- Expedient Synthesis of 2-Iminothiazolidines via Telescoping Reactions Including Iron-Catalyzed Nitrene Transfer and Domino Ring-Opening Cyclization (DROC)
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2-iminothiazolidines are important scaffold for pharmaceutical drugs. Herein, we describe a fast and easy procedure for their synthesis by a telescoping reaction integrating an iron-catalyzed nitrene transfer under mild conditions. The aziridination react
- Coin, Guillaume,de Ferrier de Montal, Oriane,Dubourdeaux, Patrick,Latour, Jean-Marc
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- On the enantioselectivity of aziridination of styrene catalysed by copper triflate and copper-exchanged zeolite Y: Consequences of the phase behaviour of enantiomeric mixtures of N-arene-sulfonyl-2-phenylaziridines
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By synthesising S-2-phenyl-N-(4-nitrophenyl)aziridine from S-phenylglycinol, it has been demonstrated that the aziridination of styrene by [N-(4-nitrobenzenesulfonyl)imino]phenyliodinane (nosyliminophenyliodinane, PhINNs) in the presence of S,S-2,2′-isopr
- Jeffs, Laura,Arquier, Damien,Kariuki, Benson,Bethell, Donald,Page, Philip C. Bulman,Hutchings, Graham J.
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- Catalytic asymmetric heterogeneous aziridination of styrene using Cu 2+ -exchanged zeolite Y: Effect of the counter-cation on enantioselectivity and on the reaction profile
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Effective catalysts have Cu2+ -exchange levels of ca. 40-60% of the maximum concentration for electroneutrality and, consequently, Cu-zeolite Y catalysts contain an additional counter-cation (H+, Li-, Na+, Ksup
- Gullick, John,Ryan, Darragh,McMorn, Paul,Bethell, Donald,King, Frank,Hancock, Frederick,Hutchings, Graham
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- CO2-activated NaClO-5H2O enabled smooth oxygen transfer to iodoarene: A highly practical synthesis of iodosylarene
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A safe, rapid, and environmentally friendly synthesis of iodosylarene (ArIO) has been developed using NaClO under a carbon dioxide (CO2) atmosphere. Exposure of iodoarene to NaClO-5H2O in acetonitrile under CO2 (1 atm) resulted in the clean formation of ArIO within 10 minutes in high yield. The absence of a base in this method enables the direct use of in-situ-generated iodosylarene not only for a variety of oxidative transformations (synthesis of sulfilimine, pentavalent bismuth, benzyne adduct, etc.), but also for the synthesis of iodonium ylide and imino-λ3-iodane in one pot.
- Miyamoto, Kazunori,Watanabe, Yuichiro,Takagi, Taisei,Okada, Tomohide,Toyama, Takashi,Imamura, Shinji,Uchiyama, Masanobu
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- Ligand Redox Noninnocence in [CoIII(TAML)]0/- Complexes Affects Nitrene Formation
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The redox noninnocence of the TAML scaffold in cobalt-TAML (tetra-amido macrocyclic ligand) complexes has been under debate since 2006. In this work, we demonstrate with a variety of spectroscopic measurements that the TAML backbone in the anionic complex [CoIII(TAMLred)]- is truly redox noninnocent and that one-electron oxidation affords [CoIII(TAMLsq)]. Multireference (CASSCF) calculations show that the electronic structure of [CoIII(TAMLsq)] is best described as an intermediate spin (S = 1) cobalt(III) center that is antiferromagnetically coupled to a ligand-centered radical, affording an overall doublet (S = 1/2) ground-state. Reaction of the cobalt(III)-TAML complexes with PhINNs as a nitrene precursor leads to TAML-centered oxidation and produces nitrene radical complexes without oxidation of the metal ion. The ligand redox state (TAMLred or TAMLsq) determines whether mono-or bis-nitrene radical complexes are formed. Reaction of [CoIII(TAMLsq)] or [CoIII(TAMLred)]- with PhINNs results in the formation of [CoIII(TAMLq)(Na¢Ns)] and [CoIII(TAMLq)(Na¢Ns)2]-, respectively. Herein, ligand-to-substrate single-electron transfer results in one-electron-reduced Fischer-type nitrene radicals (Na¢Ns-) that are intermediates in catalytic nitrene transfer to styrene. These nitrene radical species were characterized by EPR, XANES, and UV-vis spectroscopy, high-resolution mass spectrometry, magnetic moment measurements, and supporting CASSCF calculations.
