- Aggregation induced convertible third-order nonlinear optical absorptions of the phenoxazinium containing films prepared by sol-gel method
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The preparation and optical properties of phenoxazinium dye containing optical films by a sol-gel method are reported. The monomer of the phenoxazinium dye substituted with a hydroxyl group, prepared from 3-methoxyaniline by a five-step sequence, can be directly converted to the sol-gel precursor. The preparation and optical properties of phenoxazinium dye containing optical films are reported by in situ sol-gel spin coating with different mole ratios of the precursor to tetraethylorthosilicate. The UV-visible absorption spectra of the films were recorded and the dye aggregation phenomena were discussed. The third-order nonlinear optical properties of the films were measured by a picosecond Z-Scan method at 532 nm. The results indicate that the third-order nonlinear optical absorptions of the films are turned from the reverse saturation absorption with lower dye doping ratios to saturation absorption with higher doping ratios, which induced by the dye aggregation.
- Zhang, Fei,Miao, Jia-Tao,Fang, Yu,Sun, Ru,Guo, Xiao-Zhi,Song, Ying-Lin,Ge, Jian-Feng
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Read Online
- Electronically tuneable orthometalated RuII–NHC complexes as efficient catalysts for C–C and C–N bond formations via borrowing hydrogen strategy
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The catalytic activities of a series of simple and electronically tuneable cyclometalated RuII–NHC complexes (2a–d) were explored in various C–C/N bond formations following the borrowing hydrogen process. Slight modifications in the ligand backbone were noted to tune the activities of these complexes. Among them, the complex 2d featuring a 1,2,4-triazolylidene donor with a 4-NO2–phenyl substituent displayed the highest activity for the coupling of diverse secondary and primary alcohols with a low catalyst loading of 0.01 mol% and a sub-stoichiometric amount of inexpensive KOH base. The efficacy of this simple system was further showcased in the challenging one-pot unsymmetrical double alkylation of secondary alcohols using different primary alcohols. Moreover, the complex 2d also effectively catalyses the selective mono-N-methylation of various aromatic and aliphatic primary amines using methanol to deliver a range of N-methyl amines. Mechanistically, the β-alkylation reaction follows a borrowing hydrogen pathway which was established by the deuterium labelling experiment in combination with various control experiments. Intriguingly, in situ1H NMR and ESI-MS analyses evidently suggested the involvement of a Ru–H species in the catalytic cycle and further, the kinetic studies revealed a first order dependence of the reaction rate on the catalyst as well as the alcohol concentrations.
- Illam, Praseetha Mathoor,Rit, Arnab
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- Photoinduced Hydroarylation and Cyclization of Alkenes with Luminescent Platinum(II) Complexes
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Photoinduced hydroarylation of alkenes is an appealing synthetic strategy for arene functionalization. Herein, we demonstrated that aryl radicals generated from electron-deficient aryl chlorides/bromides could be trapped by an array of terminal/internal aryl alkenes in the presence of [Pt(O^N^C^N)] under visible-light (410 nm) irradiation, affording anti-Markovnikov hydroarylated compounds in up to 95 % yield. Besides, a protocol for [Pt(O^N^C^N)]-catalyzed intramolecular photocyclization of acrylanilides to give structurally diverse 3,4-dihydroquinolinones has been developed.
- Cheng, Hanchao,Lam, Tsz-Lung,Liu, Yungen,Tang, Zhou,Che, Chi-Ming
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supporting information
p. 1383 - 1389
(2020/11/30)
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- Novel hybrid conjugates with dual estrogen receptor α degradation and histone deacetylase inhibitory activities for breast cancer therapy
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Hormone therapy targeting estrogen receptors is widely used clinically for the treatment of breast cancer, such as tamoxifen, but most of them are partial agonists, which can cause serious side effects after long-term use. The use of selective estrogen receptor down-regulators (SERDs) may be an effective alternative to breast cancer therapy by directly degrading ERα protein to shut down ERα signaling. However, the solely clinically used SERD fulvestrant, is low orally bioavailable and requires intravenous injection, which severely limits its clinical application. On the other hand, double- or multi-target conjugates, which are able to synergize antitumor activity by different pathways, thus may enhance therapeutic effect in comparison with single targeted therapy. In this study, we designed and synthesized a series of novel dual-functional conjugates targeting both ERα degradation and histone deacetylase inhibiton by combining a privileged SERD skeleton 7-oxabicyclo[2.2.1]heptane sulfonamide (OBHSA) with a histone deacetylase inhibitor side chain. We found that substituents on both the sulfonamide nitrogen and phenyl group of OBHSA unit had significant effect on biological activities. Among them, conjugate 16i with N-methyl and naphthyl groups exhibited potent antiproliferative activity against MCF-7 cells, and excellent ERα degradation activity and HDACs inhibitory ability. A further molecular docking study indicated the interaction patterns of these conjugates with ERα, which may provide guidance to design novel SERDs or PROTAC-like SERDs for breast cancer therapy.
