Synthesis of xanthene and coumarin derivatives in water by using β-Cyclodextrin

Simple and green procedure was developed for the synthesis of various xanthene and coumarin derivatives using beta-cyclodextrin (beta-CD) as reusable catalyst at 70 degrees C in water. Condensation of salicylaldehyde (1 mmol) and dimedone (2 mmol) or 1,3 cyclohexadione (2 mmol) gave corresponding xanthene derivatives, while condensation of salicylaldehyde (1 mmol) with Meldrum's acid (1 mmol) or 4-Hydroxy-6-methyl-2H-pyran-2-one (1 mmol) gave respective coumarin derivatives in impressive yields. Involvement of beta-CD as catalyst was ascertained by inclusion complex evaluation of beta-CD-salicylaldehyde with H-1 NMR analysis at 70 degrees C.