An efficient, convenient and green method has been introduced for the synthesis of biologically active xanthene derivatives through a one-pot condensation of aldehydes, 2-naphthol, and dimedone/naphthols in the presence of boron sulphonic acid (B(HSO4)3) as an efficient heterogeneous reusable solid acid catalyst under solvent-free conditions with good to excellent yields. Different types of aromatic and aliphatic aldehydes were used in the reaction and in all cases the products synthesized successfully. In addition, short reaction times, straightforward procedure, non-toxicity, and reusability of the catalyst are other noteworthy advantages of the present method.
