- Effect of the ancillary ligand in N-heterocyclic carbene iridium(III) catalyzed N-alkylation of amines with alcohols
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A series of air-stable N-heterocyclic carbene (NHC) Ir(III) complexes (Ir1-6), bearing various combinations of chlorine, pyridine and NHC ligands, were assayed for the N-alkylation of amines with alcohols. It was found that Ir3, with two monodentate 1,3-bis-methyl-imidazolylidene (IMe) ligands, emerged as the most active complex. A large variety of amines and primary alcohols were efficiently converted into mono-N-alkylated amines in 53–96% yields. As a special highlight, for the challenging MeOH, selective N-monomethylation could be achieved using KOH as a base under an air atmosphere. Moreover, this catalytic system was successfully applied to the gram-scale synthesis of some valuable compounds.
- Feng, Xinshu,Huang, Ming
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- Ruthenium(ii) complexes with N-heterocyclic carbene-phosphine ligands for theN-alkylation of amines with alcohols
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Metal hydride complexes are key intermediates forN-alkylation of amines with alcohols by the borrowing hydrogen/hydrogen autotransfer (BH/HA) strategy. Reactivity tuning of metal hydride complexes could adjust the dehydrogenation of alcohols and the hydrogenation of imines. Herein we report ruthenium(ii) complexes with hetero-bidentate N-heterocyclic carbene (NHC)-phosphine ligands, which realize smart pathway selection in theN-alkylated reactionviareactivity tuning of [Ru-H] species by hetero-bidentate ligands. In particular, complex6cbwith a phenyl wingtip group and BArF?counter anion, is shown to be one of the most efficient pre-catalysts for this transformation (temperature is as low as 70 °C, neat conditions and catalyst loading is as low as 0.25 mol%). A large variety of (hetero)aromatic amines and primary alcohols were efficiently converted into mono-N-alkylated amines in good to excellent isolated yields. Notably, aliphatic amines, challenging methanol and diamines could also be transformed into the desired products. Detailed control experiments and density functional theory (DFT) calculations provide insights to understand the mechanism and the smart pathway selectionvia[Ru-H] species in this process.
- Huang, Ming,Li, Yinwu,Lan, Xiao-Bing,Liu, Jiahao,Zhao, Cunyuan,Liu, Yan,Ke, Zhuofeng
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supporting information
p. 3451 - 3461
(2021/05/03)
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- Novel phosphoramidite ligand, preparation method thereof and application thereof in asymmetric carbonylation reaction
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I Application of the asymmetric II carbonylating reaction strategy, and the synthetic problems of the hexahydropyrrolindole alkaloid and the dimeric cyclic amine alkaloid are effectively solved by using the monodentate chiral ligand to solve the problem of low enantioselectivity in the asymmetric domino Heck Heck and carbonylation reaction.
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Paragraph 0052-0054; 0056
(2021/09/29)
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- Selective mono-N-methylation of nitroarenes with methanol catalyzed by atomically dispersed NHC-Ir solid assemblies
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A series of N-heterocyclic carbene-iridium (NHC-Ir) coordination assemblies based on bis-pyrenoimidazolium salts are prepared, and shown to function as efficient solid molecular catalysts in selective mono-N-methylation of nitroarenes with methanol under mild conditions. The atomically dispersed active Ir(I) centers and the large π-conjugation rings endow the solid catalysts with an exceptionally high activity and selectivity for a broad substrate scope. Such solid NHC-Ir coordination assemblies are robust, which can be easily recovered and reused more than 10 runs without significant loss of their catalytic activity and selectivity. When combined with a subsequent formylation using the same solid catalysts under ambient conditions, this novel protocol can afford diverse formamides in excellent yields, further highlighting the applicability of the present solid catalysts for an efficient diversification of nitroarenes to a broad number of functional amines.
- Chen, Jiangbo,Chen, Zhe-Ning,Tu, Tao,Wang, Jiaquan,Wen, Daheng,Wu, Jiajie,Xu, Xin,Zheng, Qingshu
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p. 337 - 344
(2020/07/03)
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- EffectiveN-methylation of nitroarenes with methanol catalyzed by a functionalized NHC-based iridium catalyst: a green approach toN-methyl amines
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Compound [IrBr(CO)2(κC-tBuImCH2PyCH2OMe)] featuring a flexible pyridine/OMe functionalized NHC ligand κ1C coordinated efficiently catalyzes the selectiveN-monomethylation of nitroarenes using methanol as both the reducing agent and the C1 source. A range of functionalized nitroarenes including heterocyclic or sterically hindered derivatives have been efficiently converted to the correspondingN-monomethyl amines in good yields at low catalyst loadings using sub-stoichiometric amounts of Cs2CO3as a base. Mechanistic investigations support a borrowing-hydrogen mechanism in which methanol acts as the hydrogen source and methylating agent. Further, the hydrogen transfer reduction of nitrobenzene to aniline under optimized reaction conditions should proceed through a direct mechanism involving nitrosobenzene andN-phenylhydroxylamine intermediates.
