- Study on the design, synthesis and structure-activity relationships of new thiosemicarbazone compounds as tyrosinase inhibitors
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52 Structure-based thiosemicarbazone compounds bearing various substituted-lipophilic part, including substituted-benzaldehyde, substituted-phenylalkan-1-one and their biphenyl-type thiosemicarbazone analogs, were designed, synthesized and evaluated as new tyrosinase inhibitors. The results demonstrated that 22 compounds have potent inhibitory activities against tyrosinase with the IC50 value of lower than 1.0 μM. On the basis of the obtained experimental data, the structure-activity relationships (SARs) were rationally derived. Besides, the inhibition mechanism and the inhibitory kinetics of selected compounds 3d and 6e were investigated, revealing that such type of compounds were belonged to the reversible and competitive tyrosinase inhibitors. To verify the safety of these developed thiosemicarbazone compounds, four randomly selected compounds 3d, 4e, 6a and 9a were also tested in 293T cell line for the evaluation of the cytotoxicity. Interestingly, all these compounds almost did not perform any toxicity to 293T cells even at a high concentration of 1000 μmol/L. Taken together, these results suggested that such compounds could serve as the highly efficient and more safe candidates for the treatment of tyrosinase-related disorders.
- Song, Senchuan,You, Ao,Chen, Zhiyong,Zhu, Guoxun,Wen, Huan,Song, Huacan,Yi, Wei
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Read Online
- Alkyl-GeMe3: Neutral Metalloid Radical Precursors upon Visible-Light Photocatalysis
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Single-electron transfer (SET) oxidation of ionic hypervalent complexes, in particular alkyltrifluoroborates (Alkyl-BF3?) and alkylbis(catecholato)silicates (Alkyl-Si(cat)2?), have contributed substantially to alkyl radical generation compared to alkali or alkaline earth organometallics because of their excellent activity–stability balance. Herein, another proposal is reported by using neutral metalloid compounds, Alkyl-GeMe3, as radical precursors. Alkyl-GeMe3 shows comparable activity to that of Alkyl-BF3? and Alkyl-Si(cat)2? in radical addition reactions. Moreover, Alkyl-GeMe3 is the first successful group 14 tetraalkyl nucleophile in nickel-catalyzed cross-coupling. Meanwhile, the neutral nature of these organogermanes offset the limitation of ionic precursors in purification and derivatization. A preliminary mechanism study suggests that an alkyl radical is generated from a tetraalkylgermane radical cation with the assistance of a nucleophile, which may also result in the development of more non-ionic alkyl radical precursors with a metalloid center.
- Wei, Li-Pu,Xiao, Bin,Xu, Qing-Hao
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supporting information
(2022/02/17)
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- Dealkenylative Ni-Catalyzed Cross-Coupling Enabled by Tetrazine and Photoexcitation
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A new and general method to functionalize the C(sp3)-C(sp2) bond of alkyl and alkene linkages has been developed, leading to the dealkenylative generation of carbon-centered radicals that can be intercepted to undergo Ni-catalyzed C(sp3)-C(sp2) cross-coupling. This one-pot protocol leverages the easily procured alkene feedstocks for organic synthesis with excellent functional group compatibility without the need for a photoredox catalyst.
- Cao, Yuhui,Che, Jinteng,Chen, Han,Chen, Si-Cong,Fang, Xianhe,Guo, Yinliang,Guo, Zhixian,Kong, Lingran,Li, Chen,Lu, Jia-Tian,Luo, Tuoping,Zhang, Nan,Zhu, Qi
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p. 14046 - 14052
(2021/09/13)
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- Micelle enabled C(sp2)-C(sp3) cross-electrophile coupling in waterviasynergistic nickel and copper catalysis
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A robust and sustainable C(sp2)-C(sp3) cross-electrophile coupling was developedvianickel/copper synergistic catalysis under micellar conditions. This protocol provided a general method to access alkylated arenes with good to excellent yields on a very large scale.
- Ye, Ning,Wu, Bin,Zhao, Kangming,Ge, Xiaobin,Zheng, Yu,Shen, Xiaodong,Shi, Lei,Cortes-Clerget, Margery,Regnier, Morgan Louis,Parmentier, Michael,Gallou, Fabrice
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supporting information
p. 7629 - 7632
(2021/08/09)
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- Nickel-Catalyzed, para-Selective, Radical-Based Alkylation of Aromatic Ketones
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A direct, para-selective, radical-based alkylation of aromatic ketones with alkanes has been developed using a nickel catalyst with oxamide as the ligand. Acetophenones bearing electron-withdrawing substituents were functionalized directly with simple alkanes with high para-selectivity while acetophenones with electron-donating groups were mainly para-functionalized. A mechanistic study indicated that C-H bond activation of the aromatic ring may be the rate-determining step of the reaction.
