- Light-emitting diode light–enabled denitrative etherification of 4-nitrobenzonitrile under catalyst-free conditions at room temperature
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In this study, we have developed a catalyst-free procedure for denitrative etherification of electron-deficient nitroarenes. In this method, the reaction failed in the dark but was enabled by white light-emitting diode light (6 W) in the presence of NaOH/dimethylformamide at room temperature with short reaction times. Interestingly, the reaction in the dark is completed almost immediately once a small quantity of water is added to the reaction mixture. Ultraviolet irradiation (λ = 254 nm) was not effective for this reaction to proceed.
- Soltani, Roghaye,Abdollahi, Fatemeh,Ghaderi, Arash
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Read Online
- Cross-Coupling Reactions of Aryl Halides with Primary and Secondary Aliphatic Alcohols Catalyzed by an O,N,N-Coordinated Nickel Complex
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A synthesis of alkyl aryl ethers was achieved via the cross-coupling of aryl halides with primary and secondary aliphatic alcohols catalyzed by a bench-stable nickel complex supported by a monoanionic O,N,N-tridentate ligand. This nickel-catalyzed reaction proceeds smoothly in the absence of a phosphine ligand, affording alkyl aryl ethers in moderate to good yields. (Figure presented.).
- Hashimoto, Toru,Shiota, Keisuke,Funatsu, Kei,Yamaguchi, Yoshitaka
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supporting information
p. 1625 - 1630
(2021/01/26)
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- Dual aminoquinolate diarylboron and nickel catalysed metallaphotoredox platform for carbon-oxygen bond construction
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Herein, aminoquinolate diarylboron complexes are utilized as photocatalysts in dual Ni/photoredox catalyzed carbon-oxygen construction reactions. Via this unified metallaphotoredox platform, diverse (hetero)aryl halides can be conveniently coupled with acids, alcohols and water. This method features operational simplicity, broad substrate scope and good compatibility with functional groups. This journal is
- Day, Craig,Jia, Xin,Wei, Lanfeng,Xu, Liang,Zu, Weisai
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supporting information
p. 8273 - 8276
(2020/08/17)
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- Ligand-free Cu(ii)-catalyzed aerobic etherification of aryl halides with silanes: An experimental and theoretical approach
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Owing to their wide occurrence in nature and immense applications in various fields, the synthesis of aryl alkyl ethers has remained a focus of interest. In contrast to the conventional/traditional methods of etherification, herein, we have reported a more efficient method, which is better yielding and more general in application. The etherification of aryl halides by alkoxy/phenoxy silanes was catalyzed by copper acetate in the presence of cesium carbonate and oxygen in DMF at 145 °C. All the as-synthesized compounds were characterized via the 1H-NMR and 13C-NMR spectroscopic techniques. Density functional theory calculations using the B3LYP functional were performed to elucidate the reaction mechanism. The C-O coupling reaction between 2-nitroiodobenzene and tetramethoxysilane was used as a model reaction. The activation energy barriers for the generation of catalytic species (31.6 kcal mol-1) and the σ-bond metathesis (16.0 kcal mol-1), oxidative addition/reductive elimination (20.3 kcal mol-1), halogen atom transfer (19.2 kcal mol-1) and single electron transfer (SET) (29.5 kcal mol-1) mechanisms for the C-O coupling reaction were calculated. Calculations for the key reaction steps were repeated with the B3PW91, PBEH1PBE, wB97XD, CAM-B3LYP and mPW1LYP functionals. The formation of catalytic species via a single electron transfer reaction between tetramethoxysilane and copper acetate, formation of methoxy radicals and methoxylation of copper showed an overall energy barrier of 31.6 kcal mol-1, and therefore is the rate determining step.
- Ahmed, Muhammad Naeem,Ahmad, Khalil,Yasin, Khawaja Ansar,Farooq, Tayyaba,Khan, Bilal Ahmad,Roy, Soumendra K.
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p. 11316 - 11333
(2019/07/31)
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- Unprecedented alkylation of carboxylic acids by boron trifluoride etherate
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The alkylation of carboxylic acids by an ethyl moiety of boron trifluoride etherate in the absence of ethyl alcohol from the reaction system is unexpected and novel. Both aromatic and aliphatic carboxylic acids were clearly alkylated affording good yields in short reaction times with the exception of nicotinic acid that necessitated an overnight reaction. It was noted that while ortho-substituted hydroxyl groups of carboxylic acids investigated were not affected by alkylation, those of meta- and para-substituted carboxylic acids were partially etherified. Furthermore, the alkylation reaction was found to be compatible with a range of functional groups such as halogens, amino and nitro groups except for the alkene function of undecylenic acid that underwent polymerisation with concomitant alkylation of its carboxylic acid function.
