Facile one-pot green synthesis of 2-amino-4H-benzo[g]chromenes in aqueous ethanol under ultrasound irradiation

Abstract

We report an efficient green one-pot approach for the synthesis of eighteen novel dihydro-4H-benzo[g]chromene derivatives under ultrasound irradiation conditions. The three-component condensation reaction proceeded through Knoevenagel-Michael reaction of chosen active methylene compounds and 2-hydroxynaphthalene-1,4-dione with different substituted aldehydes in the presence of ammonium acetate in water and ethanol mixture at room temperature, which furnished high yields of products (91–98%) in a rapid reaction time of 5–15 min. This procedure offers 95% of the atom economy and 100% of carbon efficiency together with other eco-friendly benefits.

Graphical Abstract

Keywords:

• Dihydro-4H-benzo[g]chromenes
• green solvent medium
• multi-component
• room temperature
• ultrasound irradiation

Acknowledgments

The authors thank the National Research Foundation (NRF) of South Africa for the financial support, and the University of KwaZulu-Natal for research facilities.

Disclosure statement

No potential conflict of interest was reported by the author(s).