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Haller J, Hense T, Hoppe D. Experimental and Theoretical Studies of the Internal Stereodifferentiation Occurring During the Lithiation of β-Stereogenic Alkyl Carbamates. Kinetic Resolutions by (-)-Sparteine-Mediated Deprotonation. European J Org Chem 2006. [DOI: 10.1002/jlac.199619960408] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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2
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Balle T, Begtrup M, Jaroszewski JW, Liljefors T, Norrby PO. Regioselectivity in lithiation of 1-methylpyrazole: experimental, density functional theory and multinuclear NMR study. Org Biomol Chem 2006; 4:1261-7. [PMID: 16557314 DOI: 10.1039/b517607g] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction of 1-methylpyrazole with n-BuLi in THF followed by reaction with monodeuteromethanol (CH3OD) under kinetically controlled conditions leads to functionalisation at the methyl group, whereas reaction under thermodynamically controlled conditions leads to functionalisation at the pyrazole 5-position. The observed regioselectivity can be correctly predicted, at least qualitatively, using density functional B3LYP/6-31+G(d,p) calculations only when solvation effects (IEFPCM) are taken into account. The 1H,6Li HOESY and NOESY NMR spectra of the thermodynamic product 5-lithio-1-methylpyrazole (5-Li) in [D8]THF are consistent with an oligomeric structure.
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Affiliation(s)
- Thomas Balle
- Department of Medicinal Chemistry, Danish University of Pharmaceutical Sciences, Universitetsparken 2, DK-2100, Copenhagen, Denmark.
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3
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Jacobson MA, Keresztes I, Williard PG. On the mechanism of THF catalyzed vinylic lithiation of allylamine derivatives: structural studies using 2-D and diffusion-ordered NMR spectroscopy. J Am Chem Soc 2005; 127:4965-75. [PMID: 15796563 DOI: 10.1021/ja0479540] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
N-Lithio-N-(trialkylsilyl)allylamines can be deprotonated in the presence of ethereal solvents exclusively at the cis-vinylic position to yield 3,N-dilithio-N-(trialkylsilyl)allylamines under mild conditions. Low temperature (1)H and (7)Li NMR ((1)H NOESY, TOCSY, (1)H/(7)Li HSQC, and DO-NMR) studies on the solution structure of 3,N-dilithio-N-(tert-butyldimethylsilyl)allylamine identified three major aggregates in THF (monomer, dimer and tetramer), but the aggregate structures failed to explain the solvent dependence and regiochemical outcome of the reaction. Low temperature (1)H NMR (NOESY, TOCSY, DO-NMR) studies on the solution structure of N-lithio-N-(tert-butyldimethylsilyl)allylamine in the presence of nBuLi identified amide/nBuLi mixed aggregates in both the ethereal solvent THF (1:1 dimer) and the hydrocarbon solvent toluene (1:3 tetramer). Addition of 2 equiv of THF to toluene solutions induces the formation of the same THF solvated 1:1 dimer as observed in neat THF. NMR evidence suggests that in THF the mixed aggregate has close contact between the olefin and the beta-CH(2) of nBuLi, while in the absence of THF, the allyl chain appears to be pointed away from the nearest nBuLi residues.
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4
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Vázquez-Hernández M, Rosquete-Pina GA, Juaristi E. Salt Effects on the Conformational Behavior of 5-Carboxy- and 5-Hydroxy-1,3-dioxane1. J Org Chem 2004; 69:9063-72. [PMID: 15609939 DOI: 10.1021/jo048900b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The varied and essential involvement of metal ions and inorganic salts in biological and chemical processes motivated the present study where 5-carboxy- and 5-hydroxy-1,3-dioxanes are used as model frameworks for the evaluation of the conformational behavior of oxygen-containing receptors in the presence of Li(+), Na(+), K(+), Ag(+), Mg(2+), Ca(2+), Ba(2+), and Zn(2+). Thus, the position of equilibria, established by means of BF(3), between diastereomeric cis- and trans-5-substituted-2-phenyl-1,3-dioxanes, in solvent THF and in the presence of 0, 1, and 5 equiv of salt, has been determined. The observed Delta G(o) degrees values for the conformational equilibria of 5-carboxy-1,3-dioxane show that Ag(+), Li(+), and Ca(2+) complexation leads to increased stability of the axial isomer. In the case of the 5-hydroxy-1,3-dioxane, Mg(2+), Ag(+), and Zn(2+) are the metal ions that stabilize the axial conformer of the heterocycle upon association. Interpretation of the experimental observations was based on DFT molecular modeling studies at the Becke3LYP/6-31G* and Becke3LYP/6-31+G** levels of theory. Although gas-phase calculations give Delta E values that are too large when modeling equilibria involving ionic species in polar solution, the computational results confirm the structural and energetic consequences of metal cation coordination to the oxygen atom in carbonyls or ethers. The results derived from the present study contribute to our understanding of the chemical processes involved in molecular recognition and physiological events.
