- Photoinduced Acetylation of Anilines under Aqueous and Catalyst-Free Conditions
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A green and efficient visible-light induced functionalization of anilines under mild conditions has been reported. Utilizing nontoxic, cost-effective, and water-soluble diacetyl as photosensitizer and acetylating reagent, and water as the solvent, a variety of anilines were converted into the corresponding aryl ketones, iodides, and bromides. With advantages of environmentally friendly conditions, simple operation, broad substrate scope, and functional group tolerance, this reaction represents a valuable method in organic synthesis.
- Yang, Yu-Ming,Yan, Wei,Hu, Han-Wei,Luo, Yimin,Tang, Zhen-Yu,Luo, Zhuangzhu
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p. 12344 - 12353
(2021/09/02)
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- Selective Electrochemical Oxygenation of Alkylarenes to Carbonyls
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An efficient electrochemical method for benzylic C(sp3)-H bond oxidation has been developed. A variety of methylarenes, methylheteroarenes, and benzylic (hetero)methylenes could be converted into the desired aryl aldehydes and aryl ketones in moderate to excellent yields in an undivided cell, using O2 as the oxygen source and lutidinium perchlorate as an electrolyte. On the basis of cyclic voltammetry studies, 18O labeling experiments, and radical trapping experiments, a possible single-electron transfer mechanism has been proposed for the electrooxidation reaction.
- Li, Xue,Bai, Fang,Liu, Chaogan,Ma, Xiaowei,Gu, Chengzhi,Dai, Bin
-
supporting information
p. 7445 - 7449
(2021/10/02)
-
- Design, synthesis, biological evaluation and inhibition mechanism of 3-/4-alkoxy phenylethylidenethiosemicarbazides as new, potent and safe tyrosinase inhibitors
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Tyrosinase plays important roles in many different disease related processes, and the development of its inhibitors is particularly important in biotechnology. In this study, thirty-nine 3-/4-alkoxyphenylethyli-denethiosemicarbazides were synthesized as novel tyrosinase inhibitors based on structure-based molecular design. Our experimental results demonstrated that thirty-one of them possess remarkable tyrosinase inhibitory activities with IC50 value below 1μM, and 5a, 6e, 6g and 6t did not display any toxicity to 293T cell line at the concentration of 1000μmol/L. According to the inhibitory activities, several compounds were selected for detail investigation on the structure–activity relationships (SARs), mechanisms of enzyme inhibition, inhibitory kinetics and cytotoxicity. In particular, the interaction between the selected inhibitors and the active center of tyrosinase was considered and discussed in detail based on their structural characteristics. Taken together, the results presented here demonstrated that the newly designed compounds are promising candidates for the treatment of tyrosinase-related disorders and further development of them may have significant contribution in biomedical science.
- Liao, Bing,Mai, Yuliang,Shi, Huahong,Song, Senchuan,Wang, Fei
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p. 369 - 379
(2020/05/14)
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- Facile preparation of 5-alkyl-1-aryltetrazoles with arenes, acyl chlorides, hydroxylamine, and diphenylphosphoryl azide
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Successive treatment of arenes with acyl chlorides and AlCl3, the addition of water and removal of solvent, the reaction with NH2OH?HCl and K2CO3, and the reaction with diphenylphosphoryl azide and DBU under warming conditions gave the corresponding 5-alkyl-1-aryltetrazoles efficiently in good to moderate yields. The present method is one-pot transformation of arenes into 5-alkyl-1-aryltetrazoles using the Friedel-Crafts acylation and the Beckmann rearrangement under transition-metal-free conditions.
- Shibasaki, Kaho,Togo, Hideo
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p. 1816 - 1830
(2020/11/19)
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- A molybdenum based metallomicellar catalyst for controlled and chemoselective oxidation of activated alcohols in aqueous medium
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A surfactant based oxodiperoxo molybdenum complex, which could activate molecular oxygen, has been employed as a catalyst for controlled oxidation of benzylic alcohols to corresponding carbonyls. The oxidation reactions were carried out under aqueous environment, however, in the absence of any extraneous base or co-catalyst. Sensitive/oxidizable functional groups like cyano, sulfide, hydroxyl, aryl-hydroxyl, alkene (internal/terminal), alkyne (internal/terminal), and acetal were tolerated during the transformations. Such selectivity is attributed to the mild nature of the catalyst. The methodology could also be scaled-up for multi-gram synthesis and the protocol is likely to find practical use since it requires an inexpensive recyclable-catalyst and easily available oxidant (under green conditions). A plausible mechanism is proposed with the help of preliminary computational study.
