123331-40-8Relevant academic research and scientific papers
Exploiting the Imidazolium Effect in Base-free Ammonium Enolate Generation: Synthetic and Mechanistic Studies
Young, Claire M.,Stark, Daniel G.,West, Thomas H.,Taylor, James E.,Smith, Andrew D.
, p. 14394 - 14399 (2016/11/11)
N-Acyl imidazoles and catalytic isothiourea hydrochloride salts function as ammonium enolate precursors in the absence of base. Enantioselective Michael addition–cyclization reactions using different α,β-unsaturated Michael acceptors have been performed to form dihydropyranones and dihydropyridinones with high stereoselectivity. Detailed mechanistic studies using RPKA have revealed the importance of the “imidazolium” effect in ammonium enolate formation and have highlighted key differences with traditional base-mediated processes.
Regiospecific Synthesis, Structure, and Fluorescence Properties of Highly Substituted Imidazopyridines and Pyridobenzimidazoles
Knoelker, Hans-Joachim,Boese, Roland,Hitzemann, Rainer
, p. 327 - 339 (2007/10/02)
1-(Arylacetyl)imidazoles 1 react with acetylenedicarboxylic esters to provide highly functionalized imidazopyridines 2 in up to 89percent yield.The scope and limitations of this novel condensation reaction have been investigated, and a mechanistic interpretation is presented.A strong effect on the yield of this reaction is observed for electron-donating and electron-withdrawing substituents in the para position of the aryl ring.Moreover, the transformation is shown to proceed in a regiospecific manner starting with 4,5-unsymmetrically substituted 1-(arylacetyl)imidazoles (1d-g) and is extended to the synthesis of the corresponding pyridobenzimazoles 12.The crystal structure of derivative 2a has been determined by X-ray analysis.Imidazopyridines 2 and pyridobenzimidazoles 12, obtained by this procedure, are highly fluorescent in the visible region with characteristically large Stokes shifts.