- Zhao, Chenxi,Tang, Chu,Li, Changhao,Ning, Wentao,Hu, Zhiye,Xin, Lilan,Zhou, Hai-Bing,Huang, Jian
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- Anchimerically Assisted Selective Cleavage of Acid-Labile Aryl Alkyl Ethers by Aluminum Triiodide and N, N-Dimethylformamide Dimethyl Acetal
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Aluminum triiodide is harnessed by N,N-dimethylformamide dimethyl acetal (DMF-DMA) for the selective cleavage of ethers via neighboring group participation. Various acid-labile functional groups, including carboxylate, allyl, tert-butyldimethylsilyl (TBS), and tert-butoxycarbonyl (Boc), suffer the conditions intact. The method offers an efficient approach to cleaving catechol monoalkyl ethers and to uncovering phenols from acetal-type protecting groups such as methoxymethyl (MOM), methoxyethoxymethyl (MEM), and tetrahydropyranyl (THP) chemoselectively.
- Sang, Dayong,Yue, Huaxin,Zhao, Zhengdong,Yang, Pengtao,Tian, Juan
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p. 6429 - 6440
(2020/07/14)
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- Bimetallic Bis-NHC-Ir(III) Complex Bearing 2-Arylbenzo[d]oxazolyl Ligand: Synthesis, Catalysis, and Bimetallic Effects
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Herein, an unprecedented bimetallic bis-NHC Cp*Ir complex 1 bearing 2-arylbenzo[d]oxazolyl and NHC ligands is reported. A significant increase in activity was observed for N-methylation of amines and reduction of aldehydes with MeOH catalyzed by 1 compared to the monometallic analogues (2-11). Under the optimal conditions, it showed to be highly effective in N-methylation of nitroarenes with MeOH as both C1 and H2 source. Substrates, including aromatic amines, ketones, and nitro compounds with various functional groups, can be well-tolerated. Mechanistic studies and DFT calculation highlight the significance of bimetallic centers cooperativity.
- Huang, Shuang,Hong, Xi,Cui, He-Zhen,Zhan, Bing,Li, Zhi-Ming,Hou, Xiu-Feng
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p. 3514 - 3523
(2020/10/09)
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- Manganese-Catalyzed One-Pot Conversion of Nitroarenes into N-Methylarylamines Using Methanol
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A manganese-catalyzed one-pot conversion of nitroarenes into N-methylarylamines has been developed. This transfer hydrogenation method employs a well-defined bench stable Mn PN3P pincer precatalyst in combination with methanol as both the reductant and the C1 source. A selection of commercially available nitroarenes was converted into N-methylarylamines in synthetically useful yields.
- Mast, Nicolas,Morrill, Louis C.,Reed-Berendt, Benjamin G.
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supporting information
(2020/03/03)
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- Ruthenium(II) Complexes of Heteroditopic N-Heterocyclic Carbene Ligands: Efficient Catalysts for C-N Bond Formation via a Hydrogen-Borrowing Strategy under Solvent-Free Conditions
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Both imidazol-2-ylidene (ImNHC) and 1,2,3-triazol-5-ylidene (tzNHC) have evolved to be elite groups of N-heterocyclic carbene (NHC) ligands for homogeneous catalysis. To develop efficient ruthenium(II)-based catalysts incorporating these ligands for C-N bond-forming reactions via hydrogen-borrowing methodology, we utilized chelating ligands integrated with ImNHC and mesoionic tzNHC donors connected via a CH2 spacer with a diverse triazole backbone. The synthesized ruthenium(II) complexes 3 are found to be highly efficient for C-N bond formation across a wide range of primary amine and alcohol substrates under solvent-free conditions, and among all of the complexes studied here, catalyst 3a with a mesityl substituent displayed maximum activity. To our delight, catalyst 3a is also effective for the selective mono-N-methylation of various anilines utilizing methanol as a coupling partner, known to be relatively more difficult than other alcohols. Furthermore, complex 3a also delivers various substituted quinolines successfully via the reaction of 2-aminobenzyl alcohol with several secondary alcohols. Importantly, catalyst 3a exhibited the highest activity among the reported ruthenium(II) complexes for both the N-benzylation of aniline [achieving a turnover number (TON) of 50000] and the realization of quinoline 8a by reacting 2-aminobenzyl alcohol with 2-phenylethanol (attaining a TON of 30000).
- Donthireddy,Mathoor Illam, Praseetha,Rit, Arnab
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supporting information
p. 1835 - 1847
(2020/01/31)
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- N-Methylation of Amines with Methanol in Aqueous Solution Catalyzed by a Water-Soluble Metal-Ligand Bifunctional Dinuclear Iridium Catalyst
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The N-methylation of amines with methanol in aqueous solution was proposed and accomplished by using a water-soluble metal-ligand bifunctional dinuclear iridium catalyst. In the presence of [(Cp*IrCl)2(thbpym)][Cl]2 (1 mol %), a range of desirable products were obtained in high yields under environmentally benign conditions. Notably, this research exhibited the potential of transition metal-catalyzed activation of methanol as a C1 source for the construction of the C-N bond in aqueous solution.
