Black yet green: A heterogenous carbon-based acid catalyst for the synthesis of biscyclic derivatives under eco-friendly conditions

In this study, a simple, cost-efficient and green protocol has been described for the synthesis of biscoumarin and bisdimedone derivatives via one-pot Knoevenagel-Michael reaction of aromatic aldehydes with 4-hydroxycoumarin and dimedone, respectively. This approach has defined a new way of synthesizing products (4a-i and 5a-i) in high yields using carbon sulfonic acid as a heterogeneous solid acid catalyst. All the reactions have been executed in a greener medium in short reaction times with high-to-excellent yields. This organic synthesis adheres to the principles of green chemistry as the catalyst is cheap, gentle toward environment, easy to handle and reusable up to six cycles, easily separable through filtration, green reaction media and high yield of derivatives in short reaction time. The structure of the synthesized compounds was established by spectral analysis. [GRAPHICS] .

Automated summary

This study describes a simple, cost-efficient and green protocol for synthesizing biscoumarin and bisdimedone derivatives in high yields through one-pot Knoevenagel-Michael reaction. The use of carbon sulfonic acid as a catalyst allows for the reactions to be conducted in a greener medium with short reaction times and excellent yields.