- Synthesis and biological evaluations of 1,2-diaryl pyrroles as analogues of combretastatin A-4
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A series of novel 1,2-diaryl pyrroles as analogues of combretastatin A-4 (CA-4, 1a) were synthesized and evaluated for their antitumour potential against three cancer cell lines. Most compounds exhibited growth inhibition against all of the cancer cell lines. Compound 7q not only exhibited prominent antitumour efficacy with IC50 values of 0.390 μm in SGC-7901, 0.070 μm in HT-1080 and 0.045 μm in KB cell lines but also showed low activity with IC50 values of 30.08 μm in normal L929 cell line. Moreover, compound 7q inhibited tubulin polymerization into microtubules and caused microtubule destabilization. A molecular docking study of 7q was performed to determine its binding mode at the colchicine site in the tubulin dimer. 1,2-Diaryl pyrroles as combretastatin A-4 analogues were synthesized and evaluated for anti-proliferative activities. Compound 7q exhibited antitubulin activity.
- Sun, Jun,Chen, Lei,Liu, Chunjiang,Wang, Zhan,Zuo, Daiying,Pan, Jiatong,Qi, Huan,Bao, Kai,Wu, Yingliang,Zhang, Weige
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- Synthesis and antimitotic activity of novel 5-aminoisoxazoles bearing alkoxyaryl moieties
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5-Aminoisoxazoles containing trimethoxy- and methylenedioxyphenyl moieties were prepared by heterocyclization of electrophilic alkenes with tetranitromethane in the presence of triethylamine with subsequent reduction of resulting 5-nitroisoxazoles. The cr
- Vasilenko, Dmitry A.,Averina, Elena B.,Zefirov, Nikolay A.,Wobith, Birgit,Grishin, Yuri K.,Rybakov, Victor B.,Zefirova, Olga N.,Kuznetsova, Tamara S.,Kuznetsov, Sergei A.,Zefirov, Nikolay S.
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- Iron-catalyzed domino decarboxylation-oxidation of α,β-unsaturated carboxylic acids enabled aldehyde C-H methylation
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A practical and general iron-catalyzed domino decarboxylation-oxidation of α,β-unsaturated carboxylic acids enabling aldehyde C-H methylation for the synthesis of methyl ketones has been developed. This mild, operationally simple method uses ambient air as the sole oxidant and tolerates sensitive functional groups for the late-stage functionalization of complex natural-product-derived and polyfunctionalized molecules.
- Gong, Pei-Xue,Xu, Fangning,Cheng, Lu,Gong, Xu,Zhang, Jie,Gu, Wei-Jin,Han, Wei
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supporting information
p. 5905 - 5908
(2021/06/18)
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- Electro-reductive Fragmentation of Oxidized Lignin Models
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Lignin provides a potential sustainable source for production of electron-rich aromatic compounds. Recently, electrochemical lignin degradation via an oxidation/reduction sequence under mild conditions has garnered much attention within the lignin community, as electrochemistry simplifies redox reactions and offers an electron source/sink for synthesis without using stoichiometric oxidants or reductants. This paper describes a fundamental approach for the electrochemical fragmentation of the primary connection in native lignin, β-O-4. Potential-controlled electrolysis enables selective reduction and provides fragmentation products and/or coupling products in isolated yields of 59-92%.
- Yang, Cheng,Magallanes, Gabriel,Maldonado, Stephen,Stephenson, Corey R. J.
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p. 15927 - 15934
(2021/06/30)
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- Mild Deprotection of Dithioacetals by TMSCl/NaI Association in CH3CN
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A mild process using a combination of TMSCl and NaI in acetonitrile is used to regenerate carbonyl compounds from a variety of dithiane and dithiolane derivatives. This easy to handle and inexpensive protocol is also efficient to deprotect oxygenated and mixed acetals as 1,3-dioxanes, 1,3-dioxolanes and 1,3-oxathianes quantitatively. As a possible extension of this method, it was also shown that nitrogenated substrates such as hydrazones, N-tosylhydrazones, and ketimines reacted well under these conditions to give the expected ketones in high yields. The methodology proposed herein is a good alternative to the existing methods since it does not use metals, oxidants, reducing agents, acidic or basic media, and keto-products were obtained in high to excellent yields.
