Envirocat EPZ-10: A Solid Acid Catalyst for the Synthesis of 1,8-Dioxo-octahydroxanthenes in Aqueous Medium

Abstract

An efficient method for synthesis of 1,8-dioxo-octahydroxanthenes using EPZ-10 as a heterogeneous catalyst is developed. In this method, aldehydes and dimedone / cyclohexane-1,3-dione are heated at 70 °C in the presence of a catalytic amount of EPZ-10 in water as a universal solvent, affording the corresponding 1,8-dioxo-octahydroxanthenes in moderate to excellent yields. Also, domino Knoevenagel / hetero-Michael-addition reaction is described in water without any catalyst with excellent yields. The major advantages of this method are excellent yields, short reaction time, and ease of operation. This green protocol works well with dimedone as well as cyclohexane-1,3-dione.

Keywords:

• 1,8-Dioxo-octahydroxanthenes
• domino reaction
• Envirocat EPZ-10
• heterogeneous catalyst
• xanthenedione derivatives

ACKNOWLEDGMENTS

D. M. P. and K. A. U. thank the University Grants Commission, New Delhi, for financial assistance [F.2-3/2007(Policy/SR)] and for a research project fellowship, respectively.

Notes

^a Yields refer to pure isolated products.

^a Yields refer to pure isolated products.

^b All products gave satisfactory spectroscopic (IR, ¹H NMR, MS) analysis.