- Thiruvengetam, Prabaharan,Chakravarthy, Rajan Deepan,Chand, Dillip Kumar
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p. 123 - 133
(2019/07/19)
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- Metal-Free Photoinduced Transformation of Aryl Halides and Diketones into Aryl Ketones
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The acylation of aryl halides to prepare aryl ketones without metal catalyst represents an important yet challenging topic towards more sustainable ketone synthesis. Herein, we describe a simple and efficient metal-free protocol for the acylation of aryl halides with diketone under the irradiation of light utilizing N-methylpiperidine as base under an air atmosphere. This reaction can tolerate a wide range of functional groups and the corresponding ketones can be obtained in modest to good yields.
- Yao, Qiuli,Liu, Wenbo,Liu, Peng,Ren, Linjing,Fang, Xuehong,Li, Chao-Jun
-
supporting information
p. 2721 - 2724
(2019/01/14)
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- Metal-organic layers as multifunctional two-dimensional nanomaterials for enhanced photoredox catalysis
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Metal-organic layers (MOLs) have recently emerged as a novel class of molecular two-dimensional (2D) materials with significant potential for catalytic applications. Herein we report the design of a new multifunctional MOL, Hf12-Ir-Ni, by laterally linking Hf12 secondary building units (SBUs) with photosensitizing Ir(DBB)[dF(CF3)ppy]2+ [DBB-Ir-F, DBB = 4,4′-di(4-benzoato)-2,2′-bipyridine; dF(CF3)ppy = 2-(2,4-difluorophenyl)-5-(trifluoromethyl)pyridine] bridging ligands and vertically terminating the SBUs with catalytic Ni(MBA)Cl2 [MBA = 2-(4′-methyl-[2,2′-bipyridin]-4-yl)acetate] capping agents. Hf12-Ir-Ni was synthesized in a bottom-up approach and characterized by TEM, AFM, PXRD, TGA, NMR, ICP-MS, UV-vis, and luminescence spectroscopy. The proximity between photosensitizing Ir centers and catalytic Ni centers (～0.85 nm) in Hf12-Ir-Ni facilitates single electron transfer, leading to a 15-fold increase in photoredox reactivity. Hf12-Ir-Ni was highly effective in catalytic C-S, C-O, and C-C cross-coupling reactions with broad substrate scopes and turnover numbers of ～4500, ～1900, and ～450, respectively.
- Lan, Guangxu,Quan, Yangjian,Wang, Maolin,Nash, Geoffrey T.,You, Eric,Song, Yang,Veroneau, Samuel S.,Jiang, Xiaomin,Lin, Wenbin
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supporting information
p. 15767 - 15772
(2019/10/11)
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- Design, synthesis, docking studies and monoamine oxidase inhibition of a small library of 1-acetyl- and 1-thiocarbamoyl-3,5-diphenyl-4,5-dihydro-(1h)-pyrazoles
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New N-acetyl/N-thiocarbamoylpyrazoline derivatives were designed and synthesized in high yields to assess their inhibitory activity and selectivity against human monoamine oxidase A and B. The most important chiral compounds were separated into their single enantiomers and tested. The impact of the substituents at N1, C3 and C5 positions as well the influence of the configuration of the C5 on the biological activity were analyzed. Bulky aromatic groups at C5 were not tolerated. p-Prenyloxyaryl moiety at C3 oriented the selectivity toward the B isoform. The results were also corroborated by molecular modelling studies providing new suggestions for the synthesis of privileged structures to serve as lead compounds for the treatment of mood disorders and neurodegenerative diseases.
- Guglielmi, Paolo,Carradori, Simone,Poli, Giulio,Secci, Daniela,Cirilli, Roberto,Rotondi, Giulia,Chimenti, Paola,Petzer, Anél,Petzer, Jacobus P.
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-
- NOVEL COMPOUND AND PHARMACEUTICAL COMPOSITION CONTAINING THE SAME
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Disclosed are compounds of formula (I) below and pharmaceutically acceptable salts thereof: Formula (I), in which each of variables L, R3, R4, Y, Z1, Z2 and Z3 is defined herein. Also disclosed is a method for treating a cancer with a compound of formula (I) or a salt thereof and a pharmaceutical composition containing same.
- -
-
Page/Page column 36; 12
(2019/02/15)
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- Design, synthesis and structure-based optimization of novel isoxazole-containing benzamide derivatives as FtsZ modulators
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Antibiotic resistance among clinically significant bacterial pathogens is becoming a prevalent threat to public health, and new antibacterial agents with novel mechanisms of action hence are in an urgent need. Utilizing computational docking method and structure-based optimization strategy, we rationally designed and synthesized two series of isoxazol-3-yl- and isoxazol-5-yl-containing benzamide derivatives that targeted the bacterial cell division protein FtsZ. Evaluation of their activity against a panel of Gram-positive and -negative pathogens revealed that compounds B14 and B16 that possessed the isoxazol-5-yl group showed strong antibacterial activity against various testing strains, including methicillin-resistant Staphylococcus aureus and penicillin-resistant S. aureus. Further molecular biological studies and docking analyses proved that the compound functioned as an effective inhibitor to alter the dynamics of FtsZ self-polymerization via a stimulatory mechanism, which finally terminated the cell division and caused cell death. Taken together, these results could suggest a promising chemotype for development of new FtsZ-targeting bactericidal agent.
