isolated from the electrochemical cell. Such a flexible approach is able to successfully halogenate substrates bearing oxidatively labile functionalities, which are challenging for direct electrochemical halogenation. In addition, low-polar organic solvents, redox-active metal catalysts, and variable temperature conditions, inconvenient for direct electrochemical reactions, could be readily employed for our on-site halogenation. Hence, a wide range of substrates including arenes, heteroarenes, alkenes, alkynes, and ketones all exhibit excellent halogenation yields. Moreover, the simultaneously generated H2at the cathode during halide electrolysis can also be utilized for on-site hydrogenation. Such a strategy of paired halogenation/hydrogenation maximizes the atom economy and energy efficiency of halide electrolysis. Taking advantage of the on-site production of halogen and H2gases using portable halide electrolysis but not being suffered from electrolyte separation and restricted reaction conditions, our approach of flexible halogenation coupled with hydrogenation enables green and scalable synthesis of organic halides and value-added products.
- Shang, Xiao,Liu, Xuan,Sun, Yujie
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supporting information
p. 2037 - 2043
(2021/03/26)
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- Solvent-free preparation of α,α-dichloroketones with sulfuryl chloride
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An efficient and facile method is reported for the synthesis of a series of α,α-dichloroketones. The direct dichlorination of methyl ketones and 1,3-dicarbonyls using an excess amount of sulfuryl chloride affords the corresponding gem-dichloro compounds in moderate to excellent yields. Moreover, the protocol features high yields, broad substrate scope, and simple reaction conditions without using any catalysts and solvents.
- Tu, Dewei,Luo, Juan,Jiang, Wengao,Tang, Qiang
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supporting information
(2021/09/15)
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- Nitrosoarene-Catalyzed HFIP-Assisted Transformation of Arylmethyl Halides to Aromatic Carbonyls under Aerobic Conditions
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A rare metal-free nucleophilic nitrosoarene catalysis accompanied by highly hydrogen-bond-donor (HBD) solvent, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), organocatalytically converts arylmethyl halides to aromatic carbonyls. This protocol offers an effective means to access a diverse array of aromatic carbonyls with good chemoselectivity under mild reaction conditions. The activation of arylmethyl halides by HFIP to generate stable carbocation and autoxidation of in situ generated hydroxylamine to nitrosoarene in the presence of atmospheric O2 are the keys to success.
- Pradhan, Suman,Sharma, Vishali,Chatterjee, Indranil
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supporting information
p. 6148 - 6152
(2021/08/03)
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- A General Method for the Dibromination of Vicinal sp3C-H Bonds Exploiting Weak Solvent-Substrate Noncovalent Interactions
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A general procedure of 1,2-dibromination of vicinal sp3 C-H bonds of arylethanes using N-bromosuccinimide as the bromide reagent without an external initiator has been established. The modulation of the strength of the intermolecular noncovalent interactions between the solvent and arylethane ethanes, quantitatively evaluated via quantum chemical calculations, allows us to circumvent the fact that arylethane ethane cannot be dibrominated through traditional methods. The mechanism was explored by both experiments and quantum chemical calculations, revealing a radical chain with HAA process.
- Qi, Zaojuan,Li, Weihe,Niu, Yanning,Benassi, Enrico,Qian, Bo
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p. 2399 - 2404
(2021/03/03)
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- Oxidative Cleavage of Alkenes by O2with a Non-Heme Manganese Catalyst
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The oxidative cleavage of C═C double bonds with molecular oxygen to produce carbonyl compounds is an important transformation in chemical and pharmaceutical synthesis. In nature, enzymes containing the first-row transition metals, particularly heme and non-heme iron-dependent enzymes, readily activate O2 and oxidatively cleave C═C bonds with exquisite precision under ambient conditions. The reaction remains challenging for synthetic chemists, however. There are only a small number of known synthetic metal catalysts that allow for the oxidative cleavage of alkenes at an atmospheric pressure of O2, with very few known to catalyze the cleavage of nonactivated alkenes. In this work, we describe a light-driven, Mn-catalyzed protocol for the selective oxidation of alkenes to carbonyls under 1 atm of O2. For the first time, aromatic as well as various nonactivated aliphatic alkenes could be oxidized to afford ketones and aldehydes under clean, mild conditions with a first row, biorelevant metal catalyst. Moreover, the protocol shows a very good functional group tolerance. Mechanistic investigation suggests that Mn-oxo species, including an asymmetric, mixed-valent bis(μ-oxo)-Mn(III,IV) complex, are involved in the oxidation, and the solvent methanol participates in O2 activation that leads to the formation of the oxo species.
- Bennett, Elliot L.,Brookfield, Adam,Guan, Renpeng,Huang, Zhiliang,Mcinnes, Eric J. L.,Robertson, Craig M.,Shanmugam, Muralidharan,Xiao, Jianliang
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supporting information
p. 10005 - 10013
(2021/07/19)
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- 1,3-Dibromo-5,5-dimethylhydantoin (DBH)/DMSO mediated oxidative difunctionalization of styrenes: Microfluidic synthesis of pentafluorophenoxy ketone
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A practical and mild synthesis of pentafluorophenoxy ketone in a continuous flow microfluidic reactor has been developed through 1,3-Dibromo-5,5-dimethylhydantoin (DBH)/DMSO mediated oxidative coupling of styrenes with pentafluorophenol. Moreover, a series of pentafluorophenoxy ketone products were provided in moderate to good yields under metal-free conditions. A magnifying continuous flow system was erected to verify the appliance of this method.