- Han, Xingyou,Li, Feng,Liu, Peng,Meng, Chong,Tung, Nguyen Thanh
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p. 5815 - 5824
(2020/05/26)
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- Efficient monomethylation synthesis method of aromatic primary amine
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The invention relates to the field of organic synthesis, in particular to an efficient monomethylation synthesis method of aromatic primary amine. The method comprises the steps as follows: aromatic primary amine is used as a material to react with formaldehyde or paraformaldehyde, and a corresponding hexahydro-1,3,5-triaryl-1,3,5-triazine compound is obtained; the compound is subjected to catalytic hydrogenation under the action of a Pd/C catalyst, and a monomethylate of aromatic primary amine is obtained. The method has the greatest characteristics that the operation is simple, the conditionis mild, the raw material is cheap and easy to obtain, and the monomethylate of aromatic primary amine with high yield and high selectivity can be obtained. Posttreatment is simple, the production efficiency is improved, industrial mass production can be realized easily, and no equipment corrosion or environmental pollution can be caused.
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Paragraph 0031; 0034; 0035
(2019/05/15)
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- N -Methylation of ortho -substituted aromatic amines with methanol catalyzed by 2-arylbenzo [d] oxazole NHC-Ir(iii) complexes
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Seven new chelated cyclometalated Ir complexes of ABON,P, ABON,O, and ABON,C(carbene) based on a rigid and tunable 2-arylbenzo[d]oxazole backbone have been prepared for the N-methylation of amines. Among these three coordinated modes, ABON,C(carbene)-chelated iridium-based catalysts exhibited good performance in the monomethylation of aromatic amines with methanol (MeOH) as the green methylation reagent. The steric-modified synthesis of ABON,C(carbene) complexes was described. The most active ABON,C(carbene) complex with marginal steric hindrance as a catalyst was obtained from the benzoxazole ring without a substituent and methyl group of the benzimidazole ring on the N-heterocyclic carbene (NHC) ligand. A variety of amines including para- and meta-substituted aromatic amines, as well as heterocyclic amines, were formulated as suitable substrates. Importantly, this catalyst considerably promoted the yield of the N-methylation of ortho-substituted aromatic amines. Controlled kinetic experiments and deuterium-labeling reactions of these ortho-substituted amines were conducted under optimized conditions. On the basis of the experimental results, a plausible mechanism was proposed.
- Huang, Shuang,Hong, Xi,Cui, He-Zhen,Zhou, Quan,Lin, Yue-Jian,Hou, Xiu-Feng
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p. 5072 - 5082
(2019/04/17)
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- Highly selective hydrogenation of amides catalysed by a molybdenum pincer complex: Scope and mechanism
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A series of molybdenum pincer complexes has been shown for the first time to be active in the catalytic hydrogenation of amides. Among the tested catalysts, Mo-1a proved to be particularly well suited for the selective C-N hydrogenolysis of N-methylated formanilides. Notably, high chemoselectivity was observed in the presence of certain reducible groups including even other amides. The general catalytic performance as well as selectivity issues could be rationalized taking an anionic Mo(0) as the active species. The interplay between the amide CO reduction and the catalyst poisoning by primary amides accounts for the selective hydrogenation of N-methylated formanilides. The catalyst resting state was found to be a Mo-alkoxo complex formed by reaction with the alcohol product. This species plays two opposed roles-it facilitates the protolytic cleavage of the C-N bond but it encumbers the activation of hydrogen.
- Leischner, Thomas,Artús Suarez, Lluis,Spannenberg, Anke,Junge, Kathrin,Nova, Ainara,Beller, Matthias
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p. 10566 - 10576
(2019/12/02)
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- Synthesis of N-alkylamino benzene-alkyl ether and application thereof
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The invention discloses synthesis of N-alkylamino benzene-alkyl ether. The N-alkylamino benzene-alkyl ether is prepared by performing hydrogenation reduction and alkylation on the nitryl benzene-alkylether, and can be directly prepared from the amino benzene-alkyl ether. The invention further discloses application of the N-alkylamino benzene-alkyl ether as the gasoline additive, specifically thegasoline antiknock agent. An Octane value of the gasoline can be obviously improved when the 0.1-5.0% of the gasoline antiknock agent is added in the gasoline, and the knocking produced by the combustion of the gasoline in an engine is reduced.
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Paragraph 0036; 0037; 0038
(2019/01/08)
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- Selective N-monomethylation of primary anilines with dimethyl carbonate in continuous flow
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Selective N-monomethylation of anilines has been achieved under continuous flow conditions using dimethyl carbonate as a green methylating agent in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene. Our methodology takes advantage of the expanded process windows available in the continuous flow regime to safely induce monomethylation in superheated solvents at high pressure. We propose selective N-monomethylation is achieved via an in situ protection-deprotection pathway, which is supported by the observed reactivities of several putative reaction intermediates. The robust and scalable method was applicable to a broad range of primary aniline substrates including ortho-, meta-, and para-substituted anilines, as well as electron-rich and electron-deficient anilines. The synthetic precursor of diazepam, 5-chloro-2-(methylamino)benzophenone, was selectively synthesized under our optimized conditions.
