(±)-CSA Catalyzed Multicomponent Synthesis of Indeno Naphthopyrans and Tetrahydrobenzo[a]xanthen-11-ones Under Ultrasonic Irradiation

Aims: This study was designed to synthesis of Naphthopyrans and xanthenes derivatives in green chemistry approach.

Methodology: New 13-aryl-indeno[1,2-b]naphtha[1,2-e]pyran-12(13H)-ones and tetrahydrobenzo[a]xanthen-11-ones were obtained by multi-component reaction of 2-naphthol, aromatic aldehydes, indane-1,3-dione or 5,5-dimethylcyclohexane-1,3-dione in the presence of (±)-camphor-10-sulfonic acid (CSA) catalyst under ultrasonic irradiation.

Results: 13-aryl-indeno[1,2-b]naphtha[1,2-e]pyran-12(13H)-ones and tetrahydrobenzo[a]xanthen-11-ones were obtained in high yields. However, 13-aryl-indeno[1,2-b]naphtha[1,2-e]pyran-12(13H)-one derivatives gave better yields under this conditions.

Conclusion: The desired compounds were obtained in high yields in short reaction times. The advantages of this method are using a powerful nontoxic, inexpensive, eco-friendly, recyclable, easy to handle, and water-soluble organo-catalyst, building several new bonds in one-pot multi-component reaction, low power consumption, short reaction times and high yields.