- Wang, Jie,Pang, Yu-Bo,Tao, Na,Zeng, Runsheng,Zhao, Yingsheng
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supporting information
p. 854 - 857
(2020/01/31)
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- Preparation method of siponimod intermediate
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The invention relates to a preparation method of a siponimod intermediate, belonging to the field of medicinal chemistry. The preparation method comprises the following steps: with cyclohexylbenzene as a starting material, carrying out reactions such as Friedel-Crafts acylation, bromination, oxidation, esterification, trifluoromethylation and hydrolysis to obtain 4-cyclohexyl-3-trifluoromethyl benzoic acid. Such a technical scheme provided by the invention is simple and convenient to operate, easy to implement, mild in reaction conditions, high in yield, high in purity, low in cost and suitable for industrial production.
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Paragraph 0053-0055
(2020/11/01)
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- A Practical Method for Continuous Production of sp3-Rich Compounds from (Hetero)Aryl Halides and Redox-Active Esters
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A practically useful coupling reaction between aromatic halides and redox-active esters was realized by nickel catalysis through the use of a packed zinc bed column in continuous flow. Multiple reuse of the column showed a negligible decrease in efficiency, affording high space/time yields. A wide range of substrates, including a number of heteroaryl halides and polyfunctional materials were coupled in generally good yields. Longer-time and larger-scale experiments further demonstrates the robustness of the system.
- Watanabe, Eiichi,Chen, Yiding,May, Oliver,Ley, Steven V.
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supporting information
p. 186 - 191
(2019/12/24)
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- Preparation of Alkyl Indium Reagents by Iodine-Catalyzed Direct Indium Insertion and Their Applications in Cross-Coupling Reactions
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An efficient method for the synthesis of alkyl indium reagent by means of an iodine-catalyzed direct indium insertion into alkyl iodide in THF is reported. The thus-generated alkyl indium reagents effectively underwent Pd-catalyzed cross-coupling reactions with various aryl halides, exhibiting good compatibility to a variety of sensitive functional groups. By replacing THF with DMA and using 0.75 equiv of iodine, less reactive alkyl bromide could be used as substrate for indium insertion with equal ease.
- Zhi, Man-Ling,Chen, Bing-Zhi,Deng, Wei,Chu, Xue-Qiang,Loh, Teck-Peng,Shen, Zhi-Liang
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p. 3017 - 3023
(2019/02/26)
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- Cesium carbonate-catalyzed indium insertion into alkyl iodides and their synthetic utilities in cross-coupling reactions
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A catalytic amount of cesium carbonate (10?mol%) was found to be capable of effectively catalyzing the insertion of indium powder into alkyl iodides. The thus-generated alkyl indium reagents could readily undergo palladium-catalyzed cross-coupling reactions with a wide variety of aryl halides, showing compatibility to a range of important functional groups.
- Feng, Xue-Xin,Wu, Zhen,Wang, Qing-Dong,Chen, Bing-Zhi,Rao, Weidong,Yang, Jin-Ming,Shen, Zhi-Liang
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- From alkylarenes to anilines via site-directed carbon–carbon amination
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Anilines are fundamental motifs in various chemical contexts, and are widely used in the industrial production of fine chemicals, polymers, agrochemicals and pharmaceuticals. A recent development for the synthesis of anilines uses the primary amination of C–H bonds in electron-rich arenes. However, there are limitations to this strategy: the amination of electron-deficient arenes remains a challenging task and the amination of electron-rich arenes has a limited control over regioselectivity—the formation of meta-aminated products is especially difficult. Here we report a site-directed C–C bond primary amination of simple and readily available alkylarenes or benzyl alcohols for the direct and efficient preparation of anilines. This chemistry involves a novel C–C bond transformation and offers a versatile protocol for the synthesis of substituted anilines. The use of O2 as an environmentally benign oxidant is demonstrated, and studies on model compounds suggest that this method may also be used for the depolymerization of lignin.
