- Design, synthesis and biological evaluation of some novel diastereoselective β-lactams bearing 2-mercaptobenzothiazole and benzoquinoline
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We report the synthesis of some novel β-lactam hybrids of 2-mercaptobenzothiazole and benzoquinoline. These compounds were synthesized by a [2 + 2]-cycloaddition reaction of imines 8a-d and ketenes derived from substituted acetic acids. The reaction was totally diastereoselective leading exclusively to the formation of cis-β-lactams 10a-m. All products were obtained in good to excellent yields and their structures were established based on IR, 1H NMR, 13C NMR spectral data and elemental analysis. Schiff bases 8a-d and β-lactam hybrids 10a-m were evaluated for antimicrobial activities against six bacterial species. The minimum inhibitory concentration (MIC) values indicate that two of the β-lactams, 10k and 10m, have good activities against the two Gram-negative bacteria, E. coli and P. aeruginosa, while three of the Schiff bases, 8a-c, are active against P. aeruginosa and the Gram-positive pathogen S. aureus. The molecular and cellular basis for these observed antibacterial properties are not determined. Moreover, the five most active compounds showed acceptably low cytotoxicity (less than 25% cell growth inhibition after 72 h of incubation) against the MCF-7 cell line, and below 10% in vitro hemolytic activity at 50 and 200 μM concentrations. These results suggest a need for further inquiry into the reason for why these compounds are bioactive, and as to what their full biological activities and antibiotic potential may be. The cis stereochemistry of β-lactam 10a was confirmed by X-ray crystallographic studies.
- Borazjani, Nassim,Jarrahpour, Aliasghar,Rad, Javad Ameri,Mohkam, Milad,Behzadi, Maryam,Ghasemi, Younes,Mirzaeinia, Somayyeh,Karbalaei-Heidari, Hamid Reza,Ghanbari, Mohammad Mehdi,Batta, Gyula,Turos, Edward
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- Synthesis, spectral, and electrochemical properties of meso-5,10,15,20- tetrakis (2'-chlorobenzoquinolin-3'-yl)porphyrins
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The synthesis, characterization, and redox and spectral properties of the meso-5,10,15,20-tetrakis(2'-chlorobenzoquinolin-3'-yl)porphyrin are reported. The synthesis of the porphyrin was performed by following the modified Lindsey procedure, and its zinc(II) derivative was prepared by using the conventional method. The electronic properties of the compound were investigated by cyclic voltammetry and spectroscopy. This compound shows unusual redox behavior with difficulty in oxidation and ease of reduction compared to tetraphenylporphyrin.
- Prasath,Bhavana
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- Intramolecular Participation by an Amide Group in Ester Hydrolysis
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The rate coefficient for hydrolysis of 1-acetoxy-8-acetylaminonaphthalene to 1-hydroxy-8-acetylaminonaphthalene in aqueous sodium hydroxide shows a curved dependence on hydroxide ion concentration.Similar results are observed for the 3,6-disulphonate and five substituted 1-benzoyloxy-8-benzoylamino-3,6-disulphonates.In the proposed mechanism the ester group undergoes intermolecular attack by hydroxide ion in competition with intramolecular attack by the amide group.The latter generates an imide intermediate in equilibrium with the ester via a rapid acyl transfer, and since the imide is hydrolysed slowly to product its formation inhibits the ester hydrolysis.
- Hibbert, Frank,Sellens, Rowena J.
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- Chemoselective reduction of nitroarenes, N-acetylation of arylamines, and one-pot reductive acetylation of nitroarenes using carbon-supported palladium catalytic system in water
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Developing and/or modifying fundamental chemical reactions using chemical industry-favorite heterogeneous recoverable catalytic systems in the water solvent is very important. In this paper, we developed convenient, green, and efficient approaches for the chemoselective reduction of nitroarenes, N-acetylation of arylamines, and one-pot reductive acetylation of nitroarenes in the presence of the recoverable heterogeneous carbon-supported palladium (Pd/C) catalytic system in water. The utilize of the simple, effective, and recoverable catalyst and also using of water as an entirely green solvent along with relatively short reaction times and good-to-excellent yields of the desired products are some of the noticeable features of the presented synthetic protocols. Graphic abstract: [Figure not available: see fulltext.].
- Zeynizadeh, Behzad,Mohammad Aminzadeh, Farkhondeh,Mousavi, Hossein
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p. 3289 - 3312
(2021/05/11)
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- Novel hybrid conjugates with dual estrogen receptor α degradation and histone deacetylase inhibitory activities for breast cancer therapy
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Hormone therapy targeting estrogen receptors is widely used clinically for the treatment of breast cancer, such as tamoxifen, but most of them are partial agonists, which can cause serious side effects after long-term use. The use of selective estrogen receptor down-regulators (SERDs) may be an effective alternative to breast cancer therapy by directly degrading ERα protein to shut down ERα signaling. However, the solely clinically used SERD fulvestrant, is low orally bioavailable and requires intravenous injection, which severely limits its clinical application. On the other hand, double- or multi-target conjugates, which are able to synergize antitumor activity by different pathways, thus may enhance therapeutic effect in comparison with single targeted therapy. In this study, we designed and synthesized a series of novel dual-functional conjugates targeting both ERα degradation and histone deacetylase inhibiton by combining a privileged SERD skeleton 7-oxabicyclo[2.2.1]heptane sulfonamide (OBHSA) with a histone deacetylase inhibitor side chain. We found that substituents on both the sulfonamide nitrogen and phenyl group of OBHSA unit had significant effect on biological activities. Among them, conjugate 16i with N-methyl and naphthyl groups exhibited potent antiproliferative activity against MCF-7 cells, and excellent ERα degradation activity and HDACs inhibitory ability. A further molecular docking study indicated the interaction patterns of these conjugates with ERα, which may provide guidance to design novel SERDs or PROTAC-like SERDs for breast cancer therapy.
