86803-30-7Relevant academic research and scientific papers
Preparation and diels-alder chemistry of 4-vinylimidazoles
Lovely, Carl J.,Du, Hongwang,Sivappa, Rasapalli,Bhandari, Manojkumar R.,He, Yong,Dias, H. V. Rasika
, p. 3741 - 3749 (2008/02/04)
(Chemical Equation Presented) Various 4-vinylimidazole derivatives have been prepared from the corresponding 4-iodoimidazoles or from urocanic acid. Several methods for the elaboration of these vinylimidazoles and their Diels-Alder reactions are reported. All of the vinylimidazoles prepared in the course of this study react with N-phenylmaleimide quite readily with mild thermal activation providing a single cycloadduct, in most cases the initial, nonaromatic adduct. With more electron rich substrates, there is a tendency for these initial cycloadducts to undergo aromatization, ene reaction, and oxidation although this can be circumvented to a large extent by the choice of reaction conditions. Limited reactions were observed with other dienophiles, providing the expected cycloadducts in most cases, although an abnormal adduct was obtained in one case with dimethyl acetylene dicarboxylate. These substrates also participate in regioselective Diels-Alder reactions with monoactivated dienophiles, but require fairly forcing conditions, thus only providing the aromatized cycloadducts in modest yields. An investigation of substituent effects at the 2-position of the imidazole moiety was undertaken, in which electron-donating and weakly electron-withdrawing substituents are tolerated. In addition, several substrates with terminally substituted vinyl moieties have been investigated.
Regioselective synthesis of 1-benzyl- and 1-methyl-4- vinylimidazole and their reactions with N-phenylmaleimide
Lovely, Carl J.,Du, Hongwang,Rasika Dias
, p. 1 - 7 (2007/10/03)
The regioselective synthesis of 1-benzyl- and 1-methyl-4- vinylimidazole from 4,5-diiodoimidazole is described. Their Diels-Alder reactions with N-phenylmaleimide provide a variety of adducts, including the anticipated enamine and the corresponding aromatized isomer. However, additional products including ene adducts, a bis Diels-Alder adduct and oxidation products were isolated.