- Xu, Jia,Hua, Jiawei,Bian, Mixue,Li, Yuguang,He, Wei,Yang, Zhao,Liu, Chengkou,Fang, Zheng,Guo, Kai
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- A practical synthesis of α-bromo/iodo/chloroketones from olefins under visible-light irradiation conditions
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A practical synthesis of α-bromo/iodo/chloroketones from olefins under visible-light irradiation conditions has been developed. In the presence of PhI(OAc)2 as promoter and under ambient conditions, the reactions of styrenes and triiodomethane undergo the transformation smoothly to deliver the corresponding α-iodoketones without additional photocatalyst in good yields under sunlight irradiation. Meanwhile, the reactions of styrenes with tribromomethane and trichloromethane generate the desired α-bromoketones and α-chloroketones in high yields by using Ru(bpy)3Cl2 as a photocatalyst under blue LED (450–455 nm) irradiation.
- Wang, Zhihui,Wang, Lei,Wang, Zhiming,Li, Pinhua,Zhang, Yicheng
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supporting information
p. 429 - 432
(2020/02/29)
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- Visible light mediated selective oxidation of alcohols and oxidative dehydrogenation of N-heterocycles using scalable and reusable La-doped NiWO4nanoparticles
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Visible light-mediated selective and efficient oxidation of various primary/secondary benzyl alcohols to aldehydes/ketones and oxidative dehydrogenation (ODH) of partially saturated heterocycles using a scalable and reusable heterogeneous photoredox catalyst in aqueous medium are described. A systematic study led to a selective synthesis of aldehydes under an argon atmosphere while the ODH of partially saturated heterocycles under an oxygen atmosphere resulted in very good to excellent yields. The methodology is atom economical and exhibits excellent tolerance towards various functional groups, and broad substrate scope. Furthermore, a one-pot procedure was developed for the sequential oxidation of benzyl alcohols and heteroaryl carbinols followed by the Pictet-Spengler cyclization and then aromatization to obtain the β-carbolines in high isolated yields. This methodology was found to be suitable for scale up and reusability. To the best of our knowledge, this is the first report on the oxidation of structurally diverse aryl carbinols and ODH of partially saturated N-heterocycles using a recyclable and heterogeneous photoredox catalyst under environmentally friendly conditions.
- Abinaya, R.,Balasubramaniam, K. K.,Baskar, B.,Divya, P.,Mani Rahulan, K.,Rahman, Abdul,Sridhar, R.,Srinath, S.
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p. 5990 - 6007
(2021/08/24)
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- Continuous Flow Synthesis of 2H-Thiopyrans via thia-Diels–Alder Reactions of Photochemically Generated Thioaldehydes
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Herein, we report a novel protocol for the photochemical generation of thioaldehydes in a continuous flow process which were in situ reacted with electron rich 1,3-butadienes in thia-Diels–Alder reactions. A broad range of 3,6-dihydro-2H-thiopyrans were formed as products in much higher yields and productivities as compared to classical batch processes. Moreover, greatly reduced reaction times and a facile large-scale preparation of products were achieved by fully exploiting the advantages of continuous flow technology.
- Sachse, Florian,Gebauer, Konrad,Schneider, Christoph
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- Synthesis of a New Phorbazole and Its Derivatives
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Phorbazoles are chlorinated marine alkaloids containing pyrrole, oxazole and phenol ring units, and differ in the number and positions of chlorine atoms. They are isolated from sea sponges and nudibranchs. In this work, a convenient synthetic method leading to a new phorbazole and its derivatives is developed. This synthesis of synthetic phorbazole G and its derivatives is achieved in seven steps in good overall yields of 26-52%. It involves formation of the pyrrole-oxazole skeleton followed by chlorination. The pyrrole-oxazole skeleton is synthesized from pyrrole and substituted acetophenones, and the key step involves cyclodehydration of amide intermediates to give protected oxazoles, followed by hydrolysis.
- Louglin, Wendy A.,Muderawan, I Wayan,Young, David J.
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- Synthesis, characterization, reactivity, and catalytic studies of heterobimetallic vanadium(V) complexes containing hydrazone ligands
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Six heterobimetallic alkali metal dioxidovanadium(V) coordination polymer complexes {[M6{VO(μ-O)}2(μ-OH)4(μ4-slox/nph)].n DMF}∞ where M = Na, K, and Cs; n = 1 for (1), 0 for (2)-(6) of two dihydrazone ligands, disalicylaldehydeoxaloyldihydrazone (H4slox) and bis(2-hydroxy-1-naphthaldehyde)oxaloyldihydrazone (H4nph) are reported. All the complexes have been characterized by various physicochemical techniques such as elemental analyses, molar conductance, IR, NMR, UV–vis, and cyclic voltammetry. The IR, 1HNMR, and 13CNMR spectral data suggest that the dihydrazones are coordinated through phenolate/naphtholate oxygen, enolate oxygen, and azine nitrogen atoms to the metal centres. The structure of complex {[Na6{VO(μ-O)}2(μ-OH)4(μ4-slox)].DMF}∞ (1) is also determined by single-crystal X-ray data, which revealed that the H4slox coordinated via all possible dative sites to metal centres as tetrabasic octadentate ligand. The vanadium metal centres adopted distorted square-pyramidal coordination geometries, and the sodium atoms are also in five coordination atmospheres. The electronic spectra of the complexes showed LMCT bands in addition to intra-ligand π → π* and n → π* transitions. As evident from the cyclic voltammetry, the complexes showed two metal-centred electron transfer reactions {[(VVVV(slox)2?/VVVIV(slox)3?] and [(VVVIV(slox)3?/VVVIV(slox)4?]}, in addition to the ligand centred electron transfer reactions. Further, bovine serum albumin (BSA interaction studies of the complexes {[Na6{VO(μ-O)}2(μ-OH)4(μ4-slox)].DMF}∞ (1) and [Na6{VO(μ-O)}2(μ-OH)4(μ4-nph)]∞ (4) revealed strong binding affinity. Moreover, the catalytic studies of the complexes (1) and (4) were found to be effective for the oxidation of alcohols into their corresponding aldehydes and ketones and bromination of some organic substrates in the presence of H2O2 as an oxidizing agent.