- Zhao, Chenxi,Tang, Chu,Li, Changhao,Ning, Wentao,Hu, Zhiye,Xin, Lilan,Zhou, Hai-Bing,Huang, Jian
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- Silver(I) Promoted the C4-H Bond Phosphonation of 1-Naphthylamine Derivatives with H-Phosphonates
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A simple and efficient protocol for silver-promoted direct C-H phosphonation of 1-naphthylamine derivatives with H-phosphonates was described. This reaction proceeded smoothly for 1-naphthylamine derivatives at the C4 site, providing a facile and efficient route to 4-phosphonated 1-naphthylamine derivatives. This phosphonation could tolerate a diverse type of functional groups at the pyridinyl and naphthyl moieties. Further functionalization of the phosphonated product was also explored at the C2 and C8 sites, such as fluoridation, methylation, methoxylation, and amination. In addition, DFT studies of the reaction intermediate showed that the most electrophilic reactive site is at the C4 site in the naphthyl ring.
- Zhao, Lixiao,Sun, Mengmeng,Yang, Fan,Wu, Yangjie
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p. 11519 - 11530
(2021/09/02)
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- Chlorination Reaction of Aromatic Compounds and Unsaturated Carbon-Carbon Bonds with Chlorine on Demand
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Chlorination with chlorine is straightforward, highly reactive, and versatile, but it has significant limitations. In this Letter, we introduce a protocol that could combine the efficiency of electrochemical transformation and the high reactivity of chlorine. By utilizing Cl3CCN as the chloride source, donating up to all three chloride atom, the reaction could generate and consume the chlorine in situ on demand to achieve the chlorination of aromatic compounds and electrodeficient alkenes.
- Liu, Feng,Wu, Na,Cheng, Xu
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supporting information
p. 3015 - 3020
(2021/05/05)
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- A novel construction of acetamides from rhodium-catalyzed aminocarbonylation of DMC with nitro compounds
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Dimethyl carbonate (DMC), an environment-friendly compound prepared from CO2, shows diverse reactivities. In this communication, an efficient procedure using DMC as both a C1 building block and solvent in the aminocarbonylation reaction with nitro compounds has been developed. W(CO)6acts both a CO source and a reductant here.
- Bao, Zhi-Peng,Miao, Ren-Guan,Qi, Xinxin,Wu, Xiao-Feng
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supporting information
p. 1955 - 1958
(2021/03/02)
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- Preparation method of acetamide compound
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The invention discloses a preparation method of an acetamide compound, the preparation method comprises the following steps: reacting tetracarbonyl dichloride rhodium, 1, 3-bis (diphenylphosphine) propane, tungsten carbonyl, sodium phosphate, sodium iodide, water, a nitro compound and dimethyl carbonate at 120 DEG C for 24 hours, and after the reaction is completed, performing post-treatment to obtain the acetamide compound. According to the preparation method, dimethyl carbonate serves as a C1 source and also serves as a green solvent, operation is easy, reaction starting raw materials are low in price and easy to obtain, the tolerance range of substrate functional groups is wide, and reaction efficiency is high. Various acetamide compounds can be synthesized according to actual needs, so that the practicability of the method is widened while the operation is convenient.
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Paragraph 0035-0047
(2021/05/19)
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- Cu(OTf)2-Mediated Cross-Coupling of Nitriles and N-Heterocycles with Arylboronic Acids to Generate Nitrilium and Pyridinium Products**
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Metal-catalyzed C–N cross-coupling generally forms C?N bonds by reductive elimination from metal complexes bearing covalent C- and N-ligands. We have identified a Cu-mediated C–N cross-coupling that uses a dative N-ligand in the bond-forming event, which, in contrast to conventional methods, generates reactive cationic products. Mechanistic studies suggest the process operates via transmetalation of an aryl organoboron to a CuII complex bearing neutral N-ligands, such as nitriles or N-heterocycles. Subsequent generation of a putative CuIII complex enables the oxidative C–N coupling to take place, delivering nitrilium intermediates and pyridinium products. The reaction is general for a range of N(sp) and N(sp2) precursors and can be applied to drug synthesis and late-stage N-arylation, and the limitations in the methodology are mechanistically evidenced.
- Bell, Nicola L.,Xu, Chao,Fyfe, James W. B.,Vantourout, Julien C.,Brals, Jeremy,Chabbra, Sonia,Bode, Bela E.,Cordes, David B.,Slawin, Alexandra M. Z.,McGuire, Thomas M.,Watson, Allan J. B.
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supporting information
p. 7935 - 7940
(2021/03/03)
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- Visible-light-induced Beckmann rearrangement by organic photoredox catalysis
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A facile and general strategy for efficient direct conversion of oximes to amides using an inexpensive organic photocatalyst and visible light is described. This radical Beckmann rearrangement can be performed under mild conditions. Various alkyl aryl ketoximes and diaryl ketoximes can be effectively converted into the corresponding amides in excellent yields.
- Tang, Li,Wang, Zhi-Lv,Wan, Hai-Lan,He, Yan-Hong,Guan, Zhi
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supporting information
p. 6182 - 6186
(2020/09/01)
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- The immobilized copper species on nickel ferrite (NiFe2O4@Cu): a magnetically reusable nanocatalyst for one-pot and quick reductive acetylation of nitroarenes to N-arylacetamides
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In this study, a green protocol for synthesis of N-arylacetamides was introduced. Magnetically, nanoparticles of the immobilized copper species on nickel ferrite, NiFe2O4@Cu, were synthesized and then characterized using SEM, EDX, XRD, VSM, ICP-OES, BET and XPS analyses. The XPS analysis approved that the immobilized copper species on NiFe2O4 only contain Cu(0) and its oxide form as CuO. The prepared nanocomposite system represented a perfect catalytic activity toward one-pot and quick reductive acetylation of various nitroarenes to the corresponding N-arylacetamides. All reactions were carried out in a mixture of H2O–EtOH (1.5–0.5) within 2–10?min using the combination system of NaBH4 and Ac2O in a one-pot approach and via a two-step procedure. The utilized Cu nanocomposite was magnetically separated from the reaction mixture and reused for 5 consecutive cycles without the significant loss of its catalytic activity.