- Bi, Fangchao,Song, Di,Zhang, Nan,Liu, Zhiyang,Gu, Xinjie,Hu, Chaoyu,Cai, Xiaokang,Venter, Henrietta,Ma, Shutao
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- Air-stable μ2-hydroxyl bridged cationic binuclear complexes of zirconocene perfluorooctanesulfonates: their structures, characterization and application
-
Three air-stable zirconocene perfluoro-octanesulfonates were successfully synthesized by treatment of C8F17SO3Ag with (RCp)2ZrCl2 [R = H, n-Bu, t-Bu]. According to X-ray analysis, they have μ2-hydroxyl bridged cationic binuclear structures: (i) [CpZr(OH2)3]2(μ2-OH)2(OSO2C8F17)4·2THF·4H2O (1a·2THF·4H2O), (ii) [n-BuCpZr(OH2)3]2(μ2-OH)2(OSO2C8F17)4·6H2O (2a·6H2O), and (iii) [t-BuCpZr(OH2)3]2(μ2-OH)2(OSO2C8F17)4·2C3H6O·8H2O (3a·2C3H6O·8H2O). The ligands of water and organic molecules in the complexes originated from the moist air and solvent during their recrystallization. These complexes were characterized with different techniques, and found to show water tolerance, air/thermal stability as well as strong Lewis acidity. Moreover, the complexes showed highly catalytic activity in various reactions of C–C bond formation. With good recyclability, they should find wide applications in organic chemistry.
- Zhang, Xiaohong,Xu, Xinhua,Li, Ningbo,Liang, Zhiwu,Tang, Zilong
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supporting information
p. 1926 - 1932
(2018/03/21)
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- NEW TARGETED CYTOTOXIC ISOCOMBRETAQUINOLINE DERIVATIVES AND CONJUGATES THEREOF
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The present invention is directed to novel natural product-derived combretastatin- based compounds useful as payloads in drug-conjugates constructs with cell target binding moieties (CTBM) and payload-linker compounds useful in connection with drug conjugates. The present invention further relates to new isoNH2CombretaQuinoline compositions including the aforementioned payloads, payload-linkers and drug conjugates, and methods for using these payloads, payload-linkers and drug conjugates, to treat pathological conditions including cancer.
- -
-
Paragraph 00143
(2018/10/25)
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- Pd(II)-Catalyzed Denitrogenative and Desulfinative Addition of Arylsulfonyl Hydrazides with Nitriles
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A Pd(II)-catalyzed denitrogenative and desulfinative addition of arylsulfonyl hydrazides with nitriles has been successfully achieved under mild conditions. This transformation is a new method for the addition reaction to nitriles with arylsulfonyl hydrazides as arylating agent, thus providing an alternative synthesis of aryl ketones. The reported addition reaction is tolerant to many common functional groups, and works well in the presence of electron-donating and electron-withdrawing substituents. Notably, the reported denitrogenative and desulfinative addition was also appropriate for alkyl nitriles, making this newly developed transformation attractive.
- Meng, Mengting,Yang, Liangfeng,Cheng, Kai,Qi, Chenze
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p. 3275 - 3284
(2018/03/25)
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- Preparation method of aromatic ketone
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The invention discloses a preparation method of aromatic ketone. Under the effects of a palladium catalyst and a nitrogen-containing ligand, nitrile compounds and arylsulfonylhydrazide take desulfurization addition reaction in an organic solvent; after the reaction is completed, post treatment is performed to obtain aromatic ketone. The reaction is applicable to aromatic nitrile compounds, and isalso applicable to aliphatic nitrile compounds; the reaction realizes the wide substrate applicability and functional group tolerance; the potential application value is realized in the aspect of aryl-carbonyl building.
- -
-
Paragraph 0056; 0057; 0058; 0060
(2018/09/11)
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- Design, synthesis, and discovery of 5-((1,3-diphenyl-1H-pyrazol-4-yl)methylene)pyrimidine-2,4,6(1H,3H,5H)-triones and related derivatives as novel inhibitors of mPGES-1
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Human mPGES-1 has emerged as a promising target in exploring a next generation of anti-inflammatory drugs, as selective mPGES-1 inhibitors are expected to discriminatively suppress the production of induced PGE2 without blocking the normal biosynthesis of other prostanoids including homeostatic PGE2. Therefore, this therapeutic approach is believed to reduce the adverse effects associated with the application of traditional non-steroidal anti-inflammatory drugs (tNSAIDs) and selective COX-2 inhibitors (coxibs). Identified from structure-based virtue screening, the compound with (Z)-5-benzylidene-2-iminothiazolidin-4-one scaffold was used as lead in rational design of novel inhibitors. Besides, we further designed, synthesized, and evaluated 5-((1,3-diphenyl-1H-pyrazol-4-yl)methylene)pyrimidine-2,4,6(1H,3H,5H)-triones and structurally related derivatives for their in vitro inhibitory activities. According to in vitro activity assays, a number of these compounds were capable of inhibiting human mPGES-1, with the desirable selectivity for mPGES-1 over COX isozymes.