- Borthakur, Rosmita,Dhanpat, Shobha A.,Kumar, Arvind,Kurbah, Sunshine D.,Lal, Ram A.,Syiemlieh, Ibanphylla
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supporting information
(2020/10/21)
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- Design, Synthesis, and Biological Evaluation of Novel 1,3-Oxazole Sulfonamides as Tubulin Polymerization Inhibitors
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A series of novel 1,3-oxazole sulfonamides were constructed and screened for their potential to inhibit cancer cell growth. These compounds were evaluated against the full NCI-60 human tumor cell lines, with the majority exhibiting promising overall growth inhibitory properties. They displayed high specificity within the panel of leukemia cell lines versus all other lines tested. When examined in the dose-response assay, GI50 values fell within the low micromolar to nanomolar ranges. 1,3-Oxazole sulfonamide 16 displayed the best average growth inhibition, whereas the 2-chloro-5-methylphenyl and 1-naphthyl substituents on the sulfonamide nitrogen proved to be the most potent leukemia inhibitors with mean GI50 values of 48.8 and 44.7 nM, respectively. In vitro tubulin polymerization experiments revealed that this class of compounds effectively binds to tubulin and induces the depolymerization of microtubules within cells.
- Barnes, Korry L.,Sisco, Edward
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supporting information
p. 1030 - 1037
(2021/06/28)
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- Synthesis and anti-methicillin-resistant Staphylococcus aureus activity of 5,7-dibromo-2-benzoylbenzofurans alone and in combination with antibiotics
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A series of 5,7-dibromo-2-benzoylbenzofurans were synthesized by the Rap–Stoermer condensation of 5,7-dibromosalicylaldehyde with diverse phenacyl bromides and evaluated for in-vitro antibacterial activities against methicillin-sensitive Staphylococcus aureus (MSSA) ATCC 29213, methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300, and MRSA ATCC 33591 by agar dilution method. The synergistic effects were determined by using the agar dilution checkerboard assay. The derivatives bearing carboxylic acid functional groups exhibited reasonable activity against MRSA strains with the best MIC = 32 μg/mL (9b, 9d). Moreover, the additive or synergistic interactions against MRSA strains was observed in six combinations (1b + cefuroxime/gentamicin, 1c + ciprofloxacin/gentamicin, 9b + gentamicin, and 9c + ciprofloxacin) with the fractional inhibitory concentration index (FICI) values in the range of 0.375–1.0. Significantly, the MICs of these antibiotics were reduced 2–4-fold. The results of the MTT assay illustrated the low mammalian cell cytotoxicity of these potent compounds.
- Phan, Phuong-Thuy T.,Nguyen, Hong-Nhung T.,Kim, Son N.,Pham, Tuan-Anh N.
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supporting information
p. 786 - 796
(2020/12/09)
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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 comprises the following step: (A) providing a compound (I) with an unsaturated double bond, a reagent with trifluoromethyl, and a catalyst; wherein the catalyst is represented by the following 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 reagent with a trifluoromethyl to perform an oxidation of the compound with the unsaturated double bond by using the catalyst at air or an oxygen condition to get a compound presented as formula (III):
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Paragraph 0053-0059
(2021/03/19)
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- Mild oxidation of benzyl alcohols to benzyl aldehydes or ketones catalyzed by visible light
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Induced by visible light, mild oxidation condition to prepare benzyl aldehydes or ketones have been developed by using bromotrichloromethane as photochemical oxidant. This method avoids high temperature, pressure and peroxidation with only visible light as the green driving force.
- Cheng, Dongping,Li, Xiaonian,Ren, Shujian,Xu, Xiaoliang
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supporting information
(2021/07/02)
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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; 0115-0120; 0179-0181
(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; 0074
(2021/07/10)
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- Novel 4-(piperazin-1-yl)quinolin-2(1H)-one bearing thiazoles with antiproliferative activity through VEGFR-2-TK inhibition
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A new series of 2-(4-(2-oxo-1,2-dihydroquinolin-4-yl)piperazin-1-yl)-N-(4-phenylthiazol-2-yl)acetamide derivatives were synthesized and evaluated for anticancer activity. All target compounds showed anticancer activity higher than that of their 2-oxo-4-piperazinyl-1,2-dihydroquinolin-2(1H)-one precursors. Multidose testing of target compounds was performed against breast cancer T-47D cell line. Five compounds showed higher cytotoxic activity than Staurosporine. The dihalogenated derivative showed the best cytotoxic activity with IC50 2.73 ± 0.16 μM. In addition, the VEGFR-2 inhibitory activity of all synthetic compounds was evaluated. Two compounds of 6-fluoro-4-(piperazin-1-yl)quinolin-2(1H)-ones showed inhibitory activity comparable to sorafenib with IC50 46.83 ± 2.4, 51.09 ± 2.6 and 51.41 ± 2.3 nM, respectively. The cell cycle analysis of two compounds namely, 2-(4-(6-fluoro-2-oxo-1,2-dihydroquinolin-4-yl)piperazin-1-yl)-N-(4-phenylthiazol-2-yl)acetamide and N-(4-(4-chlorophenyl)thiazol-2-yl)-2-(4-(2-oxo-1-phenyl-1,2-dihydroquinolin-4-yl)piperazin-1-yl)acetamide revealed that the arrest of cell cycle occurred at S phase. In apoptosis assay, the same two compounds were able to induce significant levels of early and late apoptosis. In a similar manner to Sorafenib, docking of target compounds with VEGFR-2 protein 4ASD showed HB with Cys919 in hinge region of enzyme and HB with both Glu885 and Asp1046 in gate area. Using SwissADME, all target compounds were predicted to be highly absorbed from gastrointestinal tract with no BBB permeability. It is clear that the two compounds are promising antiproliferative candidates that require further optimization.