- Zeynizadeh, Behzad,Shokri, Zahra,Mohammadzadeh, Iman
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p. 859 - 870
(2019/12/24)
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- Quinoline conjugated imidazopyridine and pyridopyrimidine synthesis in water as highly selective fluoride sensors via a catalyst-free four-component reaction
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Abstract: A green and convenient procedure for the synthesis of quinoline-conjugated imidazopyridines and pyridopyrimidines has been developed by a simple one-pot reaction in the absence of any transition metal catalyst in water. This green process can be readily performed by reacting inexpensive starting materials of 2-chloroquinoline-3-carbaldehyde, malononitrile, 1,1-bis(methylthio)-2-nitroethylene, and diamine in aqueous solution. The present synthesis shows attractive characteristics, such as the use of water as reaction media, convenient one-pot operation, and reduced waste production without the use of any base or metal promoters. The products are purified by crystallization from ethanol, and the process does not involve any hazardous solvent. Also, the fluorescence study of these conjugated systems was also considered, which revealed that they have highly selective sensing of fluoride. Graphic abstract: [Figure not available: see fulltext.].
- Mahajer, Fatemeh,Noorakhtar, Farzaneh,Rezvanian, Atieh,Ziarani, Ghodsi Mohammadi
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p. 1581 - 1589
(2020/10/15)
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- An Electrochemical Beckmann Rearrangement: Traditional Reaction via Modern Radical Mechanism
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Abstract: Electrosynthesis as a potential means of introducing heteroatoms into the carbon framework is rarely studied. Herein, the electrochemical Beckmann rearrangement, i. e. the direct electrolysis of ketoximes to amides, is presented for the first time. Using a constant current as the driving force, the reaction can be easily carried out under neutral conditions at room temperature. Based on a series of mechanistic studies, a novel radical Beckmann rearrangement mechanism is proposed. This electrochemical Beckmann rearrangement does not follow the trans-migration rule of the classical Beckmann rearrangement.
- Tang, Li,Wang, Zhi-Lv,He, Yan-Hong,Guan, Zhi
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p. 4929 - 4936
(2020/08/21)
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- The immobilized Cu nanoparticles on magnetic montmorillonite (MMT?Fe3O4?Cu): As an efficient and reusable nanocatalyst for reduction and reductive-acetylation of nitroarenes with NaBH4
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In this study, the immobilization of copper nanoparticles on superparamagnetic montmorillonite, MMT?Fe3O4?Cu, was studied. Magnetically nanoparticles (MNPs) of iron oxide (Fe3O4) were primarily prepared by a chemical co-precipitation method. Next, the prepared Fe3O4 MNPs were intercalated within the interlamellar spaces and external surface of sodium-exchanged montmorillonite. Finally, Cu NPs were immobilized on magnetic montmorillonite by a simply mixing of an aqueous solution of CuCl2·2H2O with MMT?Fe3O4 followed by the reduction with NaBH4. Characterization of MMT?Fe3O4 clay system represented that through the immobilization of Fe3O4 MNPs, disordered-layers structure of MMT was easily reorganized to an ordered-layers arrangement. The synthesized composite systems were characterized using FT-IR, SEM, EDX, XRD, VSM, BET and ICP-OES analyses. SEM analysis exhibited that dispersion of Cu NPs, with the size distribution of 15–25 nm, on the surface of magnetic clay was taken place perfectly. BET surface analysis indicated that after the immobilization of Fe3O4 and Cu species, the surface area and total pore volume of MMT?Fe3O4?Cu system was decreased. Next, the Cu-clay nanocomposite system showed a perfect catalytic activity towards reduction of nitroarenes to anilines as well as reductive-acetylation of nitroarenes to acetanilides using NaBH4 and Ac2O in water as a green and economic solvent. The copper magnetic clay catalyst can be easily separated from the reaction mixture by an external magnetic field and reused for six consecutive cycles without the significant loss of its catalytic activity.
- Zeynizadeh, Behzad,Rahmani, Soleiman,Tizhoush, Hengameh
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- Polystyrene-supported phosphine oxide-catalysed Beckmann rearrangement of ketoximes in 1,1,1,3,3,3-hexafluoro-2-propanol
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A polystyrene-supported phosphine oxide-catalysed Beckmann rearrangement of ketoximes in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) has been developed. Good substrate compatibility, mild reaction conditions, good yields as well as the reusability of the catalyst/solvent made this procedure more environmentally benign.
- Wang, Yaoyao,Chen, Qun,He, Mingyang,Wang, Liang
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p. 210 - 214
(2018/12/04)
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- SO2F2-Activated Efficient Beckmann Rearrangement of Ketoximes for Accessing Amides and Lactams
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A novel, mild and practical protocol for the efficient activation of the Beckmann rearrangement utilizing the readily available and economical sulfuryl fluoride (SO2F2 gas) has been developed. The substrate scope of the operationally simple methodology has been demonstrated by 37 examples with good to nearly quantitative isolated yields (over 90 % yield in most cases) in a short time, including B(OH)2, COOH, NH2, and OH substituted substrates. A tentative mechanism was proposed involving formation and elimination of key intermediate, sulfonyl ester.
