- Supported bilayer lipid membrane arrays on photopatterned self-assembled monolayers
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This work demonstrates the use of photocleavable cholesterol derivatives to create supported bilayer lipid membrane arrays on silica. The photocleavable cholesteryl tether is attached to the surface by using the reaction of an amine-functionalized self-assembled monolayer (SAM) and the N- hydroxysuccinimide-based reagent 9. The resultant SAM contains an orthonitrobenzyl residue that can be cleaved by photolysis by using soft (365 nm) UV light regenerating the original amine surface, and which can be patterned using a mask. The photoreaction yield was ≈75% which was significantly higher than previously found for related ortho-nitrobenzyl photochemistry on gold substrates. The SAMs were characterized by means of contact angle measurements, ellipsometry and X-ray photoelectron spectroscopy. Patterned surfaces were characterized with SEM and AFM. After immersing the patterned surface into a solution containing small unilamellar vesicles of egg phosphatidylcholine (PC), supported lipid membranes were formed comprised of lipid bilayer over the amine functionalized "hydrophilic" regions and lipid monolayer over the cholesteryl "hydrophobic" regions. This was confirmed by fluorescence microscopy and AFM. FRAP studies yielded a lateral diffusion coefficient for the probe molecule of 0.14±0.05 μm 2s-1 in the bilayer regions and ≈0.01 μm 2s-1 in the monolayer regions. This order of magnitude difference in diffusion coefficients effectively serves to isolate the bilayer regions from one another, thus creating a bilayer array.
- Han, Xiaojun,Pradeep, Singh N. D.,Critchley, Kevin,Sheikh, Khizar,Bushby, Richard J.,Evans, Stephen D.
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Read Online
- Nitration of aromatics with dinitrogen pentoxide in a liquefied 1,1,1,2-tetrafluoroethane medium
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Regardless of the sustainable development path, today, there are highly demanded chemical productions still operating that bear environmental and technological risks inherited from the previous century. The fabrication of nitro compounds, and nitroarenes in particular, is traditionally associated with acidic wastes formed in nitration reactions exploiting mixed acids. However, nitroarenes are indispensable for industrial and military applications. We faced the challenge and developed a greener, safer, and yet effective method for the production of nitroaromatics. The proposed approach comprises the application of an eco-friendly nitrating agent, namely dinitrogen pentoxide (DNP), in the medium of liquefied 1,1,1,2-tetrafluoroethane (TFE) - one of the most non-hazardous Freons. Importantly, the used TFE is not emitted into the atmosphere but is effortlessly recondensed and returned into the process. DNP is obtainedviathe oxidation of dinitrogen tetroxide with ozone. The elaborated method is characterized by high yields of the targeted nitro arenes, mild reaction conditions, and minimal amount of easy-to-utilize wastes.
- Fauziev, Ruslan V.,Kharchenko, Alexandr K.,Kuchurov, Ilya V.,Zharkov, Mikhail N.,Zlotin, Sergei G.
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p. 25841 - 25847
(2021/08/09)
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- Synthesis and antitumor effects of novel benzyl naphthyl sulfoxide/sulfone derivatives derived from Rigosertib
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In this work, a series of novel benzyl naphthyl sulfoxides/sulfones derived from Rigosertib were designed and synthesized as potential antitumor agents. The in vitro cytotoxicity against four human cancer cell lines (HeLa, MCF-7, HepG2 and SCC-15) and two normal human cell lines (HUVEC and 293T) indicated that some of the sulfones and sulfoxides possessed potent antineoplastic activity that reached nanomolar levels and relatively low toxicity to normal cells. Among them, (2-methoxy-5-((naphthalen-2-ylsulfonyl)methyl)phenyl)glycine (15b) was found to be a promising antitumor drug candidate that could significantly inhibit tumor cell migration and induce tumor cell apoptosis via the p53-Bcl-2-Bax signaling pathway at nanomolar concentrations.
