Tautomeric equilibria for ionized oxamic acid - inhibitor of LDH

Subject Areas : Journal of the Iranian Chemical Research

Ewa D. Raczyńska ¹ , Małgorzata Hallmann ² , Kinga Duczmal ³

1 - Department of Chemistry, Warsaw University of Life Sciences (SGGW), 02-776 Warszawa, Poland
2 - Department of Chemistry, Warsaw University of Life Sciences (SGGW), 02-776 Warszawa, Poland
3 - Department of Chemistry, Warsaw University of Life Sciences (SGGW), 02-776 Warszawa, Poland

Received: 2011-02-26 Accepted : 2011-03-12 Published : 2011-03-31

Keywords: DFT, Oxamic acid, Amide-iminol tautomerism, Ionization, &pi, -electron delocalization,

Abstract :

Amide-iminol tautomerism was studied for ionized oxamic acid (OA+•) in the gas phase using theDFT method with the UB3LYP functional and various basis sets {6-31++G(d,p), 6-311+G(d,p), and augcc-pVDZ}. Among twenty tautomers-rotamers possible for OA+•, eleven isomers were found to bethermodynamically stable. Similarly as for the neutral molecule, ionization (OA → OA+• + e) favors theamidization process (amide ← iminol). Isomerization seems to change solely the conformationalpreferences. π-Electron delocalization in the NCO and OCO moieties is close to that for n-π conjugatedfragments.

References:

[1] (a) V. Gold, Pure Appl. Chem. 51 (1979) 1725-1801, (b) Glossary of Terms Used in Physical Organic
Chemistry, IUPAC Recommendations, 1994.
E.D. Raczyńska & et al. / J. Iran. Chem. Res. 4 (2011) 113-122
122
[2] J. Elguero, C. Marzin, A.R. Katritzky, P. Linda, Adv. Heterocycl. Chem. Supplement 1, Academic
Press, New York, 1976.
[3] E.D. Raczyńska, W. Kosińska, B. Ośmiałowski, R. Gawinecki, Chem. Rev. 105 (2005) 3561-3612.
[4] A.R. Clarke, D.B. Wigley, W.N. Chia, D.A. Barstaw, T. Atkinson, J.J. Holbrook, Nature, 324 (1986)
699-702.
[5] E. Gawlita, P. Paneth, V.E. Anderson, Biochemistry 34 (1995) 6050-6058.
[6] R.K. Schmidt, J.E. Gready, J. Mol. Struct. (Theochem) 498 (2000) 101-112.
[7] P. O'Carra, S. Barry, Methods in Enzymology, M. Jakoby & M. Wilchek (Eds.), Academic Press,
London, 1974.
[8] R.I. Brinkworth, C.J. Masters, D.J. Winzor, Biochem. J. 151 (1975) 631-636.
[9] E.A. Sevriukov, L.P. Evseev, Vopr. Med. Khim. 40 (1994) 23-25.
[10] I. Safarik, M. Safarikova, J. Chromatogr. B772 (1999) 33-53.
[11] T. Larsen, J. Diary Res. 72 (2005) 209-216.
[12] K. Duczmal, M. Hallmann, E.D. Raczyńska, J.-F. Gal, P.-C. Maria, Polish J. Chem. 81 (2007) 1011-
1020.
[13] E.D. Raczyńska, M. Hallmann, K. Duczmal, Polish J. Chem. 82 (2008) 1077-1090.
[14] B. Bankiewicz, S. Wojtulewski, S. Grabowski, J. Org. Chem. 75 (2010) 1419-1426.
[15] E.D. Raczyńska, M. Hallmann, K. Duczmal, Comput. Theor. Chem. 964 (2011) 310-317.
[16] R.G. Parr, W. Yang, Density Functional Theory of Atoms and Molecules, Oxford University Press,
New York, 1989.
[17] (a) A.D. Becke, J. Chem. Phys. 98 (1993) 5648-5652, (b) C. Lee, W. Yang, R.G. Parr, Phys. Rev. B
37 (1988) 785-789.
[18] (a) W.J. Hehre, L. Radom, P.v.R. Schleyer, J. A. Pople, Ab initio Molecular Theory, Wiley, New
York, 1986, (b) F. Jensen, Introduction to Computational Chemistry, John Wiley & Sons, New York,
1999.
[19] D.E. Woon, T.H. Dunning, J. Chem. Phys. 98 (1993) 1358-1371.
[20] (a) E.D. Raczyńska, M. Hallmann, K. Kolczyńska, T.M. Stępniewski, Symmetry 2 (2010) 1485-
1509, (b) E.D. Raczyńska, T.M. Krygowski, K. Duczmal, M. Hallmann, XVIII International
Conference on Physical Organic Chemistry, Warsaw, 2006.
[21] M.J. Firsch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R. Cheeseman, J.A. Jr.
Montgomery, T. Vreven, K.N. Kudin, J.C. Burant, J.M. Millam, S.S. Iyengar, J. Tomasi, V. Barone,
B. Mennucci, M. Cossi, G. Scalmani, N. Rega, R. Petersson, H. Nakatsuji, M. Hada, M. Ehara, K.
Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, J. Nakai, M. Klene, X.
Li, J.E. Knox, H.P. Hratchian, J.B. Cross, V. Bakken, C. Adamo, R. Jaramillo, R. Gomperts, R.E.
Stratmann, O. Yazyev, A.J. Austin, R. Cammi, C. Pomelli, J.W. Ochterski, A.Y. Ayala, K.
Morokuma, G.A. Voth, P. Salvador, J.J. Dannenberg, V.G. Zakrzewski, S. Dapprich, A.D. Daniels,
M.C. Strain, O. Farkas, D.K. Malick, A.D. Rabuck, K. Raghavachari, J.B. Foresman, J.V. Oritz, Q.
Cui, A.G. Baboul, S. Clifford, J. Cioslowski, B.B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I.
Komaromi, R.L. Martin, D.J. Fox, T. Keith, M.A. Al-Laham, C.Y. Peng, A. Nanayakkara, M.
Challacombe, P.M.W. Gill, B. Johnson, W. Chen, M.W. Wong, C. Gonzalez, J.A. Pople, Gaussian-
03, Revision E.01, Gaussian, Inc., Wallingford CT, 2004.
[22] D. Yu, D.A. Armstrong, A. Rauk, Chem. Phys. 202 (1996) 243-252.
[23] J.A. Long, N.J. Harris, K. Lammertsma, J. Org. Chem. 66 (2001) 6762-6767.
[24] (a) J. Kruszewski, T.M. Krygowski, Bull. Acad. Pol. Sci. Sér. Sci. Chim. 20 (1972) 907-915, (b) J.
Kruszewski, T.M. Krygowski, Tetrahedron Lett. (1972) 3839-3842, (c) T.M. Krygowski, J.
Kruszewski, Bull. Acad. Pol. Sci. Sér. Sci. Chim. 22 (1974) 871-876.
[25] T.M. Krygowski, J. Chem. Inf. Comput. Sci. 33 (1993) 70-78.
[26] W.G. Mallard, P.J. Linstrom (Eds.), NIST Chemistry WebBook, NIST Standard Reference Database,
National Institute of Standards and Thechnology, Gaithersburg, MD 20899, 2005.