- Yao, Yunxin,Zhao, Guangkuan,Hamze, Abdallah,Alami, Mouad,Provot, Olivier
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p. 5775 - 5779
(2020/08/17)
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- Sequential Cleavage of Lignin Systems by Nitrogen Monoxide and Hydrazine
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The cleavage of representative lignin systems has been achieved in a metal-free two-step sequence first employing nitrogen monoxide for oxidation followed by hydrazine for reductive C?O bond scission. In combining nitrogen monoxide and lignin, the newly developed valorization strategy shows the particular feature of starting from two waste materials, and it further exploits the attractive conditions of a Wolff-Kishner reduction for C?O bond cleavage for the first time. (Figure presented.).
- Altmann, Lisa-Marie,Heinrich, Markus R.,Hofmann, Dagmar,Hofmann, Laura Elena,Prusko, Lea
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- Visible light induced redox neutral fragmentation of 1,2-diol derivatives
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A homogeneous, redox-neutral photo fragmentation of diol derivatives was developed. Under photo/hydrogen atom transfer (HAT) dual catalysis, diol derivatives such as lignin model compounds and diol monoesters undergo selective β C(sp3)-O bond cleavage to afford ketones, phenols and acids effectively.
- Chen, Kang,Schwarz, Johanna,Karl, Tobias A.,Chatterjee, Anamitra,K?nig, Burkhard
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p. 13144 - 13147
(2019/11/11)
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- Aerobic oxidation of alcohols with air catalyzed by decacarbonyldimanganese
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The oxidation of alcohols to carbonyl compounds using air as the terminal oxidant is highly desirable. As described in previous reports, the abstraction of α-H of the alcohol is the most important step, and it typically requires not only a metal catalyst but also complex ligands, co-catalysts and bases. Herein, we report a practical and efficient method for the oxidation of primary alcohols, secondary alcohols, 1,2-diols, 1,2-amino alcohols, and other α-functionalized alcohols using a commercially available catalyst, Mn2(CO)10, and no additives. Preliminary mechanistic studies indicated that an alkoxyl radical intermediate existed in our system, and a plausible mechanism consistent with the experimental results and literature was proposed.
- Meng, Shan-Shui,Lin, Li-Rong,Luo, Xiang,Lv, Hao-Jun,Zhao, Jun-Ling,Chan, Albert S. C.
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supporting information
p. 6187 - 6193
(2019/11/20)
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- Fine Tuning the Redox Potentials of Carbazolic Porous Organic Frameworks for Visible-Light Photoredox Catalytic Degradation of Lignin β-O-4 Models
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We report a facile approach to fine tune the redox potentials of π-conjugated porous organic frameworks (POFs) by copolymerizing carbazolic electron donor (D) and electron acceptor (A) based comonomers at different ratios. The resulting carbazolic copolymers (CzCPs) exhibit a wide range of redox potentials that are comparable to common transition-metal complexes and are used in the stepwise photocatalytic degradation of lignin β-O-4 models. With the strongest oxidative capability, CzCP100 (D:A = 0:100) exhibits the highest efficiency for the oxidation of benzylic β-O-4 alcohols, while the highly reductive CzCP33 (D:A = 66:33) gives the highest yield for the reductive cleavage of β-O-4 ketones. CzCPs also exhibit excellent stability and recyclability and represent a class of promising heterogeneous photocatalysts for the production of fine chemicals from sustainable lignocellulosic biomass.