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Affiliation(s)
- Maribel Vázquez-Hernández
- Departamento de Química, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apartado Postal 14-740, 07000 México, D.F., México
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5
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Hampe D, Günther W, Görls H, Anders E. Metal 4-Alkylidene-4H-pyridin-1-ides and 2H-Imidazol-4-ones from Novel HighlyN-(Pyridin-4-yl)methyl-Substituted Azomethines. European J Org Chem 2004. [DOI: 10.1002/ejoc.200400460] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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6
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Köhn U, Anders E. Synthesis of chiral lithium carbamates from (S)-2-(N,N-dialkyl-aminomethyl)pyrrolidines and (S)-methoxymethylpyrrolidine. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)02388-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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7
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Gaul C, Arvidsson PI, Bauer W, Gawley RE, Seebach D. Computational, ReactIR-, and NMR-spectroscopic investigations on the chiral formyl anion equivalent N-(alpha-lithiomethylthiomethyl)-4-isopropyl-5,5-diphenyloxazolidin-2-one and related compounds. Chemistry 2001; 7:4117-25. [PMID: 11686589 DOI: 10.1002/1521-3765(20011001)7:19<4117::aid-chem4117>3.0.co;2-i] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The 4-isopropyl-3-methylthiomethyl-5,5-diphenyloxazolidin-2-one is readily lithiated in THF on the exocyclic CH2 group (1 --> 2) to give a synthetically useful chiral nucleophilic formylating reagent. We have now studied the lithiation reaction by ReactIR spectroscopy and the structure of the organolithium reagent by computational methods and by NMR-spectroscopic measurements. The lithiation is complete at -78 degrees C within 90 seconds, and it is accompanied by a decrease of the C=O wavenumber by 50 cm(-1). The NMR data (collected in [D8]THF) give no evidence for 13C,6Li coupling or for aggregation; from DPFGSE-ROE spectra the single diastereoisomer of the lithium compound 2 seen in the NMR spectra (NMR-spectroscopic measurements from -105 to -20 degrees C) is assigned like configuration; the 13C=O signal of the oxazolidinone undergoes a 7 ppm downfield shift upon lithiation (1 --> 2); line-shape analyses of the signals from the diastereotopic CH2 and CMe2 protons in lithiated 4,4-dimethyl-3-methylthiomethyloxazolidin-2-one (model compound 7) reveal a deltaH(double dagger) of 8.9 +/- 0.2 kcal mol(-1) for enantiomerization. The theoretical calculations provide an energy-minimum structure for the lithium compound 2 with coordination of the carbonyl oxygen to lithium, with an antiperiplanar arrangement of the C,Li and S,CH3 bonds, and with relative like configuration of the two stereocenters--in perfect agreement with the conclusions from the IR- and NMR-spectroscopic measurements!