- Jumbam, Ndze D.,Maganga, Yamkela,Masamba, Wayiza,Mbunye, Nomthandazo I.,Mgoqi, Esethu,Mtwa, Sphumusa
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p. 387 - 392
(2018/09/06)
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- Cu(ii)-catalyzed esterification reaction via aerobic oxidative cleavage of C(CO)-C(alkyl) bonds
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A novel Cu(ii)-catalyzed aerobic oxidative esterification of simple ketones for the synthesis of esters has been developed with wide functional group tolerance. This process is assumed to go through a tandem sequence consisting of α-oxygenation/esterification/nucleophilic addition/C-C bond cleavage and carbon dioxide is released as the only byproduct.
- Ma, Ran,He, Liang-Nian,Liu, An-Hua,Song, Qing-Wen
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supporting information
p. 2145 - 2148
(2016/02/09)
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- Liquid crystallinity-embodied imidazolium-based ionic liquids and their chiral mesophases induced by axially chiral tetra-substituted binaphthyl derivatives
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We synthesised novel imidazolium-based ionic liquids with thermotropic liquid crystallinity by introducing phenylcyclohexyl and/or cyanobiphenyl mesogenic cores and hexyl or dodecyl methine chains into both sites of imidazolium moieties facing bromide anions. The liquid crystalline ionic liquids (LCILs) thus synthesised showed a nematic or smectic mesophase in both the heating and cooling processes, indicating the enantiotropic nature of the liquid crystallinity. The LCILs bearing the same types of double mesogenic cores [LCIL-2] showed a smectic A phase in the temperature range from 115 to 175 °C, whereas the LCILs with different types of double mesogenic cores [LCIL-3 and LCIL-4] showed nematic phases in the temperature ranges from 58 to 88 °C and 43 to 95 °C, respectively. The axially chiral binaphthyl derivatives substituted by LC groups at the 2,2′, 6,6′ positions of the binaphthyl rings were synthesised and used as chiral dopants with large helical twisting powers. The mixtures of the LCILs and the (R)- and (S)-binaphthyl derivatives exhibited induced chiral nematic phases with right-and left-handed helical senses, respectively. The ionic conductivities of the LCILs were evaluated to be 10-7-10-4 S cm-1, depending on the isotropic, LC, and crystal phases. The temperature dependence of the ionic conductivities indicates that the LCILs can be regarded as semi-conducting materials. The LCILs might be used as anisotropic ionic conductors and can even serve as anisotropic solvents and electrolytes in electrochemical polymerisations. This journal is
- Ahn, Sangbum,Yamakawa, Shohei,Akagi, Kazuo
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supporting information
p. 3960 - 3970
(2015/04/27)
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- Practical Ligand-Free Copper-Catalysed Short-Chain Alkoxylation of Unactivated Aryl Bromides
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An efficient and practical short-chain alkoxylation of unactivated aryl bromides has been developed with special attention focussed on the applicability of the reaction. Sodium alkoxide is used as the nucleophile, and the corresponding alcohol as the solvent. The reaction requires neither precious metals nor organic ligands. It uses a catalytic system consisting of copper(I) bromide as a catalyst, the corresponding alkyl formate as a noncontaminating cocatalyst, and lithium chloride as an additive. A wide range of substrates and test cases highlight the synthetic utility of the approach. Considering the commercial accessibility and affordability of the feedstocks, this protocol shows promise as a new alternative for the sustainable preparation of aryl alkyl ethers.
- Guo, Ying,Fan, Xue-Min,Nie, Min,Liu, Hong-Wei,Liao, Dao-Hua,Pan, Xian-Dao,Ji, Ya-Fei
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p. 4744 - 4755
(2015/08/03)
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- Synthesis and anticonvulsant activity evaluation of 4-butyl-5-(4- alkoxyphenyl)-2H-1,2,4-triazole-3(4H)-ones
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A series of 4-butyl-5-(4-alkoxyphenyl)-2H-1,2,4-triazole-3(4H)-ones (6a-6u) was designed and synthesized. The anticonvulsant effects and neurotoxicity of the compounds were evaluated with maximal electroshock test and rotarod test. Among the synthetic compounds, 4-butyl-5-(4-(2-fluorinebenzyl)phenyl)-2H-1,2,4- triazole-3 (4H)-one (6k) was the most potent with ED50 value of 27.4 mg/kg and protective index (PI = TD50/ED50) value of 12.0. Besides the anti-MES efficacy, the potency of compound 6k against seizures induced by pentylenetetrazole (PTZ), 3-mercaptopropionic acid (3-MP), and bicuculline (BIC) was also established, which suggested that the mechanisms of action including enhancing of GABAergic activity might be involved in its anticonvulsant activity.
