Synthesis of electron-deficient dienes bearing a chromonyl moiety via the reaction of 3-formylchromones with ylidenemalononitriles and ethyl α-cyano-β-methylcinnamate

Ultrasound-promoted synthesis of novel N-arylamino-3,5′-biquinoline derivatives: their applications in live-cell imaging and in vitro anticancer activity evaluation

A novel strategy for the construction of functionalized N-arylamino-3,5′-biquinoline has been developed.

An expedient metal-free cascade route to chromonyl diene scaffolds: thermodynamic vs. kinetic control

A piperidine-catalyzed reaction between 3-formylchromone, 1,3-dimethyl barbituric acid, and ylidenemalononitriles is developed that offers chromonyl diene products in good yields. This cascade reaction proceeds via the insertion of ylidenemalononitriles between the Knoevenagel adduct obtained from 3-formylchromone and 1,3-dimethylbarbituric acid, where the pyrimidine-based enaminone is integrated with the chromone through the central diene linker. Similarly, introducing pyrimidine-based enaminone into the terminal part of the chromonyl diene scaffold gave an equilibrium mixture of rotational isomers in DMSO, which could be separated and isolated by crystallization. The computational analysis confirmed the role of barbiturate in directing the type of final chromonyl diene via kinetic or thermodynamic control. Moreover, computations revealed that one of these species, observed in the NMR spectra, is produced by the bond cleavage in the spirocyclic intermediate.