- Seo, Hyowon,Bédard, Anne-Catherine,Chen, Willie P.,Hicklin, Robert W.,Alabugin, Alexander,Jamison, Timothy F.
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p. 3124 - 3128
(2017/12/11)
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- Electronic effect of substituents on anilines favors 1,4-addition to: Trans -β-nitrostyrenes: Access to N -substituted 3-arylindoles and 3-arylindoles
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A simple and an efficient method for the regioselective synthesis of N-alkyl/aryl/H 3-arylindole derivatives from N-substituted anilines and trans-β-nitrostyrenes has been described using 10 mol% of bismuth(iii) triflate as a catalyst in acetonitrile at 80 °C. The present protocol profits from the formation of new C-C and C-N bonds, broad substrate scope and moderate to good yields.
- Gattu, Radhakrishna,Bhattacharjee, Suchandra,Mahato, Karuna,Khan, Abu T.
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supporting information
p. 3760 - 3770
(2018/05/30)
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- N-Methylation of Amines with Methanol Catalyzed by a Cp?Ir Complex Bearing a Functional 2,2′-Bibenzimidazole Ligand
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A new type of Cp?Ir complex bearing a functional 2,2′-bibenzimidazole ligand was designed, synthesized, and found to be a highly effective and general catalyst for the N-methylation of a variety of amines with methanol in the presence of a weak base (0.3 equiv of Cs2CO3).
- Liang, Ran,Li, Shun,Wang, Rongzhou,Lu, Lei,Li, Feng
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supporting information
p. 5790 - 5793
(2017/11/10)
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- Stereospecific copper-catalyzed domino ring opening and sp3 C-H functionalization of activated aziridines with N-alkylanilines
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Copper efficiently catalyzed nucleophilic ring opening, sp3 C-H functionalization, and C-N bond formation in the presence of tert-butyl hydroperoxide to afford functionalized imidazolidines starting from N-sulfonylaziridines and Nalkylanilines. The products were obtained in high optical purities (95 → 99% ee) with excellent functional group tolerance.
- Sengoden, Mani,Bhowmick, Abhisikta,Punniyamurthy, Tharmalingam
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supporting information
p. 158 - 161
(2017/11/27)
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- Topical Intestinal Aminoimidazole Agonists of G-Protein-Coupled Bile Acid Receptor 1 Promote Glucagon Like Peptide-1 Secretion and Improve Glucose Tolerance
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The role of the G-protein-coupled bile acid receptor TGR5 in various organs, tissues, and cell types, specifically in intestinal endocrine L-cells and brown adipose tissue, has made it a promising therapeutical target in several diseases, especially type-2 diabetes and metabolic syndrome. However, recent studies have shown deleterious on-target effects of systemic TGR5 agonists. To avoid these systemic effects while stimulating glucagon-like peptide-1 (GLP-1) secreting enteroendocrine L-cells, we have designed TGR5 agonists with low intestinal permeability. In this article, we describe their synthesis, characterization, and biological evaluation. Among them, compound 24 is a potent GLP-1 secretagogue, has low effect on gallbladder volume, and improves glucose homeostasis in a preclinical murine model of diet-induced obesity and insulin resistance, making the proof of concept of the potential of topical intestinal TGR5 agonists as therapeutic agents in type-2 diabetes.
- Lasalle, Manuel,Hoguet, Vanessa,Hennuyer, Nathalie,Leroux, Florence,Piveteau, Catherine,Belloy, Lo?c,Lestavel, Sophie,Vallez, Emmanuelle,Dorchies, Emilie,Duplan, Isabelle,Sevin, Emmanuel,Culot, Maxime,Gosselet, Fabien,Boulahjar, Rajaa,Herledan, Adrien,Staels, Bart,Deprez, Benoit,Tailleux, Anne,Charton, Julie
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p. 4185 - 4211
(2017/06/05)
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- Base-oxidant promoted metal-free N-demethylation of arylamines
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A metal-free oxidative N-demethylation of arylamines with triethylamine as a base and tert-butyl hydroperoxide (TBHP) as oxidant is reported in this paper. The reaction is general, practical, inexpensive, non-toxic, and the method followed is environmentally benign, with moderate to good yields. [Figure not available: see fulltext.]
