Synthesis of Substituted Imidazo[1,2-a]Pyridin-3-yl-Acetic Acids by Multicomponent Condensation of 2-Aminopyridines with Arylglyoxals and Meldrum’s Acid
:
An efficient and facial one-pot synthesis of 4-aryl-3,4-dihydrobenzo[g]quinoline-
2,5,10(1H)-triones was developed for the first time. The process proceeded via the
three-component cyclocondensation of 2-amino-1,4-naphthoquinone with Meldrum’s acid
and substituted benzaldehydes under green conditions. The fused 3,4-dihydropyridin-2(1H)-
one-ring naphthoquinones have been synthesized with good to high yields in refluxing
ethanol as a green reaction medium. This protocol is simple and effective as well as does
not involve the assistance of the catalyst, additive, or hazardous solvents.
Auto Tandem Catalysis: Asymmetric Vinylogous Cycloaddition / Kinetic Resolution Sequence for the Enantioselective Synthesis of Spiro‐Dihydropyranone from Benzylidene Meldrum’s Acid