1,721,168 research outputs found
Conformational Preferences For N,n-dimethyl-2-haloacetamides (halo=f, Cl, Br And I) Through Theoretical And Experimental Studies: An Unexpected Orbital Interaction
No full textConformational preferences and orbital interactions of N,N-dimethyl-2- fluoroacetamide (1), N,N-dimethyl-2-chloroacetamide (2), N,N-dimethyl-2- bromoacetamide (3) and N,N-dimethyl-2-iodoacetamide (4) were analyzed using experimental infra-red data, theoretical calculations and NBO analysis. The conformational equilibria of compounds 1-4 can be represented by their cis and gauche rotamers. The gauche form of 1 is stable in the vapor phase and in a non-polar solvent, but the cis is predominant in a polar solvent. For 2-4 the gauche form is more stable than the cis, in both the vapor and liquid phases. These conformational preferences were attributed to the orbital interaction between two antibonding orbitals, π* C=O→σ*C-X. This unexpected interaction was possibly due to the high (0.3) electron density on π* C=O, which results from the interaction between one nitrogen lone pair and π*C=O. © 2005 Elsevier B.V. All rights reserved.7281-37984Vassilev, N.G., Dimitrov, S., (1999) J. Mol. Struct., 484, p. 39Lehninger, A.L., Nelson, D.L., Cox, M.M., (1993) Principles of Biochemistry, , Worth New YorkGreenberg Breneman, C.M.A., Liebman, J.F., (2002) The Amide Linkage: Structural Significance in Chemistry, Biochemistry and Materials Science, , Wiley New YorkWiberg, K.B., Breneman, C.M., (1992) J. Am. Chem. Soc., 114, p. 831Vargas, R., Garza, J., Dixon, D., Hay, B.P., (2001) J. Phys. Chem. a, 105, p. 774Sandrone, G., Dixon, D.A., Hay, B.P., (1999) J. Phys. Chem. a, 103, p. 893Rogers, M.T., Woodbrey, J.C., (1962) J. Phys. Chem., 66, p. 540Drakenberg, T., Dahlqvist, K., Forsen, S., (1972) J. Phys. Chem., 76, p. 2178Hobson, R.F., Reeves, L.W., (1973) J. Phys. Chem., 77, p. 419Wunderlich, M.D., Leung, L.K., Sandberg, J.A., Meyer, K.D., Yoder, C.H., (1978) J. Am. Chem. Soc., 100, p. 1500Ross, B.D., Wong, L.T., True, N.S., (1985) J. Phys. Chem., 89, p. 836Jackowski, K., Les, A., (1995) J. Mol. Struct., 331, p. 295Suarez, C., Tafazzoli, M., True, N.S., Gerrard, S., Lemaster, C.B., Lemaster, C.L., (1995) J. Phys. Chem., 99, p. 8170Yamada, S., (1996) J. Org. Chem., 61, p. 941Crawford, S.M.N., Taha, A.N., True, N.S., Lemaster, C.B., (1997) J. Phys. Chem., 101, p. 4699Basso, E.A., Pontes, R.M., (2002) J. Mol. Struct. (Theochem), 594, p. 199Briggs, R.S., O'Hagan, D., Howard, J.A.K., Yufit, D.S., (2003) J. Fluorine Chem., 119, p. 9Tormena, C.F., Rittner, R., Abraham, R.J., Basso, E.A., Pontes, R.M., (2000) J. Chem. Soc. Perkin Trans., 2, p. 2054Tormena, C.F., Amadeu, N.S., Rittner, R., Abraham, R.J., (2002) J. Chem. Soc. Perkin Trans., 2, p. 773Olivato, P.R., Guerrero, S.A., Yreijo, M.H., Rittner, R., Tormena, C.F., (2002) J. Mol. Struct., 607, p. 87Martins, M.A.P., Rittner, R., Olivato, P.R., (1981) Spectrosc. Lett., p. 505Klapstein, D., Olivato, P.R., Oike, F., Martins, M.A.P., Rittner, R., (1988) Can. J. Spectrosc., 33, p. 161Frisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Zakrzewski, V.G., Pople, J.A., (1998) Gaussian 98, Revision A.7, , Gaussian, PittsburghPeterson, K.A., Figgen, D., Goll, E., Stoll, H., Dolg, M., (2003) J. Chem. Phys., 119, p. 11113Extensible Computational Chemistry Environment Basis Set Database, Version 02/25/04, , http://www.emsl.pnl.gov/forms/basisform.htmlGlendening, E.D., Reed, A.E., Carpenter, J.E., Weinhold, F., NBO Version 3.1, , (Included in the Gaussian 98 package of programsRef. [23])Brunck, T.K., Weinhold, F., (1979) J. Am. Chem. Soc., 101, p. 1700Goodman, L., Gu, H., Pophristic, V., (2005) J. Phys. Chem., 109, p. 1223Weinhold, F., (2001) Nature, 411, p. 539Tormena, C.F., Freitas, M.P., Rittner, R., Abraham, R.J., (2004) J. Phys. Chem. a, 108, p. 5161Freitas, M.P., Tormena, C.F., Rittner, R., Abraham, R.J., (2003) Spectrochim. Acta a, 59, p. 1783Bodot, H., Dicko, D.D., Gounelle, Y., (1967) Bull. Soc. Chim. Fr., p. 870Olivato, P.R., Rittner, R., (1996) Rev. Heteroat. Chem., 15, p. 11
Conformational And Electronic Interaction Studies Of Some α-mono-heterosubstituted Carbonyl Compounds
No full text[No abstract available]15115159Meyer, M., O'Hagan, D., (1992) Chem. Br., pp. 785-788Karabatsos, G.J., Fenoglio, D.J., Rotational isomerism about sp2-sp3 carbon-carbon single bonds (1970) Topics in Stereochemistry, 5, pp. 167-203. , (Eds.) E. L. Eliel and N. L. Allinger John Wiley and Sons Inc., New YorkDuddeck, H., Substituent effects in 13c chemical shifts in aliphatic molecular systems. Dependence on constitution and stereochemistry (1986) Topics in Stereochemistry, 16, pp. 219-324. , (Eds.) E. L. Eliel, S. H. Wilen and N. L. Allinger John Wiley and Sons Inc., New YorkRittner, R., Substituent effects of α-heteroatoms. Stereochemical consequences (1987) Recent Advances in Organic NMR Spectroscopy, pp. 127-136. , (Eds.) J. B. Lambert and R. Rittner Norell Press, Div. of Norell Inc., Landisville, New Jersey, Chap.8Eisenstein, O., Anh, N.T., Jean, Y., Devaquet, A., Cantacuzène, J., Salem, L., (1974) Tetrahedron, 30, pp. 1717-1723Godunov, I.A., Yakolev, N.N., (1994) Russ. Chem. Bull., 43, pp. 723-731. , Engl. TranslGodunov, I.A., Yakolev, N.N., Belozerskii, I.S., (1994) Russ. J. Phys. Chem., 68, pp. 1057-1064. , Engl. TranslSaegebarth, E., Krisher, L.C., (1970) J. Chem. Phys., 52, pp. 3555-3562Shapiro, B.L., Tseng, C.K., Johnston M.D., Jr., (1973) J. Magn. Reson., 10, pp. 65-73Durig, J.R., Hardin, J.A., Phan, H.V., Little, T.S., (1989) Spectrochim. Acta, 45 A, pp. 1239-1255Yates, K., Klemenko, S.L., Csizmadia, I.G., (1969) Spectrochim Acta Part A, 25, pp. 765-778Meyer, A.Y., Allinger, N.L., Yuh, Y., (1980) Isr. J. Chem., 20, pp. 57-64Durig, J.R., Lin, J., Tolley, C.L., Little, T.S., (1991) Spectrochim. Acta, 47 A, pp. 105-123Durig, J.R., Lin, J., Phan, H.V., (1992) J. Raman Spetrosc., 23, pp. 253-266Cook, B.R., Crowder, G.A., (1967) J. Chem. Phys., 47, pp. 1700-1702Olivato, P.R., Viertler, H., Wladislaw, B., Sauvageau, P., Sandorfy, C., (1979) J. Chem. Phys., 70, pp. 