- Ding, Kai,Zhou, Ziyuan,Zhou, Shuo,Yuan, Yaxia,Kim, Kyungbo,Zhang, Ting,Zheng, Xirong,Zheng, Fang,Zhan, Chang-Guo
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p. 858 - 862
(2018/02/21)
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- Tropylium Ion Catalyzes Hydration Reactions of Alkynes
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The hydration of alkynes is one of the most atom-economic and versatile synthetic protocols to access carbonyl compounds. This fundamental reaction, however, often requires transition-metal catalysts or harsh reaction conditions to promote the addition of water to the carbon–carbon triple bond. In this work, it is demonstrated that the non-benzenoid aromatic tropylium ion can be used as an organic Lewis acid promoter for the hydration of alkynes under simple reaction conditions with excellent outcomes.
- Oss, Giulia,Ho, Junming,Nguyen, Thanh Vinh
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supporting information
p. 3974 - 3981
(2018/08/17)
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- Transition-Metal- and Halogen-Free Oxidation of Benzylic sp 3 C-H Bonds to Carbonyl Groups Using Potassium Persulfate
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Aryl carbonyl compounds including acetophenones, benzophenones, imides, and benzoic acids are prepared from benzyl substrates using potassium persulfate as oxidant with catalytic pyridine in acetonitrile under mild conditions. Neither transition metals nor halogens are involved in the reactions.
- Hu, Yixin,Zhou, Lihong,Lu, Wenjun
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p. 4007 - 4016
(2017/08/29)
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- Design, synthesis and pharmacology of 1,1-bistrifluoromethylcarbinol derivatives as liver X receptor β-selective agonists
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A novel series of 1,3-bistrifluoromethylcarbinol derivatives that act as liver X receptor (LXR) β-selective agonists was discovered. Structure-activity relationship studies led to the identification of molecule 62, which was more effective (Emax) and selective toward LXRβ than T0901317 and GW3965. Furthermore, 62 decreased LDL-C without elevating the plasma TG level and significantly suppressed the lipid-accumulation area in the aortic arch in a Bio F1B hamster fed a diet high in fat and cholesterol. We demonstrated that our LXRβ agonist would be potentially useful as a hypolipidemic and anti-atherosclerotic agent. In this manuscript, we report the design, synthesis and pharmacology of 1,3-bistrifluoromethylcarbinol derivatives.
- Koura, Minoru,Matsuda, Takayuki,Okuda, Ayumu,Watanabe, Yuichiro,Yamaguchi, Yuki,Kurobuchi, Sayaka,Matsumoto, Yuuki,Shibuya, Kimiyuki
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p. 2668 - 2674
(2015/06/08)
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- A general, mild and efficient palladium-catalyzed 2,2,2-trifluoroethoxylation of activated aryl bromides and bromo-chalcones: Bromo-chalcones a new coupling partner in cross-coupling reaction
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An efficient protocol for Pd-catalyzed 2,2,2-trifluoroethoxylation of activated aryl bromides and bromo-chalcones has been developed. We unveil a fascinating insight into the Pd-catalyzed C-O cross-coupling reaction. Pd/tBuXPhos (L1) ligand system facilitates the C-O cross-coupling reaction between 2,2,2-trifluoroethanol and activated aryl bromides at both higher (115 °C) and lower temperatures (40 °C). Unprecedentedly, this catalyst system facilitates the C-O cross-coupling reaction in short span of reaction times, generally 5-25 min (at 115 °C). The structurally simple analogue of tBuXPhos ligand so called JohnPhos (L2) ligand is also facilitated the C-O bond formation with activated aryl bromides and bromo-chalcones. Interestingly, under the optimal conditions (L1), methanol is also coupled rapidly with activated aryl bromides. These catalyst systems (L1 and L2) fail to couple electron rich aryl bromides with 2,2,2-trifluoroethanol, thus these catalyst systems allow the reductive elimination through an electronic pathway of reductive elimination. The unusual reactivity of 2,2,2-trifluoroethanol in Pd-catalyzed C-O cross-coupling reaction makes that the chemistry of fluorinated molecules is unique than that of non-fluorinated analogues. The bromo-chalcones can be used as a new coupling partner in the cross-coupling reaction.