- Zhang, Guofu,Zhao, Yiyong,Xuan, Lidi,Ding, Chengrong
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supporting information
p. 4911 - 4915
(2019/07/31)
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- 4-Imidazol-1-yl-butane-1-sulfonic acid ionic liquid: Synthesis, structural analysis, physical properties and catalytic application as dual solvent-catalyst
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4-Imidazol-1-yl-butane-1-sulfonic acid (ImBu-SO3H) has been successfully synthetized and fully characterized by FT-IR and high-resolution NMR spectroscopy (1H, 13C). The “plausible” alternative structures of ImBu-SO3H were discussed on the basis of its NMR data. The ionic liquid showed interesting dual solvent-catalyst property, which was studied experimentally for the acetylation of a variety of functionalized alcohols, phenols, thiols, amines and α-tocopherol (α-CTP) as the most active form of vitamin E with acetic anhydride and which provided good yields within a short reaction time. ImBu-SO3H was successfully recycled by product extraction with an average recovered yield of 82% for 5 subsequent runs. The catalytic activity of the recycled ImBu-SO3H showed almost no loss even after five consecutive runs.
- Khaligh, Nader Ghaffari,Mihankhah, Taraneh,Johan, Mohd Rafie,Juan, Joon Ching
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p. 866 - 878
(2019/07/12)
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- Silver-Catalyzed para -Selective C-H Amination of 1-Naphthylamides with Azodicarboxylates at Room Temperature
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A simple and efficient protocol for para -selective C-H amination of 1-naphthylamide derivatives under silver catalysis is described. This reaction system could proceed without the help of directing group and a broad range of substrates were proved to be well tolerated. In addition, control experiments suggested that this reaction might not proceed via a single-electron-transfer process.
- Bai, He-Yuan,Ding, Tong-Mei,Hou, Si-Hua,Li, Quan-Zhe,Ma, Yan-Yan,Wang, Xun-Hui,Zhang, Shu-Yu,Zhao, Deng-Gao
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supporting information
p. 2697 - 2704
(2019/06/19)
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- METHOD FOR PRODUCING AMIDE COMPOUND
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PROBLEM TO BE SOLVED: To provide a novel method for producing an amide compound which does not require severe reacting conditions without directly using hydroxylamine and its derivative. SOLUTION: There is provided a method for producing an amide compound which comprises: a step of transferring a ketone compound and an oxime compound to oxime in the presence of an organic solvent and an acid catalyst; and a step of subjecting the oxime to Beckmann rearrangement. The acid catalyst preferably is hydrochloric acid, sulfuric acid, methanesulfonic acid, tosyl acid monohydrate, trifluoromethanesulfonic acid, bistrifluoromethane sulfonimide, a boron trifluoride-diethyl ether complex, scandium trifluoromethanesulfonate (III), iron trifluoromethanesulfonate (III), copper trifluoromethanesulfonate (II), bismuth(III) trifluoromethanesulfonate, titanium tetrachloride or iron trichloride. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0029; 0031
(2018/09/30)
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- Direct and Catalytic Amide Synthesis from Ketones via Transoximation and Beckmann Rearrangement under Mild Conditions
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The Br?nsted acid-catalyzed synthesis of secondary amides from ketones under mild conditions is described via transoximation and Beckmann rearrangement using O-protected oximes as more stable equivalents of explosive O-protected hydroxylamines. This methodology could be applied to highly rearrangement-selective amide synthesis from α-branched alkyl aryl ketones and performed on a 1-g scale. The presence of water is essential for this reaction, and its role was clarified by isotope-labeling experiments.
- Hyodo, Kengo,Hasegawa, Genna,Oishi, Naoki,Kuroda, Kazuma,Uchida, Kingo
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p. 13080 - 13087
(2018/11/02)
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- Biogenic CuFe2O4 magnetic nanoparticles as a green, reusable and excellent nanocatalyst for acetylation reactions under solvent-free conditions
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A convenient green method has been developed for the synthesis of biogenic CuFe2O4 magnetic nanoparticles using tea extracts within a very short reaction time. The prepared nanoparticles with an average size of 8.78 nm have been used as an effective catalyst for the acetylation of various alcohols, phenols and amines in good to excellent yields under solvent-free conditions. The catalyst was characterized by XRD, XPS, VSM, SEM and TEM study. A magnetic study of the fresh and recycled catalyst after the fourth cycle was performed by VSM measurement. The main advantages of this protocol are simple biogenic synthesis of the catalyst, a reusable and heterogeneous catalytic system, and short reaction times with excellent yields.
- Chutia, Rituparna,Chetia, Bolin
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p. 15200 - 15206
(2018/09/29)
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- Synthesis of a Zeolitic Imidazolate-Zinc Metal-Organic Framework and the Combination of its Catalytic Properties with 2,2,2-Trifluoroethanol for N-Formylation
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A novel protocol is reported for the N-formylation of amines with formic acid by using the nanoporous zeolitic imidazolate framework ZIF-8 as a heterogeneous catalyst in 2,2,2-trifluoroethanol.
- Alamgholiloo, Hassan,Rostamnia, Sadegh,Hassankhani, Asadollah,Banaei, Reza
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supporting information
p. 1593 - 1596
(2018/06/08)
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- Air-stable Bis(pentamethylcyclopentadienyl) Zirconium Perfluorooctanesulfonate as an Efficient and Recyclable Catalyst for the Synthesis of N-substituted Amides
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Bis(pentamethylcyclopentadienyl) zirconium perfluorooctanesulfonate is an air-stable and water-tolerant Lewis acid. This complex exhibited good thermal stability and high solubility in polar organic solvents. The compound showed relatively strong acidity, with an acid strength of 0.8Ho≤3.3, and high catalytic efficiency for the synthesis of N-substituted amides via the reaction of carboxylic acids with amines, the Ritter reaction of nitriles with alcohols, and the amination of alcohols with amides. Moreover, the complex had good reusability. This catalytic system affords a simple and efficient way to synthesize N-substituted amides.
- Li, Ningbo,Wang, Lingxiao,Zhang, Liting,Zhao, Wenjie,Qiao, Jie,Xu, Xinhua,Liang, Zhiwu
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p. 3532 - 3538
(2018/08/01)
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- Electrolysis assisted acetylation of primary aromatic amines in the acetic acid using platinum electrode
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Electrolysis assisted synthesis of anilides from primary aromatic amines in the acetic acid solvent using platinum electrode have been carried out at controlled potential for the investigation of a new ecofriendly synthetic method. The reaction is an example of oxidation of amines with substitution. Controlled potential electrolysis was carried out at platinum plates of dimensions 1.0 cm × 0.5 cm as working as well as counter electrode. Various parameters of the reaction with yield are reported here.