- Tang, Lin,Chen, Tingting,Yang, Hongpeng,Wen, Xiaoxue,Sun, Yunbo,Liu, Shuchen,Peng, Tao,Zhang, Shouguo,Wang, Lin
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p. 37462 - 37471
(2021/12/07)
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- Platinum-Based Modification of Styrylbenzylsulfones as Multifunctional Antitumor Agents: Targeting the RAS/RAF Pathway, Enhancing Antitumor Activity, and Overcoming Multidrug Resistance
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Inhibiting/disturbing the RAS/RAF pathway may benefit the treatment of cancer and overcome the resistance. Utilizing such a pathway as the target, nine styrylbenzylsulfone derivatives generated from the platinum-based modification of the side chain of Rig
- Liu, Zhikun,Wang, Meng,Wang, Hengshan,Fang, Lei,Gou, Shaohua
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p. 186 - 204
(2020/01/22)
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- Exploring the nitro group reduction in low-solubility oligo-phenylenevinylene systems: Rapid synthesis of amino derivatives
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A small series of amino oligo-phenylenevinylenes (OPVs) were successfully synthesized from their nitro-analogs in a rapid, simple, and highly efficient fashion employing a sodium sulfide/pyridine system as a reducing agent. In this research, classic and sustainable reduction methodologies including NH4HCO2/Zn and a choline chloride/tin (II) chloride deep eutectic solvent (DES) were also evaluated, showing degradation products, incomplete reactivity, and product isolation difficulties in all cases. The straightforward Na2S/pyridine synthetic protocol proved to maintain the E-E stereochemistry of the OPV backbone that has been previously assembled by the Mizoroki–Heck cross-coupling reaction. Also, the optoelectronic properties were determined and discussed, considering the amino group insertion in these conjugated systems as a contribution for future construction of novel materials with applications in supramolecular electronics, light harvesting, and photocatalysis.
- Acelas, Mauricio,Sierra, Andrés Felipe,Sierra, César A.
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supporting information
p. 1335 - 1352
(2020/03/04)
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- Highly efficient protocol for the aromatic compounds nitration catalyzed by magnetically recyclable core/shell nanocomposite
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An efficient protocol for the nitration of aromatic compounds in the presence of a catalytic amount of sulfuric acid-functionalized silica-based magnetic core/shell nanocomposite was reported. The designed products were obtained in high yields in relatively short reaction times at room temperature under solvent-free conditions. The nanocatalyst was simply recovered from the reaction mixture by using an external magnet and efficiently reused for several times. The characterization of particle size, morphology and elemental analysis of the nanocatalyst were provided by scanning electron microscopy, transmission electron microscopy and energy-dispersive X-ray spectroscopy analyses, respectively.
- Maleki, Ali,Aghaei, Morteza,Paydar, Reza
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p. 485 - 490
(2017/01/10)
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- Synthesis and biological evaluation of cinnamido linked benzophenone hybrids as tubulin polymerization inhibitors and apoptosis inducing agents
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A new class of hybrid molecules containing cinnamide subunit linked to benzophenone as inhibitors of tubulin polymerization were synthesized and evaluated for their anticancer potential. These hybrids exhibit anticancer activity with IC50 values ranging from 0.06 to 16.3 μM. Compounds 4f and 4g possessing fluoro and trifluoromethyl on the cinnamido subunit showed significant cytotoxic activity with IC50 values 0.06 and 0.09 μM against HeLa cell line, respectively. These compounds showed cell cycle arrest at G2/M phase of the cell cycle and inhibited tubulin polymerization followed by activation of caspase-3 activity and apoptotic cell death. Further in vitro tubulin polymerization assay showed that the level of tubulin inhibition was comparable to that of 2a for the compounds 4f and 4g. Moreover, Hoechst 33258 staining and DNA fragmentation assay suggested that these compounds induce cell death by apoptosis. Overall, the current study demonstrates that the synthesis of benzophenone linked cinnamide subunit conjugates as promising anticancer agents with G2/M arrest and apoptotic-inducing ability via targeting tubulin.
- Kamal, Ahmed,Reddy, Ch. Ratna,Vishnuvardhan,Mahesh,Lakshma Nayak,Prabhakar,Reddy, C. Suresh
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supporting information
p. 2309 - 2314
(2014/05/20)
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- A practical in situ generation of the schwartz reagent. reduction of tertiary amides to aldehydes and hydrozirconation
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A new, highly efficient in situ protocol (Cp2ZrCl2/LiAlH(OBu-t)3) is described for the generation of the Schwartz reagent which provides a convenient method for the amide to aldehyde reduction and the regioselective hydrozirconation-iodination of alkynes and alkenes. Highlighted are chemoselective reductions of benzamides derived by directed ortho metalation (DoM) chemistry, allowing the synthesis of valuable 1,2,3-substituted benzaldehydes. The single-step, three-component process proceeds in a very short reaction time, shows excellent functional group compatibility, and uses inexpensive and long-storage stable reducing reagents.