1677-1680Lumbroso, H., Bertin, D.M., Olivato, P.R., Bonfada, E., Mondino, M.G., Hase, Y., (1989) J. Mol. Struct., 212, pp. 113-122Gaset, A., Lafaille, L., Verdier, A., Lattes, A., (1968) Bull. Soc. Chim. Fr., pp. 4108-4112Lumbroso, H., Liégeois, Ch., Olivato, P.R., (1987) J. Mol. Struct., 162, pp. 131-139Lumbroso, H., Liégeois, Ch., Olivato, P.R., (1987) J. Mol. Struct., 162, pp. 141-149Gough, T.E., Lin, W.S., Woolford, R.G., (1967) Can. J. Chem., 45, pp. 2529-2535Yates, P., Lipinsky, S., Vossius, D., (1961) Can. J. Chem., 39, pp. 1977-1980Ramarao, M., Bothner-By, A.A., (1976) Org. Magn. Reson., 39, pp. 329-331Bonniol, A., Galsomias, J., Petrissans, J., (1979) C. R. Acad. Sci. Ser. C., 288, pp. 407-410Lumbroso, H., Liegeois, Ch., Guerrero, S.A., Olivato, P.R., Hase, Y., (1987) J. Mol. Struct., 162, pp. 141-149Olivato, P.R., Wladislaw, B., Guerrero, S.A., Russowsky, D., (1985) Phosphorus Sulfur, 24, pp. 225-233Van Der Veken, B.J., Truyen, S., Herrebout, W.A., Watkins, G., (1993) J. Mol. Struct., 293, pp. 55-58Fausto, R., Teixeira-Dias, J.J.C., (1986) J. Mol. Struct., 144, pp. 225-240Mido, Y., Hashimoto, M., (1985) J. Mol. Struct., 129, pp. 253-261Maury, C., Petrissans, J., (1991) J. Mol. Struct., 246, pp. 267-278Gutierrez, M.A., Martins, M.A., Rittner, R., (1982) Org. Magn. Reson., 20, pp. 20-25Rittner, R., Canto, E.L., Grehs, J., (1991) Spectros. Int. J., 9, pp. 31-37Pan, Y.-H., Stothers, J.B., (1967) Can. J. Chem., 45, pp. 2943-2953Cantacuzène, J., Jantzen, R., Ricard, D., (1972) Tetrahedron, 28, pp. 717-734Abraham, R.J., Griffths, L., (1981) Tetrahedron, 37, pp. 575-583Cantacuzène, D., Tordeaux, M., (1976) Can. J. Chem., 54, pp. 2759-2766Wladislaw, B., Viertler, H., Olivato, P.R., Calegão, I.C.C., Pardini, V.L., Rittner, R., (1980) J. Chem. Soc., Perkin Trans., 2, pp. 453-456Fraser, R.R., Faibish, N.C., (1995) Can. J. Chem., 73, pp. 88-94Varnali, T., Aviyente, V., Terryn, B., Ruiz-López, M.F., (1993) J. Mol. Struct., 280, pp. 169-179Phan, H.V., Durig, J.R., (1990) J. Mol. Struct., 209, pp. 333-347Karabatsos, G.J., Fenoglio, D.J., (1969) J. Am. Chem. Soc., 91, pp. 1124-1129Karabatsos, G.J., Fenoglio, D.J., (1969) J. Am. Chem. Soc., 91, pp. 3577-3582Yamaguchi, I., Matsui, K., Haccho, H., Oka, H., Hanada, Y., Matsui, N., Kawashima, I., Takeda, S., (1995) J. Mol. Struct., 352-353, pp. 309-315Guerrero, S.A., Barros, J.R.T., Wladislaw, B., Rittner, R., Olivato, P.R., (1983) J. Chem. Soc., Perkin Trans., 2, pp. 1053-1058Olivato, P.R., Guerrero, S.A., Hase, Y., Rittner, R., (1990) J. Chem. Soc., Perkin Trans., 2, pp. 465-471Olivato, P.R., Nanartonis, R., Lopes, J.C.D., Hase, Y., (1992) Phosphorus, Sulfur, Silicon and Relat. Elem., 71, pp. 107-125Olivato, P.R., Klapstein, D., Rittner, R., Silva, E.L., Lopes, J.C.D., (1992) Can. J. Appl. Spectrosc., 37, pp. 37-48Martins, M.A.P., Rittner, R., Olivato, P.R., (1981) Spectrosc. Lett., pp. 505-517Klapstein, D., Olivato, P.R., Oike, F., Martins, M.A.P., Rittner, R., (1988) Can. J. Spectrosc., 33, pp. 161-166Basso, E.A., Kaiser, C., Rittner, R., Lambert, J.B., (1993) J. Org. Chem., 58, pp. 7865-7869Jones, D., Modelli, A., Olivato, P.R., Dal Colle, M., Palo, M., Distefano, G., (1994) J. Chem. Soc., Perkin Trans., 2, pp. 1651-1656Olivato, P.R., Oike, F., Lopes, J.C.D., (1990) Phosphorus, Sulfur, Silicon and Relat. Elem., 47, pp. 391-399Olivato, P.R., Guerrero, S.A., Lopes, J.C.D., Hase, Y., Still, I.W.J., Wilson, D.K.T., (1993) Phosphorus, Sulfur, Silicon and Relat. Elem., 82, pp. 7-24Olivato, P.R., Guerrero, S.A., Lopes, J.C.D., Hase, Y., Still, I.W.J., Wilson, D.K.T., (1994) Phosphorus, Sulfur, Silicon and Relat. Elem., 95-96, pp. 391-395Oike, F., (1992), Ph.D. Dissertation, Universidade de São Paulo , São PauloRittner, R., Vanin, J.A., Wladislaw, B., (1988) Magn. Reson. Chem., 26, pp. 51-54Rittner, R., Silva, E.L., Canto, E.L., (1990) Spectros. Int. J., 8, pp. 173-182Rittner, R., Martins, M.A.P., Clar, G., (1988) Magn. Reson. Chem., 26, pp. 73-77Rittner, R., (1988) Quím. Nova, 8, pp. 170-183Nesmeyanov, A.N., Blinova, V.A., Fedin, E.I., Kritskaya, I.I., Fedorov, L.A., (1975) Dokl. Chem., 220, pp. 162-164. , Engl. TransOlivato, P.R., Guerrero, S.A., Modelli, A., Granozzi, G., Jones, D., Distefano, G., (1984) J. Chem. Soc., Perkin Trans., 2, pp. 1505-1509Olivato, P.R., Rittner, R., unpublished resultsOlivato, P.R., Mondino, M.G., (1991) Phosphorus, Sulfur, Silicon and Relat. Elem., 59, pp. 219-224Distefano, G., Dal Colle, M., Bertolasi, V., Olivato, P.R., Bonfada, E., Mondino, M.G., (1991) J. Chem. Soc., Perkin Trans., 2, pp. 1195-1199Olivato, P.R., Ribeiro, D.S., Rittner, R., Hase, Y., Del Pra, A., Bombieri, G., (1995) Spectrochim Acta Part A, 51, pp. 1479-1498Sumathi, R., Chandra, A.K., (1993) J. Mol. Struct. (Theochem), 280, pp. 49-5
A 1h Nmr And Molecular Modelling Investigation Of Diastereotopic Methylene Hydrogen Atoms
No full textThe 1H NMR spectra of methyl 3-bromo-2-methylpropionate (1a) and the corresponding chloro compound (2a) show no long-range coupling between the methyl and methylene protons. In contrast, in the analogous dihalocompounds, methyl 2,3-dibromo-2-methylpropionate (1b) and methyl 2,3-dichloro-2-methylpropionate (2b), one of the methylene protons exhibits a large 4JHH coupling (0.8 Hz) to the methyl group, but the other proton shows no observable splitting. This can be explained quantitatively by calculations of the conformational preferences in these compounds combined with the known orientation dependence of the 4JHH couplings. One conformer predominates in the dihalo compounds 1b and 2b, and this is responsible for the 4JHH coupling. In 1a and 2a all three conformers are populated and the 4JHH couplings average to zero. The technique is a potentially general method of unambiguously assigning diastereotopic methylene protons. Copyright © 2002 John Wiley & Sons, Ltd.404279283Ault, A., (1970) J. Chem. Educ., 47, p. 813Sanders, J.K.M., Hunter, B.K., (1993) Modern NMR Spectroscopy - A Guide for Chemists, 2nd Ed., , Oxford University Press: New YorkCookson, D.J., Smith, B.E., (1984) J. Magn. Reson., 56, p. 510Snyder, E.I., (1963) J. Am. Chem. Soc., 85, p. 2624Mislow, K., (1978) J. Am. Chem. Soc., 100, p. 911Waugh, J.S., Cotton, F.A., (1961) J. Phys. Chem., 65, p. 562Abraham, R.J., Rittner, R., Unpublished resultsAbraham, R.J., Tormena, C.F., Rittner, R., (2001) J. Chem. Soc. Perkin Trans. 