Multicomponent synthesis of novel azo-linked 9-Aryl-1H-xanthene-1,8(2H)-diones using ionic liquid [BDBDMIm]HSO4

The synthesis of ten novel azo dyes derived from 9-Aryl-1H-xanthene-1,8(2H)-dione derivatives from one equivalent of azo-linked salicylaldehydes and two equivalent of dimedone in the presence of 3,3'-(butane-1,4-diyl)bis(1,2-dimethyl-1H-imidazol-3-ium)hydrogensulfate, as a green media, in short reaction time and high yield is reported. Azo-linked aldehydes containing electron withdrawing groups (such as nitro and halide) or electron releasing groups (such as methyl and methoxy group) were employed and reacted well to give the corresponding xanthenes in the yields ranging from 82 to 95%. This method provides several advantages such as environmental friendliness, solvent free, simple work-up, and mild reaction condition. All of synthesized compounds were characterized by FT-IR, 1HNMR and 13CNMR spectroscopy and elemental analyses.