Eco-friendly and efficient one-pot synthesis of alkyl- or aryl-14H-dibenzo[a,j]xanthenes in water

Alkyl- or aryl-14H-dibenzo[a,j]xanthene derivatives are synthesized efficiently by the reaction of β-naphthol and aliphatic and aromatic aldehydes in the presence of KAl(SO4)2•12H2O (alum) under aqueous condition at 100 °C. Different types of aromatic and aliphatic aldehydes are used in the reaction and in all cases the products synthesized successfully. Several solvents were examined for this reaction; however, in terms of reaction yield and time, water was found to be the optimum solvent.