- De Bruin, Bas,Oudsen, Jean-Pierre H.,Rietdijk, Niels R.,Siegler, Maxime A.,Tepaske, Martijn A.,Tromp, Moniek,Van Der Vlugt, Jarl Ivar,Van Leest, Nicolaas P.,Venderbosch, Bas
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supporting information
p. 552 - 563
(2020/02/20)
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- Uncatalyzed Oxidative C?H Amination of 9,10-Dihydro-9-Heteroanthracenes: A Mechanistic Study
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A new method for the one-step C?H amination of xanthene and thioxanthene with sulfonamides is reported, without the need for any metal catalyst. A benzoquinone was employed as a hydride (or two-electron and one-proton) acceptor. Moreover, a previously unknown and uncatalyzed reaction between iminoiodanes and xanthene, thioxanthene and dihydroacridines (9,10-dihydro-9-heteroanthracenes or dihydroheteroanthracenes) is disclosed. The reactions proceed through hydride transfer from the heteroarene substrate to the iminoiodane or benzoquinone, followed by conjugate addition of the sulfonamide to the oxidized heteroaromatic compounds. These findings may have important mechanistic implications for metal-catalyzed C?H amination processes involving nitrene transfer from iminoiodanes to dihydroheteroanthracenes. Due to the weak C?H bond, xanthene is an often-employed substrate in mechanistic studies of C?H amination reactions, which are generally proposed to proceed via metal-catalyzed nitrene insertion, especially for reactions involving nitrene or imido complexes that are less reactive (i.e., less strongly oxidizing). However, these substrates clearly undergo non-catalyzed (proton-coupled) redox coupling with amines, thus providing alternative pathways to the widely assumed metal-catalyzed pathways.
- van Leest, Nicolaas P.,Grooten, Lars,van der Vlugt, Jarl Ivar,de Bruin, Bas
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supporting information
p. 5987 - 5993
(2019/04/03)
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- Double Functionalization of Styrenes by Cu-Mediated Assisted Tandem Catalysis
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The double functionalization of styrenes through Cu-mediated assisted tandem catalysis was developed. The reaction was initiated by Cu-catalyzed aziridination and the subsequent nucleophilic ring-opening, which was triggered by the addition of (NH4)2S2O8 as an oxidant of Cu-catalyst to form a variety of C–C and C–X bonds. The expansion to three contiguous catalytic cycles led to the synthesis of functionalized indolines by one-pot operation.
- Kawauchi, Daichi,Ueda, Hirofumi,Tokuyama, Hidetoshi
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supporting information
p. 2056 - 2060
(2019/03/13)
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- Design, synthesis, and antiplasmodial evaluation of a series of novel sulfoximine analogues of carbohydrate-based thiochromans
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Sulfone/sulfoxide-containing carbohydrate derived thiochromans were found to be highly active antiplasmodial agents. However, the inability of the sulfone/sulfoxide functional groups for further derivatization and manipulation limited the potential for further exploration. In this study, based on the interesting and important physicochemical properties, as well as amenability of sulfoximines (isosters of sulfones) for further derivatization, a series of novel sulfoximine-type carbohydrate-derived thiochroman derivatives have been successfully synthesized, characterized, and evaluated for their antiplasmodial activity. Although the replacement of the sulfone functional group with a sulfoximine unit improved the antiplasmodial activity of the scaffolds, the activity was highly dependent on the configuration of the stereogenic centre at the sulfur atom. Moreover, analysis of the crystal structures of the sulfoximine analogues revealed that the bond between the sulfur and nitrogen atoms of the sulfoximine functional group is not a true double bond but rather a polarized single bond.