- Rangarajan,Devi, Kavita,Ayushee,Prasad, Ashok K.,Pal Singh, Rishi
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p. 8307 - 8314
(2015/10/05)
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- Strong Lewis acid air-stable cationic titanocene perfluoroalkyl(aryl) sulfonate complexes as highly efficient and recyclable catalysts for C-C bond forming reactions
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A series of strong Lewis acid air-stable titanocene perfluoroalkyl(aryl) sulfonate complexes Cp2Ti(OH2)2(OSO 2X)2·THF (X = C8F17, 1·THF; X = C4F9, 2·H2O· THF; X = C6F5, 3) were successfully synthesized by the treatment of Cp2TiCl2 with C8F 17SO3Ag, C4F9SO3Ag and C6F5SO3Ag, respectively. In contrast to well-known titanocene bis(triflate), these complexes showed no change in open air over three months. TG-DSC analysis showed that 1·THF, 2·H 2O·THF and 3 were thermally stable at 230 °C, 220°C and 280°C, respectively. Conductivity measurements showed that these complexes underwent ionic dissociation in CH3CN solution. X-ray analysis results confirmed that 2·H2O·THF and 3 were cationic. ESR spectra showed that the Lewis acidity of 1·THF (1.06 eV) was higher than that of Sc3+ (1.00 eV) and Y3+ (0.85 eV). UV/Vis spectra showed a significant red shift due to the strong complex formation between 10-methylacridone and 2·H2O·THF. Fluorescence spectra showed that the Lewis acidity of 2 (λem = 477 nm) was higher than that of Sc3+ (λem = 474 nm). These complexes showed high catalytic ability in various carbon-carbon bond forming reactions. Moreover, they show good reusability. Compared with 1·THF, 2·H2O·THF and 3 exhibit higher solubility and better catalytic activity, and will find broad applications in organic synthesis. This journal is the Partner Organisations 2014.
- Li, Ningbo,Wang, Jinying,Zhang, Xiaohong,Qiu, Renhua,Wang, Xie,Chen, Jinyang,Yin, Shuang-Feng,Xu, Xinhua
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supporting information
p. 11696 - 11708
(2014/07/22)
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- Synthesis and structure of an air-stable μ2-hydroxy-bridged binuclear complex of bis(methylcyclopentadienyl)dizirconium(IV) perfluorooctanesulfonate and its application in Lewis acid-catalyzed reactions
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Air-stable binuclear complex of bis(methylcyclopentadienyl)zirconium perfluorooctanesulfonate (1a) was successfully synthesized by the reaction of (CH3Cp)2ZrCl2 with C8F 17SO3Ag. The compound 1a was characterized by different techniques and found to have the nature of air-stability, water tolerance, thermally-stability and strong Lewis-acidity. In addition, its solubility was higher than that of our previously reported uninuclear zirconocene bis(perfluorooctanesulfonate). It showed high catalytic efficiency in the Friedel-Crafts acylation of alkyl aryl ethers and the Mannich reaction and could be reused.
- Zhang, Xiaohong,Lou, Cong,Li, Ningbo,Xu, Xinhua,Qiu, Renhua,Yin, Shuangfeng
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supporting information
p. 241 - 245
(2013/11/06)
-
- Reactivity switch enabled by counterion: Highly chemoselective dimerization and hydration of terminal alkynes
-
A counterion-controlled reactivity tuning in Pd-catalyzed highly chemoselective and regioselective dimerization and hydration of terminal alkynes is reported. The use of acetate as counterion favors the formation of an alkenyl alkynyl palladium intermediate which forms hitherto less reported 1,3-diaryl-substituted conjugated enynes after reductive elimination. Using chloride, which is a better leaving group, leads to anion exchange on the alkenylpalladium intermediate with hydroxide which after reductive elimination and tautomerization delivered the hydration products.
- Xu, Caixia,Du, Weiyuan,Zeng, Yi,Dai, Bin,Guo, Hao
-
supporting information
p. 948 - 951
(2014/03/21)
-
- Comparison of a series of laccase mediators in the electro-oxidation reactions of non-phenolic lignin model compounds
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The electro-oxidations of non-phenolic lignin model compounds in an electrolytic mediator system (EMS) have been investigated with several laccase mediators, including N-hydroxyphthalimide (NHPI), 1-hydroxybenzotriazole (HBT), violuric acid (VLA), 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS), under the same reaction conditions. In the bulk electrolyses of the monomeric model compound [1-(4′-ethoxy-3′-methoxyphenyl)ethanol (1G)], oxidation with NHPI gave the corresponding Cα=O product (2G) in high yield, whereas the oxidations with HBT, VLA, and TEMPO afforded 2G in moderate yields. The highest reaction selectivity for the guaiacylunits was found in the oxidation conducted in the presence of ABTS, although the yield was low. In the bulk electrolyses of the dimeric model compound [4-ethoxy-3-methoxyphenylglycerol- β-guaiacyl ether (3G)], the oxidation with NHPI gave the corresponding Cα=O product (4G) in high yield, whereas the oxidations with HBT, VLA, and TEMPO gave 4G in low yields. In contrast, the oxidation with ABTS gave a Cα-Cβ cleavage product (5G) in 5.5% yield. The selectivity of the mediators in the EMS reaction effectively reflected the mechanisms of their reactions, as reported for the laccase mediator system. NHPI was confirmed to be the best mediator in the present system for the selective Cα-carbonylation of the non-phenolic β-O-4 structures in lignin.