- Hassan, Abdelfattah,Badr, Mohamed,Hassan, Heba A.,Abdelhamid, Dalia,Abuo‐Rahma, Gamal El‐Din A.
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- Light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds
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Visible light-induced organic reactions are important chemical transformations in organic chemistry, and their efficiency highly depends on suitable photocatalysts. However, the commonly used photocatalysts are precious transition-metal complexes and elaborate organic dyes, which hamper large-scale production due to high cost. Here, for the first time, we report a novel strategy: light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds, allowing high-value-added aromatic ketones and carboxylic acids to be easily prepared in high-to-excellent yields using readily available alkyl arenes, methyl arenes and aldehydes as materials. The mechanistic investigations showed that the treatment of inexpensive and readily available sodium trifluoromethanesulfinate with oxygen under irradiation of light could in situ form a pentacoordinate sulfide intermediate as an efficient photosensitizer. The method represents a highly efficient, economical and environmentally friendly strategy, and the light and oxygen-enabled sodium trifluoromethanesulfinate photocatalytic system represents a breakthrough in photochemistry. This journal is
- Fu, Hua,Liu, Can,Liu, Yong,Yang, Haijun,Zhu, Xianjin
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supporting information
p. 4357 - 4363
(2020/07/14)
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- Facile Approach to Geminal HeterodihalogenationOne-Pot Synthesis of α-Bromo-α-Chloro Ketones
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An efficient and practical protocol for the geminal heterodihalogenation of methyl ketones by using readily available dimethyl sulfoxide and a combination of HCl and HBr is reported. Control experiments suggested that the acidity of the solution, as well as the oxidizing ability and nucleophilicity of the dimethyl sulfoxide might work cooperatively in ensuring the success of the tandem substitution. Its operational simplicity, easy accessibility, and mild oxidative conditions suggest that the present strategy might be useful for the assembly of bromochloromethyl functional groups in drug discovery.
- Bian, Ming,Tang, Dong-Min,Zhou, Jin-Feng
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- A metal-free heterogeneous photocatalyst for the selective oxidative cleavage of CC bonds in aryl olefins: via harvesting direct solar energy
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Selective cleavage of CC bonds is highly important for the synthesis of carbonyl containing fine chemicals and pharmaceuticals. Novel methodologies such as ozonolysis reactions, Lemieux-Johnson oxidation reaction etc. already exist. Parallel to these, catalytic methods using homogeneous catalysts also have been discovered. Considering the various advantages of heterogeneous catalysts such as recyclability and stability, couple of transition metal-based heterogeneous catalysts have been applied for this reaction. However, the pharmaceutical industries prefer to use metal-free catalysts (especially transition metal-free) to avoid further leaching in the final products. This is for sure a big challenge to an organic chemist and to the pharmaceutical industries. To make this feasible, a mild and efficient protocol has been developed using polymeric carbon nitrides (PCN) as metal-free heterogeneous photocatalysts to convert various olefins into the corresponding carbonyls. Later, this catalyst has been applied in the gram scale synthesis of pharmaceutical drugs using direct solar energy. Detailed mechanistic studies revealed the actual role of oxygen, the catalyst, and the light source.
- Das, Shoubhik,Hatami, Nareh,Jooss, Christian,Lange, Niklas Simon,Ronge, Emanuel,Schilling, Waldemar,Zhang, Yu
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supporting information
p. 4516 - 4522
(2020/08/10)
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- 1,2-Diethoxyethane catalyzed oxidative cleavage of gem-disubstituted aromatic alkenes to ketones under minimal solvent conditions
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Aerobic oxidation using pure dioxygen gas as the oxidant has attracted much attention, but its application in synthetic chemistry has been significantly hampered by the complexity of catalytic system and potential risk of high-energy dioxygen gas. By employing 1,2-diethoxyethane as a catalyst and ambient air as an oxidant, an efficient protocol for the construction of various aryl-alkyl and diaryl ketones through oxidative cleavage of gem-disubstituted aromatic alkenes under minimal solvent conditions has been achieved.
- Liu, Kai-Jian,Deng, Ji-Hui,Zeng, Tang-Yu,Chen, Xin-Jie,Huang, Ying,Cao, Zhong,Lin, Ying-Wu,He, Wei-Min
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supporting information
p. 1868 - 1872
(2020/01/31)
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- One-pot synthesis of 4-aryl-2-aminothiazoles from styrenes and thioureas promoted by tribromoisocyanuric acid
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A simple and efficient one-pot protocol has been developed for the conversion of styrenes into 4-aryl-2-aminothiazoles using readily available starting materials. Tribromoisocyanuric acid was successfully used for the co-bromination and oxidation of styrenes to give phenacyl bromides, which in the presence of thioureas produced the corresponding 4-aryl-2-aminothiazoles in 48–70% yield. The protocol involves three reactions in one process: a tandem (formation of phenacyl bromides from styrenes) followed by a telescoped (conversion to thiazole) reaction.