- Chizema, Munashe,Mabasa, Tommy F.,Hoppe, Heinrich C.,Kinfe, Henok H.
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p. 254 - 261
(2018/11/23)
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- Iron(MCP) Complexes Catalyze Aziridination with Olefins As Limiting Reagents
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Herein described are the first efficient nitrogen-atom transfer reactions mediated by iron N,N′-dimethyl-N,N′-bis(2-pyridinylmethyl)cyclohexane-1,2-diamine- (MCP-) and 2-({1-[(pyridin-2-ylmethyl)pyrrolidin-2-yl]pyrrolidin-1-yl}methyl)pyridine-type (PDP-type) complexes. These catalysts affect styrene aziridination under mild conditions based on a limiting quantity of olefin substrate.
- Shehata, Mina F.,Ayer, Suraj K.,Roizen, Jennifer L.
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p. 5072 - 5081
(2018/05/15)
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- Safer Synthesis of (Diacetoxyiodo)arenes Using Sodium Hypochlorite Pentahydrate
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A practical method for the preparation of (diacetoxyiodo)arene ArI(OAc)2 is described. The use of commercially available sodium hypochlorite pentahydrate (NaClO·5H2O) enabled safe, rapid, and inexpensive oxidation of iodoarenes with electron-withdrawing and -donating substituents. The method allows tandem divergent access to synthetically useful organo-λ3-iodanes such as hydroxyl(tosyloxy)iodobenzene, iodosylbenzene, iodonium ylide, etc.
- Watanabe, Ayumi,Miyamoto, Kazunori,Okada, Tomohide,Asawa, Tomotake,Uchiyama, Masanobu
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p. 14262 - 14268
(2018/11/23)
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- Copper(I) catalyzed regioselective asymmetric alkoxyamination of aryl enamide derivatives
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The copper(I) catalyzed reaction of an enamide with an iminoiodane, in the presence of an alcohol, triggers the direct alkoxyamination of the double bond. This transformation represents a straightforward access to α-amino aminals in a completely regio- an
- Nakanishi, Masafumi,Minard, Corinne,Retailleau, Pascal,Cariou, Kevin,Dodd, Robert H.
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supporting information; experimental part
p. 5792 - 5795
(2011/12/05)
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- An efficient, overall [4+1] cycloadditon of 1,3-dienes and nitrene precursors
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Intermolecular cycloadditions of conjugated dienes and nitrene precursors usually produce aziridines. A generally useful method was lacking to directly provide the [4+1] cycloadducts, 3-pyrrolines. We have realized this transformation by using an uniquely active catalyst, copper(II) 1,1,1,5,5,5-hexafluoroacetylacetonate ([Cu(hfacac)2]). The method is applicable to a wide array of dienes with good yields. When 1,4-disubsituted dienes are used as substrates, good-to-excellent cis or trans selectivity can be obtained. Interestingly, the cis or trans preference depends on the nature of the substituents, rather than diene geometry. Mechanistic studies reveal that the [4+1] cycloaddition proceeds through diene aziridination and subsequent ring expansion. Among common copper catalysts, only [Cu(hfacac)2] can efficiently catalyze both steps, which explains the unique efficiency of the catalyst.
- Wu, Qiong,Hu, Jian,Ren, Xinfeng,Zhou, Jianrong
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supporting information; experimental part
p. 11553 - 11558
(2011/11/29)
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- SYSTEM FOR FLUORINATING ORGANIC COMPOUNDS
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Described herein are fluorinated organic compounds and methods of making fluorinated organic compounds, for example, using palladium complexes. Also described herein are compositions and kits containing compounds and palladium complexes described herein.
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Page/Page column 175-176
(2009/10/09)
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- Palladium-mediated fluorination of arylboronic acids
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(Chemical Equation Presented) Saving the best for last: Novel palladium complexes allow mild, two-step fluorination of aryl boronic acids (see scheme). The reaction is regiospecific, functional-group tolerant, has a broad substrate scope, and is ideally suited for the introduction of fluorine substituents at a late stage for aryl fluoride synthesis.