- Botla, Vinayak,Barreddi, Chiranjeevi,Daggupati, Ramana V,Malapaka, Chandrasekharam
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p. 1469 - 1473
(2016/09/19)
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- A Dual-Catalytic Strategy to Direct Asymmetric Radical Aminotrifluoromethylation of Alkenes
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A novel asymmetric radical aminotrifluoromethylation of alkenes has been developed for the first time, providing straightforward access to densely functionalized CF3-containing azaheterocycles bearing an α-tertiary stereocenter with excellent enantioselectivity. The key to success is not only the introduction of a Cu(I)/chiral phosphoric acid dual-catalytic system but also the use of urea with two acidic N-H as both the nucleophile and directing group. The utility of this method is illustrated by facile transformations of the products into other important compounds useful in organic synthesis and medicinal chemistry.
- Lin, Jin-Shun,Dong, Xiao-Yang,Li, Tao-Tao,Jiang, Na-Chuan,Tan, Bin,Liu, Xin-Yuan
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supporting information
p. 9357 - 9360
(2016/08/12)
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- NOVEL PYRIDAZONES AND TRIAZINONES FOR THE TREATMENT AND PROPHYLAXIS OF HEPATITIS B VIRUS INFECTION
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The invention provides novel compounds having the general formula wherein R1, R2, R3, X and a are as described in the description and in the claims, as well as or pharmaceutically acceptable salts thereof. The invention also contains compositions including the compounds and methods of using the compounds.
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Page/Page column 25; 26
(2016/02/29)
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- Copper(II)-catalyzed oxidative N-nitrosation of secondary and tertiary amines with nitromethane under an oxygen atmosphere
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The combination of a catalytic amount of Cu(OTf)2 and less than a stoichiometric amount of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) under an O2 atmosphere effectively promoted the N-nitrosation of both secondary aromatic/aliphatic amines and tertiary aromatic amines with nitromethane (CH3NO2) leading to the preparation of N-nitrosamine derivatives.
- Sakai, Norio,Sasaki, Minoru,Ogiwara, Yohei
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supporting information
p. 11638 - 11641
(2015/07/15)
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- Thiol activated prodrugs of sulfur dioxide (SO2) as MRSA inhibitors
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Drug resistant infections are becoming common worldwide and new strategies for drug development are necessary. Here, we report the synthesis and evaluation of 2,4-dinitrophenylsulfonamides, which are donors of sulfur dioxide (SO2), a reactive sulfur species, as methicillin-resistant Staphylococcus aureus (MRSA) inhibitors. N-(3-Methoxyphenyl)-2,4-dinitro-N-(prop-2-yn-1-yl)benzenesulfonamide (5e) was found to have excellent in vitro MRSA inhibitory potency. This compound is cell permeable and treatment of MRSA cells with 5e depleted intracellular thiols and enhanced oxidative species both results consistent with a mechanism involving thiol activation to produce SO2.
- Pardeshi, Kundansingh A.,Malwal, Satish R.,Banerjee, Ankita,Lahiri, Surobhi,Rangarajan, Radha,Chakrapani, Harinath
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p. 2694 - 2697
(2015/06/08)
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- Two consecutive palladium(II)-promoted C-H alkenylation reactions for the synthesis of 3-alkenylquinolones
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Highly substituted quinolones are obtained through an efficient and atom economical procedure that involves two consecutive palladium(II)-catalyzed C-H alkenylation reactions. A selective 6-endo intramolecular C-H alkenylation leads to 4-substituted quinolones that have been further functionalized at C-3 through a second intermolecular C-H alkenylation reaction.
- Ortiz-de-Elguea, Vernica,Sotomayor, Nuria,Lete, Esther
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supporting information
p. 463 - 473
(2015/03/05)
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- Mn(III)-based oxidative cyclization of N-aryl-3-oxobutanamides. facile synthesis and transformation of substituted oxindoles
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The oxidation of 3-oxo-N-phenylbutanamides 1 with manganese(III) acetate in ethanol afforded dimeric 3,3'-biindoline-2,2'-dione derivatives 3-5. A similar reaction of N,2-disubstituted N-aryl-3-oxobutanamides 6 in acetic acid produced 3-acetylindolin-2-ones 7 bearing various substituents in good to excellent yields. The acetylindolinones 7 were easily deacetylated by treatment using neutral alumina in diethyl ether. Both the acetylindolinones 7 and deacetylated indolinones 8 were transformed by reduction into the substituted 1H-indoles.
- Kikue, Nobutaka,Takahashi, Tetsuya,Nishino, Hiroshi
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p. 540 - 562
(2015/03/04)
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- IMIDAZOL- OR 1,2,4-TRIAZOL-DERIVATIVES AND THEIR USE
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The present invention is directed to novel compounds of formula (I), pharmaceutically acceptable salts or solvates thereof, and their use.
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Page/Page column 59
(2016/01/01)
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- Catalytic methylation of aromatic amines with formic acid as the unique carbon and hydrogen source
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A novel methodology is presented for the direct methylation of amines, using formic acid as a unique source of carbon and hydrogen. Based on ruthenium(II) catalysts, the formation of the N - CH3group proceeds via an efficient formylation/transfer hydrogenation pathway.