- Kumar, Sanjeev
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p. 1227 - 1230
(2020/06/27)
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- Synthesis of oxindole from acetanilide via Ir(iii)-catalyzed C-H carbenoid functionalization
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Herein we disclose the first report on the synthesis of oxindole derivatives from acetanilide via Ir(iii)-catalyzed intermolecular C-H functionalization with diazotized Meldrum's acid. A broad range of substituted anilides were found to react smoothly under the Ir(iii)-catalytic system to afford the corresponding N-protected oxindoles. The N-protecting groups, such as Ac, Bz or Piv, can be easily removed to furnish the oxindole. Various synthetic applications of the synthesized oxindole were also demonstrated.
- Patel, Pitambar,Borah, Gongutri
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supporting information
p. 443 - 446
(2017/01/03)
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- Co3O4 nanoparticles prepared by oxidative precipitation method: an efficient and reusable heterogeneous catalyst for N-formylation of amines
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Abstract: N-formylation of different amines was carried out with formic acid in the presence of the Co3O4 nanoparticles as an efficient, stable heterogeneous catalyst to give the corresponding formamides under solvent-free conditions. This method has advantages over the reported methods such as high yields, mild conditions, easy work-up and short reaction times. The catalyst was characterized by different techniques such as XRD, SEM and FT-IR spectroscopy. Graphical Abstract: [Figure not available: see fulltext.]
- Marjani, Ahmad Poursattar,Hosseini, Seyed Ali,Shokri, Zahra,Maleki, Nasim
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p. 413 - 422
(2017/01/14)
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- Diazepinium perchlorate: a neutral catalyst for mild, solvent-free acetylation of carbohydrates and other substances
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Diazepinium perchlorate, an essentially neutral organic salt possessing excellent stability, has been found to be well suited for the acetylation of free as well as partially protected sugars, phenols, thiophenols, thiols and other alcohols as well as amines. The diazepinium perchlorate-catalyzed acetylation is mild, organic and solvent-free and leaves acid sensitive protecting groups such as TBDMS/TBDPS/Tr ethers and isopropylidene/benzylidene acetals present on a substrate unaffected. Regioselective hydroxyl protection in partially protected carbohydrate derivatives/polyhydroxylic compounds was possible and was proved to be a convenient time-saving alternative to the conventional synthesis of such compounds. Easy preparation of the catalyst, mild reaction conditions and an environmentally benign protocol are some of the notable features of this reaction. The results obtained on the acetylation of phenols and thiophenols could be rationalized through their local nucleophilicity index obtained from DFT calculations.
- Giri, Santosh Kumar,Gour, Rajesh,Kartha, K. P. Ravindranathan
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p. 13653 - 13667
(2017/03/11)
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- Palladium-Catalyzed, ortho-Selective C-H Halogenation of Benzyl Nitriles, Aryl Weinreb Amides, and Anilides
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A palladium-catalyzed, ortho-selective C-H halogenation methodology is reported herein. The highlight of the work is the highly selective C(sp2)-H functionalization of benzyl nitriles in the presence of activated C(sp3)-H bond, which results in good yields of the halogenated products with excellent regioselectivity. Along with benzyl nitriles, aryl Weinreb amides and anilides have been evaluated for the transformation using aprotic conditions. Mechanistic studies yield interesting aspects with respect to the pathway of the reaction and the directing group abilities.
- Das, Riki,Kapur, Manmohan
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p. 1114 - 1126
(2018/06/18)
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- Impregnated copper on Fe3O4: an efficient magnetically separable nanocatalyst for rapid and selective acylation of amines
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The present paper describes the synthesis of N-arylacetamides through acetylation of arylamines with Ac2O in the presence of magnetically recyclable Fe3O4/Cu NPs. All reactions were carried out efficiently in H2O within 2–10?min to give the products in 89–95% yields. Selective acetylation of amines versus alcohols was carried out successfully with this acetylating system. In addition, acetylation of amines and phenols was taken place with the same reactivity. Reusability of the nanocatalyst was examined 5 times without significant loss of its catalytic activity.
- Shokri, Zahra,Zeynizadeh, Behzad
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p. 2467 - 2474
(2017/10/30)
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- Eco-friendly, catalyst and solvent-free, synthesis of acetanilides and N-benzothiazole-2-yl-acetamides
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An expeditious and green synthesis of acetamides in a solvent-free simple way is described, without catalyst or additives, and in good yield by an instantaneous reaction of anilines or 2-aminothiazoles and acetic anhydride without external heating, and with simple purification. Sixteen substituted acetanilides and four N-benzothiazole-2-yl-acetamides were formed, but aliphatic amines of low molecular weight were not as effective as aromatic ones, and only cyclohexylamine and the enaminone ethyl 3-amino-2-butenoate afforded the corresponding acetamides in good yield.
- Cunha, Silvio,De Santana, Louren?o L. B.
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p. 1137 - 1144
(2017/05/01)
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- Preparation, characterization and application of RHA/TiO2 nanocomposites in the acetylation of alcohols, phenols and amines
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In this work, anatase-phase nano-titania was prepared by embedding in rice husk ash, and identified using a variety of techniques. The obtained nanocomposite (RHA/TiO2) was used as a green and inexpensive catalyst for the promotion of the acetylation of alcohols, phenols and amines with Ac2O at room temperature under solvent free conditions. The procedure gave the products in excellent yields during all reaction times. Also this catalyst can be reused for several times without loss of its catalytic activity.