2, p. 815Abraham, R.J., (1999) Prog. Nucl. Magn. Reson. Spectrosc., 35, p. 85Abraham, R.J., Oliver, W.L., (1971) Org. Magn. Reson., 13, p. 725Abraham, R.J., Fisher, J., Loftus, P., (1988) Introduction to NMR Spectroscopy, , John Wiley & SonsAbraham, R.J., Jones, A.D., Warne, M.A., Rittner, R., Tormena, C.F., (1996) J. Chem. Soc. Perkin Trans. 2, p. 533Abraham, R.J., Tormena, C.F., Rittner, R., (1999) J. Chem. Soc. Perkin Trans. 2, p. 1663Tormena, C.F., Rittner, R., Abraham, R.J., Basso, E.A., Pontes, R.M., (2000) J. Chem. Soc. Perkin Trans. 2, p. 2054PCMODEL, Version 7, , Serena Software: Bloomington, IN, USAFrisch, M.J., Trucks, C.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Zakrzewski, V.G., Pople, J.A., (1998) Gaussian 98, , Gaussian Inc.: Pittsburgh, PAFurniss, B.S., Hannaford, A.J., Rogers, V., Smith, P.W.G., Tatchell, A.R., (1978) Vogel's Textbook of Practical Organic Chemistry, 4th Ed., , Longman Inc.: New Yor
Conformational And Electronic Interaction Studies Of Some P-substituted α-methylsulfonyl-α-diethoxyphosphorylacetophenones
No full textThe analysis of the IR carbonyl band of the α-methylsulfonyl-α-diethoxyphosphoryl p-substituted acetophenones p-Y-Ph-C(O)CH(SO2Me)[P(O)(OEt)2] (Y = OMe 1, H 2, F 3, Cl 4, Br 5 and NO2 6) supported by HF/6-31G(d,p) ab initio calculations of the α-methylsulfonyl-α-diethoxyphosphoryl acetophenone 2, indicated the existence of a single stable c1 conformer in gas phase and in solvents of increasing polarity, along with the presence of second less stable conformation in gas phase. The c1 conformer present the (SO2Me) group and the [P(O)(OEt2)] groups in a syn-clinal (gauche) geometry and is stabilised through of the Oδ-(CO)...Pδ+(PO), Oδ-[PO(OEt)]...Cδ+(CO), Oδ-(PO)...Cδ+(CO), Oδ-(CO)...Sδ+(SO2Me) and Oδ-(SO2)...Cδ+(CO) electronic interactions along with Hδ+(SO2Me).... Oδ-(CO), Hδ+(CH2)[POEt].... Oδ-(SO2Me), Hδ+(o-Ph).... Oδ-(CO) and Hδ+(o′-Ph).... Oδ-(PO) intramolecular hydrogen bonds. The almost constant negative carbonyl frequency shifts (Δν) for the title compounds 1-6 with respect to the parent acetophenones 7-14 corroborates the prevalence of the electronic interactions over the -Iσ inductive effect of the α-substituents for the title compounds and gives strong support for the existence of the crossed Oδ-(CO)...Sδ+(SO2Me) and Oδ-(SO2)...Cδ+(CO) (charge transfer and electrostatic); Oδ-(CO)...Pδ+(PO) and Oδ-[PO(OEt)]...Cδ+(CO), (electrostatic) interactions. © 2008 Elsevier B.V. All rights reserved.8921-3300304Distefano, G., Dal Colle, M., Bertolasi, V., Olivato, P.R., Bonfada, E., Mondino, M.G., (1991) J. Chem Soc., Perkin Trans., 2, p. 1195Olivato, P.R., Bonfada, E., Rittner, R., (1992) Magn. Reson. Chem., 30, p. 81Dal Colle, M., Bertolasi, V., de Palo, M., Distefano, G., Jones, D., Modelli, A., Olivato, P.R., (1995) J. Chem. Phys., 99, p. 15011Olivato, P.R., Guerrero, S.A., Rittner, R., (1997) Phosphorus Sulfur Silicon, 130, p. 155Olivato, P.R., Hui, M.LT., Rodrigues, A., Ruiz Filho, R., Rittner, R., Zukerman-Schpector, J., Distefano, G., Dal Colle, M., (2003) J. Mol. Struct., 645, p. 259Olivato, P.R., Reis, A.K.C.A., Ruiz Filho, R., Zukerman-Schpector, J., Rittner, R., (2004) J. Mol. Struct. (Theochem.), 677, p. 199Olivato, P.R., Ruiz Filho, R., Zuckerman-Schpector, J., Dal Colle, M., Distefano, G., (2001) J. Chem. Soc., Perkin Trans., 2, p. 97Jones, D., Dal Colle, M., Distefano, G., Ruiz Filho, R., Olivato, P.R., (2001) J. Organomet. Chem., 625, p. 121Olivato, P.R., Reis, A.K.C.A., Zukerman-Schpector, J., Tormena, C., Rittner, R., Domingues, N.L.C., Dal Colle, M., (2006) J. Mol. Struct., 798, p. 57Sega, E.M., Reis, A.K.C.A., Olivato, P.R., Rodrigues, A., Carvalho, J.E., Castilho, R.F., Rittner, R., Höehr, N.F., (2008) Clin. Chim. Acta, 389, p. 177Reis, A.K.C.A., Olivato, P.R., Rittner, R., (2005) Magn. Reson. Chem., 43, p. 85Galactic Industries Corporation, 1991-1998M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R. Cheeseman, V.G. Zakrzewski, J.A. Montgomery Jr., R.E. Stratmann, J.C. Burant, S. Dapprich, J.M. Millam, A.D. Daniels, K.N. Kudin, M.C. Strain, O. Farkas, J. Tomasi, V. Barone, M. Cossi, R. Cammi, B. Mennucci, C. Pomelli, C. Adamo, S. Clifford, J. Ochterski, G.A. Petersson, P.Y. Ayala, Q. Cui, K. Morokuma, D.K. Malick, A.D. Rabuck, K. Raghavachari, J.B. Foresman, J. Cioslowski, J.V. Ortiz, B.B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. Gomperts, R.L. Martin, D.J. Fox, T. Keith, M.A. Al-Laham, C.Y. Peng, A. Nanayakkara, C. Gonzalez, M. Challacombe, P.M.W. Gill, B. Johnson, W. Chen, M.W. Wong, J.L. Andres, M. Head-Gordon, E.S. Repogle, J.A. Pople, Gaussian 98, Revision A.6, Gaussian, Pittsburg, PA, 1998Riddick, J.A., Bunger, W.B., (1970) Techniques of Organic Chemistry, vol. II: Organic Solvents. third ed., , Wiley, New YorkMarch, J., (1985) Advanced Organic Chemistry. third ed., , Wiley, New YorkHansh, C., Leo, A., Hoekman, D., (1995) Exploring QSAR Hydrophobic, Electronic and Steric Constants, , American Chemical Society, Washington, D
Theoretical And Experimental Investigation On The Rotational Isomerism In A-fluoroacetophenones