- Luo, Jian,Zhang, Xiang,Lu, Jingzhi,Zhang, Jian
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p. 5062 - 5070
(2017/08/17)
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- Selective arylthiolane deprotection by singlet oxygen: A promising tool for sensors and prodrugs
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A routine thioketal protecting group reacts rapidly and selectively with singlet oxygen to reveal ketone products in good (aryl 1,3-dithiolane) to excellent (aryl 1,3-oxathiolane) yields. Arylthiolanes are stable to biologically relevant reactive oxygen species and can be used as a light-activated gating mechanism for activating fluorescent sensors or small molecule prodrugs.
- Lamb, Brian M.,Barbas, Carlos F.
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supporting information
p. 3196 - 3199
(2015/05/27)
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- Synthesis and biological evaluation of 3-alkyl-1,5-diaryl-1H-pyrazoles as rigid analogues of combretastatin A-4 with potent antiproliferative activity
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A series of novel 3-alkyl-1,5-diaryl-1H-pyrazoles were synthesized as combretastatin A-4 (CA-4) analogues and evaluated for antiproliferative activity against three human cancer cell lines (SGC-7901, A549 and HT-1080). Most of the target compounds displayed moderate to potent antiproliferative activity, and 7k was found to be the most potent compound. Structure-activity relationships indicated that compounds with a trimethoxyphenyl A-ring at the N-1 position of the pyrazole skeleton were more potent than those with the A-ring at the C-5 position. Tubulin polymerization and immunostaining experiments revealed that 7k potently inhibited tubulin polymerization and disrupted tubulin microtubule dynamics in a manner similar to CA-4. Computational modelling demonstrated that the binding of 7k to the colchicine binding site on microtubules may involve a similar mode as CA-4.
- Xu, Qile,Qi, Huan,Sun, Maolin,Zuo, Daiying,Jiang, Xuewei,Wen, Zhiyong,Wang, Zhiwei,Wu, Yingliang,Zhang, Weige
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- N-Functionalized Amino Acids Promoted Aerobic Copper-Catalyzed Oxidation of Benzylic Alcohols in Water
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Instead of traditional N,N-bidentate ligands, N-functionlized amino acids were used as powerful N,O-bidentate ligands in aerobic copper/TEMPO-catalyzed system for promoting oxidation of benzylic alcohols. Under the optimized reaction conditions, a wide range of primary and secondary benzylic alcohols have been efficiently converted into aldehydes and ketones with good to excellent yields in water.
- Zhang, Guofu,Lei, Jie,Han, Xingwang,Luan, Yuxin,Ding, Chengrong,Shan, Shang
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p. 779 - 784
(2015/03/30)
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- Regioselective aerobic oxidative Heck reactions with electronically unbiased alkenes: Efficient access to α-alkyl vinylarenes
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Branched-selective oxidative Heck coupling reactions have been developed between arylboronic acids and electronically unbiased terminal alkenes. The reactions exhibit high catalyst-controlled regioselectivity favoring the less common branched isomer. The reactions employ a catalyst composed of Pd(TFA)2/dmphen (TFA = trifluoroacetate, dmphen = 2,9-dimethyl-1,10-phenanthroline) and proceed efficiently at 45-60 °C under 1 atm of O2 without requiring other additives. A broad array of functional groups, including aryl halide, allyl silane and carboxylic acids are tolerated.
- Zheng, Changwu,Stahl, Shannon S.
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supporting information
p. 12771 - 12774
(2015/08/18)
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- Peculiarities of the cascade cleavage of the polarized C - C-fragment in α-ketoacetylenes on reaction with ethylene diamine
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The reaction of diarylketoacetylenes with ethylenediamine (EDA) leads to arylmethylketones and 2-substituted imidazoline derivatives. This transformation involves complete cleavage of the triple bond via initial intermolecular Michael-addition with subsequent intramolecular Michaeladdition. Final fragmentation can be presented as a retro-Mannich reaction, accompanied by three formal reductive stages (formation of three C-H bonds), while the other carbon undergoes a formal oxidation, in which three C-N bonds (C-N and C=N) are formed. ARKAT-USA, Inc.