- Shiraishi, Takumi,Sannami, Yumi,Kamitakahara, Hiroshi,Takano, Toshiyuki
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p. 440 - 446
(2013/10/01)
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- Novel Ethanediamone Hepcidine Antagonists
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The present invention relates to novel hepcidin antagonists of formula (I), pharmaceutical compositions comprising them and the use thereof as medicaments, in particular for treatment of disorders in iron metabolism, such as, in particular, iron deficiency diseases and anaemias, in particular anaemias in connection with chronic inflammatory diseases (ACD: anaemia of chronic disease and AI: anaemia of inflammation).
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-
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- Ultrasound assisted Friedel-Crafts acylation of aromatics using ferric sulphate as catalyst
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The use of ultrasound in the acylation reactions of various aromatics and polyaromatics with different acyl chlorides, in the presence of catalytic amount of ferric sulphate at room temperature, gives good yields of the respective ketones with a short reaction time. A facile and simple synthesis of various aromatic ketones using Friedel-Crafts acylation has been established from the corresponding acid chlorides and aromatic or polyaromatic compounds, respectively under mild reaction conditions with shorter reaction times (30-45 min) and in reasonable yields. This method offers the advantage of low cost and ease of purification of the products because of the small amount of ferric sulphate used in these reactions.
- Sridharan, Anandhi,Gopalakrishnan, Geetha
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scheme or table
p. 1192 - 1195
(2011/10/18)
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- Racemization of secondary alcohols catalyzed by ruthenium: Application to chemoenzymatic dynamic resolution
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In this paper, we have shown that the [RuCl2(p-cymene)] 2 complex associated with simple hemisalen ligands is able to racemize (S)-1-phenylethanol. The influence on the racemization process of the ligand's structure as well as the nature of a co-catalyst have been evaluated and optimized. This [RuCl2(p-cymene)]2/Ligand/TEMPO racemization system was then associated with the Candida Antarctica B lipase in order to carry out dynamic kinetic resolution experiments on rac-phenylethanol. This led us to identify the best conditions for effective DKR, which was then applied to various secondary benzylic and aliphatic alcohols. It was thus possible to obtain (R)-1-cyclohexylethyl acetate from rac-1-cyclohexylethanol in quantitative conversion and with high enantioselectivity (98%).
- Merabet-Khelassi, Mounia,Vriamont, Nicolas,Aribi-Zouioueche, Louisa,Riant, Olivier
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experimental part
p. 1790 - 1796
(2012/01/03)
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- Bis(μ-iodo)bis[(-)-sparteine]-dicopper: A versatile catalyst for direct O-Arylation and O-Alkylation of phenols and aliphatic alcohols with haloarenes
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The easy to prepare dimeric bis(μ-iodo)bis[(-)-sparteine]- dicopper ([CuI{(-)-spa}]2 complex) is shown to be versatile catalyst for O-arylation and O-alkylation with various aryl halides with phenols and aliphatic alcohols respectively, including less reactive aryl chlorides, such as chlorobenzene under mild conditions.
- Satyanarayana, Ponnam,Maheswaran, Hariharasarma,Kantam, Mannepalli Lakshmi,Bhargava, Suresh
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supporting information; experimental part
p. 788 - 790
(2011/08/22)
-
- Triton B-mediated efficient and convenient alkoxylation of activated aryl and heteroaryl halides
-
A simple and convenient one-pot synthesis of aryl alkyl ethers by the alkoxylation of aryl halides with alcohol in the presence of Triton B as a base is described. The procedure is applicable for a variety of aryl and heteroaryl halides, and yields are very good. The use of a nonmetallic base and solvent-free conditions are important features of the reaction. Copyright Taylor & Francis Group, LLC.
- Meshram,Goud, P. Ramesh,Reddy, B. Chennakesava,Kumar, D. Aravind
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experimental part
p. 2122 - 2129
(2010/08/13)
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- Palladium-catalysed synthesis of aryl-alkyl ethers using alkoxysilanes as nucleophiles
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Changing the activator from tetrabutyl ammonium fluoride (TBAF) to sodium hydroxide unexpectedly switches the catalytic pathway of the Hiyama coupling reaction of vinyl trialkoxysilanes with aryl bromides into a Pd catalysed C-O bond forming reaction; if
- Milton, Edward J.,Fuentes, Jose A.,Clarke, Matthew L.