- González-Lainez, Miguel,Jiménez, M. Victoria,Passarelli, Vincenzo,Pérez-Torrente, Jesús J.
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p. 3458 - 3467
(2020/06/17)
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- Highly Efficient Binuclear Copper-catalyzed Oxidation of N,N-Dimethylanilines with O2
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A binuclear copper-salicylate complex, [Cu(Sal)2(NCMe)]2 (Sal=salicylate), was found to be an active catalyst for the oxidation of N,N-dimethylanilines by O2, affording the corresponding N-methyl-N-phenylformamides as major products. The reactions were carried out with a O2 balloon and the S/C (substrate/catalyst ratio) of the model reaction could be up to 1×105, providing a practical and highly efficient catalytic protocol for accessing N-methyl-N-phenylformamides.
- Liu, Yuxia,Yan, Yonggang,Xue, Dong,Wang, Zhongfu,Xiao, Jianliang,Wang, Chao
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p. 2221 - 2225
(2020/03/23)
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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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- Expedient stereospecific Co-catalyzed tandem C-N and C-O bond formation of: N -methylanilines with styrene oxides
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Cobalt(ii)-catalyzed stereospecific coupling of N-methylanilines with styrene oxides is developed via tandem C-N and C-O bond formation using tert-butyl hydroperoxide (TBHP) as an oxidant. Optically active epoxide can be reacted with high optical purity.
- Satheesh, Vanaparthi,Vivek Kumar, Sundaravel,Punniyamurthy, Tharmalingam
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supporting information
p. 11813 - 11816
(2018/12/01)
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- Application of Diazaphospholidine/Diazaphospholene-Based Bisphosphines in Room-Temperature Nickel-Catalyzed C(sp2)-N Cross-Couplings of Primary Alkylamines with (Hetero)aryl Chlorides and Bromides
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We report herein on the synthesis and catalytic application of a family of o-phenylene-bridged bisphosphine ancillary ligands featuring a bulky N-heterocyclic phosphine (NHP) donor fragment paired with an adjacent PR2 donor group (R = alkyl, aryl), whereby the incorporation of phosphorus into either a saturated or unsaturated heterocyclic ring serves as a means of modulating the donicity of the NHP fragment. Screening of these ancillary ligands in representative nickel-catalyzed C(sp2)-N cross-coupling test reactions allowed for the identification of one variant, featuring a saturated NHP structure and an adjacent diphenylphosphino donor group (i.e., NHP-DalPhos), as being particularly effective in reactions involving primary alkylamines. Notably, application of the derived precatalyst (NHP-DalPhos)NiCl(o-tolyl) (C1) enabled the typically challenging monoarylation of structurally diverse primary alkylamines with (hetero)aryl chlorides or bromides at room temperature. Also described are the results of our comparative density functional theory computational analysis of nickel-catalyzed primary alkylamine C(sp2)-N cross-couplings employing PAd-DalPhos or NHP-DalPhos.
- Gatien, Alexandre V.,Lavoie, Christopher M.,Bennett, Raymond N.,Ferguson, Michael J.,McDonald, Robert,Johnson, Erin R.,Speed, Alexander W. H.,Stradiotto, Mark
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p. 5328 - 5339
(2018/05/14)
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- Highly Selective N-Monomethylanilines Synthesis from Nitroarene and Formaldehyde via Kinetically Excluding of the Thermodynamically Favorable N,N-Dimethylation Reaction
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The synthesis of N-monomethylamine remains a challenging topic because the N,N-dimethylation reaction is thermodynamically favorable. In this work, the kinetically controlled N-monomethylamine synthesis from nitroarene and paraformaldehyde/H2 is reported to have superhigh N-monomethylamine selectivity in the presence of a Pd/TiO2 catalyst. The superior selectivity should be attributed to the preferential adsorption of the primary amine over N-monomethylamine on the Pd/TiO2 surface, as elucidated by NH3/Me2NH-TPD, while the excellent catalytic activity could be associated with the good H2 activation ability and high amine adsorbing capacity of the catalyst, as elucidated by NH3-TPD and H2-TPR tests. Good results were obtained with a variety of nitroarenes containing methyl, methoxyl, hydroxyl, fluoride, trifluoromethyl, ester, and amide substituents as starting materials, and the potential synthetic utility of this protocol in pharmaceutical is illustrated by N-monomethylation of drug molecules, such as clinidipine, nimesulide, procaine, and methyl aminosalicylate.