- Vasilevsky, Sergei F.,Davydova, Maria P.,Tomilin, Denis N.,Sobenina, Lyubov N.,Mamatuyk, Victor I.,Pleshkova, Nadezhda V.
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p. 132 - 144
(2014/08/18)
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- Hydration of aromatic terminal alkynes catalyzed by iron(III) sulfate hydrate under chlorine-free conditions
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The hydration of aromatic terminal alkynes performed in acetic acid in the presence of catalytic hydrate ironIII sulfate, Fe2(SO 4)3·nH2O (4-9 mol %), yields the derived aryl methyl ketones with good to excellent yields. Under comparable conditions (18 mol %, 95 C, 24 h), bifunctional substrates were transformed into the monoacetyl or the diacetyl derivatives, depending on the structure of the aromatic diyne. The reaction is compatible with aryl substituents of different nature and ring positions, including hydroxyl, carbonyl groups, and cumulated hydrocarbons. The soft character of the non nucleophilic sulfate anion allows for activation of the triple bond toward carbonoxygen bond formation in the Br?nsted acidic medium. The proposed protocol is based on readily available and non toxic materials, in the absence of chlorine atoms in either the solvent or the metal catalyst.
- Bassetti, Mauro,Ciceri, Samuele,Lancia, Federico,Pasquini, Chiara
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supporting information
p. 1608 - 1612
(2014/03/21)
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- Simple, copper(I)-catalyzed oxidation of benzylic/allylic alcohols to carbonyl compounds: Synthesis of functionalized cinnamates in one pot
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An environmentally benign [Cu(I)]-catalyzed oxidation of activated (benzylic/allylic) alcohols to the corresponding carbonyl compounds is presented. Interestingly, the reaction was also compatible with benzylic alcohols containing ortho-bromo substituents on the aromatic ring without competing with the expected intermolecular Buchwald coupling. Significantly, the catalytic system enables the synthesis of cinnamate-esters in a sequential domino one-pot fashion via oxidation followed by Wittig-Horner protocol. Copyright
- Reddy, Alavala Gopi Krishna,Mahendar, Lodi,Satyanarayana, Gedu
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supporting information
p. 2076 - 2087
(2014/07/07)
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- A continuous flow solution to achieving efficient aerobic anti-Markovnikov Wacker oxidation
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An aerobic anti-Markovnikov Wacker oxidation for the flow-synthesis of arylacetaldehydes is reported. In the process, flow chemistry techniques have provided a means to control and minimise the over-oxidation of sensitive products. The reaction showed general applicability to various functionalised styrenes and provided a process capable of a multi-gram scale. Copyright
- Bourne,Ley
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supporting information
p. 1905 - 1910
(2013/08/23)
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- Highly selective Wacker reaction of styrene derivatives: A green and efficient aerobic oxidative process promoted by benzoquinone/NaNO 2/HClO4 under mild conditions
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A green and efficient catalytic redox system for the aerobic oxidative Wacker oxidation of styrene derivatives at room temperature using molecular oxygen as the terminal oxidant without copper chloride has been developed. The newly developed system exhibited excellent catalytic activity for the smooth transformation of terminal styrene derivatives to the desired methyl ketones with up to 96% yield and >99% selectivity. The Royal Society of Chemistry 2013.
- Zhang, Guofu,Xie, Xiaoqiang,Wang, Yong,Wen, Xin,Zhao, Yun,Ding, Chengrong
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supporting information
p. 2947 - 2950
(2013/07/25)
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- L-Proline: An efficient N,O-bidentate ligand for copper-catalyzed aerobic oxidation of primary and secondary benzylic alcohols at room temperature
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A novel and highly practical copper-catalyzed aerobic alcohol oxidation system with l-proline as the ligand at room temperature has been developed. A wide range of primary and secondary benzylic alcohols tested have been smoothly transformed into corresponding aldehydes and ketones with high yields and selectivities.