- Seddighi, Mohadeseh,Shirini, Farhad,Goli-Jolodar, Omid
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p. 1003 - 1010
(2016/08/08)
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- Mild and efficient palladium-catalyzed direct trifluoroethylation of aromatic systems by C-H activation
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The introduction of trifluoroalkyl groups into aromatic molecules is an important transformation in the field of organic and medicinal chemistry. However, the direct installation of fluoroalkyl groups onto aromatic molecules still represents a challenging and highly demanding synthetic task. Herein, a simple trifluoroethylation process that relies on the palladium-catalyzed C-H activation of aromatic compounds is described. With the utilization of a highly active trifluoroethyl(mesityl)iodonium salt, the developed catalytic method enables the first highly efficient and selective trifluoroethylation of aromatic compounds. The robust catalytic procedure provides the desired products in up to 95 % yield at 25 °C in 1.5 to 3 hours and tolerates a broad range of functional groups. The utilization of hypervalent reagents opens new synthetic possibilities for direct alkylations and fluoroalkylations in the field of transition-metal-catalyzed C-H activation.
- T?th, Balázs L.,Kovács, Szabolcs,Sályi, Gerg?,Novák, Zoltán
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supporting information
p. 1988 - 1992
(2016/02/18)
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- Phosphovanadomolybdic acid catalyzed desulfurization-oxygenation of secondary and tertiary thioamides into amides using molecular oxygen as the terminal oxidant
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In the presence of phosphovanadomolybdic acids, e.g., H6PV3Mo9O40, desulfurization-oxygenation of various kinds of structurally diverse secondary and tertiary thioamides proceeded efficiently using molecular oxygen as the terminal oxidant, affording the corresponding amides in moderate to excellent yields. In addition, 18O-labeled amides could readily be synthesized using H218O as the oxygen source.
- Xu, Ning,Jin, Xiongjie,Suzuki, Kosuke,Yamaguchi, Kazuya,Mizuno, Noritaka
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p. 4865 - 4869
(2016/07/06)
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- Me2AlCl-mediated carboxylation, ethoxycarbonylation, and carbamoylation of indoles
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Various 1-methyl-, 1-triisopropylsilyl-, and 1-benzylindoles are carboxylated under CO2 pressure (3.0 MPa) with the aid of 1.0 molar equiv of Me2AlCl to give 1-substituted indole-3-carboxylic acids in good to excellent yields. Mechanistic studies suggest that the intermediate, an indol-3-ylaluminum ate complex, was reversibly formed by electrophilic addition of Me2AlCl to the substrate followed by deprotonation of the resulting adduct. This method is successfully extended to alkoxycarbonylation with ethyl chloroformate and carbamoylation with naphthalen-1-yl isocyanate, which afford ethyl indole-3-carboxylates and N-naphthalen-1-ylindole-3-carboxamides, respectively.
- Nemoto, Koji,Tanaka, Shinya,Konno, Megumi,Onozawa, Satoru,Chiba, Masafumi,Tanaka, Yuuki,Sasaki, Yosuke,Okubo, Ryo,Hattori, Tetsutaro
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p. 734 - 745
(2016/01/15)
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- Synthesis, biological evaluation and mechanism study of a class of cyclic combretastatin A-4 analogues as novel antitumour agents
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In the course of our search for novel antitumor agents, a series of cyclic combretastatin A-4 (CA-4) analogues bearing an amide group, A-B or B-C ring condensation, and CC or CN bond in the B ring were designed, synthesized and identified as new microtubule inhibitors. The structure-activity relationship (SAR) studies showed that the hexa-cyclic compounds bearing B-C ring condensation, containing a CC bond in the B ring (4a) provided excellent antiproliferative activities at nanomolar concentrations against various cancer cell lines (IC50 = 46-80 nM). 4a inhibited tubulin assembly at a micromolar range (IC50 = 2.56 ± 0.15 μM) as evidenced by a molecular docking study, which revealed that 4a exerted tubulin polymerisation inhibitory activity by binding to the colchicine binding site of tubulin. Further molecular biology studies showed that 4a disrupted intracellular microtubule polymerisation and thus induced G2/M phase arrest and apoptotsis in A549 cells. Altogether, these results we obtained can guide the design of novel potent molecules for future development.
- Yan, Jun,Pang, Yanqing,Chen, Jie,Sheng, Jianfei,Hu, Jinhui,Huang, Ling,Li, Xingshu
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p. 98527 - 98537
(2015/12/04)
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- Cleavage of C-N bonds in guanidine derivatives and its relevance to efficient C-N bonds formation
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Efficient nonenzymatic decomposition of guanidine derivatives with high structural and functional diversity into anilide products is achieved in the presence of PdII/Cu(II) carboxylates/CO, relying on a dual C-N bonds cleavage strategy. In this decomposition process, the cooperative action of PdII species, Cu(II) carboxylates, and CO provides not only the N-acylating agents but also an initiator to trigger this C-N bonds cleavage sequence. The current results indicate that PdII/Cu(II) carboxylates/CO system provides a convenient and practical method for highly selective cleavage of unreactive C-N single bonds.
- Chang, Denghu,Zhu, Dan,Zou, Peng,Shi, Lei
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p. 1684 - 1693
(2015/03/30)
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- Carboxyl activation of 2-mercapto-4,6-dimethylpyrimidine through n-acyl-4,6-dimethylpyrimidine-2-thione: A chemical and spectrophotometric investigation
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2-Mercapto-4,6-dimethylpyrimidine, as effective carboxyl activating group, has been successfully proved by converting it into respective acyl derivatives and the subsequent conversion to the amides and esters respectively using amines, amino alcohols and alcohols. The aminolysis and esterification were monitored chemically and spectrophotometrically. This paved way to establish that the above mercaptopyrimidine derivative is an efficient carboxyl activating group applicable in solid phase peptide synthesis.
