New multicomponent approach for the synthesis of benzo[c]coumarin derivatives over MgO under solvent-free conditions

Synthesis, Electrochemical Studies, Molecular Docking, and Biological Evaluation as an Antimicrobial Agent of 5-Amino-6-cyano-3-hydroxybenzo[c]coumarin Using Ni-Cu-Al-CO3 Hydrotalcite as a Catalyst

New insights via a multicomponent cyclocondensation reaction of 2-hydroxy benzaldehyde acetoacetic ester and malononitrile were attained under efficient conditions. A detailed mechanistic study exhibits that the reaction via multicomponent, one-pot, two-step incooperating three-components' reactants under nominal conditions efficiently synthesizes the intermediates in shorter than reported time along with the formation of a novel compound [5-amino-6-cyano-3-hydroxybenzo[c]coumarin] in the presence of Ni-Cu-Al-CO₃ hydrotalcite as a heterogeneous catalyst. Hydrotalcite functions as an efficient and versatile catalyst as it is safe, easy to work up, and recyclable many times under ambient conditions, and the reaction time is shorter. The aforementioned conditions make these solid basic heterogeneous catalysts environmentally friendly. The product yield obtained was 89%. The product was characterized using FTIR, LCMS, and NMR. Electrochemical studies were also carried out to check the reduction and oxidation behavior. The synthesized product showed antimicrobial activity. Antimicrobial activity against human pathogens, viz, S. Aureus, P. Aeruginosa, and P. Bulgaria, was studied by using the agar well diffusion method. The molecular docking studies of 5-amino-6-cyano-3-hydroxybenzo[c]coumarin exhibit its suitable attachment at the active center of the type IIA topoisomerases and gyrase enzymes which suggest its potential antibacterial activity when compared using ciprofloxacin drug as the control.

Synthesis and mechanism of novel fluorescent coumarin–dihydropyrimidinone dyads obtained by the Biginelli multicomponent reaction

Coumarin-β-ketoesters were used to synthesize new blue-fluorescent compounds exhibiting ICT. The Knoevenagel intermediate suggests that our Biginelli reaction passing by this mechanistic way is unlikely.