- Liu, Jianzhong,Qiu, Xu,Huang, Xiaoqiang,Luo, Xiao,Zhang, Cheng,Wei, Jialiang,Pan, Jun,Liang, Yujie,Zhu, Yuchao,Qin, Qixue,Song, Song,Jiao, Ning
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- Copper(II)-catalyzed preparation of alkylindium compounds and applications in cross-coupling reactions both in aqueous media
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An efficient water-based method for the synthesis of alkylindium compound in the presence of a catalytic amount of cheap and readily available CuSO4·5H2O (10 mol%) was developed. The thus-generated alkylindium compounds effectively underwent palladium-catalyzed cross-coupling reactions with a myriad of aryl halides in aqueous media, leading to the cross-coupled products in modest to high yields. The mildness of the formed alkyl organometallics allowed the tolerance to various important functional groups incorporated in both substrates of alkyl iodides and aryl halides.
- Wang, Peng,Chen, Bing-Zhi,Guo, Yi-Cong,Rao, Weidong,Shen, Zhi-Liang
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supporting information
(2019/11/11)
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- Cobalt(II)-catalyzed preparation of alkylindium reagents and applications in cross-coupling with aryl halides
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The direct insertion of indium powder into alkyl iodides was found to be efficiently catalyzed by a catalytic amount of cobalt(II) bromide (10 mol%). Upon subjection of the thus-formed alkylindium compounds to palladium-catalyzed cross-coupling reactions with a wide range of aryl halides, a series of cross-coupled products could be obtained in moderate to good yields with the tolerance to many important functional groups.
- Wang, Peng,Song, Xuan-Di,Chen, Bing-Zhi,Rao, Weidong,Shen, Zhi-Liang
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- Nickel-catalyzed C-N bond activation: Activated primary amines as alkylating reagents in reductive cross-coupling
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Nickel-catalyzed reductive cross coupling of activated primary amines with aryl halides under mild reaction conditions has been achieved for the first time. Due to the avoidance of stoichiometric organometallic reagents and external bases, the scope regarding both coupling partners is broad. Thus, a wide range of substrates, natural products and drugs with diverse functional groups are tolerated. Moreover, experimental mechanistic investigations and density functional theory (DFT) calculations in combination with wavefunction analysis have been performed to understand the catalytic cycle in more detail.
- Yue, Huifeng,Zhu, Chen,Shen, Li,Geng, Qiuyang,Hock, Katharina J.,Yuan, Tingting,Cavallo, Luigi,Rueping, Magnus
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p. 4430 - 4435
(2019/04/29)
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- Preparation method of 4-cycloalkylacetophenone derivatives
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The invention discloses a preparation method of 4-cycloalkylacetophenone derivatives, and belongs to the technical field of organic compounds. A 2-substituted acetophenone derivative or a 3-substituted acetophenone derivative is used as an initiator, so raw materials are easy to obtain and have many kinds; and the 4-substituted cycloalkyl acetophenone derivatives obtained by using the method are various, can be directly used, and can also be used in other further reactions. The preparation method has the advantages of simplicity in reaction operation and post-treatment, high yield, and no generation of a large amount of metal salts, is a green method with high atom economy, and is suitable for large-scale production.
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Paragraph 0027-0029
(2019/01/08)
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- Direct arylation of strong aliphatic C–H bonds
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Despite the widespread success of transition-metal-catalysed cross-coupling methodologies, considerable limitations still exist in reactions at sp3-hybridized carbon atoms, with most approaches relying on prefunctionalized alkylmetal or bromide coupling partners1,2. Although the use of native functional groups (for example, carboxylic acids, alkenes and alcohols) has improved the overall efficiency of such transformations by expanding the range of potential feedstocks3–5, the direct functionalization of carbon–hydrogen (C–H) bonds—the most abundant moiety in organic molecules—represents a more ideal approach to molecular construction. In recent years, an impressive range of reactions that form C(sp3)–heteroatom bonds from strong C–H bonds has been reported6,7. Additionally, valuable technologies have been developed for the formation of carbon–carbon bonds from the corresponding C(sp3)–H bonds via substrate-directed transition-metal C–H insertion8, undirected C–H insertion by captodative rhodium carbenoid complexes9, or hydrogen atom transfer from weak, hydridic C–H bonds by electrophilic open-shell species10–14. Despite these advances, a mild and general platform for the coupling of strong, neutral C(sp3)–H bonds with aryl electrophiles has not been realized. Here we describe a protocol for the direct C(sp3) arylation of a diverse set of aliphatic, C–H bond-containing organic frameworks through the combination of light-driven, polyoxometalate-facilitated hydrogen atom transfer and nickel catalysis. This dual-catalytic manifold enables the generation of carbon-centred radicals from strong, neutral C–H bonds, which thereafter act as nucleophiles in nickel-mediated cross-coupling with aryl bromides to afford C(sp3)–C(sp2) cross-coupled products. This technology enables unprecedented, single-step access to a broad array of complex, medicinally relevant molecules directly from natural products and chemical feedstocks through functionalization at sites that are unreactive under traditional methods.
