Efficient One-Pot Condensation of β-Naphthol, Aldehydes, and Cyclic 1,3-Dicarbonyl Compounds Catalyzed by p-TSA Under Solvent-Free and Sonication Conditions

Abstract

A facile and efficient procedure has been developed by one-pot condensation of β-naphthol, aldehydes, and cyclic 1,3-dicarbonyl compounds for the synthesis of 8,9,10,12-tetrahydrobenzo[a]xanthen-11-one or 8,9-dihydrobenzo-[f]cyclopenta[b]chromen-10(11H)-one derivatives catalyzed by p-toluenesulfonic acid under solvent-free and sonication conditions.

Keywords:

• One-pot condensation
• p-TSA
• solvent-free
• ultrasound irradiation

ACKNOWLEDGMENT

We are grateful to the Science and Technology Projects of Zhejiang (Nos. 2008C11046 and 2007C21111) for financial support.

Notes

^a Reaction conditions: benzaldehyde 1a (1 mmol), β-naphthol 2 (1 mmol), 5,5-dimethyl-cyclohexane-1,3-dione 3 (1.2 mmol), p-TSA (0.1 mmol), solvent (3 mL), 70°C.

^b Isolated yield.

^c The reaction was carried out by stirring instead of sonic irradiation.

^a Reaction conditions: aldehyde 1 (1 mmol), β-naphthol 2 (1 mmol), 5,5-dimethyl-cyclohexane-1,3-dione 3 (1.2 mmol), p-TSA (0.1 mmol), 70°C.

^b Isolated yield.

^c Cyclopentane-1,3-dione was substituted for 5,5-dimethyl-cyclohexane-1,3-dione 3.

^a Reaction conditions: aldehyde 1 (1 mmol), β-naphthol 2 (1 mmol), cyclopentane-1,3-dione 5 (1.2 mmol), p-TSA (0.1 mmol), 70°C.

^b Isolated yield.