116343-85-2Relevant academic research and scientific papers
Spectral Properties and Isomerism of Nitro Enamines. Part 2. 3-Amino-2-nitrocrotonic Esters
Chiara, Jose Luis,Gomez-Sanches, Antonio,Marcos, Enrique Sanchez,Bellanato, Juana
, p. 385 - 392 (2007/10/02)
The IR, Raman, 1H and 13C spectra of a series of 3-amino-2-nitrocrotonic esters (3), with both primary and secundary amino groups, have been studied.The spectral data show that these compounds exist in solution as equilibrium mixtures of the two enantiomeric quasi-s-cis-(Z) isomers (3A') and (3A'') and the planar, and less polar s-cis (E)-(3C) isomer, the ratio :(3B) beeing strongly dependent on the polarity of the medium.The E- and Z-forms can be easily distinguished by their vibrational and NMR spectra, and are separated by very low energie barriers (Γ 50-70 kJ mol-1), the magnitude of which decreases on increasing the electron-donor capacitiy of the substituent at the amino function.The spectral data and AM1 calculations indicate a strong polarization of the nitro enamine system with a large negative charge accumulation at C-2 and, to a lesser extent, at the NO2 group.This group acts as a weak ?- and strong ?-acceptor, and the ester group acts as a weak ?-acceptor group and a ?-donor.
Studies on Nitroenamines. Part III. Synthesis and Spectral Properties of 4-Acyl-1-arylimidazoles
Gomez-Sanchez, A.,Hidalgo, F. J.,Chiara, J. L.
, p. 1757 - 1764 (2007/10/02)
The catalytic (C/Pd) hydrogenation of 3-arylamino-2-nitro-2-enones (1) in the presence of carboxylic ortho esters (2) affords 4-acyl-1-arylimidazoles (3) in yields (20-70percent) which depend on the degree of substitution of the imidazole ring.The spectra