- Perry, Ian B.,Brewer, Thomas F.,Sarver, Patrick J.,Schultz, Danielle M.,DiRocco, Daniel A.,MacMillan, David W. C.
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- Thiyl radical promoted chemo- and regioselective oxidation of CC bonds using molecular oxygen: Via iron catalysis
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The first example of the thiyl radical promoted ligand-free iron-catalyzed oxidative cleavage of alkenes using molecular oxygen (1 atm) has been developed. The reaction proceeds under mild reaction conditions with high efficiency and high chemo- and regioselectivity. It features a broad substrate scope and excellent functional group compatibility, enabling facile access to valuable molecules for application in medicinal chemistry. Preliminary mechanistic studies reveal that a vital intermediate dioxetane might be involved in the reaction and a thiyl radical plays a synergistic role in facilitating the selective oxidation of the CC bond.
- Xiong, Baojian,Zeng, Xiaoqin,Geng, Shasha,Chen, Shuo,He, Yun,Feng, Zhang
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supporting information
p. 4521 - 4527
(2018/10/17)
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- Harnessing Alkyl Amines as Electrophiles for Nickel-Catalyzed Cross Couplings via C-N Bond Activation
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We developed a strategy to harness alkyl amines as alkylating agents via C-N bond activation. This Suzuki-Miyaura cross coupling of alkylpyridinium salts, readily formed from primary amines, is the first example of a metal-catalyzed cross coupling via C-N bond activation of an amine with an unactivated alkyl group. This reaction enjoys broad scope and functional group tolerance. Primary and secondary alkyl groups can be installed. Preliminary studies suggest a NiI/NiIII catalytic cycle.
- Basch, Corey H.,Liao, Jennie,Xu, Jianyu,Piane, Jacob J.,Watson, Mary P.
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supporting information
p. 5313 - 5316
(2017/04/27)
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- Phenol Derivatives as Coupling Partners with Alkylsilicates in Photoredox/Nickel Dual Catalysis
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Photoredox/nickel dual catalysis via single electron transmetalation allows coupling of Csp3-Csp2 hybridized centers under mild conditions. A procedure for the coupling of electron-deficient aryl triflates, -tosylates, and -mesylates with alkylbis(catecholato)silicates is presented. This method represents the first example of the use of phenol derivatives as electrophilic coupling partners in photoredox/nickel dual catalysis.
- Patel, Niki R.,Molander, Gary A.
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supporting information
p. 7271 - 7275
(2016/08/30)
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- Direct C(sp3)-H Cross Coupling Enabled by Catalytic Generation of Chlorine Radicals
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Here we report the development of a C(sp3)-H cross-coupling platform enabled by the catalytic generation of chlorine radicals by nickel and photoredox catalysis. Aryl chlorides serve as both cross-coupling partners and the chlorine radical source for the α-oxy C(sp3)-H arylation of cyclic and acyclic ethers. Mechanistic studies suggest that photolysis of a Ni(III) aryl chloride intermediate, generated by photoredox-mediated single-electron oxidation, leads to elimination of a chlorine radical in what amounts to the sequential capture of two photons. Arylations of a benzylic C(sp3)-H bond of toluene and a completely unactivated C(sp3)-H bond of cyclohexane demonstrate the broad implications of this manifold for accomplishing numerous C(sp3)-H bond functionalizations under exceptionally mild conditions.
- Shields, Benjamin J.,Doyle, Abigail G.
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supporting information
p. 12719 - 12722
(2016/10/13)
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- Novel piperidinyl monocarboxylic acids as S1P1 receptor agonists
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The present invention relates to novel compounds acting as agonists at S1P (sphingosine-1-phosphate) receptors, compositions containing these compounds, use of these compounds in medicine and their process of preparation.