- de Andrade, Vitor S.C.,de Mattos, Marcio C.S.
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supporting information
(2020/07/03)
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- Facile Synthesis of α-Haloketones by Aerobic Oxidation of Olefins Using KX as Nonhazardous Halogen Source
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An operationally simple and safe synthesis of α-haloketones using KBr and KCl as nonhazardous halogen sources is reported. It involves an iron-catalysed reaction of alkenes with KBr/KCl using O2 as terminal oxidant under the irradiation of visible-light. This strategy avoids the risks associated with handling halo-contained electrophiles (Cl2, Br2, NCS, NBS). The process is tolerant to several functional groups, and extended to a range of substituted styrenes in up to 89% yield. A radical reaction pathway is proposed based on control experiments and spectroscopy studies.
- Luo, Zhibin,Meng, Yunge,Gong, Xinchi,Wu, Jie,Zhang, Yulan,Ye, Long-Wu,Zhu, Chunyin
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supporting information
p. 173 - 177
(2020/01/02)
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- Utility of N -Bromosuccinimide-Water Combination as a Green Reagent for Synthesis of N,S-Heterocycles and Dithiocarbamates from Styrenes
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An efficient and unprecedented green protocol has been developed for the synthesis of N,S-heterocycles from styrenes and alkyl dithiocarbamates with high to excellent yields. The reaction of primary or secondary amines, CS 2, and styrenes was carried out in water in the presence of a catalytic amount of an inorganic base. All products were made by using an N -bromosuccinimide-H 2O combination as a green and inexpensive reagent.
- Matloubi Moghaddam, Firouz,Goudarzi, Mehri
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supporting information
p. 1823 - 1827
(2020/10/02)
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- Microwave-assisted synthesis and luminescent activity of imidazo[1,2-a]pyridine derivatives
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In this work, a series of phenacyl bromide derivatives was synthesized and employed as key intermediate for the synthesis of substituted imidazo[1,2-a]pyridines. First, phenacyl bromide molecules were obtained from the bromination reaction of acetophenones assisted by microwave irradiation, obtaining the products 4a-v in a 15 minutes reaction with yields in the range of 50% to 99%. Subsequently, the conjugation of these molecules with 2-aminopyridine conduced to the production of imidazo[1,2-a]pyridine derivatives (7a-v) in a 60-second reaction with yields of 24% to 99%. Improved yields were determined with respect to those obtained with more tedious methodologies like thermally and mechanically assisted routes. Intense luminescence emissions in the purple and blue regions of the electromagnetic spectra were observed under UV excitation according to the nature of the substituents. This environmentally friendly methodology is expected to constitute an important class of organic compounds for the development of biomarkers, photochemical sensors, and medicinal applications.
- Rodríguez, Juan C.,Maldonado, Rony A.,Ramírez-García, Gonzalo,Díaz Cervantes, Erik,de la Cruz, Fabiola N.
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p. 2279 - 2287
(2020/03/16)
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- Bioinspired catalysis and bromoperoxidase like activity of a multistimuli-responsive supramolecular metallogel: Supramolecular assembly triggered by pi-pi stacking and hydrogen bonding interactions
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We report the synthesis and characterization of a new self-assembled VO2-L metallogel. Gel formation was investigated by dissolving VO2-L in various solvents and it was found that water/methanol (1?:?9 (v/v) ratio) induces gel formation. The single crystal X-ray structure of the VO2-L metallogel exhibits C-H?O and N-H?O hydrogen bonding interactions and pi-pi stacking. The VO2-L xerogel obtained after removing the solvents was found to exhibit outstanding performance in catalysis. Bromoperoxidase-like activity of the VO2-L metallogel was also reported. The present catalytic studies are simple and proceed under mild conditions.
- Kurbah, Sunshine Dominic,Lal, Ram A.
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p. 5410 - 5418
(2020/04/17)
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- A metal-free aerobic oxidative bromination of anilines and aryl ketones with 2-methylpyridinium nitrate as a reusable ionic liquid
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An aerobic oxidative bromination of anilines and aryl ketones catalyzed by recyclable 2-methylpyridinium nitrate ionic liquid is achieved in water using hydrobromic acid as the bromine source and molecular oxygen as the oxidant. The catalytic system shows good efficiency and atom economy.
- Li, Ming-Fang,Wang, Jian,Ke, Yong-Xin,Pan, Song-Cheng,Yin, Hong,Du, Wenting,Li, Jing-Hua
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p. 267 - 270
(2020/01/08)
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- Synthesis of 1,2-Dicyano-3-arylcycl[3.2.2]azines – First 1,2-Dicarbonitriles Based on Cyclazine Heterocycle
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The first 1,2-dicarbonitriles have been prepared for cyclazine systems. In particular, a synthetic procedure to 1,2-dicyano-3-arylcycl[3.2.2]azines has been developed. Unexpected chlorination of 3-arylcycl[3.2.2]azine-1,2-dicarboxylic acid derivatives by thionyl chloride at 4-position was found, which according to theoretical considerations can proceed by the electrophilic (SEAr) mechanism. The compounds are blue fluorophores in 450–480 nm region with quantum yields in toluene of ca. 30 % for non-chlorinated derivatives, which decrease to 3–4 % for chlorinated ones.