- Savourey, Solne,Lefvre, Guillaume,Berthet, Jean-Claude,Cantat, Thibault
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supporting information
p. 14033 - 14036
(2015/02/19)
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- Design and syntheses of highly emissive aminobenzopyrano-xanthene dyes in the visible and far-red regions
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New derivatives of aminobenzopyrano-xanthene (ABPX) dyes have been designed and synthesized with high fluorescence quantum yields in the visible and far-red regions. It was kinetically demonstrated that the structurally rigid conjugation of the xanthene moiety, which is closely related to the reduction of the nonradiative deactivation process, is an effective molecular design for the drastic enhancement of fluorescence emission efficiency.
- Kamino, Shinichiro,Murakami, Miho,Tanioka, Masaru,Shirasaki, Yoshinao,Watanabe, Keiko,Horigome, Jun,Ooyama, Yousuke,Enomoto, Shuichi
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supporting information
p. 258 - 261
(2014/01/23)
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- Alkaline earth metal ion induced coil-helix-coil transition of lysine-coumarin-azacrown hybrid foldamers with OFF-OFF-ON fluorescence switching
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A new metal-ion-responsive and fluorescent foldamer, OPLM8, composed of eight lysine-coumarin-azacrown units, has been designed and synthesized. The flexible OPLM8 can be forced into a well-defined helix structure only upon the addition of alkaline earth metal ions. The structural change is based on the crown ether moieties being positioned in the requisite arrangement along the peptide chain, that is, at i, i+4 spacing, such that the alkaline earth metal ions can mediate the formation of four sandwich complexes between them. Moreover, varying the chelator-to-metal-ion ratio from 2:1 to 1:1 resulted in disassembly of the sandwich complexes leading to collapse of the helical structure to a random coil. These metal-ion-induced structural transitions could not only be monitored by the CD amplitude change but also easily probed by unique OFF-OFF-ON fluorescence intensity changes from 0.7-fold to 14-fold as the structure changed from the folded helix to a random coil. To further verify that the helix formation was indeed induced by metal-ion complexation, two kinds of control octamers with only four metal-ion chelators on the side chains were studied. One, which was capable of forming two sandwich complexes between the i and i+4 residues, displayed a negative Cotton couplet with the magnitude of its A value close to half that of OPLM 8, and the second had four metal-ion chelators positioned in the same turn, and hence was incapable of forming intramolecular metal complexes and showed different induced CD signals. Collectively, the photospectroscopic data and the results of the control studies suggest that alkaline earth metal ions can efficiently promote the flexible octamer OPLM8 into a well-organized helix by the formation of sandwich complexes between substituents at an i, i+4 spacing. Switching off the helix: An alkaline earth metal ion responsive and fluorescence-detectable foldamer (OPLM8) has been designed and synthesized. Variation of the chelator-to-metal-ion ratio resulted in the assembly and disassembly of sandwich complexes between fluoroionophores with i, i+4 spacing on the peptide backbone, leading to the formation and collapse of the helical structure, and was probed by OFF-OFF-ON fluorescence switching (see graphic). Copyright
- Lin, Yu-Chen,Chen, Chao-Tsen
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supporting information
p. 2531 - 2538
(2013/03/28)
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- General and efficient method for direct N-monomethylation of aromatic primary amines with methanol
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The direct N-monomethylation of aromatic primary amines, including arylamines, arylsulfonamides and amino-azoles, using methanol as a methylating agent has been accomplished in the presence of a [CpIrCl2]2/NaOH system. From both synthetic and environmental points of view, the reaction is highly attractive because of low catalyst loading, broad substrate scope and excellent selectivities.
- Li, Feng,Xie, Jianjiang,Shan, Haixia,Sun, Chunlou,Chen, Lin
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p. 8645 - 8652
(2015/03/05)
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- SECOND-ORDER NONLINEAR OPTICAL COMPOUND AND NONLINEAR OPTICAL ELEMENT COMPRISING THE SAME
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Problem to Be Solved: to provide a chromophore having a far superior nonlinear optical activity to conventional chromophores and to provide a nonlinear optical element comprising said chromophore. Solution: a chromophore comprising a donor structure D, a π-conjugated bridge structure B, and an acceptor structure A, the donor structure D comprising an aryl group substituted with a substituted oxy group; and a nonlinear optical element comprising said chromophore.