No full textThe geometries involved in the conformational equilibria of α-fluoroacetophenone, p-nitro-α-fluoroacetophe- none, and p-methoxy-α-fluoroacetophenone were investigated. Theoretical calculations showed that cis and gauche forms (F - C - C=0) are their most stable conformers and that in the vapor phase the gauche conformer is predominant. The three compounds were synthesized, and the conformational behavior in solution was estimated from infrared (IR) and nuclear magnetic resonance (NMR) spectra obtained in solvents of different polarity. Their IR spectra showed one carbonyl absorption for the cis and one for the gauche conformer, and that the cis conformer was preferred in the more polar solvents, 1JCF, 2JC(O)F, and 2JHF coupling constants were obtained from their NMR spectra, and they also showed a preference for the cis conformer when more polar solvents were used. The vapor phase calculations showed a conformational preference for the gauche form. However, when the solvent effects were included in the calculations, the results were in complete agreement with the experimental data (NMR and IR), the cis conformer being the most stable one. © 2009 American Chemical Society.1131229062913Moss, S.J., Murphy, C.D., Hamilton, J.T.G., McRoberts, W.C., O'Hagan, D., Schaffrath, C., Harper, D.B., (2000) Chem. Commun, p. 2281O'Hagan, D., Harper, D.B.J., (1999) Fluor. Chem, 100, p. 127Purser, S., Moore, P.R., Swallow, S., Gouverneur, V., (2008) Chem. Soc. Rev, 37, p. 320O'Hagan, D., (2008) Chem. Soc. Rev, 37, p. 308Phan, H.V., Durig, J.R., (1990) J. Mol. Struct. (THEOCHEM), 209, p. 333Pontes, R.M., Fiorin, B.C., Basso, E.A., (2004) Chem. Phys. Lett, 395, p. 205Abraham, R.J., Tormena, C.F., Rittner, R., (1999) J. Chem. Soc, Perkin Trans, 2, p. 1663Abraham, R.J., Jones, A.D., Warne, M.A., Rittner, R., Tormena, C.F., (1996) J. Chem. Soc, Perkin Trans. 2, p. 533Abraham, R.J., Tormena, C.F., Rittner, R., (2001) J. Chem. Soc, Perkin Trans. 2, p. 815van der Veken, B.J., Truyen, S., Herrebout, W.A., Watkins, G., (1993) J. Mol. Struct, 293, p. 55Tormena, C.F., Rittner, R., Abraham, R.J., Basso, E.A., Pontes, R.M., (2000) J. Chem. Soc, Perkin Trans, 2, p. 2054Tormena, C.F., Amadeu, N.S., Rittner, R., Abraham, R.J., (2002) J. Chem Soc, Perkin Trans. 2, p. 773Olivato, P.R., Guerrero, S., Hase, Y., Rittner, R., (1990) J. Chem. Soc, Perkin Trans. 2, p. 465Catalano, D., Celebre, G., Emsley, J.W., Longeri, M., Luca, G.D., Veracini, C.A., (1998) J. Chem. Soc, Perkin Trans. 2, p. 1823Rodriguez, A.M., Giannini, F.A., Baldoni, H.A., Santagata, L.N., Zamora, M.A., Zacchino, S., Sosa, C.P., Csizmadia, I.G., (1999) J. Mol. Struct, 463, p. 271Frisch, M.J., (2003) Gaussian 03, , Gaussian Inc, Pittsburgh, PAHehre, W.J., (2003) A Guide to Molecular Mechanics and Quantum Chemical Calculations, , Wavefunction Inc: Irvine, CAFliikiger, P., Liithi, H.P., Portmann, S., Weber, J., (2000) Molekel 4.3, , Swiss Center for Scientific Computing: Manno, Switzerland;Portmann, S., Liithi, H.P., (2000) CHIMIA, 54, p. 766Tomasi, J., Scrocco, E., Miertus, S., (1981) Chem. Phys, 55, p. 117Bridge, C.F., O'Hagan, D.J., (1997) Fluor. Chem, 82, p. 21Yoshinaga, F., Tormena, C.F., Freitas, M.P., Rittner, R., Abraham, R.J., (2002) J. Chem. Soc, Perkin Trans. 2, p. 1494Eliel, E.L., Wilen, S.H., Mander, L.N., (1994) Stereochemistry of Organic Compounds, , Wiley: New Yor
Experimental And Theoretical Studies Of Intramolecular Hydrogen Bonding In 3-hydroxytetrahydropyran: Beyond Aim Analysis
No full textThe conformational preferences of 3-hydroxytetrahydropyran (1) were evaluated using infrared and nuclear magnetic resonance spectroscopic data in solvents of different polarities. Theoretical calculations in the isolated phase and including the solvent effect were performed, showing that the most stable conformations for compound 1 are those containing the substituent in the axial and equatorial orientations. The axial conformation is more stable in the isolated phase and in a nonpolar solvent, while the equatorial conformation is more stable than the axial in polar media. The occurrence of intramolecular hydrogen-bonded O-H⋯O in the axial conformer was detected from infrared spectra in a nonpolar solvent at different concentrations. Our attempt to evaluate this interaction using population natural bond orbital and topological quantum theory of atoms in molecules analyses failed, but topological noncovalent interaction analysis was capable of characterizing it. © 2014 American Chemical Society.1181527942800Eliel, E.L., Samuel, H.W., Doyle, M.P., (2001) Basic Organic Stereochemistry, , Wiley-Interscience: New YorkCortéz-Guzman, F., Hernández-Trujillo, J., Cuevas, G., The Nonexistence of Repulsive 1,3-diaxial Interactions in Monosubstituted Cyclohexanes (2003) J. Phys. Chem. A, 107, pp. 9253-9256Ribeiro, D.S., Rittner, R., The Role of Hyperconjugation in the Conformational Analysis of Methylcyclohexane and Methylheterocyclohexanes (2003) J. Org. Chem., 68, pp. 6780-6787Taddei, F., Kleinpeter, E., The Anomeric Effect in Substituted Cyclohexanes. I. The Role of Hyperconjugative Interactions and Steric Effect in Monosubstituted Cyclohexanes (2004) J. Mol. Struct.: THEOCHEM, 683, pp. 29-41Freitas, M.P., Tormena, C.F., Rittner, R., Interaction in trans-2-Halocyclohexanols-an Infraredand Theoretical Study (2001) J. Mol. Struct., 570, pp. 175-180Freitas, M.P., Tormena, C.F., Oliveira, P.R., Rittner, R., Halogenated Six-Membered Rings: A Theoretical Approach for Substituent Effects in Conformational Analysis (2002) J. Mol. Struct.: THEOCHEM, 589-590, pp. 147-151Freitas, M.P., Tormena, C.F., Luizar, C., Ferreira, M.M.C., Rittner, R., Substituent Interactions in trans -2-Substituted Methoxycyclohexanes: An Explanation to the Conformational Behaviour in a Chemometric and Theoretical View (2002) J. Mol. Struct. THEOCHEM, 618, pp. 219-224Freitas, M.P., Tormena, C.F., Rittner, R., Abraham, R.J., Conformational Analysis of trans -2-Halocyclohexanols and their Methyl Ethers: A 1H NMR, Theoretical and Solvation Approach (2003) J. Phys. Org. Chem., 16, pp. 27-33Freitas, M.P., Tormena, C.F., Rittner, R., Abraham, R.J., Conformational Properties of trans -2-Halo-acetoxycyclohexanes: 1H NMR, Solvation and Theoretical Investigation (2005) J. Mol. Struct., 734, pp. 211-217Freitas, M.P., Rittner, R., Tormena, C.F., Abraham, R.J., Conformational Analysis and Stereoelectronic Effects in trans -1,2-Dihalocyclohexanes: 1H NMR and Theoretical Investigation (2005) Spectrochim. Acta, Part A, 61, pp. 1771-1776Bocca, C.C., Basso, E.A., Fiorin, B.C., Tormena, C.F., Dos Santos, F.P., Conformational Behavior of cis -2-Methoxy, cis -2-Methylthio, and cis -2-Methylselenocyclohexanol: A Theoretical and Experimental Investigation (2006) J. Phys. Chem. A, 110, pp. 9438-9442Cedran, J.C., Dos Santos, F.P., Basso, E.A., Tormena, C.F., Conformational Preferences of 2-Methoxy, 2-Methylthio, and 