- Wang, Hongli,Yuan, Hangkong,Yang, Benqun,Dai, Xingchao,Xu, Shan,Shi, Feng
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p. 3943 - 3949
(2018/05/23)
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- Identification of thienopyridine carboxamides as selective binders of HIV-1: Trans Activation Response (TAR) and Rev Response Element (RRE) RNAs
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Small organic molecules that can selectively bind to RNA with specificity are relatively rare. Here we report the synthesis, biochemical and structural studies of thienopyridine carboxamide derivatives with the capacity of selectively recognizing and binding with HIV-1 TAR and RRE RNAs that are essential elements for viral replication.
- Li, Xue-Dong,Liu, Li,Cheng, Liang
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p. 9191 - 9196
(2019/01/03)
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- Formation of Phenyliodonio-Substituted Spirofurooxindole Trifluoroacetates from N-Substituted 3-Oxopentanediamides via Phenyliodine Bis(trifluoroacetate)-Mediated Oxidative Cascade Reactions
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The reaction of N-substituted 3-oxopentanediamides with phenyliodine bis(trifluoroacetate) (PIFA) was found to give a novel class of phenyliodonio-substituted spirofurooxindole trifluoroacetates under metal-free conditions. The reaction is postulated to proceed via a cascade process involving an oxidative C—O bond formation, an oxidative C—C bond formation and a final iodination step. (Figure presented.).
- Hu, Bei,Cao, Yang,Zhang, Bobo,Zhang-Negrerie, Daisy,Du, Yunfei
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supporting information
p. 2542 - 2548
(2017/08/16)
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- Improved and General Manganese-Catalyzed N-Methylation of Aromatic Amines Using Methanol
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A novel lutidine-based manganese PNP-pincer complex has been synthesized for the selective N-methylation of aromatic amines with methanol. Using borrowing hydrogen methodology, a selection of differently functionalized aniline derivatives is selectively methylated in good yields.
- Neumann, Jacob,Elangovan, Saravanakumar,Spannenberg, Anke,Junge, Kathrin,Beller, Matthias
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supporting information
p. 5410 - 5413
(2017/04/27)
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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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- N′-3-(Trifluoromethyl)phenyl Derivatives of N-Aryl-N′-methylguanidines as Prospective PET Radioligands for the Open Channel of the N-Methyl- d -aspartate (NMDA) Receptor: Synthesis and Structure-Affinity Relationships
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N-Methyl-d-aspartate (NMDA) receptor dysfunction has been linked to several neuropsychiatric disorders, including Alzheimer's disease, epilepsy, drug addiction, and schizophrenia. A radioligand that could be used with PET to image and quantify human brain NMDA receptors in the activated "open channel" state would be useful for research on such disorders and for the development of novel therapies. To date, no radioligands have shown well-validated efficacy for imaging NMDA receptors in human subjects. In order to discover improved radioligands for PET imaging, we explored structure-affinity relationships in N′-3-(trifluoromethyl)phenyl derivatives of N-aryl-N′-methylguanidines, seeking high affinity and moderate lipophilicity, plus necessary amenability for labeling with a positron-emitter, either carbon-11 or fluorine-18. Among a diverse set of 80 prepared N′-3-(trifluoromethyl)phenyl derivatives, four of these compounds (13, 19, 20, and 36) displayed desirable low nanomolar affinity for inhibition of [3H](+)-MK801 at the PCP binding site and are of interest for candidate PET radioligand development.
- Naumiec, Gregory R.,Jenko, Kimberley J.,Zoghbi, Sami S.,Innis, Robert B.,Cai, Lisheng,Pike, Victor W.