-
supporting information; experimental part
p. 2645 - 2648
(2009/10/30)
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- Synthesis of 5-aryl-5′-formyl-2,2′-bithiophenes as new precursors for nonlinear optical (NLO) materials
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A series of formyl-substituted 5-aryl-2,2′-bithiophenes 5 were synthesized using two different methods: Vilsmeier-Haack-Arnold reaction (VHA) or through Suzuki coupling. The synthesis of compounds 5 through the Vilsmeier-Haack-Arnold reaction, starting from inexpensive and easily available precursors such as acetophenones, gave the title compounds in low yields after four reaction steps. On the other hand Suzuki coupling of functionalized arylboronic acids 7 and the 5-bromo-5′-formyl-2,2′-bithiophene 6 gave compounds 5 in good yields in only one step.
- Herbivo, Cyril,Comel, Alain,Kirsch,Raposo, M. Manuela M.
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experimental part
p. 2079 - 2086
(2009/07/18)
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- An efficient procedure for the TEMPO-catalyzed oxidation of alcohols to aldehydes and ketones using ferric chloride hexahydrate as terminal oxidant
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A simple, efficient procedure for the oxidation of alcohols by catalytic 2,2,6,6-tetramethyl-piperidyl-l-oxy (TEMPO) was developed using FeCl 3·6H2O as the terminal oxidant. The reaction gives high yield of the corresponding aldehydes and ketones with no over oxidation to the acid.
- Kumar, R. Senthil,Karthikeyan,Perumal, Paramasivan T.
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p. 720 - 725
(2008/09/21)
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- Chain amplification in photoreactions of N-alkoxypyridinium salts with alcohols: Mechanism and kinetics
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Photosensitized electron transfer from a variety of singlet- and triplet-excited donors to N-methoxypyridinium salts leads to N-O bond cleavage. Hydrogen atom abstraction by the resulting methoxy radical from an added alcohol generates an α-hydroxy radical that reduces another pyridinium molecule, thus leading to chain propagation. For example, thioxanthone-sensitized reactions of 4-cyano-N-methoxypyridinium, P1, with several aliphatic and benzyl alcohols gave quantum yields for products formation (an aldehyde or a ketone and protonated 4-cyanopyridinium) of ～15-20, at reactant concentrations of ～0.02-0.04 M. The reaction can also be sensitized with triplet benzopheone, which in this case acts as an electron donor. Energetic limitations on chain propagation are imposed by the relationship between the oxidation potential of the α-hydroxy radical and the reduction potential of the pyridinium salt. The chain reactions proceed despite ～0.25 eV endothermicity for the electron-transfer step. Chain reactions with the harder-to-reduce 4-phenyl-N-methoxypyridinium, however, are limited in scope because of increased endothermicity for electron transfer. The thioxanthone-sensitized reaction of P1 with benzhydrol was studied in detail by a combination of steady state and transient kinetics. The bimolecular rate constants for the chain propagation reactions:hydrogen atom abstraction by the methoxy radical and electron transfer from the diphenylketyl radical to P1 are ～6 × 106 and 1.1 × 106 M-1 s-1, respectively. The kinetic data indicate that deuterium atom abstraction by the methoxy radical from the solvent, acetonitrile-d3, is a dominant chain-terminating process. Because of a large deuterium isotope effect, ～7, the quantum amplification is strongly suppressed when the reaction is carried out in acetonitrile.
- Shukla, Deepak,Ahearn, Wendy G.,Farid, Samir
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p. 6809 - 6819
(2007/10/03)
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- Neutral, metal-free hydration of alkynes using microwave irradiation in superheated water
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A novel methodology for the hydration of alkynes in superheated water using microwave irradiation is reported. Extension of this methodology to hydroamination of alkynes is also described.
- Vasudevan, Anil,Verzal, Mary K.
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p. 631 - 634
(2007/10/03)
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- Antimony(V) chloride-benzyltriethylammonium chloride complex as an efficient catalyst for friedel-crafts acylation reactions
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A novel catalytic system, the complex of antimony(V) chloride (SbCl 5) and benzyltriethylammonium chloride (TEBA), C6H 5CH2NEt3(SbCl5)2Cl complex, is described for Friedel-Crafts acylation reactions of aromatics with acyl and sulfonyl chlorides. The catalyst has a number of useful characteristics, such as ready access, minimal toxicity, reusability, insensitivity to atmosphere and moisture, rapid acylation with high yield, and ease of operation.