- Furuya, Takeru,Kaiser, Hanns Martin,Ritter, Tobias
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supporting information; experimental part
p. 5993 - 5996
(2009/03/11)
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- Silver-catalyzed intermolecular amination of C-H groups
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(Chemical Equation Presented) Teamwork: The dinuclear silver complex [Ag2(OTf)2(bp)2] (OTf = trifluoromethane- sulfonate, bp = bathophenanthroline) catalyzes the intermolecular amination of saturated C-H bonds by using Phl=NNs (Ns = p-nitrosulfonyl) as the nitrene precursor (see scheme). Preliminary investigations suggest that the dinuclear structural motif is crucial to catalytic performance.
- Li, Zigang,Capretto,Rahaman,He, Chuan
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p. 5184 - 5186
(2008/03/18)
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- Gold(III)-catalyzed nitrene insertion into aromatic and benzylic C-H groups
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Simple AuCl3 can mediate direct nitrene insertion into aromatic and benzylic C-H groups at room temperature. Copyright
- Li, Zigang,Capretto, David A.,Rahaman, Ronald O.,He, Chuan
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p. 12058 - 12059
(2008/03/27)
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- NOVEL THIOPHENE SULFOXIMINES FOR TREATING COMPLEMENT-MEDIATED DISEASES AND CONDITIONS
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Disclosed are compounds for treating the symptoms of an acute or chronic disorder mediated by the classical pathway of the complement cascade. Said compounds are of Formula I I or a solvate, hydrate, pharmaceutically acceptable salt, or prodrug thereof; wherein Ra, Rb, and Rc are defined in the specification, as are A Z, Q, R1 and R2.
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Page/Page column 86-87
(2008/06/13)
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- Catalytic asymmetric heterogeneous aziridination of styrene derivatives using bis(oxazoline)-modified Cu2+-exchanged zeolite Y
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The copper-catalysed aziridination of styrene derivatives using either Cu(OTf)2 as a homogeneous catalyst or copper-exchanged zeolite Y modified as a heterogeneous catalyst with bis(oxazoline) using [N-(p-nitrophenylsulfonyl)imino]phenyliodinane (PhI=NNs) as nitrene donor is described and discussed. For the homogeneously catalysed reaction virtually all the substituted derivatives gave lower yields of the aziridine with lower ee when compared with styrene, although 4-chlorostyrene did give enhanced ee. For the heterogeneous catalysed reaction the styrene derivatives often gave enhanced yield, particularly when the substituent was in the 4-position. Particularly high ee was observed for 2-chlorostyrene (95%) and 4-chlorostyrene (94%) and in general the ee observed for the heterogeneously catalysed reaction with the 2- and 4-substituted derivates was significantly higher than that for the equivalent homogeneously catalysed reaction. With copper-exchanged zeolite Y the leaching of Cu2+ into solution during reaction was much lower for the substituted styrene derivatives (0.4-7% of total Cu) than with styrene itself (10.3% of the total Cu). The effect of reaction time on aziridine yield reveals an S-shaped profile that is accentuated by the position of the substituent and this effect is observed for both the homogeneously catalysed pathway and the heterogeneously catalysed reaction. A series of competitive experiments in which styrene was co-reacted with equivalent quantities of 2-, 3- and 4-chlorostyrene revealed that the reaction of styrene enhanced by the other substrate, but the rate of reaction of the substituted styrene was decreased. Co-reaction of 2- and 4-chlorostyrene reveals interesting competitive effects, which are discussed in terms of the nature of the active site.