- Zhao, Yigang,Snieckus, Victor
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supporting information
p. 390 - 393
(2014/04/03)
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- Aromatic nitration with bismuth nitrate in ionic liquids and in molecular solvents: A comparative study of Bi(NO3)3·5H 2O/[bmim][PF6] and Bi(NO3)3· 5H2O/1,2-DCE systems
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A suspension of bismuth nitrate pentahydrate (BN) in [bmim][PF6] or [bmim][BF4] imidazolium ionic liquid (IL) is an effective reagent for ring nitration of activated aromatics under mild conditions without the need for external promoters. Nitration can also be effected in 1,2-DCE, MeCN, or MeNO2 without additives. Nitration of activated arenes (anisole, toluene, ethylbenzene, cumene, p-xylene, mesitylene, durene, and 1,3-dimethoxybenzene) is considerably faster (time to completion) in BN/[bmim][PF6] relative to BN/1,2-DCE and there are also differences in isomer distributions (for anisole, toluene, and ethylbenzene). With introduction of strongly deactivating substituents (-CHO; -MeCO; -NO 2) the BN/IL system is no longer active but reactions still proceed with BN/1,2-DCE in reasonable yields. The ready availability and low cost of BN, simple operation, and absence of promoters, coupled to recycling and reuse of the IL, provide an attractive alternative to classical nitration methods for activated arenes. Switching from Bi(NO3)3·5H 2O/[bmim][PF6] to Bi(NO3)3· 5H2O/1,2-DCE increases the scope of the substrates that can be nitrated.
- Jacoway, Jonathan,Kumar, G. G. K. S. Narayana,Laali, Kenneth K.
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p. 6782 - 6785,4
(2012/12/12)
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- Ethylammonium nitrate (EAN)/Tf2O and EAN/TFAA: Ionic liquid based systems for aromatic nitration
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Acting as in situ sources of triflyl nitrate (TfONO2) and trifluoroacetyl nitrate (CF3COONO2), the EAN/Tf 2O and EAN/TFAA systems, generated via metathesis in the readily available ethylammonium nitrate (EAN) ionic liquid as solvent, are powerful electrophilic nitrating reagents for a wide variety of aromatic and heteroaromatic compounds. Comparative nitration experiments indicate that EAN/Tf2O is superior to EAN/TFAA for nitration of strongly deactivated systems. Both systems exhibit low substrate selectivity (K T/KB = 5-10) in (Figure presented) between values reported for covalent nitrates and preformed nitronium salts.
- Aridoss, Gopalakrishnan,Laali, Kenneth K.
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experimental part
p. 8088 - 8094
(2011/11/13)
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- OXADIAZOLE COMPOUNDS, THEIR PREPARATION AND USE
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The present invention relates to oxadiazole compounds in all their stereoisomeric and tautomeric forms and mixtures thereof in all ratios; and their pharmaceutically acceptable salts, pharmaceutically acceptable solvates, pharmaceutically acceptable prodrugs and pharmaceutically acceptable polymorphs. The invention also relates to processes for the manufacture of the oxadiazole compounds and to pharmaceutical compositions containing them. The said compounds and their pharmaceutical compositions are useful in the treatment of cancer, particularly chronic myeloid leukemia (CML). The present invention further provides a method of treatment of cancer by administering a therapeutically effective amount of said compounds or their pharmaceutical compositions, to a mammal in need thereof.
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Page/Page column 69
(2011/09/30)
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- Schwartz Reagents: Methods of In Situ Generation and Use
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Embodiments of the invention provide a method of using Schwartz Reagent, Cp2Zr(H)Cl, without accumulating or isolating it. Methods provide mixtures of Cp2ZrCl2, reductants that selectively reduce Cp2ZrCl2, and substrates. After reaction of Cp2ZrCl2 and the reductant, an intermediate reduction product is formed, apparently Schwartz Reagent. The in situ Schwartz Reagent then selectively reduces certain functional groups on the substrate. Substrates include tertiary amides, tertiary benzamides, aryl O-carbamates, and heteroaryl N-carbamates, which are reduced to aldehydes, benzaldehydes, aromatic alcohols, and heteroaromatics, respectively. Compared to prior methods, reagents are inexpensive and stable, reaction times are short, and reaction temperature in certain cases is conveniently room temperature. It has been estimated that using the in situ method described herein instead of synthesized or commercially obtained Schwartz Reagent provides a 50% reduction in cost.