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Page/Page column 12
(2012/11/06)
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- NOVEL PIPERIDINYL MONOCARBOXYLIC ACIDS AS S1P1 RECEPTOR AGONISTS
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The present invention relates to novel compounds acting as agonists at S1P (sphingosine-1-phosphate) receptors, compositions containing these compounds, use of these compounds in medicine and their process of preparation.
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Page/Page column 27
(2012/11/06)
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- Ruthenium-catalyzed para-selective oxidative cross-coupling of arenes and cycloalkanes
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A novel, direct para-selective oxidative cross-coupling of benzene derivatives with cycloalkanes catalyzed by ruthenium was developed. A wide range of arenes bearing electron-withdrawing substituents was functionalized directly with simple cycloalkanes with high para-selectivity; arenes with electron-donating groups were mainly para-functionalized. Benzoic acid can be used directly.
- Guo, Xiangyu,Li, Chao-Jun
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supporting information; experimental part
p. 4977 - 4979
(2011/11/12)
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- A novel catalytic method for the regeneration of carbonyl compounds from oximes using aluminum nitrate and NaBr as catalyst
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A wide variety of aldoximes and ketoximes were regenerated to corresponding carbonyl compounds with Al(NO3)3·9H2O in presence of catalytic amounts of NaBr in CH2Cl2 at room temperature.
- Ghorbani-Choghamarani, Arash,Zeinivand, Javad
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experimental part
p. 1083 - 1086
(2011/10/02)
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- Radical pairs with rotational fluidity in the photochemical reaction of acetophenone and cyclohexane in the zeolite NAY: A 13C CPMAS NMR and product analysis study
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The photochemical reaction of acetophenone and cyclohexane in the zeolite NaY occurs by combination of the geminate radical pairs to give products that reveal a significant amount of rotational fluidity, which was also documented by intermolecular nuclear dipolar interaction measurements using cross polarization 13C NMR (CPMAS) experiments. The Royal Society of Chemistry 2009.
- Amboya, Ammee,Nguyen, Tina,Huynh, Hien T.,Brown, Ashley,Ratliff, Gretchen,Yonutas, Heather,Cizmeciyan, Deniz,Natarajan, Arunkumar,Garcia Garibay, Miguel A.
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experimental part
p. 2322 - 2326
(2009/09/26)
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- Facile preparation of organozinc bromides using electrogenerated highly reactive zinc and its use in cross-coupling reaction
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Highly reactive zinc was readily prepared by electrolysis of a DMF solution containing pyrene as a mediator with a platinum cathode and a zinc anode. Preferential reduction of pyrene occurred to generate the corresponding radical anion, which reduced zinc ions generated from anodic dissolution to give zero valent zinc with high reactivity. The reactive zinc was successfully used for an efficient transformation of bromoalkanes into the corresponding organozinc bromides. Organozinc bromides obtained were further used successfully in Pd-catalyzed cross-coupling reaction with various aryl iodides and bromides.
- Kurono, Nobuhito,Inoue, Tomio,Tokuda, Masao
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p. 11125 - 11131
(2007/10/03)
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- METHOD FOR CARRYING OUT CHEMICAL REACTIONS INVOLVING COMPOUNDS ADSORBED ON FLUORINATED CARRIER MATERIALS BY MEANS OF FLUORINE-FLUORINE INTERACTIONS
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The invention relates to a method for carrying out a chemical reaction of a compound (B), involving a compound (A-F) which is adsorbed on a fluorinated carrier material (FT) by means of fluorine-fluorine interactions, forming an addition compound (A-F):(FT). The inventive method is characterised in that said addition compound (A-F):(FT) is suspended in a suitable solvent containing the compound B, whereby said compound B is reacted to form the reaction product B', in the presence of the adsorbed compound A-F.
