Laccase from Basidiomycetous Fungus–Catalyzed Synthesis of Substituted Benzopyranocoumarins via Domino Reaction

Abstract

The present investigation provides a simple and convenient route to organic synthesis of substituted benzopyranocoumarin, which is important because it is a probable HIV protease inhibitor. The reaction of α,β-unsaturated derivatives of coumarins with catechol or 1,4-hydroquinones was catalyzed using laccase in an aqueous medium. Quinones, generated in situ by the oxidation of the corresponding catechol or 1,4-hydroquinones, underwent a domino reaction with chalcones to produce benzopyranocoumarins.

Keywords:

• Aqueous medium
• benzopyranocoumarin
• domino reaction
• laccase
• reusability

ACKNOWLEDGMENTS

M. Kidwai and R. Poddar are thankful to the Council of Scientific and Industrial Research, New Delhi, for providing financial assistance. S. Diwaniyan and R.C. Kuhad acknowledge financial support from the Department of Biotechnology.

Notes

^a Reaction conditions: 1 mmol 2 or 4 and 1.5 mmol of 1a were taken in 15 mL of buffer solution, and THF was added to dissolve the reactants; 0.5 mL of 30% H₂O₂ was added to the resultant solution and stirred well for 4 h.

^b Yield refers to the isolated and unoptimized yield.

^a Reaction conditions: 1 mmol 2 or 4 and 1.5 mmol of 1a were taken in 15 mL of solvents; 400 U of laccase and 0.5 mL of 30% H₂O₂ were added to the resultant solution and stirred well for 4 h.

^b Yield refers to the isolated and unoptimized yield.

^a Reaction conditions: 1 mmol 2 or 4 and 1.5 mmol of 1a were taken in 15 mL of solvents; 400 U of laccase and 0.5 mL of 30% H₂O₂ were added to the resultant solution and stirred well for 4 h.

^b Yield refers to the isolated and unoptimized yield.