P. Aulaskari, M. Ahlgrén, J. Rouvinen
Jul 1, 1996
Citations
0
Influential Citations
14
Citations
Journal
Journal of Heterocyclic Chemistry
Abstract
1-R-5-[(2-Nitro-2-phenyl)ethenyl]imidazoles (R = Bn, Me, H) 6a,b,c were synthesized by the Knoevenagel reaction of the corresponding aldehydes 4a,b,c with phenylnitromethane 5. The E-isomers 6a,b,c were precipitated from the reaction mixture as crystalline compounds in 89, 81 and 60% yields, respectively. Traces of the Z-isomers 6a′b′,c′ were found in the reaction mixtures but could be obtained in a ratio of 4:3 from the E-form with UV irradiation. The E-forms were more stable and the Z-isomers changed again to the E-isomers in several weeks.