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Page/Page column 25-26; 28
(2008/06/13)
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- Elevation of HDL cholesterol by 2-[(aminothioxomethyl)-hydrazono]-2-arylethyl carbamates
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This invention relates to the treatment of atherosclerosis via raising the level of HDL cholesterol by administration of a compound of the formula STR1 wherein: R1, R2, and R3 are independently hydrogen, C1 -C6 alkyl or --(CH2)0-6 Ph where Ph is phenyl optionally substituted by halogen, cyano, nitro, C1 -C6 alkyl, C1 -C6 alkoxy, trifluoromethyl, C1 -C6 alkoxycarbonyl, --CO2 H or OH; R4 and R5 are independently hydrogen, C1 -C6 alkyl, C3 -C8 cycloalkyl, or --(CH2)0-6 Ar1 where Ar1 is phenyl, naphthyl, furanyl, pyridinyl or thienyl and Ar1 can be optionally substituted by halogen, cyano, nitro, C1 -C6 alkyl, phenyl, C1 -C6 alkoxy, phenoxy, trifluoromethyl, C1 -C6 alkoxycarbonyl, --CO2 H or OH; and Ar is phenyl, naphthyl, furanyl, pyridinyl or thienyl or Ar is optionally substituted by halogen, cyano, nitro, C1 -C6 alkyl, C3 -C6 cycloalkyl, phenyl, C1 -C6 alkoxy, phenoxy, trifluoromethyl, C1 -C6 alkoxycarbonyl, --CO2 H or OH.
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- A new paradigm for biohydroxylation by Beauveria bassiana ATCC 7159
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The biohydroxylation of a series of amides and related amino, keto and hydrocarbon substrates by the fungal biocatalyst Beauveria bassiana ATCC 7159 has been examined. The product distributions, together with data obtained from selective inhibition experiments using the cyt.P-450 inhibitors isosafrole, 1-aminobenzotriazole and phenylacetylene, suggest that B. bassiana contains a range of hydroxylase enzymes with different substrate specificities. A paradigm is presented for the interpretation of the results of microbial hydroxylation and for the application of existing active site models for B. bassiana.
- Holland, Herbert L.,Morris, Terence A.,Nava, Phillip J.,Zabic, Mirjana
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p. 7441 - 7460
(2007/10/03)
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- Media controlled photo - Favorskii type rearrangement of α-chloro acetophenones: Synthesis of phenylacetic acids
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Photolysis of substituted α-chloro acetophenones has been studied in different solvent systems wherein 1,2-aryl migration is found to be media controlled. Effect of substituents on the migratory aptitude and a direct access to phenylacetic acids, in practical yields, has been described.
- Dhavale, Dilip D.,Mali, Vasant P.,Sudrik, Surendra G.,Sonawane, Harikisan R.
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p. 16789 - 16794
(2007/10/03)
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- Synthesis of Certain Mesogenic Azomethines Derived from 4-Cycloalkylanilines and from 4-Cycloalkylbenzaldehydes
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General procedures are described for the synthesis of members of five pairs of related homologous series of mesogenic azomethines differing in the mode of linkage of the CH=N group and containing a cycloalkyl group in a terminal position.
- Byron, D. J.,Matharu, A. S.,Rees, M.,Wilson, R. C.
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p. 229 - 238
(2007/10/02)
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- A New Approach to Aromatic Substitution - para-Specific Alkylation of Acetophenone by Alkyl Radicals in Strongly Acidic Media
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Acetophenone in 25percent oleum is substituted by various alkyl radicals specifically in the para-position.The radicals used include cyclohexyl, 3-chloro-1-methylpropyl, 3-bromo-1-methylpropyl, 4-chloro-1-methylbutyl, 4-bromo-1-methylbutyl, 5-bromo-1-methylpentyl, 5-acetoxy-1-methylpentyl, 3-carboxy-1-methylpropyl, 4-carboxy-1-methylbutyl and 5-carboxy-1-methylpentyl.They were all generated by hydrogen atom abstraction at the radical position by dimethylaminium radicals, generated in turn from protonated dimethylchloramine and ferrous sulphate.Yields were generally poor to moderate but utilised simple conditions and cheap reagents.
- Din, Laily Bin,Meth-Cohn, Otto,Walshe, Nigel D. A.
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p. 781 - 786
(2007/10/02)
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- Organic Reactions in Liquid-Crystalline Solvents. 9. Investigation of the Solubilization of Guest Molecules in a Smectic (Crystal-B) Liquid Crystal by Deuterium NMR, Calorimetry, Optical Microscopy, and Photoreactivity Methods.
