A Study for the Synthesis of Dibenzo[a, j]Xanthenes and 1-Amidoalkyl 2-Naphthols Catalyzed by [Hmim][HSO4] as a Green, Efficient and Reusable Catalyst Under Solvent-Free Conditions

A convenient and efficient procedure for the synthesis of 14-aryl or alkyl-14H-dibenzo[a,j]xanthenes by condensation of 2-naphthol and aldehydes in the presence of Methylimidazolium hydrogensulfate, as a Br?nsted acidic ionic liquid ([Hmim]HSO4), is described. Both aromatic and aliphatic aldehydes reacted easily to afford the corresponding 14-aryl or alkyl-14H-dibenzo[a,j]xanthenes in good yields under solvent-free conditions. Moreover, the synthesis of 1-amidoalkyl 2-naphthols is studied by condensation of aromatic aldehydes with amides or urea and 2-naphthol in the presence of [Hmim]HSO4. Using solvent-free conditions, non-toxic and inexpensive materials, simple and clean work-up, short reaction times and high yields of the products are the advantages of this method.