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Affiliation(s)
- C Gaul
- Laboratorium für Organische Chemie der Eidgenössischen Technischen Hochschule Zürich, ETH-Zentrum, Switzerland
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8
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Ojea V, Ruiz M, Shapiro G, Pombo-Villar E. Conjugate additions of 1-propenylphosphonates to metalated Schöllkopf's bis-lactim ether: stereocontrolled access to 2-amino-3-methyl-4-phosphonobutanoic acids. J Org Chem 2000; 65:1984-95. [PMID: 10774017 DOI: 10.1021/jo991402w] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Diastereoselectivity in the conjugate addition of metalated Schöllkopf's bis-lactim ethers 5a-e to (E)- and (Z)-1-propenylphosphonates 4a,b was studied experimentally and theoretically and utilized to achieve a direct and stereocontrolled synthesis of all four diastereoisomers of 2-amino-3-methyl-4-phosphonobutanoic acid, 6a,b and their enantiomers. The relative stereochemistry was assigned from an NMR study of cyclic derivatives 13a,b. According to semiempirical calculations, both in vacuo (PM3) or a dielectric continuum (PM3/COSMO), initial lithium-phosphoryl coordination, without an energy barrier, to form a solvated chelate complex is followed by the rate-determining reorganization to the 1,4-addition product through an eight-membered transition state. The translation of the Z,E geometry into a syn, anti configuration at the adducts originates from an orientational preference in the transition state for a compact disposition of the reaction partners.
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Affiliation(s)
- V Ojea
- Novartis Pharma Ltd., Basel, Switzerland.
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9
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Goldfuss B, Steigelmann M, Khan SI, Houk KN. Rationalization of enantioselectivities in dialkylzinc additions to benzaldehyde catalyzed by fenchone derivatives. J Org Chem 2000; 65:77-82. [PMID: 10813898 DOI: 10.1021/jo991070v] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Three (-)-fenchyl alcohol derivatives, ¿(1R,2R,4S)-exo-(2-Ar)-1,3, 3-trimethylbicyclo[2.2.1] heptan-2-ol, Ar = o-anisyl (2), 2-N-methylimidazolyl (3), 2-N,N-dimethylbenzylamine (4)¿ were synthesized, characterized by X-ray analyses, and employed as precatalysts in diethyl zinc additions to benzaldehyde. Directions and relative degrees of enantioselectivities are rationalized by QM/MM ONIOM computations of mu-O transition structure models. Enantioselectivities arise from repulsive interactions between "transferring" or "passive" alkyl groups at the zinc centers and the substituents at donor groups or the bicyclo[2.2.1]heptane moieties. These results enable predictions for ligand-tuning to improve catalyst efficiency of fenchone-based ligands in dialkylzinc additions to aldehydes.
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Affiliation(s)
- B Goldfuss
- Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany.
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10
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Katritzky AR, Piffl M, Lang H, Anders E. Regioselectivity of the Reactions of Heteroatom-Stabilized Allyl Anions with Electrophiles. Chem Rev 1999; 99:665-722. [PMID: 11749429 DOI: 10.1021/cr9404297] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alan R. Katritzky
- Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, and Institut für Organische Chemie und Makromolekulare Chemie der Friedrich-Schiller-Universität Jena, Humboldtstrasse 10, D-07743 Jena, Germany
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11
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Arvidsson PI, Hilmersson G, Ahlberg P. Stereoselective Diamine Chelates of a Chiral Lithium Amide Dimer: New Insights into the Coordination Chemistry of Chiral Lithium Amides. J Am Chem Soc 1999. [DOI: 10.1021/ja9827550] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Per I. Arvidsson
- Contribution from the Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
| | - Göran Hilmersson
- Contribution from the Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
| | - Per Ahlberg
- Contribution from the Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
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12
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Coitiño EL, Ciuffarin E, Floris FM, Tomasi J. Degenerate Lithium−Hydrogen Exchange Reactions: An Alternative Mechanism for Metalation of CH4 in Gas Phase and Tetrahydrofuran Solution. J Phys Chem A 1998. [DOI: 10.1021/jp981463i] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Elena L. Coitiño
- Laboratorio de Quimica Teórica y Computacional, Facultad de Ciencias, Edificio Malvín Norte, CC 10773 Montevideo, Uruguay
