Environmentally benign and one-pot synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes catalyzed by acyclic Brønsted acidic ionic liquid [H-NMP][HSO4] under green conditions

A convenient and efficient direct protocol for the preparation of 14-aryl-14H-dibenzo[a,j]-xanthenes was described. The condensation of 2-naphthol with various aromatic aldehydes in the presence of a catalytic amount of [H-NMP][HSO4] as a Brønsted acidic ionic liquid under solvent-free conditions at 110 °C was described. This method has the following advantages: the reaction workup is very easy, and the catalyst is smoothly recycled to catalyze the preparation of 14-aryl-14H-dibenzo[a,j]xanthenes with high yields through a green and one-pot procedure. The corresponding products have been obtained in excellent yields, with high purity, and in short reaction times.

Graphical abstractA convenient and efficient direct protocol for the preparation of 14-aryl-14H-dibenzo[a,j]xanthenes was described. The condensation of β-naphthol with various aromatic aldehydes in the presence of a catalytic amount of [HNMP][HSO4] as a Brønsted acidic ionic liquid under solvent-free conditions at 110 °C was described. The corresponding products have been obtained in excellent yields, with high purity, and in short reaction times.Figure optionsDownload full-size imageDownload as PowerPoint slide