2-Methylselenocyclohexyl- N, N -dimethylcarbamate: A Theoretical and Experimental Investigation (2007) J. Phys. Chem. A, 111, pp. 11701-11705Basso, E.A., Abiko, L.A., Gauze, G.F., Pontes, R.M., Conformational Analysis of cis -2-HalocyclohexanolsSolvent Effects by NMR and Theoretical Calculations (2011) J. Org. Chem., 76, pp. 145-153Silla, J.M., Cormanich, R.A., Duarte, C.J., Freitas, M.P., Ramalho, T.C., Barbosa, T.M., Santos, F.P., Rittner, R., Alkyl Group Effect on the Conformational Isomerism of trans -2-Bromoalkoxycyclohexanes Analyzed by NMR Spectroscopy and Theoretical Calculation (2011) J. Phys. Chem. A, 115, pp. 10122-10127Basso, E.A., Kaiser, C., Rittner, R., Lambert, J.B., Axial Equatorial Proportions for 2-Substituted Cyclohexanones (1993) J. Org. Chem., 58, pp. 7865-7869Freitas, M.P., Rittner, R., Tormena, C.F., Abraham, R.J., Conformational Analysis of 2-Bromocyclohexanone. A Combined NMR, IR, Solvation and Theoretical Approach (2001) J. Phys. Org. Chem., 14, pp. 317-322Yoshinaga, F., Tormena, C.F., Freitas, M.P., Rittner, R., Abraham, R.J., Conformational Analysis of 2-Halocyclohexanones: An NMR, Theoretical and Solvation Study (2002) J. Chem. Soc., Perkin Trans.2, pp. 1494-1498Freitas, M.P., Tormena, C.F., Garcia, J.C., Rittner, R., Abraham, R.J., Basso, E.A., Santos, F.P., Cedran, J.C., NMR, Solvation and Theoretical Investigations of Conformational Isomerism in 2-X-cyclohexanones (X=NMe2, OMe, SMe and SeMe) (2003) J. Phys. Org. Chem., 16, pp. 833-838Coelho, J.V., Freitas, M.P., Tormena, C.F., Rittner, R., On the4 JHH Long-range Coupling in 2-Bromocyclohexanone: Conformational Insights (2009) Magn. Reson. Chem., 47, pp. 348-351Coelho, J.V., Freitas, M.P., Ramalho, T.C., Martins, C.R., Bitencourt, M., Carmanich, R.A., Tormena, C.F., Rittner, R., The Case of Infrared Carbonyl Stretching Intensities of 2-Bromocyclohexanone: Conformational and Intermolecular Interaction Insights (2010) Chem. Phys. Lett., 494, pp. 26-30Anizelli, P.R., Vilcachagua, J.D., Cunha Neto, A., Tormena, C.F., Stereoelectronic Interaction and Their Effects on Conformational Preference for 2-Substituted Methylenecyclohexane: An Experimental and Theoretical Investigation (2008) J. Phys. Chem. A, 112, pp. 8785-8789Alabugin, I.V., Gilmore, K.M., Peterson, P.W., Hyperconjugation (2011) Wiley Interdiscip. Rev.: Comput. Mol. Sci., 1, pp. 109-141Ha, S., Gao, J., Tidor, B., Brady, J.W., Karplus, M., Solvent Effect on the Anomeric Equilibrium in D-glucose: A Free Energy Simulation Analysis (1991) J. Am. Chem. Soc., 113, pp. 1553-1557Cramer, C.J., Anomeric and Reverse Anomeric Effects in the Gas Phase and Aqueous Solution (1992) J. Org. Chem., 57, pp. 7034-7043Mo, Y., Computational Evidence that Hyperconjugative Interactions are not Responsible for the Anomeric Effect (2010) Nat. Chem., 2, pp. 666-671Huang, Y., Zhong, A.-G., Yang, Q., Liu, S., Origin of Anomeric Effect: A Density Functional of Steric Analysis (2011) J. Chem. Phys., 134, pp. 84103-84109Bauerfeldt, G.F., Cardozo, T.M., Pereira, M.S., Da Silva, C.O., The Anomeric Effect: The Dominance of Exchange Effects in Closed-Shell Systems (2013) Org. Biomol. Chem., 11, pp. 299-308Cocinero, E.J., Çarçabal, P., Vaden, T.D., Simons, J.P., Davis, B.G., Sensing the Anomeric Effect in a Solvent-Free Environment (2011) Nature, 469, pp. 76-80Freitas, M.P., Simultaneous Gauche and Anomeric Effects in α-Substituted Sulfoxides (2012) J. Org. Chem., 77, pp. 7607-7611Freitas, M.P., The Anomeric Effect on the Basis of Natural Bond Orbital Analysis (2013) Org. Biomol. Chem., 11, pp. 2885-2890Sugai, T., Lkeda, H., Ohta, H., Biocatalytic Approaches to Both Enantiomers of (2R*,3S*)-2- Allyloxy-3,4,5,6-tetrahydro-2H-pyran-3-ol (1996) Tetrahedron, 52, pp. 8123-8134Kosjek, B., Nti-Gyabaah, J., Telari, K., Dunne, L., Moore, J.C., Preparative Asymmetric Synthesis of 4,4-Dimethoxytetrahydro-2 H -pyran-3-ol with a Ketone Reductase and in Situ Cofactor Recycling using Glucose Dehydrogenase (2008) Org. Process Res. Dev., 12, pp. 584-588Sugawara, K., Imanishi, Y., Hashiyama, T., Efficient and Practical Synthesis of both Enantiomers of 6-Silyloxy-3-pyranone Derivatives (2000) Tetrahedron: Asymmetry, 11, pp. 4529-4535Chan, W.N., Evans, J.M., Hadley, M.S., Morgan, H.K.A., Stean, T.O., Thompson, M., Upton, N., Vong, A.K., Synthesis of Novel trans -4-(Substitutedbenzamido)-3,4-dihydro-2 H -benzo[ b ]-pyran-3-ol Derivatives as Potential Anticonvulsant Agents with a Distinctive Binding Profile (1996) J. Med. Chem., 39, pp. 4537-4539Sasaerila, Y., Gries, R., Gries, G., Khaskin, G., King, S., Takács, S., Hardi, Sex Pheromone Components of Male Tirathabamundella (Lepidoptera: Pyralidae) (2003) Chemoecology, 13, pp. 89-93Barker, S.A., Brimacombe, J.S., Foster, A.B., Whiffen, D.H., Zweifel, G., Intramolecular Hydrogen Bonding in some Monohydroxy Derivatives of Tetrahydrofuran, Tetrahydropyran and 1,3-dioxan (1959) Tetrahedron, 7, pp. 10-18Møller, C., Plesset, M.S., Note on an approximation treatment for many-electron systems (1934) Phys. Rev., 46, pp. 618-622Head-Gordon, M., Pople, J.A., Frisch, M.J., MP2 energy evaluation by direct methods (1988) Chem. Phys. Lett., 153, pp. 503-506Purvis III, G.D., Bartlett, R.J., A full coupled-cluster singles and doubles model: The inclusion of disconnected triples (1982) J. Chem. Phys., 76, pp. 1910-1918Weinhold, F., Natural Bond Orbital Analysis: A Critical Overview of Relationships to Alternative Bonding Perspectives (2012) J. Comput. Chem., 33, pp. 2363-2379Bader, R.F.W., (1990) Atoms in Molecules: A Quantum Theory, , Clarendon: Oxford, U.KJohnson, E.R., Keinan, S., Mori-Sánchez, P., Contreras-García, J., Cohen, A.J., Yang, W., Revealing Noncovalent Interactions (2010) J. Am. Chem. Soc., 132, pp. 6498-6506Frisch, M.J., (2009) Gaussian 09, , revision D.01Gaussian, Inc. Wallingford, CTGeertsen, J., Oddershede, J., 2nd-Order Polarization Propagator Calculations of Indirect Nuclear Spin-Spin Coupling Tensors in the Water Molecule (1984) Chem. Phys., 90, pp. 301-311Enevoldsen, T., Oddershede, J., Sauer, S.P.A., Correlated Calculations of Indirect Nuclear Spin-Spin Coupling Constants using