- Rajan
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p. 287 - 291
(2015/01/30)
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- N3 as an efficient reagent for the Schmidt reactions of ketones, arylaldehydes and aromatic carboxylic acids
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Schmidt reaction of arylaldehydes, ketones and aromatic carboxylic acids using task-specific ionic liquid, [bmim]N3 in the presence of AcOH/H2SO4 proceeds at 50-60 °C within 2-4 h to give the corresponding products. Benzaldehydes containing electron releasing groups afforded to the related benzamide derivatives. Benzonitrile derivatives were formed from the reaction of benzaldehydes containing electron withdrawing groups under these conditions. High yields of the related amides and anilines were obtained from the reaction of a variety of ketones and aromatic carboxylic acids, respectively, utilizing this procedure.
- Valizadeh, Hassan,Gholipour, Hamid,Ahmadi, Mina,Vaghefi, Sevil
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p. 1287 - 1294
(2014/11/07)
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- Amidation of phenol derivatives: A direct synthesis of paracetamol (acetaminophen) from hydroquinone
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A direct synthesis of paracetamol (acetaminophen) from hydroquinone has been developed using ammonium acetate as an amidating agent. The reaction proceeds in acetic acid at elevated temperatures without any metallic catalyst. Under these conditions, paracetamol was obtained with high yield and selectivity (>95%). The reaction has also been carried out on the multi-gram scale (44 g of hydroquinone) and a potential process has been proposed based on the recycling of the solvent and by-products. This amidation protocol has also been extended to other phenol derivatives. This journal is the Partner Organisations 2014.
- Joncour, Roxan,Duguet, Nicolas,Metay, Estelle,Ferreira, Amadeo,Lemaire, Marc
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supporting information
p. 2997 - 3002
(2014/06/10)
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- Natural organic acids promoted Beckmann rearrangement: Green and expeditious synthesis of amides under solvent-free conditions
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Naturally occurring organic acids are reported to be highly efficient promoters of the Beckmann rearrangement. Citric, oxalic, tartaric, malic, succinic, malonic, and fumaric acids efficiently promote the Beckmann rearrangement under solvent-free conditions and thermal and microwave irradiation. Tartaric acid was found to be the best promoter of the Beckmann rearrangement under conventional conditions as well as under microwave irradiation. Compared with conventional heating, microwave irradiation provides higher reaction rate and slightly higher yields.
- Rohokale, Sandeep Vasantrao,Kote, Santosh Rajaram,Deshmukh, Santosh Rangnath,Thopate, Shankar Ramchandra
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p. 575 - 578
(2014/01/17)
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- Rice husk ash: A new, cheap, efficient, and reusable reagent for the protection of alcohols, phenols, amines, and thiols
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Amild, efficient, and eco-friendly protocol for the protection of alcohols and phenols as trimethylsilyl ethers has been developed using rice husk ash as a reagent. This reagent is also able to catalyze the acetylation of alcohols, phenols, thiols, and amines with acetic anhydride. All reactions were performed under mild conditions in good to high yields. Copyright
- Shirini,Akbari-Dadamahaleh, Somayeh,Mohammad-Khah, Ali
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p. 577 - 586
(2014/06/09)
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- Rice husk: Introduction of a green, cheap and reusable catalyst for the protection of alcohols, phenols, amines and thiols
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A mild, efficient and eco-friendly protocol for the chemoselective protection of benzylic and primary and less hindered secondary aliphatic alcohols and phenols as trimethylsilyl ethers and different types of amines as N-tert-butylcarbamates is developed using rice husk (RiH) as the catalyst. This reagent is also able to catalyze the acetylation of alcohols, phenols, thiols and amines with acetic anhydride. Easy work-up, relatively short reaction times, excellent yields and low cost, availability and reusability of the catalyst are the striking features of this methodology, which can be considered to be one of the best and general methods for the protection of alcohols, phenols, thiols and amines. In addition, the use of a green reagent in the above-mentioned reactions results in a reduction of environmental pollution and of the cost of the applied methods.
- Shirini, Farhad,Akbari-Dadamahaleh, Somayeh,Mohammad-Khah, Ali,Aliakbar, Ali-Reza
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p. 164 - 170
(2014/03/21)
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- ZnAl2O4@SiO2 nanocomposite catalyst for the acetylation of alcohols, phenols and amines with acetic anhydride under solvent-free conditions
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A ZnAl2O4@SiO2 nanocomposite was prepared from metal nitrates and tetraethyl orthosilicate by the sol-gel process, and characterized by X-ray diffraction, Fourier transform infrared, transmission electron microscopy, and N2 adsorption-desorption measurements. The nanocomposite was tested as a heterogeneous catalyst for the acetylation of alcohols, phenols, and amines under solvent-free conditions. Under optimized conditions, efficient acetylation of these substrates with acetic anhydride over the ZnAl2O4@SiO2 nanocomposite was obtained. Acetylation of anilines and primary aliphatic amines proceeded rapidly at room temperature, while the reaction time was longer for the acetylation of alcohols and phenols, showing that an amine NH2 group can be selectively acetylated in the presence of alcoholic or phenolic OH groups. The catalyst can be reused without obvious loss of catalytic activity. The catalytic activity of the ZnAl2O4@SiO2 nanocomposite was higher than that of pure ZnAl2O4. The method gives high yields, and is clean, cost effective, compatible with substrates having other functional groups and it is suitable for practical organic synthesis.
- Farhadi, Saeed,Jahanara, Kosar
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p. 368 - 375
(2014/04/03)
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- Pd-Catalyzed C-H activation/oxidative cyclization of acetanilide with norbornene: Concise access to functionalized indolines
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An efficient Pd-catalyzed oxidative cyclization reaction for the synthesis of functionalized indolines by direct C-H activation of acetanilide has been developed. The norbornylpalladium species formed via direct ortho C-H activation of acetanilides is supposed to be a key intermediate in this transformation. This journal is the Partner Organisations 2014.