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The solubilization behavior of three aromatic ketones in the smectic (crystal-B) and nematic liquid-crystalline phases of trans,trans-4'-butylbicyclohexyl-4-carbonitrile (CCH-4) has been studied in detail by 2H NMR spectroscopy, differential scanning calorimetry (DSC), and thermal microscopy, and complete binary phase diagrams for each ketone/CCH-4 system have been constructed.Combined with previously reported data, the results indicate that most aromatic molecules have very low solubilities (ca. 0.2-2.0 molpercent) in the crystal-B phase of this mesogen.For a given solute, solubility in this phase increases with decreasing temperature.For bulk compositions above the solubility limit, the solute order parameters (from NMR) appear to decrease with decreasing temperature.This has been shown to be due to phase separation and the complex temperature-dependent behavior of the resulting smectic/nematic biphasic system.Other evidence indicates that the isotropic NMR behavior observed for many solute/CCH-4 mixtures at low temperatures is due to the formation of a smetic/isotropic biphasic system, not a plastic or cubic phase as has been proposed previously.The Norrish type II photoreactivity at 30 deg C and the 2H NMR behavior of γ-cyclohexylbutyrophenone-α,α-d2 over the 30-80 deg C range in CCH-4 have been investigated over a wide range of sample composition (0.6-40 molpercent).The results obtained in the temperature range below the S-N transition of the pure liquid crystal can be explained within the context of a biphasic solubilization model.
- Fahie, Brian J.,Mitchell, D. Scott,Workentin, Mark. S.,Leigh, William J.
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p. 2916 - 2929
(2007/10/02)
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- Properties of the Liquid Crystals Formed by Ceratin Azomethines Derived from 4-Cycloalkylanilines and from 4-Cycloalkylbenzaldehydes
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The liquid crystal behaviour of four homologous series of azomethines related to the nO.m series but containing a cycloalkyl group, is reported and discussed.Many of these compounds show extensive smectic polymorphism, one member of the nO.c6 series giving rise to five smectic polymorphic modofications for which phase type assignments have been made by thermal optical microscopy.Keywords: smectic polymorphism, azomethines, cycloalkyl derivatives
- Brown, J. W.,Byron, D. J.,Southcott, M.,Wilson, R. C.,Guillon, D.,et al.
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- Inhibitors of Glycolic Acid Oxidase. 4-Substituted 2,4-Dioxobutanoic Acid Derivatives
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Fourteen new 4-substituted 2,4-dioxobutanoic acids have been synthesized.These compounds, all of which contain lipophilic 4-substituents, are potent inhibitors in vitro of porcine liver glycolic acid oxidase.The I50 value of the two most potent representatives, 4-(4'-bromo-4-yl)-2,4-dioxobutanoic acid (8) and 4-thio>-4-yl>-2,4-dioxobutanoic acid (13) is 6 * 10-8 M.
- Williams, H. W. R.,Eichler, E.,Randall, W. C.,Rooney, C. S.,Cragoe, E. J.,et al.
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p. 1196 - 1200
(2007/10/02)
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- 2,4-Dioxo-4-substituted-1-butanoic acid derivatives useful in treating urinary tract calcium oxalate lithiasis
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2,4-Dioxo-4-substituted-1-butanoic acid derivatives of the formula: STR1 where R is hydrogen or C1-4 alkyl; and L is a lipophilic group consisting essentially of: STR2 where R1 and R2 are each independently selected from the group consisting of (a) hydrogen; (b) C4-12 straight or branched chain alkyl; (c) C4-7 cycloalkyl; and (d) tetrahydronaphthyl; provided that R1 and R2 may not both be hydrogen; and when one of R1 or R2 is tetrahydronaphthyl, the other must be some other substituent; and that positions 2 and 6 of the substituted phenyl moiety may not be substituted; and STR3 where R1, and R2 have the same meaning as above except tetrahydronaphthyl; R3 is bromine, chlorine, or fluorine; m is 0 to 3; or a pharmaceutically acceptable salt thereof.
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- Process for producing ethynylbenzenes
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There is disclosed a novel process for preparing anti-inflammatory ethynylbenzene derivatives represented by the general formula I: STR1 wherein Y is hydrogen, halogen or loweralkyl of 1 to 3 carbon atoms; R represents a ring having the structure: STR2 wherein x is 1 to 3, or a ring of the structure: STR3 wherein Y' is hydrogen, halogen, loweralkyl of 1 to 3 carbon atoms and loweralkoxy of 1 to 3 carbon atoms; Y" is hydrogen or halogen; and Y"' is hydrogen or halogen, provided Y, Y', Y" and Y"' are not all hydrogen at the same time, by reacting a benzyl alcohol of formula V: STR4 with a sulfonyl chloride, reducing the sulfonate VI of the formula: STR5 and dehydrohalogenating the formed β-halostyrene of the formula VII: STR6
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