Divergent Products Obtained from the Reactions of Salicylaldehyde and 4-Hydroxycoumarin in TEBAC-H₂O, KF-Al₂O₃-EtOH, and Ionic Liquid

Abstract

Controlling selectivity of the reactions of salicylaldehydes and 4-hydroxycoumarin in triethylbenzylammonium chloride–H₂O, ionic liquid, or KF-Al₂O₃-EtOH systems, respectively, resulted in the syntheses of three series of different coumarin derivatives.

Keywords:

• Aqueous media
• coumarin
• ionic liquid
• KF-Al₂O₃

ACKNOWLEDGMENTS

We are grateful to the National Natural Science Foundation of China (20802061), the Natural Science Foundation (08KJD150019), and the Qing Lan Project (08QLT001) of the Jiangsu Education Committee for financial support.

Notes

^a Reagents and conditions: salicylaldehyde 1 (0.122 g, 1 mmol), 4-hydroxycoumarin 2 (0.324 g, 2 mmol), solvent (10 mL).

^b Isolated yields.

^a Reagents and conditions: 1 (1 mmol), 2 (0.324 g, 2 mmol), KF-Al₂O₃ (0.102 g, 1 mmol), and EtOH (10 mL).

^b Isolated yields.

^a Reagents and conditions: 1 (1 mmol), 2 (0.162 g, 1 mmol), TEBAC (0.023 g, 0.1 mmol), water (10 mL).

^b Isolated yields.

^a Reagents and conditions: salicylaldehyde 1 (1 mmol), 2 (0.324 g, 2 mmol), and [BMIM]Br (2 mL).

^b Isolated yields.