- Ryan, Darragh,McMorn, Paul,Bethell, Donald,Hutchings, Graham
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p. 3566 - 3572
(2007/10/03)
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- Catalytic asymmetric heterogeneous aziridination of styrene using CuHY: Effect of nitrene donor on enantioselectivity
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The copper-catalysed aziridination of styrene with copper-exchanged zeolite Y (CuHY) and copper(II) triflate (trifluoromethanesulfonate) (Cu(OTf)2) as catalysts is described in detail. Two nitrene donors, [N-(p-tolylsulfonyl)imino)]phenyliodinane (PhI=NTs) and [N-(p-nitrophenylsulfonyl)imino]phenyliodinane (PhI=NNs) are compared. Modification of the catalyst with bis(oxazolines) affords enantioselective catalysts and a range of chiral bis-(oxazolines) has been studied. The ratio of nitrene donor to styrene is shown to be an important factor controlling both the yield and ee of aziridine formed. The best results are obtained with PhI=NNs; ee, ≥ 90%, together with high yields (≥ 85%), can readily be achieved with this nitrene donor using acetonitrile as solvent. Addition of the nitrene donor over a period of time, rather than all at the start of the reaction, is shown to enhance the yield of the aziridine but the ee is significantly decreased for both the homogeneous and the heterogeneous catalysts. Experiments in which the breakdown products of the nitrene donor, iodobenzene and the corresponding sulfonamide, are added at the star of the reaction show that a complex interplay exists at the copper active site between the reactants, products, chiral modifier and the solvent. However, the heterogeneous catalyst, CuHY, is found to give enhanced enantioselection for a range of bis(oxazolines) compared to the homogeneous catalyst, and the effect is considered to be due to the confinement of the catalyst within the micropores of the zeolite.
- Taylor, Sophia,Gullick, John,McMorn, Paul,Bethell, Donald,Page, Philip C. Bulman,Hancock, Frederick E.,King, Frank,Hutchings, Graham J.
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p. 1714 - 1723
(2007/10/03)
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- The rhodium(II)-catalyzed aziridination of olefins with {[(4- nitrophenyl)sulfonyl]imino}phenyl-λ3-iodane
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The aziridination of olefins with {(4- nitrophenylsulfonyl)imino}phenyl-λ3-iodane, NsN=IPh (1c), in the presence of [Rh2(OAc)4] proceeds in yields of up to 85% when the olefin is used in large excess. Under optimized conditions, styrene (4a) is aziridinated with 1 equiv. of NsN=IPh (1c) in 64% yield with 2 mol% of catalyst. The aziridines derived from electron-rich olefins undergo ring-opening under the conditions of the aziridination and afford rearrangement products or pyrrolidines. The aziridination is sterospecific with 1,2-dialkyl- and 1,2-arylalkyl- disubstituted olefins, but nonstereospecific with stilbene. The ρ-value for aziridination of substituted styrenes iS -0.61. No ring-opened products are observed upon aziridination of vinylcyclopropanes. In the presence of chiral Rh(II) catalysts, the aziridination is enantioselective, affording an ee of 73% with cis-β-methylstyrene (4k) and Pirrungs [Rh2{(R)-(-)-bnp}4] catalyst. The experimental results are consistent with a one-step mechanism for transfer of the nitrenoid moiety from the catalyst to the olefin.
- Müller, Paul,Baud, Corine,Jacquier, Yvan
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p. 738 - 750
(2007/10/03)
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- Preparation and evaluation of nitrene precursors (PhI=NSO2Ar) for the copper-catalyzed aziridination of olefins
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The preparation of different [N-(arenesulfonyl)imino]phenyliodinanes is described along with an evaluation of their utility as nitrene precursors for the copper-catalyzed aziridination of different olefins. The best results were obtained with p-NO2/
- Soedergren, Mikael J.,Alonso, Diego A.,Bedekar, Ashutosh V.,Andersson, Pher G.
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p. 6897 - 6900
(2007/10/03)
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- A new method for the preparation of (arylsulfonyliminoiodo)benzenes
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(Arylsulfonyliminoiodo)benzenes (3) can be prepared in 52-92% yield via the reaction of dimethoxyiodobenzene (1) with the corresponding arylsulfonamide in MeOH or CH2Cl2 at room temperature.
- Besenyei, Gabor,Nemeth, Sandor,Simandi, Laszlo I.
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p. 6105 - 6106
(2007/10/02)
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