Second-Order Polarization Propagator Approximations: SOPPA and SOPPA(CCSD) (1998) Theor. Chem. Acc., 100, pp. 275-284Sauer, S.P.A., Second-Order Polarization Propagator Approximation with Coupled-Cluster Singles and Doubles Amplitudes-SOPPA(CCSD): The Polarizability and Pyperpolarizability of Li- (1997) J. Phys. B: At., Mol. Opt. Phys., 30, pp. 3773-3780(2011), http://daltonprogram.org, Dalton2011, A Molecular Electronic Structure ProgramBarone, V., (1996) Recent Advances in Density Functional Methods, Part i, , Chong, D. P. World Scientific Publ. Co. SingaporeGlendening, E.D., Badenhoop, J.K., Reed, A.E., Carpenter, J.E., Bohmann, J.A., Morales, C.M., Landis, C.R., Weinhold, F., (2013) NBO 6.0, , Theoretical Chemistry Institute, University of Wisconsin, Madison: Madison, WI, Program implemented in the Gaussian 09 packageKeith, T.A., (2011) AIMALL, , aim.tkgristmill.comh, version 11.10.16TK Gristmill Software: Overland Park, KSContreras-García, J., Johnson, E.R., Keinan, S., Chaudret, R., Piquemal, J.-P., Beratan, D.N., Yang, W., NCIPLOT: A Program for Plotting Noncovalent Interaction Regions (2011) J. Chem. Theory Comput., 7, pp. 625-632Zweifel, G., Plamondon, J., Hydroboration of Dihydropyrans and Dihydrofurans (1970) J. Org. Chem., 35, pp. 898-902Marenich, A.V., Cramer, C.J., Truhlar, D.G., Universal Solvation Model Based on Solute Electron Density and on a Continuum Model of the Solvent Defined by the Bulk Dielectric Constant and Atomic Surface Tensions (2009) J. Phys. Chem. B, 113, pp. 6378-6396Abraham, R.J., Jones, A.D., Warne, M.A., Rittner, R., Tormena, C.F., Conformational Analysis. Part 27. NMR, Solvation and Theoretical Investigation of Conformational Isomerism in Fluoro- and l,l-difluoro-acetone (1996) J. Chem. Soc., Perkin Trans 2, pp. 533-539Helgaker, T., Jaszuński, M., Pecul, M., The Quantum-Chemical Calculation of NMR Indirect Spin-Spin Coupling Constants (2008) Prog. Nucl. Magn. Reson. Spectrosc., 53, pp. 249-268Conley, R.T., (1972) Infrared Spectroscopy, pp. 129-131. , 2 nd ed. Allyn and Bacon: BostonLane, J.R., Contreras-García, J., Piquemal, J.-P., Miller, B.J., Kjaergaard, H.G., Are Bond Critical Points Really Critical for Hydrogen Bonding? (2013) J. Chem. Theory Comput., 9, pp. 3263-3266Grabowski, S.J., What Is the Covalency of Hydrogen Bonding? (2011) Chem. Rev., 111, pp. 2597-262
Conformational Analysis Of Fluoroacetoxime And Of Its O-methyl Ether By 1h, 13c And 15n Nmr And Theoretical Calculations
No full textThe solvent dependence of the 1H, 13C and 15N NMR spectra of (E)-fluoroacetoxime [(E)-FAO] and of (E)-fluoroacetoxime 0-methyl ether [(E)-FAOME], was examined and the HF, CF and NF couplings are reported. Density functional theory (DFT) at the B3LYP/6-311++g(2df,2p) level with ZPE (zero point energy) correction was used to obtain the rotamer geometries. In both (E)-FAO and (E)-FAOME the DFT method gave two energy minima corresponding to the cis (F - C - C=N, 0°) and gauche (F - C - C=N, 124.1°) rotamers. In contrast, in (Z)-FAO the DFT method gave only one energy minimum corrsponding to the trans rotamer. The 4JHF and 1JCF couplings in (E)-FAO were analyzed by solvation theory assuming the cis and gauche forms to give Ecis - Egauche = 3.3 kcal mol-1 in the vapor phase, decreasing to 1.54 kcal mol-1 in CCl4 and - 1.19 kcal mol-1 in DMSO (1 kcal = 4.184kJ. In (E)-FAOME the observed couplings, when analysed similarly by solvation theory, gave Ecis - Egauche = 2.2 kcal mol-1 in the vapor phase, 0.91 kcal mol-1 in CCl4 and - 1.18 kcal mol-1 in DMSO. The 3JNF coupling was independent of the molecular conformation, as it did not change with the solvent polarity. Copyright © 2003 John Wiley & Sons, Ltd.1714248McCarty, C.G., (1970) The Chemistry of the Carbon-nitrogen Double Bond, , Patai S (ed). Wiley: Chichester, chap. 2Fry, A.J., Reed, R.G., (1977) The Chemistry of Double Bonded Functional Groups, Supplement A, , Patai S (ed.). Wiley: Chichester, chap. 11Goda, H., Sato, M., Ihara, H., Hirayama, C., (1992) Synthesis, p. 849(1972) CIBA Symposium, Carbon-fluorine Compounds, Chemistry, Biochemistry and Biological Activities, , Association of Scientific Publishers: AmsterdamTaylor, N.F., (1988) Fluorinated Carbohydrates, Chemical and Biochemical Aspects. ACS Symposium Series, 374. , American Chemical Society: Washington, DCO'Hagan, D., Rzepa, H.S., (1997) Chem. Commun., p. 645Saegebarth, E., Krishner, L.C., (1970) J. Chem. Phys., 52, p. 3555Durig, J.R., Hardin, J.A., Phan, H.V., Little, T.S., (1989) Spectrochim. Acta, Part A, 45, p. 1239Abraham, R.J., Jones, A.D., Warne, M.A., Rittner, R., Tormena, C.F., (1996) J. Chem. Soc., Perkin Trans. 2, p. 533Olivato, P.R., Ribeiro, D.S., Rittner, R., Hase, Y., Del Pra, D., Bombieri, G., (1995) Spectrochim. Acta, Part A, 51, p. 1479Dal Colle, M., Distefano, G., Modelli, A., Jones, D., Guerra, M., Olivato, P.R., Ribeiro, D.S., (1998) J. Phys. Chem. A, 102, p. 8037Ribeiro, D.S., Abraham, R.J., (2002) Magn. Reson. Chem., 40, p. 49Olivato, P.R., Ribeiro, D.S., Zukerman-Schpector, J., Bombieri, G., (2001) Acta Crystallogr., Sect. B, 57, p. 705Abraham, R.J., Fisher, J., Loftus, P., (1988) Introduction to NMR Spectroscopy, , Wiley: New YorkAbraham, R.J., Bretschneider, E., (1974) Internal Rotation in Molecules, , W. J. Orville-Thomas (ed.). Wiley: London, chap. 13Frisch, M.J., Trucks, C.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Zakrzewski, V.G., Pople, J.A., (1998) Gaussian 98, Revision A.7, , Gaussian: Pittsburgh, PAAbraham, R.J., Tormena, C.F., Rittner, R., (1999) J. Chem. Soc., Perkin Trans. 2, p. 1663Tormena, C.F., Rittner, R., Abraham, R.J., Basso, E.A., Pontes, R.M., (2000) J. Chem. Soc., Perkin Trans. 2, p. 2054Abraham, R.J., Tormena, C.F., Rittner, R., (2001) J. Chem. Soc., Perkin Trans. 2, p. 815Tormena, C.F., Rittner, R., Abraham, R.J., (2002) J. Phys. Org. Chem., 15, p. 211Tormena, C.F., Amadeu, N.S., Rittner, R., Abraham, R.J., (2002) J. Chem. Soc., Perkin Trans. 2, p. 773Abraham, R.J., (1999) Prog. Nucl. Magn. Reson. Spectrosc., 35, p. 85Abraham, R.J., Leonard, P., Smith, T.A.D., Thomas, W.A., (1996) Magn. Reson. Chem., 34, p. 71Hirota, E., (1970) J. Chem. Phys., 42, p. 2071Enevoldsen, T., Oddershede, J., Sauer, S.P.A., (1998) Theor. Chem. Acc., 100, p. 275Peralta, J.E., Barone, V., Contreras, R.H., (2001) J. Am. Chem. Soc., 123, p. 9162Peralta, J.E., Barone, V., Azua, M.C.R., Contreras, R.H., (2001) Mol. Phys., 99, p. 655Barone, V., Peralta, J.E., Contreras, R.H., (2001) J. Comput. Chem., 22, p. 1615Krivdin, L.B., Sauer, S.P.A., Peralta, J.E., Contreras, R.H., (2002) Magn. Reson. Chem., 40, p. 187Freitas, M.P., Rittner, R., Tormena, C.F., Abraham, R.J., (2001) J. Phys. Org. Chem., 14, p. 317Contreras, R.H., Peralta, J.E., (2000) Prog. Nucl. Magn. Reson. Spectrosc., 37, p. 321Braun, S., Kalinowski, H.O., Berger, S., (1996) 100 and More Basic NMR Experiments, , VCH: Weinhei