- Chernyak, Alexander V.,Kalashnikov, Valery V.,Kazachenko, Vladimir P.,Pushkarev, Victor E.,Simakov, Anton O.,Simonov, Sergey V.,Starikov, Andrei S.,Tarakanov, Pavel A.,Tkachev, Valery V.,Tomilova, Larisa G.,Yarkov, Alexander V.,Zhurkin, Fedor E.
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supporting information
p. 5852 - 5856
(2020/09/21)
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- Substituted 4-phenylthiazoles: Development of potent and selective A1, A3 and dual A1/A3 adenosine receptor antagonists
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Adenosine acts as a powerful signaling molecule via four distinct G protein-coupled receptors, designated A1, A2A, A2B and A3 adenosine receptors (ARs). A2A and A2B ARs are Gs-coupled, while A1 and A3 ARs inhibit cAMP production via Gi proteins. Antagonists for A1 and A3 ARs may be useful for the treatment of (neuro)inflammatory diseases including acute kidney injury and kidney failure, pulmonary diseases, and Alzheimer's disease. In the present study, we optimized the versatile 2-amino-4-phenylthiazole scaffold by introducing substituents at N2 and C5 to obtain A1 and A3 AR antagonists including dual-target compounds. Selective A1 antagonists with (sub)nanomolar potency were produced, e.g. 11 and 13. These compounds showed species differences being significantly more potent at the rat as compared to the human A1 AR, and were characterized as inverse agonists. Several potent and selective A3 AR antagonists, e.g. 7, 8, 17 and 22 (Ki values of 5–9 nM at the human A3 AR) were prepared, which were much less potent at the rat orthologue. Moreover, dual A1/A3 antagonists (10, 18) were developed showing Ki values between 8 and 42 nM. Docking and molecule dynamic simulation studies using the crystal structure of the A1 AR and a homology model of the A3 AR were performed to rationalize the observed structure-activity relationships.
- Abdelrahman, Aliaa,Yerande, Swapnil G.,Namasivayam, Vigneshwaran,Klapschinski, Tim A.,Alnouri, Mohamad Wessam,El-Tayeb, Ali,Müller, Christa E.
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supporting information
(2019/12/24)
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- Selective Debromination of α,α,α-Tribromomethylketones with HBr–H2O Reductive Catalytic System
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A debromination of α,α,α-tribromomethylketones is developed for chemoselective synthesis of α-mono- and α,α-dibromomethylketones with high selectivity under H2O–HBr reductive conditions. This method offers an efficient and direct way to synthesize α-mono or α,α-dibromomethylketone compounds in high to excellent yields through the process of HBr self-circulation in water.
- Cheng, Zhao,Guo, Hongmei,Huang, Guozheng,Rexit, Abulikemu Abudu,Wang, Hui,Zheng, Meng-Xia
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p. 6455 - 6458
(2020/10/21)
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- Nickel-Catalyzed Asymmetric Addition of Aromatic Halides to Ketones: Highly Enantioselective Synthesis of Chiral 2,3-Dihydrobenzofurans Containing a Tertiary Alcohol
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A highly enantioselective and straightforward synthetic procedure to chiral 3-hydroxy-2,3-dihydrobenzofurans has been developed by nickel/bisoxazoline-catalyzed intramolecular asymmetric addition of aryl halides to unactivated ketones, giving 2,3-dihydrobenzofurans with a chiral tertiary alcohol at the C-3 position in good yields and excellent enantioselectivities (up to 92percent yield and 98percent ee). The gram-scale reaction also proceeded smoothly without a loss of yield and enantioselectivity.
- Li, Ying,Li, Wendian,Tian, Jiangyan,Huang, Guozheng,Lv, Hui
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p. 5353 - 5357
(2020/07/14)
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- Multiple Mechanisms Mapped in Aryl Alkyl Ether Cleavage via Aqueous Electrocatalytic Hydrogenation over Skeletal Nickel
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We present here detailed mechanistic studies of electrocatalytic hydrogenation (ECH) in aqueous solution over skeletal nickel cathodes to probe the various paths of reductive catalytic C-O bond cleavage among functionalized aryl ethers relevant to energy science. Heterogeneous catalytic hydrogenolysis of aryl ethers is important both in hydrodeoxygenation of fossil fuels and in upgrading of lignin from biomass. The presence or absence of simple functionalities such as carbonyl, hydroxyl, methyl, or methoxyl groups is known to cause dramatic shifts in reactivity and cleavage selectivity between sp3 C-O and sp2 C-O bonds. Specifically, reported hydrogenolysis studies with Ni and other catalysts have hinted at different cleavage mechanisms for the C-O ether bonds in α-keto and α-hydroxy β-O-4 type aryl ether linkages of lignin. Our new rate, selectivity, and isotopic labeling results from ECH reactions confirm that these aryl ethers undergo C-O cleavage via distinct paths. For the simple 2-phenoxy-1-phenylethane or its alcohol congener, 2-phenoxy-1-phenylethanol, the benzylic site is activated via Ni C-H insertion, followed by beta elimination of the phenoxide leaving group. But in the case of the ketone, 2-phenoxyacetophenone, the polarized carbonyl πsystem apparently binds directly with the electron rich Ni cathode surface without breaking the aromaticity of the neighboring phenyl ring, leading to rapid cleavage. Substituent steric and electronic perturbations across a broad range of β-O-4 type ethers create a hierarchy of cleavage rates that supports these mechanistic ideas while offering guidance to allow rational design of the catalytic method. On the basis of the new insights, the usage of cosolvent acetone is shown to enable control of product selectivity.