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Page/Page column 111
(2012/07/14)
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- Nonlinear optical side-chain polymers post-functionalized with high-β chromophores exhibiting large electro-optic property
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Electro-optic side-chain polymers have been synthesized by the post-functionalization of methacrylate isocyanate polymers with novel phenyl vinylene thiophene vinylene bridge (FTC) nonlinear optical chromophores. For this application, FTC-based chromophores were modified in their electronic donor structure, exhibiting much larger molecular hyperpolarizabilities compared with the benchmark FTC. Of these new chromophores, absorption spectra, hyper-Rayleigh scattering experiment, and thermal analysis were carried out to confirm availability as effective nonlinear optical units for electro-optic side-chain polymers. The electro-optic coefficients (r33) of obtained polymers were investigated in the process of in situ poling by monitoring the temperature, current flow, poling field, and electro-optic signal. Compared with the nonsubstituted analogue, benxyloxy modified FTC chromophore significantly achieved higher nonlinear optical property, exhibiting molecular hyperpolarizability at 1.9 μm of 4600 × 10-30 esu and an r33 value of 150 pm/V at the wavelength of 1.31 μm. Synthesized electro-optic polymers showed high glass transition temperature (Tg), so that the temporal stability examination exhibited >78% of the electro-optic intensity remaining at 85 °C over 500 h. Copyright
- Piao, Xianqing,Zhang, Xianmin,Mori, Yuichi,Koishi, Masayuki,Nakaya, Akinari,Inoue, Shinichiro,Aoki, Isao,Otomo, Akira,Yokoyama, Shiyoshi
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- Synthesis and cytotoxicity studies of quinoline-3-carbonitrile derivatives
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A series of quinoline-3-carbonitrile derivatives were designed and synthesized. Their cytotoxicity in vitro against four cancer cell lines (A549, HT-29, MDA-MB-231 and SMMC-7721) were evaluated by standard MTT assay. The pharmacological results showed that most of the prepared compounds displayed excellent selective cytotoxicity toward SMMC-7721 cell line. Among them, compounds 7c, 7e, 11b, 11f and 11g were more active than Gefitinb against SMMC-7721 cell line.
- Zhang, Shu Lan,Zhai, Xin,Zhang, Shi Jiao,Yu, Hong Hao,Gong, Ping
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scheme or table
p. 939 - 942
(2011/11/13)
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- Selective monomethylation of anilines by Cu(OAc)2-promoted cross-coupling with MeB(OH)2
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N-Methylanilines are readily synthesized in high yields through the copper(ll)-promoted coupling of anilines and methylboronic acid. This method represents a new approach for the selective monomethylation of anilines, and it is the first reported example
- Gonzalez, Israel,Mosquera, Jesus,Guerrero, Cesar,Rodriguez, Ramon,Cruces, Jacobo
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supporting information; experimental part
p. 1677 - 1680
(2009/09/06)
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- Synthesis of a new bifunctionalised fluorescent label and physical properties of the bound form on model peptide of troponin C
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A new bifunctional fluorescent label, BRos, was synthesised in order to monitor protein dynamics using fluorescence microscopy, and the photophysical properties were compared with those of bifunctionalised rhodamine, BRho. In a labelling experiment with a model peptide of troponin C, which regulates muscle contraction and relaxation, it was found that BRos was bound to the peptide through two linkages and provided a homogeneous compound, whereas BRho gave a pair of diastereomers having different physical properties in NMR and HPLC analyses. This journal is The Royal Society of Chemistry.
- Hirayama, Tasuku,Iyoshi, Shohei,Taki, Masayasu,Maeda, Yuichiro,Yamamoto, Yukio
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p. 2040 - 2045
(2008/02/12)
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- Tricyclic dihydroquinoline derivatives,method for preparing same and pharmaceutical compositions containing same
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Compound of formula (I): wherein: represents a single or double bond, represents a ring system selected from R6a, R6b, R6c, R6d, X and Y are as defined in the description, R1 represents a hydrogen atom or a group selected from aryl, heteroaryl, cycloalkyl, optionally substituted alkyl, and COR8 wherein R8 is as defined in the description, R2, R3, R4 and R5, which may be the same or different, each represent: a hydrogen atom, a halogen atom, an alkyl group,. an alkoxy group, a hydroxy group, a polyhaloalkyl group, a nitro group, an optionally substituted amino group, a group of formula wherein m represents an integer such that 1≦m≦4, or R2 with R3, or R3 with R4, or R4 with R5, form, together with the carbon atoms carrying them, an optionally substituted, 5- to 12-membered, mono- or bi-cyclic, aromatic or non-aromatic group optionally containing 1 or 2 hetero atoms selected from O, S and N, R10 represents a hydrogen atom or an alkyl group, Ar represents an aryl, heteroaryl or arylalkyl group, its optical isomers, addition salts thereof with a pharmaceutically acceptable acid, and hydrates and solvates thereof.
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- One-pot homolytic aromatic substitutions/HWE olefinations under microwave conditions for the formation of a small oxindole library
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(Chemical Equation Presented) An efficient one-pot sequence comprising a homolytic aromatic substitution followed by an ionic Horner Wadsworth-Emmons olefination for the preparation of a small library of α,β-unsaturated oxindoles is presented. Microwave-induced heating is used to conduct these reactions. The homolytic aromatic substitution is mediated by the persistent radical effect.
- Teichert, Antje,Jantos, Katja,Harms, Klaus,Studer, Armido
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p. 3477 - 3480
(2007/10/03)
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- Benzopyranone and quinolone inhibitors of ras farnesyl transferase
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The present invention provides ras farnesyl transferase inhibiting compounds of Formula I The present invention also provides a method of treating cancer and treating or preventing restenosis or atherosclerosis. Also provided by the present invention is a pharmaceutically acceptable composition containing a compound of Formula I.