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Page/Page column 7; 11
(2010/06/19)
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- AI203/MeS03H (AMA) as a novel heterogeneous system for the nitration of aromatic compounds by magnesium nitrate hexahydrate
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Mg(NO3)2-6H2O was an efficient nitrating agent in the presence of a mixture of AI2O3/MeSO 3H (AMA) as a novel heterogeneous system for the nitration of aromatic compounds without use of any organic solvents and with high selectivity. The reaction proceeds at room temperature for the nitration of highly reactive aromatic compounds such as phenols and anilines.
- Hosseini-Sarvari, Mona,Tavakolian, Mina
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experimental part
p. 722 - 724
(2009/10/02)
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- A convenient method for the preparation of benzyl isocyanides
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Treatment of benzyl halides with silver salts (AgClO4, AgBF 4, or AgOTf) and trimethylsilyl cyanide (TMSCN) in CH 2Cl2 followed by cleavage of the carbon-silicon bond with aqueous NaHCO3 or TBAF directly afforded the corresponding isocyanides. Georg Thieme Verlag Stuttgart.
- Kitano, Yoshikazu,Manoda, Tetsuya,Miura, Teppei,Chiba, Kazuhiro,Tada, Masahiro
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p. 405 - 410
(2007/10/03)
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- Supported bismuth(III) nitrate on silica sulfuric acid as useful reagent for nitration of aromatic compounds under solvent-free conditions
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A number of aromatic compounds were nitrated to the corresponding nitroaromatic derivatives with the use of supported bismuth(III) nitrate on silica sulfuric acid under solvent-free conditions.
- Hajipour,Zarei,Ruoho
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p. 1493 - 1495
(2007/10/03)
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- Hydrogen-bonding-driven preorganized zinc porphyrin receptors for efficient complexation of C60, C70, and C60 derivatives
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This paper describes the self-assembly of a new class of foldamer-based molecular tweezers, whose rigid folded conformations are stabilized by intramolecular hydrogen bonding. Two zinc porphyrin units are introduced to the ends of molecular tweezers Zn21 and Zn22, while three zinc porphyrin units are incorporated to the S-shaped bi-tweezers Zn33, which may be regarded as a combination of two Zn21 molecules. Due to the preorganized U-shaped feature, Zn21 and Zn22 are able to strongly complex C60, C70, and C60 derivative 25 in chloroform or toluene in a 1:1 binding stoichiometry, whereas Zn33, which possesses two tweezer units, complexes the guests in a 1:2 stoichiometry. More stable complex Zn33·24 is formed between Zn33 and 24, a linear molecule bearing two C60 moieties at the ends, as a result of the cooperative interaction of two binding sites. Chiral induction is observed for all the three receptors upon complexation with C60-incorporated chiral phenylalanine derivative 29, although the complexation of 29 by the folding receptors is pronouncedly weaker than that of C60 and 25 due to increased steric hindrance. The driving force for the formation of the complexes is the well established π-π stacking between the zinc porphyrin and fullerene units. The 1H and 13C NMR, UV-vis, fluorescent, and circular dichroism spectroscopy have been used to investigate the complexing behavior of the folding receptors and the fullerene guests. The association constants of the corresponding complexes in toluene and chloroform (if possible) have been evaluated with the UV-vis and fluorescent titration experiments.
- Wu, Zong-Quan,Shao, Xue-Bin,Li, Chuang,Hou, Jun-Li,Wang, Kui,Jiang, Xi-Kui,Li, Zhan-Ting
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p. 17460 - 17468
(2007/10/03)
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- Further naphthylcombretastatins. An investigation on the role of the naphthalene moiety
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By synthesis and biological studies of new naphthalene analogues of combretastatins, we have found that the naphthalene is a good surrogate for the isovanillin moiety (3-hydroxy-4-methoxyphenyl) of combretastatin A-4, always generating highly cytotoxic analogues when combined with the 3,4,5-trimethoxyphenyl or related systems. On the other hand, when the naphthalene replaces the 3,4,5-trimethoxyphenyl moiety, the cytotoxic activity is largely decreased. The most cytotoxic naphthalene analogues of combretastatins, which also produce inhibition of tubulin polymerization, exerted their antimitotic effects through microtubule network disruption and subsequent G2/M arrest of the cell cycle in human cancer cells.