| | - Enio Ciuffarin
- Dipartimento di Chimica e Chimica Industriale, Via Risorgimento, 35. I-56100, Pisa, Italy
| | - Franca M. Floris
- Dipartimento di Chimica e Chimica Industriale, Via Risorgimento, 35. I-56100, Pisa, Italy
| | - Jacopo Tomasi
- Dipartimento di Chimica e Chimica Industriale, Via Risorgimento, 35. I-56100, Pisa, Italy
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13
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Hilmersson G, Arvidsson PI, Davidsson Ö, Håkansson M. Toward Solution-State Structure. A 6Li,1H HOESY NMR, X-ray Diffraction, Semiempirical (PM3, MNDO), and ab Initio Computational Study of a Chiral Lithium Amide. J Am Chem Soc 1998. [DOI: 10.1021/ja9724708] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Göran Hilmersson
- Contribution from the Department of Organic Chemistry, Göteborg University, S-412 96 Göteborg, Sweden, and Department of Inorganic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Per I. Arvidsson
- Contribution from the Department of Organic Chemistry, Göteborg University, S-412 96 Göteborg, Sweden, and Department of Inorganic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Öjvind Davidsson
- Contribution from the Department of Organic Chemistry, Göteborg University, S-412 96 Göteborg, Sweden, and Department of Inorganic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Mikael Håkansson
- Contribution from the Department of Organic Chemistry, Göteborg University, S-412 96 Göteborg, Sweden, and Department of Inorganic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
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14
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Goldfuss B, Schleyer PVR, Hampel F. “Lithio-Aversion” of Thiophene Sulfur Atoms in the X-ray Crystal Structures of [Li−O−SiMe2(2-C4H3S)]6 and [Li−O−CH(i-Pr)(2-C4H3S)]6: Models for Electrostatic Metal−Thiophene Interactions. Organometallics 1997. [DOI: 10.1021/om9703604] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bernd Goldfuss
- Institut für Organische Chemie der Universität Erlangen-Nürnberg, Henkestrasse 42, D-91054 Erlangen, Germany
| | - Paul von Ragué Schleyer
- Institut für Organische Chemie der Universität Erlangen-Nürnberg, Henkestrasse 42, D-91054 Erlangen, Germany
| | - Frank Hampel
- Institut für Organische Chemie der Universität Erlangen-Nürnberg, Henkestrasse 42, D-91054 Erlangen, Germany
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15
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Kessar SV, Singh P. Lewis Acid Complexation of Tertiary Amines and Related Compounds: A Strategy for alpha-Deprotonation and Stereocontrol. Chem Rev 1997; 97:721-738. [PMID: 11848886 DOI: 10.1021/cr950082n] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Kremer T, Junge M, Schleyer PVR. Mechanisms of Competitive Ring-Directed and Side-Chain-Directed Metalations in Ortho-Substituted Toluenes. Organometallics 1996. [DOI: 10.1021/om960067o] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Thomas Kremer
- Institut für Organische Chemie der Friedrich Alexander Universität Erlangen-Nürnberg, Henkestrasse 42, D-91054 Erlangen, Germany
| | - Michael Junge
- Institut für Organische Chemie der Friedrich Alexander Universität Erlangen-Nürnberg, Henkestrasse 42, D-91054 Erlangen, Germany
| | - Paul von Ragué Schleyer
- Institut für Organische Chemie der Friedrich Alexander Universität Erlangen-Nürnberg, Henkestrasse 42, D-91054 Erlangen, Germany
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17
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Koch R, Wiedel B, Anders E. Theoretical Study of the Deprotonation of Nitriles, RCH2CN: Ab Initio and PM3 Calculations of Intermediate Aggregates and Transition States. J Org Chem 1996. [DOI: 10.1021/jo9519470] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rainer Koch
- Institut für Organische Chemie und Makromolekulare Chemie der Universität Jena, Humboldtstrasse 10, D-07743 Jena, Germany
| | - Bernd Wiedel
- Institut für Organische Chemie und Makromolekulare Chemie der Universität Jena, Humboldtstrasse 10, D-07743 Jena, Germany
| | - Ernst Anders
- Institut für Organische Chemie und Makromolekulare Chemie der Universität Jena, Humboldtstrasse 10, D-07743 Jena, Germany
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18
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Strekowski L, Janda L, Patterson SE, Nguyen J. Amination by lithium alkylamide reagents of ketimines derived from 2-(trifluoromethyl)anilines and methyl halophenyl ketones and their cyclization products 2-(halophenyl)quinolin-4-amines. Tetrahedron 1996. [DOI: 10.1016/0040-4020(95)01110-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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