- Zhu, Zi-Shi,Wang, Shi-Ben,Deng, Xian-Qing,Liu, Da-Chuan,Quan, Zhe-Shan
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p. 628 - 635
(2014/05/20)
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- PROCESS FOR PREPARING ALKOXY ARYL ESTER
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The invention relates to a process for preparing a compound represented by the formula 1 which compound may optionally be further mono- or di- substituted with halogen atoms, alkyl groups having 1 to 4 C- atoms and/or alkoxy groups having 1 to 4 C- atoms, wherein R is methyl or ethyl group, comprising the step of: contacting a corresponding compound represented by the formula 2 which compound is not further substituted or further mono- or di- substituted in corresponding positions with halogen atoms, alkyl groups having 1 to 4 C- atoms and/or alkoxy groups having a to 4 C-atoms, with an alkylating agent, wherein the alkylating agent is a compound of the formula (RO)2SO2 or RX, wherein R has the above meaning and X is halogen, in the presence of a bis-quaternary ammonium salt or a polymeric quaternary ammonium salt, in a two-phase system of an aqueous solution of a base and an organic solvent.
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Page/Page column 7
(2013/04/25)
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- Novel 1,3,4-oxadiazole thioether derivatives targeting thymidylate synthase as dual anticancer/antimicrobial agents
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A series of novel 1,3,4-oxadiazole thioether derivatives (compounds 9-44) were designed and synthesized as potential inhibitors of thymidylate synthase (TS) and as anticancer agents. The in vitro anticancer activities of these compounds were evaluated against three cancer cell lines by the MTT method. Among all the designed compounds, compound 18 bearing a nitro substituent exhibited more potent in vitro anticancer activities with IC50 values of 0.7 ± 0.2, 30.0 ± 1.2, 18.3 ± 1.4 μM, respectively, which was superior to the positive control. In the further study, it was identified as the most potent inhibitor against two kinds of TS protein (for human TS and Escherichia coli TS, IC50 values: 0.62 and 0.47 μM, respectively) in the TS inhibition assay in vitro and the most potent antibacterial agents with MIC (minimum inhibitory concentrations) of 1.56-3.13 μg/mL against the tested four bacterial strains. Molecular docking and 3D-QSAR study supported that compound 18 can be selected as dual antitumor/antibacterial candidate in the future study.
- Du, Qian-Ru,Li, Dong-Dong,Pi, Ya-Zhou,Li, Jing-Ran,Sun, Jian,Fang, Fei,Zhong, Wei-Qing,Gong, Hai-Bin,Zhu, Hai-Liang
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p. 2286 - 2297
(2013/05/09)
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- Synthesis and fungicidal activity of novel 2,5-disubstituted-1,3,4- oxadiazole derivatives
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A novel series of 1,3,4-oxadiazole derivatives containing a 5-phenyl-2-furan moiety were synthesized from the intermediates diacylhydrazine 3 and acylhydrazone 5 via an efficient approach under microwave irradiation in good yields. Their structures were characterized by IR, 1H NMR, and elemental analysis. The antifungal tests indicated that the title compounds showed in vivo fungicidal activity against Botrytis cinerea and Rhizoctonia solanii at 500 μg/mL obviously. Some tested compounds even had a superiority effect over the commercial fungicides 40% Pyrimethanil SC and 3% Validamycin AS. The activity between the title compound and their precursors diacylhydrazine 3 and acylhydrazone 5 was also compared and discussed.
- Cui, Zi-Ning,Shi, Yan-Xia,Zhang, Li,Ling, Yun,Li, Bao-Ju,Nishida, Yoshihiro,Yang, Xin-Ling
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p. 11649 - 11656
(2013/02/22)
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- PROCESS FOR PREPARING ALKYL ALKOXYBENZOATES IN ONE STEP
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Process for preparing a compound of the formula by contacting, in an organic solvent in the presence of an aqueous solution of a base, hydroxy benzoic acid with a compound of the formula RnX, wherein R is an alkyl group having 1 to 6 C-atoms and X is an acid rest group having a valence n, wherein the organic solvent is an alkyl substituted aromatic hydrocarbon and the reaction is carried out at a pH of 8-10.
