Nano ZrP2O7 Catalyzed Multicomponent Reaction for an Easy Access of 4H-pyrans and 1,4-dihydropyridines

Construction of 1,4-Dihydropyridines: The Evolution of C4 Source

The field of cascade cyclization for the construction of 1,4-dihydropyridines (1,4-DHPs) has been continuously expanding during the last decades because of their broad-spectrum biological and synthetic importance. To date, many methods have been developed, mainly including the Hantzsch reaction, Hantzsch-like reaction and newly developed cascade cyclization, in which various synthons have been successively developed as C4 sources of 1,4-DHPs. This review presents the cascade cyclization synthesis strategy for the construction of 1,4-DHPs according to various C4 sources from carbonyl compounds, alkenyl fragments, alcohols, aliphatic amines, glycines and other C4 sources.

Synthesis of benzodiazepines catalyzed by CoFe2O4@SiO2-PrNH2 nanoparticles as a reusable catalyst

CoFe2O4@SiO2-PrNH2 nanoparticles have been used as an efficient catalyst for the preparation of benzodiazepines by multi-component reactions of 1,2-phenylenediamine, dimedone, different aldehydes or Meldrum’s acid and isocyanides. This method provides several advantages including mild reaction conditions, the applicability to a wide range of substrates, the reusability of the catalyst and low catalyst loading.