TY - JOUR
T1 - Three-center intramolecular hydrogen bonding in oxamide derivatives. NMR and X-ray diffraction study
AU - Martínez-Martínez, F. J.
AU - Padilla-Martínez, I. I.
AU - Brito, M. A.
AU - Geniz, E. D.
AU - Rojas, R. C.
AU - Saavedra, J. B.R.
AU - Höpfl, H.
AU - Tlahuextl, M.
AU - Contreras, R.
PY - 1998/2
Y1 - 1998/2
N2 - This contribution describes the synthesis and structural investigation of the symmetric and non-symmetric oxamides N,N′-bis(2-hydroxyphenyl)oxamide 1, N,N′-bis(5-tert-butyl-2-hydroxyphenyl)-oxamide 2, N,N′-bis(3,5-dimethyl-2-hydroxyphenyl)oxamide 3, N,N′-bis(2-hydroxybenzyl)oxamide 4, N,N′-diphenethyloxamide 5, N-(2-hydroxyphenyl)-N′-(2-methoxyphenyl)oxamide 6, N-(2-hydroxy-phenyl)-N′-phenethyloxamide 7, (1S,2R)-(-)-N-(2-hydroxyphenylcarbamoylcarbonyl)norephedrine 8, (1R,2S)-(-)-N-(2-hydroxyphenylcarbamoylcarbonyl) 9, ethyl N-(2-hydroxyphenyl)oxalamate 10 and ethyl N-(2-methoxyphenyl)oxalamate 11. The structures were established by 1H, 13C, 15N and variable temperature NMR spectroscopy. Compounds 1-4 and 6-11 are stabilized by intramolecular three-center hydrogen bonding between the amide proton and two oxygen atoms. The 1H NMR Δδ/ΔT value of the amide proton correlates with the 15N NMR chemical shift. The X-ray diffraction molecular structures of 1 and 11 showed a planar conformation with trans configuration in the solid state, corresponding to the preferred conformation found in solution.
AB - This contribution describes the synthesis and structural investigation of the symmetric and non-symmetric oxamides N,N′-bis(2-hydroxyphenyl)oxamide 1, N,N′-bis(5-tert-butyl-2-hydroxyphenyl)-oxamide 2, N,N′-bis(3,5-dimethyl-2-hydroxyphenyl)oxamide 3, N,N′-bis(2-hydroxybenzyl)oxamide 4, N,N′-diphenethyloxamide 5, N-(2-hydroxyphenyl)-N′-(2-methoxyphenyl)oxamide 6, N-(2-hydroxy-phenyl)-N′-phenethyloxamide 7, (1S,2R)-(-)-N-(2-hydroxyphenylcarbamoylcarbonyl)norephedrine 8, (1R,2S)-(-)-N-(2-hydroxyphenylcarbamoylcarbonyl) 9, ethyl N-(2-hydroxyphenyl)oxalamate 10 and ethyl N-(2-methoxyphenyl)oxalamate 11. The structures were established by 1H, 13C, 15N and variable temperature NMR spectroscopy. Compounds 1-4 and 6-11 are stabilized by intramolecular three-center hydrogen bonding between the amide proton and two oxygen atoms. The 1H NMR Δδ/ΔT value of the amide proton correlates with the 15N NMR chemical shift. The X-ray diffraction molecular structures of 1 and 11 showed a planar conformation with trans configuration in the solid state, corresponding to the preferred conformation found in solution.
UR - http://www.scopus.com/inward/record.url?scp=0043241988&partnerID=8YFLogxK
U2 - 10.1039/a704640e
DO - 10.1039/a704640e
M3 - Artículo
SN - 0300-9580
SP - 401
EP - 406
JO - Journal of the Chemical Society, Perkin Transactions 2
JF - Journal of the Chemical Society, Perkin Transactions 2
IS - 2
ER -