Substituent-induced 1h Chemical Shifts Of 3-substituted Camphors
No full textThe high-field 1H NMR analysis of 3-substituted camphors with OH, OMe, SMe, NHMe, NMe2 and Me substituents at endo and exo positions, and also with an oxo substituent, is reported. The substituent-induced chemical shifts (SCS) obtained for these difunctional systems, including those from previous work on 3-halocamphors, were examined in view of multilinear correlations with steric and electronic parameters. The resultant data show a strong contribution from the electric field mechanism, principally for the protons closer to the substituent. Carbonyl group interference on the expected SCS for the α-proton is also observed, with less deshielding than those of substituted bornanes and norbornanes. © 1997 by John Wiley & Sons, Ltd.359609613Breitmaier, E., Voelter, W., (1987) Carbon-13 NMR Spectroscopy, 3rd Ed., , VCH, Weinheim and references cited thereinZurcher, R.F., (1967) Prog. Nucl. Magn. Reson. Spectrosc., 2, p. 205Abraham, R.J., Fisher, J., (1985) Magn. Reson. Chem., 23, p. 862. , and references cited thereinApSimon, J.W., Beierbeck, H., (1971) Can. J. Chem., 49, p. 1328Schneider, H.J., Buchheit, U., Becker, N., Schmidt, G., Siehl, U., (1986) J. Am. Chem. Soc., 107, p. 7027Schneider, H.J., Buchheit, U., Hoppen, V., Schmidt, G., (1989) Chem. Ber., 122, p. 321Schneider, H.J., Buchheit, U., Becker, N., Schmidt, G., Siehl, U., (1985) J. Am. Chem. Soc., 107, p. 7027Abraham, R.J., Barlow, A.P., Rowan, A.E., (1989) Magn. Reson. Chem., 27, p. 1074Basso, E.A., Kaiser, C.R., Rittner, R., Lambert, J.B., (1994) Magn. Reson. Chem., 32, p. 205Kaiser, C.R., Rittner, R., Basso, E.A., (1994) Magn. Reson. Chem., 32, p. 503Charton, M., Motoc, I., (1983) Top. Curr. Chem., 114, p. 57Charton, M., (1975) J. Am. Chem. Soc., 97, p. 1552Taft, R.W., Topsom, R.D., (1987) Prog. Phys. Org. Chem., 16, p. 1Reynolds, W.F., Gomes, A., Maron, A., MacIntyre, D.W., Tanin, A., Hamer, G.K., Peat, I.R., (1983) Can. J. Chem., 61, p. 2376Marriott, S., Topsom, R.D., (1984) J. Am. Chem. Soc., 106, p. 7Altona, C., Ippel, J.H., Hoekzema, A.J.A.W., Erkelens, C., Groesbeek, M., Donders, L.A., Chem, M.R., 27, 504, p. 1989Basso, E.A., Kaiser, C.R., Rittner, R., Lambert, J.B., (1993) J. Org. Chem., 58, p. 7865Sanders, J.K.M., Mersh, J.D., (1983) Prog. Nucl. Magn. Reson. Spectrosc., 15, p. 353Aue, W.P., Bartholdi, E., Ernst, R.R., (1976) J. Chem. Phys., 64, p. 2229Bax, A., (1983) J. Magn. Reson., 53, p. 517Scholz, D., (1983) Synthesis, p. 944Hutchinson, J.H., Money, T., (1984) Can. J. Chem., 62, p. 1899Daniel, A., Pavia, A.A., (1971) Bull. Soc. Chim. Fr., 3, p. 1060Hassner, A., Reuss, R.H., Pinnick, H.W., (1975) J. Org. Chem., 40, p. 342
Substituent Effects On 1h And 13c Nmr Chemical Shifts In α-monosubstituted Ethyl Acetates: Principal Component Analysis And 1h Chemical Shift Calculations
No full textA principal component analysis is applied to α-monosubstituted ethyl acetates (YCH2CO2Et), where the observed chemical shifts for the α-carbon atom, the carbonyl carbon, and the α-hydrogen atoms are correlated with theoretically derived molecular properties, i.e. the partial charges on the same atoms and the electronegativity and hardness. The effects on 1H and 13C NMR chemical shifts of 12 α-substituents: F, Cl, Br, I, OMe, OEt, SMe, SEt, NMe2, NEt2, Me, and Et were investigated. A strong grouping of the same heteroatom substituents is observed, showing the chemical shift dependence on the type of substituent. Halogenated compounds represent a heterogeneous group, where the large effect of the fluorine substituent is similar to that of the oxygen derivatives (OMe and OEt). Theoretical calculations show that fluorine and oxygen derivatives exhibit similar energy curves with respect to the Y-C-C= O dihedral angle and the same conformational equilibrium between cis and trans rotamers. Sulfur, neutral substituents and halogen derivatives (Cl, Br and I) give an equilibrium between cis and gauche rotamers, with a predominance of the gauche conformers. The rotational equilibrium in solution was confirmed by 1H chemical shift calculations utilizing the CHARGE 7H program. The calculated α-hydrogen atom chemical shifts are in very good agreement with the measured values. Copyright © 2002 John Wiley & Sons, Ltd.407449454Pytela, O., Halama, A., (1995) Collect. Czech. Chem. Commun., 60, p. 1316Zalewski, R., Schneider, H.-J., Buchheit, U., (1992) Magn. Reson. Chem., 30, p. 45Edlund, U., Wold, S., (1980) J. Magn. Reson., 37, p. 183Pytela, O., (1995) Collect. Czech. Chem. Commun., 60, p. 1502Wiberg, K., Pratt, W., Bailey, W., (1980) J. Org. Chem., 45, p. 4936Rittner, R., Vanin, J., Wladislaw, B., (1988) Magn. Reson. Chem., 26, p. 51Olivato, P.R., Ruiz, R., Zukerman-Schpector, J., Dal Colle, M., Distefano, G., (2001) J. Chem. Soc. Perkin Trans. 