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Page/Page column 2
(2010/06/22)
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- Synthesis, biological evaluation, and molecular docking studies of 2-chloropyridine derivatives possessing 1,3,4-oxadiazole moiety as potential antitumor agents
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A series of new 2-chloropyridine derivatives possessing 1,3,4-oxadiazole moiety were synthesized. Antiproliferative assay results indicated that compounds 6o and 6u exhibited the most potent activity against gastric cancer cell SGC-7901, which was more potent than the positive control. Especially, compound 6o exhibited significant telomerase inhibitory activity (IC 50 = 2.3 ± 0.07 μM), which was comparable to the positive control ethidium bromide. Docking simulation was performed to position compound 6o into the active site of telomerase (3DU6) to determine the probable binding model.
- Zheng, Qing-Zhong,Zhang, Xiao-Min,Xu, Ying,Cheng, Kui,Jiao, Qing-Cai,Zhu, Hai-Liang
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scheme or table
p. 7836 - 7841
(2011/01/13)
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- Oxime Carbamate-Discovery of a series of novel FAAH inhibitors
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A series of novel oxime carbamates have been identified as potent inhibitors of the key regulatory enzyme of the endocannabinoid signaling system, fatty acid amide hydrolase (FAAH). In this Letter, the rationale behind the discovery and the biological evaluations of this novel class of FAAH inhibitors are presented. Both in vitro and in vivo results of selected targets are discussed, along with inhibition kinetics and molecular modeling studies.1.
- Sit,Conway, Charles M.,Xie, Kai,Bertekap, Robert,Bourin, Clotilde,Burris, Kevin D.
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supporting information; experimental part
p. 1272 - 1277
(2010/06/17)
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- Direct conversion of aromatic ketones to arenecarboxylic esters via carbon-carbon bond-cleavage reactions
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Aromatic methyl ketones, ss-keto esters, and trifluoromethyl-l,3- diketones can be directly converted to arene-carboxylic esters via carbon-carbon bond cleavage of pyridinium iodide intermediates in the presence of copper(II) oxide, iodine, pyridine, and potassium carbonate in alcoholic media. The advantages of the present method in terms of good yields, mild reaction conditions, and inexpensive reagents should make this protocol a valuable alternative to the existing methods.
- Yin, Guodong,Gao, Meng,Wang, Zihua,Wu, Yandong,Wu, Anxin
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experimental part
p. 369 - 372
(2009/04/07)
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- PROCESS FOR PREPARING ALKYL ALKOXYBENZOATES IN ONE STEP
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Process for preparing a compound of the formula by contacting, in an organic solvent in the presence of an aqueous solution of a base, hydroxy benzoic acid with a compound of the formula RnX, wherein R is an alkyl group having 1 to 6 C-atoms and X is an acid rest group having a valence n, wherein the organic solvent is an alkyl substituted aromatic hydrocarbon and the reaction is carried out at a pH of 8-10.
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Page/Page column 3,4,5
(2009/01/20)
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- Development of N-benzamidothioureas as a new generation of thiourea-based receptors for anion recognition and sensing
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A series of neutral N-(substituted-benzamido)-N′-phenylthioureas (substituent = p-OC2H5, p-CH3, m-CH 3, H, p-Cl, p-Br, m-Cl, and p-NO2) were designed as anion receptors, in which the thiourea binding site was attached to the benzamido moiety via an N-N bond. The absorption spectra of these N-benzamidothioureas in acetonitrile peaked at ca. 270 nm were found to show unprecedented red shifts by 7 373 to 14 325 cm-1 in the presence of anions such as AcO-, F-, and H2PO4-. Under the same conditions, the classic neutral thiourea receptors, N-(substituted-phenyl)-N′-phenylthioureas, showed absorption spectral shifts in most cases of less than 800 cm-1 with one exception of 6501 cm-1. Control experiments, effects of protic solvent, and 1H NMR titration confirmed the formation of hydrogen-bonding complexes between the new N-benzamidothiourea receptors and anions. The binding constants with AcO-, for example, are at 10 5-107 mol-1 L order of magnitude, which are 13 to 590 times those of the corresponding classic N-phenylthioureas in the same solvent. It was found that, whereas the absorption of the N-benzamidothiourea receptors showed essentially no dependence on the substituent, the substantially red-shifted new absorption band of the N-benzamidothiourea-anion binding complex was sensitively subject to the substituent. A linear relationship was found between the absorption energies of the N-benzamidothiourea-acetate binding complexes and the Hammett constants of the substituents with a negative slope of -0.34 eV. This led to the assignment that the substantially red-shifted absorption band was the ground-state intramolecular charge-transfer absorption with the substituent locating in the electron acceptor moiety. It was concluded that anion binding to the thiourea moiety of the N-benzamidothiourea receptors switched on their ground-state charge transfer. An anion-binding induced structural change was suggested to occur around the N-N bond in N-benzamidothioureas, which resulted in a substantially increased electron donating ability of the electron donor in the receptor molecules. As a consequence, the ground-state charge transfer takes place in the N-benzamidothiourea-anion binding complexes, leading to unprecedented red shifts in the absorption spectra and substantially enhanced anion binding affinities than those of the corresponding N-phenylthiourea receptors. N-Benzamido- N′-phenylthioureas represent a new generation of neutral thiourea-based anion receptors that show substantially improved anion binding performance important for anion sensing and recognition.