- Hegg, Eric L.,Jackson, James E.,Klinger, Grace E.,Saffron, Christopher M.,Zhou, Yuting
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p. 4037 - 4050
(2020/03/10)
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- Application of poly(vinylphenyltrimethylammonium tribromide) resin as an efficient polymeric brominating agent in the α-bromination and α-bromoacetalization of acetophenones
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The applications of a new supported tribromide reagent based on poly(vinylbenzyltrimethylammonium hydroxide) resin (Amberlite 717) were reported. This supported tribromide resin was used directly in α-bromination and α-bromoacetalization of acetophenones without any other catalyst under mild conditions. The effects of solvents and the amount of the supported tribromide resin on the reactions were investigated. Under the optimal conditions, most of α-bromo and α-bromoacetal of acetophenones were selectively obtained in excellent yields.
- Han, Bingbing,Zheng, Zubiao,Zheng, Dongcheng,Zhang, Lei,Cui, Peng,Shi, Jianjun,Li, Changjiang
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supporting information
p. 2512 - 2520
(2019/07/04)
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- Synthesis of Ti-Al binary oxides and their catalytic application for C-H halogenation of phenols, aldehydes and ketones
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Traditional C–H halogenation of organic compounds often requires corrosive agent or harsh condition, and current researches are focused on the use of noble metals as catalyst. In order to give an efficient, benign, activity-adjustable and cost-effective system for halogenation, a series of Ti-Al mixed oxides are prepared as catalyst through sol-gel in this work. Characterizations reveal all catalysts contain more aluminum than titanium, but preparative conditions affect their composition and crystallinity. Monitoring of particle size, zeta potential and UV–vis of preparative solution reveals that formation of catalyst colloids undergoes chemical reaction, affecting catalyst morphology. In halogenation, all catalysts show moderate to high activities, copper chloride proves to be an effective halogen source rather than sodium chloride. The chlorination and bromination are better than iodization, phenol and ketone appear to be more appropriate substrates than aldehyde. Additionally, oxide backbone of catalyst is more durable than its organic components during recycling. This study may provide new catalytic materials for progress of C–H activation.
- Su, Peigen,Fan, Chao,Yu, Heng,Wang, Wanqin,Jia, Xin,Rao, Qifan,Fu, Chenxi,Zhang, Donghua,Huang, Benhua,Pan, Cheng,Zheng, Aqun,Sun, Yang
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- NBS-mediated synthesis of β-keto sulfones from benzyl alcohols and sodium arenesulfinates
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An efficient synthetic route towards the synthesis of β-keto sulfones has been developed from secondary benzyl alcohols using N-bromosuccinimide (NBS). The present protocol utilizes NBS as oxidant as well as brominating agent, readily accessible benzyl alcohols and sodium arenesulfinates as the sulfonylating reagent under mild conditions. The control experiments revealed that the reaction proceeds via oxidation of alcohol to ketone, α-bromination of ketone and nucleophilic substitution by sodium arenesulfinate. Furthermore, the efficiency of the methodology was tested with a gram scale reaction and also shown the synthetic utility.
- Muneeswara, Madithedu,Sundaravelu, Nallappan,Sekar, Govindasamy
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supporting information
p. 3479 - 3484
(2019/05/21)
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- Heterogeneous gold-catalyzed oxidative cross-coupling of propargylic acetates with arylboronic acids leading to (E)-α-arylenones
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An efficient heterogeneous gold-catalyzed oxidative cross-coupling of propargylic acetates with arylboronic acids has been developed that proceeds smoothly in the presence of Selectfluor and provides a general and powerful tool for the preparation of various valuable α-arylenones with moderate to good yields, excellent E-selectivity, and recyclability of the gold catalyst. The reaction is the first example of heterogeneous gold-catalyzed arylative rearrangement of propargylic acetates for construction of complex enones.
- Liu, Dayi,Nie, Quan,Zhang, Rongli,Cai, Mingzhong
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supporting information
p. 29 - 34
(2018/11/30)
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- A facile transformation of alkynes into α-amino ketones by an N-bromosuccinimide-mediated one-pot strategy
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A facile transformation of alkynes into α-amino ketones by an N-bromosuccinimide-mediated one-pot cascade strategy is described. A variety of α-amino ketones are obtained in moderate to good yields under mild conditions. To overcome the multi-step synthesis, N-bromosuccinimide is involved in multiple tasks, playing a key role in the reaction course.
- Wei, Ting,Zeng, Yongming,He, Wei,Geng, Lili,Hong, Liang
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p. 383 - 385
(2018/04/11)
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- 2-Amino-4-arylthiazoles through One-Pot Transformation of Alkylarenes with NBS and Thioureas
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Treatment of alkylarenes with N-bromosuccinimide in a mixture of ethyl acetate and water at 60 °C, a mixture of acetonitrile and water at 80 °C, or a mixture of diethyl carbonate and water under irradiation with a tungsten lamp, followed by a reaction with thioureas or arenethioamides provided the corresponding 2-amino- 4-arylthiazoles or 2,4-diarylthiazoles in good to moderate yields, respectively, in one pot. The present reaction is an efficient one-pot transformation method of alkylarenes into 2-amino-4-arylthiazoles and 2,4-diarylthiazoles directly under mild and transition-metal-free conditions.