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p. 9722 - 9730
(2016/01/12)
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- New N-aryl-N′-(3-(substituted)phenyl)-N′-methylguanidines as leads to potential PET radioligands for imaging the open NMDA receptor
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An expansive set of N-aryl-N′-(3-(substituted)phenyl)-N′-methylguanidines was prepared in a search for new leads to prospective PET ligands for imaging of the open channel of the N-methyl-d-aspartate (NMDA) receptor in vivo. The N-aryl rings and their substituents were varied, whereas the N-methyl group was maintained as a site for potential labeling with the positron-emitter, carbon-11 (t1/2 = 20.4 min). At micromolar concentration, over half of the prepared compounds strongly inhibited the binding of [3H]TCP to its binding site in the open NMDA receptor in vitro. Four ligands displayed affinities that are similar or superior to those of the promising SPECT radioligand ([123I]CNS1261). The 3′-dimethylamino (19; Ki 36.7 nM), 3′-trifluoromethyl (20; Ki 18.3 nM) and 3′-methylthio (2; Ki 39.8 nM) derivatives of N-1-naphthyl-N′-(phenyl)-N′-methylguanidine were identified as especially attractive leads for PET radioligand development.
- Naumiec, Gregory R.,Cai, Lisheng,Pike, Victor W.
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supporting information
p. 225 - 228
(2015/03/03)
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- 1,7-palladium migration via C-H activation, followed by intramolecular amination: Regioselective synthesis of benzotriazoles
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A novel 1,7-palladiummigration-cyclization-dealkylation sequence for the regioselective synthesis of benzotriazoles has been developed. These reactions proceed in excellent yields with high regioselectivities. The mechanism of the reaction has also been investigated.
- Zhou, Jun,He, Jianjun,Wang, Binjie,Yang, Weijun,Ren, Hongjun
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supporting information; experimental part
p. 6868 - 6870
(2011/06/21)
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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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- Copper-catalyzed enantioselective propargylic amination of propargylic esters with amines: Copper-allenylidene complexes as key intermediates
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The scope and limitations of the copper-catalyzed propargylic amination of various propargylic esters with amines are presented, where optically active diphosphines such as Cl-MeO-BIPHEP and BINAP work as good chiral ligands. A variety of secondary amines are available as nucleophiles for this catalytic reaction to give the corresponding propargylic amines with a high enantioselectivity. The results of some stoichiometric and catalytic reactions indicate that the catalytic amination proceeds via copper-allenylidene complexes formed in situ, where the attack of amines to the electrophilic γ-carbon atom in the allenylidene complex is an important step for the stereoselection. Investigation of the relative rate constants for the reaction of several para-substituted propargylic acetates with N-methylanilines reveals that the formation of the copper-allenylidene complexes is involved in the rate-determining step. The result of the density functional theory calculation on a model reaction also supports the proposed reaction pathway involving copper-allenylidene complexes as key intermediates. The catalytic procedure presented here provides a versatile and direct method for the preparation of a variety of chiral propargylic amines.
- Hattori, Gaku,Sakata, Ken,Matsuzawa, Hiroshi,Tanabe, Yoshiaki,Miyake, Yoshihiro,Nishibayashi, Yoshiaki
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supporting information; experimental part
p. 10592 - 10608
(2010/09/10)
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- N-aryl(thio)anthranilic acid amide derivatives, their preparation and their use as VEGF receptor tyrosine kinase inhibitors
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Described are compounds of formula (I), wherein W is O or S; X is NR8; Y is CR9R10-(CH2)n wherein R9 and R10 are independently of each other hydrogen or lower alkyl, and n is an integer of
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- Soluble salts of 4-amino-2-(4,4-dimethylimidazolidin-2-on-1-yl) pyrimidine-5-carboxylic acid N-methyl-N-(3-trifluoromethylphenyl)-amide, a process for the preparation thereof, the use thereof as pharmaceuticals and starting materials
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Soluble salts of 4-amino-2-(4,4-dimethylimidazolidin-2-on-1-yl)pyrimidine-5-carboxylic acid N-methyl-N-(3-trifluoromethylphenyl)amide, a process for the preparation thereof, the use thereof as pharmaceuticals and starting materials. Salts, which are solub
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- 1H, 2H, 19F, 14N ENDOR and TRIPLE Resonance Investigations of Substituted Flavin Radicals in Their Different Protonation States
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A variety of isotopically labelled and/or substituted flavins have been converted into their corresponding radical states.Cation and neutral radicals were generated chemically and anion radicals were obtained electrochemically.By performing ENDOR and TRIPLE resonance experiments, complete sets of hyperfine coupling constants including their signs were accessible.The hyperfine data allowed (a) identification of the radical state present, (b) information to be obtained about the preferred conformational arrangements of the substituents and (c) conclusions to be drawn about the influences of the substituents on the spin density distributions of the different radical states. - KEY WORDS: ENDOR, TRIPLE resonance spectroscopy; Flavin radicals; Electrochemical generation of radicals.
- Weilbacher, E.,Helle, N.,Elsner, M.,Kurreck, H.,Mueller, F.,Allendoerfer, R. D.
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