- Huang, An-Ping,Liu, Xue-Yuan,Li, Lian-Hua,Wu, Xiao-Li,Liu, Wei-Min,Liang, Yong-Min
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p. 599 - 602
(2007/10/03)
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- 2-Hydroxymethyl-4-[5-(4-methoxyphenyl)-3-trifluoromethyl-1H-1-pyrazolyl] -1-benzenesulfonamide (DRF-4367): An orally active COX-2 inhibitor identified through pharmacophoric modulation
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Analogs of 1,5-diarylpyrazoles with a novel pharmacophore at N1 were designed, synthesized and evaluated for the in-vitro cyclooxygenase (COX-1/COX-2) inhibitory activity. The variations at/around position-4 of the C-5 phenyl ring in conjunction with a CF3 and CHF2 groups at C-3 exhibited a high degree of potency and selectivity index (SI) for COX-2 inhibition. The in-vivo evaluation of these potent compounds with a few earlier ones indicated the 4-OMe-phenyl analog 6 and the 4-NHMe-phenyl analog 9 with a CF3, and the 4-OEt-phenyl analog 19 with a CHF2 group at C-3 to possess superior potency than celecoxib. In addition to its impressive anti-inflammatory, antipyretic, analgesic and anti-arthritic properties, compound 6 (DRF-4367) was found to possess an excellent pharmacokinetic profile, gastrointestinal (GI) safety in the long-term arthritis study and COX-2 potency in human whole blood assay. Thus, compound 6 was selected as an orally active anti-inflammatory candidate for pre-clinical evaluation.
- Singh, Sunil Kumar,Vobbalareddy, Saibaba,Kalleda, Srinivasa Rao,Rajjak, Shaikh Abdul,Casturi, Seshagiri Rao,Datla, Srinivasa Raju,Mamidi, Rao N.V.S.,Mullangi, Ramesh,Bhamidipati, Ravikanth,Ramanujam, Rajagopalan,Akella, Venkateswarlu,Yeleswarapu, Koteswar Rao
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p. 2442 - 2450
(2007/10/03)
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- Deoximation of oximes with 2-iodylbenzoic acid in water in the presence of β-cyclodextrin
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Oximes of various aldehydes and ketones can be converted to the corresponding carbonyl compounds at room temperature in impressive yields with 2-iodylbenzoic acid in water in the presence of β-cyclodextrin.
- Krishnaveni, N. Srilakshmi,Surendra,Nageswar,Rao, K. Rama
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p. 1968 - 1970
(2007/10/03)
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- Catalytic Friedel-Crafts acylation of alkoxybenzenes mediated by aluminum hydrogensulfate in solution and solvent-free conditions
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Friedel-Crafts acylation of alkoxybenzenes was achieved efficiently by a reaction with aliphatic acid anhydrides in the presence of catalytic amounts of aluminum hydrogensulfate, Al(HSO4)3, in nitromethane and under solvent-free conditions. Alkylbenzenes and aryl halides, as well as aromatic anhydrides, remained intact under these conditions.
- Salehi, Peyman,Khodaei, Mohammad Mehdi,Zolfigol, Mohammad Ali,Sirouszadeh, Sara
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p. 1863 - 1864
(2007/10/03)
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- Catalytic Friedel-Crafts acylation of alkoxy benzenes by ferric hydrogensulfate
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Friedel-Crafts acylation of alkoxy benzenes is achieved efficiently by reaction with aliphatic acid anhydrides in the presence of catalytic amounts of ferric hydrogensulfate, Fe(HSO4)3, in nitromethane. Alkyl benzenes and aryl halides, as well as aromatic anhydrides, remain intact under these conditions.
- Salehi, Peyman,Khodaei, Mohammad Mahdi,Zolfigol, Mohammad Ali,Zeinoldini, Shahpour
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p. 1367 - 1373
(2007/10/03)
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- PHOTOLABILE p-METHOXYPHENACYLOXYCARBONYL GROUP FOR THE PROTECTION OF AMINES
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P-Methoxyphenacyloxycarbonyl (Phenoc) is a new photolabile protective group for amines.Various phenacyl urethanes, i.e.Phenoc protected amines, have been prepared.An application of the group in peptide synthesis is reported.
- Church, George,Ferland, Jean-Marie,Gauthier, Jean
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p. 1901 - 1904
(2007/10/02)
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- CONJUGATE REACTION OF ACETYL CHLORIDE WITH CYCLOHEXENE AND PHENETOLE IN THE PRESENCE OF ALUMINUM CHLORIDE
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In the conjugate reaction of acetyl chloride with cyclohexane and phenetole in the presence of aluminum chloride ketoalkylation of the phenetole occurs with the formation of 2- and 4-(p-ethoxyphenyl)hexahydroacetophenones.In addition, the reaction mixture contained p-cyclohexylphenetole and p-ethoxyacetophenone.
- Alisova, E. V.,Kovalev, V. A.,Pisanenko, D. A.
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p. 970 - 973
(2007/10/02)
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