- Shibasaki, Kaho,Togo, Hideo
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p. 2520 - 2527
(2019/04/04)
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- Alkyl Halides via Visible Light Mediated Dehalogenation
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Net selective bromination and chlorination of activated C-H bonds can be effected in generally high yield via a simple perhalogenation/dehalogenation sequence. The photochemical reductions require no photocatalyst, relying instead on the formation of an electron donor-acceptor complex of the substrate and reductant, or alternatively autophotocatalysis. Some reactions proceed despite any apparent photon absorption, serving as a cautionary tale for other photochemical reactions involving amines. Mechanistic experiments provide an explanation for this observation.
- Rathnayake, Manjula D.,Weaver, Jimmie D.
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supporting information
p. 9681 - 9687
(2019/11/28)
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- Method of utilizing micro channel reactor to prepare pentafluorophenoxyl ketones continuously
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The invention discloses a method of utilizing a micro channel reactor to prepare pentafluorophenoxyl ketones continuously. Cheap and easily available styrene and pentafluorophenol are taken as the primary raw materials, two step continuous reactions are carried out in a micro channel reactor to obtain pentafluorophenoxyl ketones, the reaction time is shortened to several minutes from several hours; the product yield is high, the reaction efficiency is obviously enhanced, no any pricy organic catalyst or metal catalyst is needed, the operation is simple, the cost is low, the preparation technology is easy to control, the safety is high, the reaction conditions are mild, and the method can be applied to industrial production.
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Paragraph 0036-0037
(2019/06/30)
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- 2,7-DIPHENYLOCTA-2,4,6-TRIENEDIAL, METHOD FOR PREPARING THE SAME AND METHOD FOR PREPARING CAROTENOIDS CONTAINING PHENYL SUBSTITUENTS USING THE SAME
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The present invention relates to an intermediate, a method for synthesizing the same, and a method for efficiently synthesizing a carotene compound containing a phenyl substituent using the same, wherein the intermediate needed to prepare a polyene structure of a carotene compound having a variety of physicochemical and electroelectronic properties according to electronic properties of the phenyl substituent in a single step reaction, and exhibiting improved antioxidant abilities by containing the phenyl substituent. To this end, 2,7-diphenyl-2,4,6-trienedial of chemical formula 1, which is a novel compound, and 2-((3-(5,5-dimethyl-1,3-dioxane-2-yl)-3-phenylallyl)sulfonyl)benzo[d]thiazole of chemical formula 2, and a synthesis method thereof are proposed by an efficient method using a common intermediate. The novel compound can be efficiently used for synthesis of a carotene compound containing various phenyl substituents through a Julia-Kocienski reaction or a Wittig reaction.COPYRIGHT KIPO 2019
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Paragraph 0111-0114
(2019/02/27)
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- Synthesis, crystal structure and reactivity of homobimetallic vanadium(V) complexes derived from oxaloyldihydrazone ligands
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Treatment of V2O5 with dihydrazone ligands (H4L) (disalicylaldehydeoxaloyldihydrazone (H4L1 = H4slox), bis(2-hydroxy-1-naphthaldehyde)oxaloyldihydrazone (H4L2 = H4nph) and bis(5-bromosalicylaldehyde)oxaloyldihydrazone (H4L3 = H4sloxBr)) in methanol leads to the formation of homobimetallic vanadium(V) complexes of the composition [(CH3)2NH2]2[(VO2)2(L)]·nH2O, where n = 2 (1, 2) and n = 4 (3). The reaction of complexes 1–3 with H2O2 results in the formation of bis(monooxidoperoxidovanadate(V)) complexes[{VO(O2)}2(L)]2? and the reaction with HCl leads to the formation of oxidohydroxido species of the composition [(VO(OH)(L)]2?. The complexes show great potential for the oxidation of alcohols and the oxidative bromination of some organic substrates.
- Syiemlieh, Ibanphylla,Asthana, Mrityunjaya,Kurbah, Sunshine D.,Lal, Ram A.
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p. 202 - 216
(2019/06/19)
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- Reactivity and Catalytic Activity of Homobimetallic Vanadium(V) Complex Derived from Bis(5-chlorosalicylaldehyde)oxaloyldihydrazone Ligand
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Homobimetallic vanadium(V) complex of the composition [(CH3)2NH2+]2[(VO2)2(sloxCl)].4H2O was synthesized from the reaction of V2O5 with bis(5-chlorosalicylaldehyde)oxaloyldihydrazone ligand in a 1:1 molar ratio in methanol. The structure of the complex was established by X-ray crystallography. Reactivity of the complex with H2O2 leads to bis (monooxidoperoxidovanadate(V)) [{VO(O2)}2(sloxCl)]2? formation and with HCl, oxidohydroxido complex of composition [(VO (OH)(sloxCl)]2? was formed. Binding interaction of the complex was also investigated toward protein (BSA) and it was found to be 2.21 x 108?M?1. The catalytic activity of the complex in the oxidation of alcohols and oxidative bromination of some organic substrates was also studied, and it showed a great potent as a catalyst.
- Syiemlieh, Ibanphylla,Asthana, Mrityunjaya,Lal, Ram A.
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- Atom-economical brominations with tribromide complexes in the presence of oxidants
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Bromination is an important transformation in organic synthesis, and novel efficient bromination techniques are still required. Herein, we demonstrate atom-economical brominations using (DMI)2HBr3, a novel tribromide complex, with oxidants such as DMSO and Oxone. Using this system, olefinic and aromatic brominations, as well as selective α-monobrominations of ketones proceeded well to afford the desired bromides in good yields. Importantly, in these reactions all of the bromine atoms in this complex are used to brominate.
- Yubata, Kotaro,Matsubara, Hiroshi
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supporting information
p. 1001 - 1004
(2019/03/13)
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