Efficient Synthesis of 12-Aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-one Derivatives Catalyzed by p-Dodecylbenzenesulfonic Acid in Aqueous Media Under Ultrasound Irradiation

Abstract

An efficient synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-one derivatives via the three-component condensation of aromatic aldehyde, 2-naphthol, and 5,5-dimethyl-1,3-cyclohexanedione was carried out in 76–93% yields at 40–42 °C using p-dodecylbenzenesulfonic acid as catalyst in aqueous media under ultrasound irradiation.

GRAPHICAL ABSTRACT

Keywords:

• Aqueous media
• three-component condensation
• ultrasound irradiation
• xanthene

ACKNOWLEDGMENT

We thank the Natural Science Foundation of Hebei Province (B2006000969), China, for financial support.

Notes

^a Substrate: benzaldehyde, 1 mmol; 2-naphthol, 1 mmol; 5,5-dimethyl-1,3-cyclohexanedione, 1.2 mmol; water 2 mL.

^b Stirring alone without ultrasound.

^c Solvent-free.

^d Ethanol as solvent. The product is 3-ethoxy-5,5-dimethylcyclohex-2-enone.

^e Methanol as solvent. The product is 3-methoxy-5,5-dimethylcyclohex-2-enone.

^a Substrate: aryl aldehyde, 1 mmol; 2-naphthol, 1 mmol; 5,5-dimethyl-1,3-cyclohexanedione, 1.2 mmol; DBSA, 0.1 mmol; H₂O, 2 mL.

^b Stirring alone without ultrasound.

^a Condensation of benzaldehyde, 2-naphthol, and 5,5-dimethyl-1,3-cyclohexanedione.

^b Condensation of benzaldehyde, 1-naphthol, and 5,5-dimethyl-1,3-cyclohexanedione.