- Zhang, Guofu,Han, Xingwang,Luan, Yuxin,Wang, Yong,Wen, Xin,Ding, Chengrong
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supporting information
p. 7908 - 7910
(2013/09/02)
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- Synthesis and anticancer activity of 2-benzylidene indanones through inhibiting tubulin polymerization
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In an attempt to discover a potent and selective anticancer agent, gallic acid has been modified to benzylidene indanones as tubulin polymerization inhibitors. These compounds were evaluated against several human cancer cell lines and also evaluated for inhibition of tubulin polymerase in in vitro assays. Three of the analogues exhibited strong cytotoxicity against human cancer cell lines IC50 = 10-880 nM and also showed tubulin polymerization inhibition (IC50 = 0.62-2.04 μM). Compound 9j, the best candidate of the series was found to be non-toxic in acute oral toxicity in Swiss-albino mice up to 1000 mg/kg dose.
- Prakasham,Saxena,Luqman, Suaib,Chanda, Debabrata,Kaur, Tandeep,Gupta, Atul,Yadav,Chanotiya,Shanker, Karuna,Khan,Negi, Arvind S.
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p. 3049 - 3057
(2012/07/03)
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- Dissecting alkynes: Full cleavage of polarized C≡C moiety via sequential bis-michael addition/retro-mannich cascade
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The reaction of diaryl ketoalkynes with 1,2-diamino ethane leads to the full scission of the triple bond with the formation of acetophenone and imidazoline fragments. In this transformation, one of the alkyne carbons undergoes formal reduction with the formation of three C-H bonds, whereas the other carbon undergoes formal oxidation via the formation of three C-N bonds (one π and two σ). Computational analysis confirmed that the key fragmentation step proceeds via a six-membered TS in a concerted manner. Both amines are involved in the fragmentation: the N-H moiety of one amine transfers a proton to the developing negative charge at the enolate oxygen, while the other amine provides direct stereoelectronic assistance to the C-C bond cleavage via a hyperconjugative nN → σ*C-C interaction.
- Roy, Saumya,Davydova, Maria P.,Pal, Runa,Gilmore, Kerry,Tolstikov, Genrikh A.,Vasilevsky, Sergei F.,Alabugin, Igor V.
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experimental part
p. 7482 - 7490
(2011/11/30)
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- New transformation of α-acetylenic ketones under the action of 1,2-diaminoethane
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A reaction of 3-aryl-1-(3,4,5-trimethoxyphenyl)prop-2-yn-1-ones with 1,2-diaminoethane in boiling dioxane leads to 2-aryl-4,5-dihydro-1H-imidazoles and 1-(3,4,5-trimethoxy-phenyl)ethanone.
- Davydova,Vasilevskii,Tolstikov
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experimental part
p. 188 - 190
(2011/08/21)
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- Efficient synthesis of alkyl aryl ketones & ketals via palladium-catalyzed regioselective arylation of vinyl ethers
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The combination of Pd(OAc)2 with 1,3-bis(diphenylphosphino) propane (dppp) in ethylene glycol constitutes a high-performance catalytic system for highly regioselective arylation of a range of electron-rich vinyl ethers by aryl bromides to provide, upon hydrolysis, alkyl aryl ketones and cyclic ketals in good yields with up to 3.75 × 105 TON and 15625 h-1 TOF.