- Nie, Li,Li, Zhao,Han, Jie,Zhang, Xuan,Yang, Rui,Liu, Wen-Xia,Wu, Fang-Ying,Xie, Jian-Wei,Zhao, Yu-Fen,Jiang, Yun-Bao
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p. 6449 - 6454
(2007/10/03)
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- Design and synthesis of thiol containing inhibitors of matrix metalloproteinases
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A series of thiol containing derivatives was prepared. Several of these compounds were found to inhibit matrix metalloproteinases 1, 3, and 9 with selectivity towards 3 and 9. Compounds 15, 20 and 22 were administered to rats orally at 75 μmol/kg. Drug levels of compounds 20 and 22 in the plasma were found to exceed the IC50 values for MMP 3 and 9 four hours after administration.
- Fink, Cynthia A.,Carlson, J. Eric,Boehm, Charles,McTaggart, Patricia,Qiao, Ying,Doughty, John,Ganu, Vishwas,Melton, Richard,Goldberg, Ronald
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p. 195 - 200
(2007/10/03)
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- Study of activation energy and order of reaction of some liquid crystals
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Liquid crystals of the type p-phenylene-di-p-n-alkoxy benzoate have been prepared. Kissinger isothermal decomposition method has been used for determination of activation energy values of liquid crystals. Kissinger's assessment for shape index of DTA peaks is used to find the order of reaction. There is no direct relationship between the carbon atoms in terminal methylene groups and Ea values. Order of reaction value decreases with increase in heating rate upto carbon atoms 10 in the terminal methylene group but beyond this the order increases or decreases.
- Mundhe
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p. 246 - 249
(2007/10/03)
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- Preparation of organic acids and/or esters
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Carboxylic acids and/or esters are prepared by converting the STR1 moiety in a 1-substituted 2,2-trihaloethanol, or derivative wherein X represents halogen and R is hydrogen or an acyl group to an organic acid and/or ester grouping of the formula STR2 wherein R' is hydrogen or alkyl of 1 to 6 carbon atoms, in the process which comprises reacting the 1-substituted 2,2,2-trihaloethanol or acylated derivative with molecular oxygen in the presence of a catalyst comprising a complex of a transition metal having an atomic number from 21-30, 39-48 or 57-80 and at least one molecule of a ligand containing trivalent nitrogen, phosphorus, arsenic or antimony. This reaction is carried out in a reaction medium comprising an alcohol or aqueous alcohol having 1 to 6 carbon atoms optionally containing an alkali metal, said alcoholic solvent also serving as a reactant source when carboxylic acid esters are formed.
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- STABLE 2H-PYRAN DERIVATIVES ACCESSIBLE BY CYCLOCONDENSATION OF p-SUBSTITUTED BENZOYLACETONITRILES
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The 2H-pyrans IIa-f can be prepared by thermal cyclocondensation of the ketonitriles Ia-f.The alternative structure III of the compounds obtained has been excluded unambiguously on the basis of spectral data.The compounds VII to XI have been isolated as byproducts of the said cyclocondensation of the compound Ia in acetic acid with catalysis of ammonium acetate.Probable course of the reaction investigated is discussed.
- Kuthan, Josef,Palecek, Jaroslav,Valihrach, Jiri
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p. 748 - 758
(2007/10/02)
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