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- N-methylanilines from benzylic azides
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Benzylic azides are converted into N-methylanilines efficiently in the presence of a Bronsted or Lewis acid and Et3SiH. The combination of SnCl4/Et3SiH and 4-n-butylbenzyl azide appears to form an aminodiazonium trichlorostannate(II), which undergoes the rearrangement to an iminium salt that is then reduced to N-methyl-4-n-butylaniline by Et3SiH.
- Lopez, Francisco J.,Nitzan, Dov
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p. 2071 - 2074
(2007/10/03)
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- N-DEMETHYLATION OF N,N-DIMETHYLANILINES BY PHOTOEXCITED 3-NITROCHLOROBENZENE
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The title reaction proceeds via initial electron transfer (rather than hydrogen atom transfer) from the amine to the photoexcited nitro compound, as demonstrated by methoxy substitution in the substrate and absence of CH3/CD3-discrimination.
- Doepp, Dietrich,Heufer, Joerg
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p. 1553 - 1556
(2007/10/02)
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- Kinetics and Mechanism of the Fischer-Hepp Rearrangement and Denitrosation. Part 10. Reactions of 3-Methoxy-N-methyl-N-nitrosoaniline
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Further evidence is presented in favour of an intramolecular mechanism for the acid-catalysed Fischer-Hepp rearrangement of aromatic N-nitrosamines, both in water and in ethanol solvent.In aqueous acid 3-methoxy-N-methyl-N-nitrosoaniline (IV) gives the rearrangement product 3-methoxy-N-methyl-4-nitrosoaniline (V) in >90percent yield.This figure drops a little to a constant 85percent in the presence of one of three conventional 'nitrite traps', hydrazoic acid, hydrazine, and sulphamic acid and over a five-fold range of concentration of each.Additionally the observed first-order rate constant (k0) is the same in the whole series.When nucleophilic species -, Br-, SCN- and SC(NH2)2> are added the yield of (V) drops and the product of denitrosation, 3-methoxy-N-methyl-aniline (VI), is also observed.The effect is most marked for the most powerful nucleophiles - and SC(NH2)2>.At the same time k0 increases with increasing nucleophile concentration.The results are wholly consistent with a mechanism involving parallel reactions of the protonated N-nitrosamine to give either the product of denitrosation (by nucleophile attack) which is normally reversible, or that of rearrangement where the nucleophile is not involved, and which is irreversible.The results cannot be accounted for in terms of the older intermolecular mechanism whereby the rearrangement product arises by conventional electrophilic C-nitrosation involving both the products of denitrosation.This implies strongly that the rearrangement is an intramolecular process.Similar results are reported for the variation of yields and rate constants with added nucleophiles for the same reaction in acidified ethanol, so that it is very likely that the same mechanism operates in that solvent.
- Williams, D. Lyn H.
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p. 801 - 804
(2007/10/02)
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- Kinetics and Mechanism of the Hydrolysis of Anilide Acetals
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A kinetic study of the hydrolysis of anilide acetals ArC(OMe)2NMeAr' is reported.At high pH (>10) a pH independent C-O cleavage reaction is observed producing methanol and benzimidatonium ion; the latter is further hydrolyzed to amide and ester products.Substituent and solvent effects support a simple ionizaiton mechanism with a transition state near the ion.At pH + catalysis attributable to pre-equilibrium protonation followed by rate-determining cleavage.Estimation of the pKa of the protonated anilide acetal (-1) provides an estimate of its rate of C-N cleavage (ca.108 s-1) which is near the diffusion limit.At pH 7 there is a change in the rate-determining step in product formation in this C-N cleavage reaction, and what is observed kinetically is the decomposition of the hemiorthoester ArC(OMe)2OH, the product of hydration of the dialkoxy carbocation.The principal piece of evidence for the changeover is the observation that the rate constants in acid solution are independent of the aniline moiety of the anilide acetal.
- McClelland, Robert A.,Patel, Geeta
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p. 6908 - 6911
(2007/10/02)
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- Use of nuclear magnetic resonance contact shifts to study the stability of paramagnetic coordination complexes. Bis(2,4-pentanedionato)nickel(II) complexes of substituted anilines
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The use of nuclear magnetic resonance contact shifts of ligands in paramagnetic coordination complexes to measure relative stability constants for the complexes is demonstrated. Bis(2,4-pentanedionato)nickel(II) complexes of meta-, para-, and N-substituted anilines are investigated. The effects of meta and para substituents on the stability constants are well described by a blend of the inductive and resonance effect parameters σI and σR. N-Methylation decreases the stability of the complex. N-Methyl contact shifts are strongly dependent on the meta or para substituents and linearly related to the stability of the complex.
- Rakshys Jr.
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p. 1521 - 1525
(2007/10/05)
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