- Gao, Yang,Huang, Yubing,Wu, Wanqing,Huang, Kefan,Jiang, Huanfeng
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supporting information
p. 8370 - 8373
(2014/07/22)
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- A novel silver nanoparticle embedded mesoporous polyaniline (mPANI/Ag) nanocomposite as a recyclable catalyst in the acylation of amines and alcohols under solvent free conditions
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A mesoporous polyaniline/silver (mPANI/Ag) nanocomposite has been prepared using mesoporous organic polymer polyaniline with silver nitrate via radical polymerization of aniline monomer in the presence of hydrochloric acid. The mPANI/Ag nanocomposite has been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectra (EDX), Fourier transform infrared spectroscopy (FT-IR), and ultraviolet-visible absorption spectra (UV-vis). The XRD patterns indicated that the crystalline phase of Ag is cubic. TEM images show that the Ag nanoparticles are well dispersed in the mesoporous polyaniline matrix. The mPANI/Ag acts as an efficient heterogeneous nanocatalyst in the acylation of substituted amines and alcohols using acetic acid. The catalyst is air-stable, inexpensive, easy to prepare and can be reused several times without a significant decrease in activity and selectivity. This journal is
- Mandi, Usha,Roy, Anupam Singha,Banerjee, Biplab,Islam, Sk. Manirul
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p. 42670 - 42681
(2015/02/19)
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- Visible light photoredox catalysis: Aerobic oxidation of perimidines to perimidinones
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Aerobic oxidation of a series of 2,3-dihydro-1H-perimidines to the corresponding 4- and 6-perimidinones via visible light photoredox catalysis using Ru(bpy)32+ as a catalyst was reported. The scope and limitation of this oxidation were investigated and a possible photochemical mechanism was proposed.
- Wu, Chun-Ku,Liou, Teau-Jiuan,Wei, Hao-Yi,Tsai, Pei-Shan,Yang, Ding-Yah
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p. 8219 - 8225
(2015/03/05)
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- Synthesis and biological evaluation of new rhodanine analogues bearing 2-chloroquinoline and benzo[h]quinoline scaffolds as anticancer agents
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Several rhodanine derivatives (9-39) were synthesized for evaluation of their potential as anticancer agents. Villsmeier cyclization to synthesize aza-aromatic aldehydes, rhodanine derivatives preparation and Knoevenagel type of condensation between the rhodanines and aza-aromatic aldehydes are key steps used for the synthesis of 31 compounds. In vitro antiproliferative activity of the synthesized rhodanine derivatives (9-39) was studied on a panel of six human tumor cell lines viz. HGC, MNK-74, MCF-7, MDAMB-231, DU-145 and PC-3 cell lines. Some of the compounds were capable of inhibiting the proliferation of cancer cell lines at a micromolar concentration. Six compounds are found to be potent against HGC cell lines; compound 15 is found to be active against HGC - Gastric, MCF7 - Breast Cancer and DU145 - Prostate Cancer cell lines; compound 39 is potent against MNK-74; four compounds are found to be potent against MCF-7 cell lines; three compounds are active against MDAMB-231; nine compounds are found to be potent against DU-145; three compounds are active against PC-3 cell lines. These compounds constitute a promising starting point for the development of novel and more potent anticancer agents in future.
- Ramesh, Vadla,Ananda Rao, Boddu,Sharma, Pankaj,Swarna,Thummuri, Dinesh,Srinivas, Kolupula,Naidu,Jayathirtha Rao, Vaidya
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p. 569 - 580
(2014/07/21)
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- The convenient aqueous synthesis and biological evaluation of ortho-(3,4,5-trimethoxybenzoyl)-acetanilides as novel anti-cancer agents
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A series of new ortho-(3,4,5-trimethoxybenzoyl)-acetanilides were synthesised by the cross-coupling reaction catalyzed with Pd catalyst in aqueous medium, with polyethylene glycol as additive under very mild conditions. The evaluation of these compounds as tubulin polymerization inhibitors indicated that most of these compounds were potential anti-cancer agents. Among them, compound 13, 2-hydroxy-N-(5-methoxy-2-(3,4,5-trimethoxy benzoyl)phenyl) acetamide exhibited excellent antiproliferative activity against various human cancer cell lines (GI50= 71 nM for human HeLa cell line), and good activity for inhibiting tubulin polymerization (IC50= 2.94 μM). The mechanism study indicated that compound 13 could arrest cell-cycle progression at the mitosis phase, block the formation of cdc2/cyclin B1 complex, down-regulate the p-Cdc 25C and the anti-apoptotic proteins Bcl-2 and Bcl-XL, and up-regulate the pro-apoptotic proteins Bax and Bad. This journal is
- Sheng, Jianfei,Mao, Fei,Yan, Jun,Huang, Ling,Li, Xingshu
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p. 41510 - 41520
(2014/12/11)
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- SOCl 2/β-cyclodextrin: A new and efficient catalytic system for Beckmann rearrangement and dehydration of aldoximes under aqueous condition
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A rapid and efficient synthesis of amides via Beckmann rearrangement of ketoximes and dehydration of aldoximes to corresponding nitriles with good to excellent yields has been carried out in the presence of SOCl 2/β-cyclodextrin under aqueous conditions. The β-cyclodextrin has been recovered and reused. Copyright Taylor & Francis Group, LLC.
- Patil, Dipak,Dalal, Dipak
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p. 118 - 128
(2012/10/30)
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- A simple, eco-friendly, and recyclable bi-functional acidic ionic liquid catalysts for Beckmann rearrangement
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A library of ionic liquids was prepared by varying the cations and anions. Bi-functional acidic ionic liquids were prepared by the direct combination of ionic liquids and ZnCl2. Ionic liquids were investigated in the Beckmann rearrangements. A simple, eco-friendly, and recyclable bi-functional acidic ionic liquid based protocol for Beckmann rearrangement is developed, which is based on the fine tuning of the Br?nsted and the Lewis acidity of ionic liquids.
- Kore, Rajkumar,Srivastava, Rajendra
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