- Liu, Mingcui,Hyder, Zeynab,Sun, Yawei,Tang, Weijun,Xu, Lijin,Xiao, Jianliang
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supporting information; experimental part
p. 2012 - 2015
(2010/07/04)
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- Cobalt-catalyzed oxidative kinetic resolution of secondary benzylic alcohols with molecular oxygen
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The oxidative kinetic resolution of secondary alcohols using molecular oxygen and olefins was catalyzed by the optically active ketoiminatocobalt(II) complexes. The various secondary benzylic alcohols were subjected to the aerobic oxidative reaction to afford optically active alcohols of high ee along with the corresponding ketones in high yield. The oxidation of the deuterated alcohols revealed that the accompanying olefin mediated the oxidation for conversion to the corresponding α-deuterated ketones. Copyright
- Yamada, Tohru,Higano, Sho,Yano, Takanori,Yamashita, Yoshihiro
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supporting information; experimental part
p. 40 - 41
(2009/12/03)
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- Application of the McMurry coupling reaction in the synthesis of tri- and tetra-arylethylene analogues as potential cancer chemotherapeutic agents
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Structural redesign of selected non-steroidal estrogen receptor binding compounds has previously been successful in the discovery of new inhibitors of tubulin assembly. Accordingly, tetra-substituted alkene analogues (21-30) were designed based in part on combinations of the structural and electronic components of tamoxifen and combretastatin A-4 (CA4). The McMurry coupling reaction was used as the key synthetic step in the preparation of these tri- and tetra-arylethylene analogues. The structural assignment of E, Z isomers was determined on the basis of 2D-NOESY experiments. The ability of these compounds to inhibit tubulin polymerization and cell growth in selected human cancer cell lines was evaluated. Although the compounds were found to be less potent than CA4, these analogues significantly advance the known structure-activity relationship associated with the colchicine binding site on β-tubulin.
- Tanpure, Rajendra P.,Harkrider, Amanda R.,Strecker, Tracy E.,Hamel, Ernest,Trawick, Mary Lynn,Pinney, Kevin G.
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experimental part
p. 6993 - 7001
(2009/12/24)
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- Gallic acid-based indanone derivatives as anticancer agents
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Gallic acid-based indanone derivatives have been synthesised. Some of the indanones showed very good anticancer activity in MTT assay. Compounds 10, 11, 12 and 14 possessed potent anticancer activity against various human cancer cell lines. The most potent indanone (10, IC50 = 2.2 μM), against MCF-7, that is, hormone-dependent breast cancer cell line, showed no toxicity to human erythrocytes even at higher concentrations (100 μg/ml, 258 μM). While, indanones 11, 12 and 14 showed toxicities to erythrocytes at higher concentrations.
- Saxena, Hari Om,Faridi, Uzma,Srivastava, Suchita,Kumar,Darokar,Luqman, Suaib,Chanotiya,Krishna, Vinay,Negi, Arvind S.,Khanuja
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scheme or table
p. 3914 - 3918
(2009/04/07)
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- CuCl catalyzed selective oxidation of primary alcohols to carboxylic acids with tert-butyl hydroperoxide at room temperature
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Direct oxidation of primary alcohols to the corresponding carboxylic acids is performed highly efficiently at room temperature with anhydrous tert-butyl hydroperoxide in the presence of a catalytic amount of easily available CuCl under ligand free conditions in acetonitrile. Benzylic alcohols are more reactive than aliphatic alcohols, and these benzylic alcohols are selectively oxidized to the corresponding acids in the presence of aliphatic alcohols such as 1-octanol and 1-decanol.
- Mannam, Sreedevi,Sekar
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p. 2457 - 2460
(2008/09/20)
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- Reaction of chalcones with basic hydrogen peroxide: A structure and reactivity study
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Chalcone epoxides are important intermediates for the synthesis of 3,5-diarylpyrazoles. Twenty different chalcones were oxidized with hydrogen peroxide and potassium carbonate in order to produce the corresponding epoxides. The electronic nature of the substituents on the A- and B-ring of the chalcones significantly affected the reaction outcome: (i) electron donating groups on the A-and B-ring aided the reversion of the chalcones to the corresponding benzaldehydes, (ii) electron withdrawing groups on the B-ring promoted formation of the desired chalcone-epoxides in high chemical yields, and (iii) the presence of electron withdrawing groups (A-ring of the chalcones), regardless of the substituents on the B-ring, produced a mixture of epoxide, unreacted chalcone, benzaldehyde and acetophenone.