2, 1, p. 97Horn, A., Klaeboe, P., Aleksa, V., Gruodis, A., Nielsen, C.J., Nashed, Y.E., Guirgis, G.A., Durig, J.R., (2000) J. Mol. Struct., 554, p. 251Bernandino, R.J., Cabral, B.J.C., (2001) J. Mol. Struct. (Theochem), 549, p. 253Olivato, P.R., Rittner, R., (1996) Rev. Heteroat. Chem., 15, p. 115Beeb, K., Pell, R., Seasholtz, M.B., (1998) Chemometrics: A Practice Guide, , Wiley and Sons: New YorkCanto, E.L., Tasic, L., Bruns, R.E., Ritter, R., (2001) Magn. Reson. Chem., 39, p. 316Holik, M., (1993) Chemom. Intell. Lab. Syst., 19, p. 225Holik, M., (1999) J. Mol. Struct., 483, p. 347Freitas, M.P., Campos, M.G., Tormena, C.F., Rittner, R., (2000) Can. J. Anal. Sci. Spectrosc., 45, p. 148Vogel, A., (1978) Vogel's Textbook of Practical Organic Chemistry, , Furniss BS, Hannaford AJ, Rogers V, Smith PWG, Tatchell AR (eds). Longman: New YorkRoedig, A., (1960) Methoden der Organischen Chemie, p. 601. , Muller E. (ed.). Thieme: StuttgartZaugg, H., Horrom, B., (1950) J. Am. Chem. Soc., 72, p. 3004Frisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Zakrzewski, V.G., Pople, J.A., (1998) Gaussian 98, , Gaussian, Inc.: Pittsburgh, PABecke, A.D., (1993) J. Chem. Phys., 98, p. 1372Lee, C., Yang, W., Parr, R.G., (1988) Phys. Rev. B, 37, p. 785Abraham, R.J., Canton, M., Edgar, M., Grant, G.H., Haworth, I.S., Hudson, B.D., Smith, P.E., Warne, M.A., CHARGE 7H, , personal communicationAbraham, R.J., (1999) Prog. NMR Spectros., 35, p. 85Abraham, R.J., Canton, M., Reid, M., Griffiths, L., (2000) J. Chem. Soc. Perkin Trans. 2, p. 803Freitas, M.P., Tormena, C.F., Rittner, R., Abraham, R.J., J. Mol. Spectrosc., , submitted for publicationCanto, E.L., Tasic, L., Rittner, R., (2000) Can. J. Anal. Sci. Spectrosc., 45, p. 28Abraham, R.J., Warne, M.A., Griffiths, L., (1998) Magn. Reson. Chem., 36, pp. S179Smith, M., (1994) Organic Synthesis, , McGraw-Hill: New York(1996) Pirouette, , Infometrix: Washington, D
Conformational Analysis Of Trans-2-halocyclohexanols And Their Methyl Ethers: A 1h Nmr, Theoretical And Solvation Approach
No full textThe conformational equilibria of trans-1-methoxy-2-chloro- (1), trans-1-methoxy-2-bromo- (2) and trans-1-methoxy-2-iodocyclohexane (3), and their corresponding alcohols (4-6), were studied through a combined method of NMR, theoretical calculations and solvation theory. They can be described in terms of the axial-axial and equatorial-equatorial conformations, taking into account the main rotamers of each of these conformations. From the NMR experiments at 183 K in CD2Cl2-CS2, it was possible to observe proton H2 in the ax-ax and eq-eq conformers separately for 1 and 2, but not for 3, which gave directly their populations and conformer energies. In the alcohols the proportion of the ax-ax conformer was too low to be detected by NMR under these conditions. Those HH couplings together with the values at room temperature, in a variety of solvents allowed the determination of the solvent dependence of the conformer energies and hence the vapor state energy difference. The ΔE (Eax-Eeq) values in the vapor state for 1, 2 and 3 are -0.05, 0.20 and 0.55 kcal mol-1, respectively, increasing to 1.10, 1.22 and 1.41 kcal mol-1 in CD3CN solution (1 kcal = 4.184 kJ). For 4-6 the eq-eq conformation is always much more stable in both non-polar and polar solvents, with energy differences ranging from 1.78, 1.94 and 1.86 kcal mol-1 (in CCl4) to 1.27, 1.49 and 1.54 kcal mol-1 (in DMSO), respectively. Comparison of the hydroxy and methoxy compounds gives the intramolecular hydrogen bonding energy for the alcohols as 1.40, 1.36 and 1.00 kcal mol-1 (in CCl4) for 4, 5 and 6, respectively. Copyright © 2002 John Wiley & Sons, Ltd.1612733Zefirov, N.S., Samoshin, V.V., Subbotin, A.O., Baranenkov, V.I., (1978) Tetrahedron, 34, p. 2953Carreño, M.C., Carretero, J.C., Ruano, J.L., Rodriguez, J.H., (1990) Tetrahedron, 46, p. 5649Rockwell, G.D., Grindley, T.B., (1996) Aust. J. Chem., 49, p. 379Kay, J.B., Robinson, J.B., Cox, B., Polkonja, D., (1970) J. Pharm. Pharmacol., 22, p. 214Collins, P., Ferrier, R., (1995) Monosaccharides-Their Chemistry and Their Roles in Natural Products, , Wiley: New YorkBervelt, J.P., Ottinger, R., Peters, P.A., Reisse, J., Chiurdoglu, G., (1968) Spectrochim. Acta, Part A, 24, p. 1411Allinger, J., Allinger, N.L., (1958) Tetrahedron, 2, p. 64Allinger, N.L., Allinger, J., (1958) J. Am. Chem. Soc., 80, p. 5476Basso, E.A., Kaiser, C., Rittner, R., Lambert, J.B., (1993) J. Org. Chem., 58, p. 7865Bodot, H., Dicko, D.D., Gounelle, Y., (1967) Bull. Soc. Chim. Fr., p. 870Freitas, M.P., Tormena, C.F., Rittner, R., (2001) J. Mol. Struct., 570, p. 175Wolfe, S.J., Campbell, R., (1967) J. Chem. Soc., Chem. Commum., p. 872Abraham, R.J., Bretschneider, E., (1974) Internal Rotation in Molecules, , Academic Press: London, chapt. 13Abraham, R.J., Jones, A.D., Warne, M.A., Rittner, R., Tormena, C.F., (1996) J. Chem. Soc., Perkin Trans., 2, p. 533Abraham, R.J., Tormena, C.F., Rittner, R., (1999) J. Chem. Soc., Perkin Trans., 2, p. 1663Tormena, C.F., Rittner, R., Abraham, R.J., Basso, E.A., Pontes, R.M., (2000) J. Chem. Soc., Perkin Trans., 2, p. 2054Freitas, M.P., Rittner, R., Tormena, C.F., Abraham, R.J., (2001) J. Phys. Org. Chem, 14, p. 317Abraham, R.J., Smith, T.A.D., Thomas, W.A., (1996) J. Chem. Soc., Perkin Trans., 2, p. 1949Frisch, M.J., Trucks, C.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Zakrzewski, V.G., Pople, J.A., (1998) Gaussian 98, , Gaussian: Pittsburgh, PAAbraham, R.J., Grant, G.H., Haworth, I.S., Smith, P.E., (1991) J. Comput.-Aided Mol. Des., 5, p. 21Zefirov, N.S., Gurvich, L.G., Shashkov, A.S., Krimer, M.Z., Vorob'eva, E.A., (1976) Tetrahedron, 32, p. 1211Epiotis, N.D., (1973) J. Am. Chem. Soc., 95, p. 3087Craig, N.C., Chen, A., Suh, K.H., Klee, S., Mellau, G.C., Winnewisser, B.P., Winnewisser, M., (1997) J. Am. Chem. Soc., 119, p. 4789Senderowitz, H., Fuchs, B., (1997) J. Mol. Struct. (Theochem), 395-396, p. 123Rablen, P.R., Hoffmann, R.W., Hrovat, D.A., Borden, W.T., (1999) J. Chem. Soc., Perkin Trans., 2, p. 1719Ganguly, B., Fuchs, B., (2000) J. Org. Chem., 65, p. 558Li, Z., Fan, K., Wong, M.W., (2001) J. Phys. Chem. A, 105, p. 10890Wiberg, K.B., Murcko, M.A., Laidig, K.E., Macdougall, P.J., (1990) J. Phys. Chem., 94, p. 6956Lagowski, J.J., (1976) The Chemistry of Nonaqueous Solvents, 3. , Academic Press: New YorkJones, D.C., (1928) J. Chem. Soc., p. 1193Guss, C.O., Rosenthal, R., (1955) J. Am. Chem. Soc., 77, p. 2549Sosnovskii, G.M., Astapovich, I.V., (1990) Zh. Org. Khim., 26, p. 911Bajwa, J.S., Anderson, R.C., (1991) Tetrahedron Lett., 32, p. 302
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