- Maya, Ana B. S.,Pérez-Melero, Concepción,Mateo, Carmen,Alonso, Dulce,Fernández, José Luis,Gajate, Consuelo,Mollinedo, Faustino,Peláez, Rafael,Caballero, Esther,Medarde, Manuel
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p. 556 - 568
(2007/10/03)
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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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- Diastereoselective Synthesis of Cularine Alkaloids via Enium Ions and an Easy Entry to Isoquinolines by Aza-Wittig Electrocyclic Ring Closure
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In preliminary communications, we reported the diastereoselective synthesis of cularine and sarcocapnine via the intramolecular ring closure of nitrenium and oxenium ions, a new highly diastereoselective reductive methylation with (+)-8-phenylmenthyl chloroacetate followed by reduction with sodium borohydride, and a facile entry to the isoquinoline precursors by aza-Wittig electrocyclic ring closure. We now report the full details of the syntheses of (+)-O-demethylcularine, (+)-cularine, (+)-sarcocapnidine, (+)-sarcocapnine, and (+)-crassifoline and describe different methods of synthesis of their precursors.
- Rodrigues, J. Augusto R.,Abramovitch, Rudolph A.,De Sousa, Joana D. F.,Leiva, Genaro C.
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p. 2920 - 2928
(2007/10/03)
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- Tele nucleophilic aromatic substitutions in 1-nitro-3- and 1,3-dinitro- 5-trichloromethylbenzene, and 3-trichloromethylbenzonitrile. A new synthesis of the 1,4-benzothiazine-3(4H)-one ring system from 3 nitrobenzoic acid
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3-Trichloromethylnitrobenzene 2, 1,3-dinitro-5-trichloromethylbenzene 13 and 3-trichloromethylbenzonitrile 18 react with sodium methoxide to give 4- methoxy-3-nitrobenzaldehyde 6, 4-methoxy-3,5-dinitrobenzaldehyde 15 and 5- dimethoxymethyl-2-methoxybenzonitrile 19, respectively. Compounds 2 and 13 react with methyl thioglycolate to afford dichloromethylacetates 7 and 16, respectively. These products are the result of tele nucleophilic aromatic substitution. Compound 18 reacted with methyl thioglycolate to give acetate 20 resulting from nucleophilic displacement of cyanide. Reductive cyclisation of 7 afforded benzothiazine 11. (C) 2000 Elsevier Science Ltd.
- Giannopoulos, Thomas,Ferguson, John R.,Wakefield, Basil J.,Varvounis, George
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p. 447 - 453
(2007/10/03)
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- Arylmethylphosphonic acid derivatives useful in treating bone wasting diseases
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Benzyl-phosphonate compounds represented by the formula I: STR1 are disclosed as useful in treating bone wasting diseases and as an immunosuppresant.
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- 13C NMR Spectra of Substituted o-Nitroanisoles and n-Butyl o-Nitrophenyl Ethers
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13C NMR analyses of substituted o-nitroanisoles and n-butyl o-nitrophenyl ethers are reported. Key Words: 13C NMR - o-Nitroanisoles - n-Butyl o-nitrophenyl ethers
- Zeegers, Petrus J.,Thompson, Malcolm J.
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p. 497 - 499
(2007/10/02)
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- Cerium(IV)-induced nitration of cinnamic acids. Novel remote electrophilic substitution
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The treatment of (E)-3,4-dimethoxycinnamic acid with ceric amonium nitrate in trifluoroacetic acid afforded (E)1,2-dimethoxy-4-nitro-5-(2-nitroethenyl)benzene in 79percent yield.The unusual ipso substitution of the carboxylic acid moiety by a nitro functional center illustrated a new reaction manifold of cerium(IV).Six cinnamic acids were examined to ascertain the generality of the transformation.The bidentate nitrato structure of the metal salt is believed to account for the nitrating ability of this system.
- Peterson, John R.,Do, Hoang D.,Dunham, Andrew J.
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p. 1670 - 1674
(2007/10/02)
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