- Holt Jr., Herman,LeBlanc, Regan,Dickson, John,Brown, Toni,Maddox, Jessica R.,Lee, Moses
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p. 465 - 470
(2007/10/03)
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- PHARMACEUTICAL FORMULATIONS USEFUL TO TREAT INFLAMMATORY AND IMMUNE DISORDERS
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A pharmaceutical formulation is provided for the treatment of inflammatory and/or immune disorders, particularly those mediated by platelet activating factor (“PAF”) or a product of 5-lipoxygenase. The formulation, in one embodiment, is an essentially anhydrous ointment containing an active agent selected from the group consisting of 2,5-diaryl tetrahydrofurans, 2,5-diaryl tetrahydrothiophenes, 2,4-diaryl tetrahydrofurans, 2,4-diaryl tetrahydrothiophenes, 1,3-diaryl cyclopentanes, 2,4-diaryl pyrrolidines, and 2,5-diaryl pyrrolidines, and an enhancer composition containing one or more C3-18 esters such as diethyl succinate, propylene carbonate, diisopropyl adipate and glyceryl triacetate. In another embodiment, the formulation is a cream, gel, lotion, oil, or the like, containing the: active agent in crystalline form. The invention also encompasses the novel crystalline form of the active agent, and methods for using the formulations to treat individuals with inflammatory and/or immune disorders. Also encompassed is use of isopropyl alcohol (IPA) to enhance stability of the active agent and pharmaceutical formulations.
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- On the radical Brook rearrangement. Reactivity of α-silyl alcohols, α- silyl alcohol nitrite esters, and β-haloacylsilanes under radical-forming conditions
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Two alkoxyl radical generation methods, lead tetraacetate treatment of alcohols and photolysis of nitrites, were applied to α-silyl alcohols 21 and to the corresponding nitrites 25 with a view to forming α-silyl alkoxyl radicals 23 and studying their possible radical Brook rearrangement to α- silyloxy carbon radicals 24. LTA treatment of 21 led to their quick and efficient conversion into mixed acetyl-silyl acetals 33 under very mild conditions. Photolysis of α-alkylmonosubstituted α-silyl nitrites 25 to the corresponding aldehydes is considered to proceed through α-silyl alkoxyl radical intermediates 23. A concerted process is, however, proposed for the case of the benzyl nitrites analogues. On the basis of these results, it is postulated that resonance stabilization can have a major influence on the evolution of α-silyl alkoxyl radicals: should this stabilization be possible, they quickly evolve by α-silyl fragmentation; otherwise, they tend to undergo radical Brook rearrangement. It was also found that the radical Brook rearrangement of α-silyl cyclopropyloxyl radicals generated from β- bromoacylsilanes under standard tin-radical conditions is too slow to compete with β-fragmentation.
- Paredes,Alonso
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p. 2292 - 2304
(2007/10/03)
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- Propenone derivatives
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The present invention relates to propenone derivatives represented by the following formula (I): STR1 wherein R1 represents hydrogen, substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl, or YR5 (wherein Y represents S or O; and R5 represents substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, or a substituted or unsubstituted cyclic ether residue); R2 and R3 independently represent hydrogen, lower alkyl, or substituted or unsubstituted aralkyl, or alternatively R2 and R3 are combined to form substituted or unsubstituted methylene or ethylene; R4 represents hydrogen, hydroxy, lower alkyl, substituted or unsubstituted aralkyl, lower alkoxy, substituted or unsubstituted aralkyloxy, or halogen; and X represents substituted or unsubstituted indolyl; or pharmaceutically acceptable salts thereof.
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