Cyanation and bromination of electron-rich aromatics by BrCN under solvent-free conditions catalyzed by AlCl3: A new examples of Beckmann-type rearrangement

A convenient route for cyanation and bromination of some electron-rich aromatics (anisole, 1,3-dimethoxybenzene, 1,4-dimethoxybenzene, 1,3,5-trimethoxybenzene and β-naphthol) by BrCN in the presence of aluminum trichloride (AlCl3), as catalyst, by grinding method under solvent-free conditions at room temperature to 60 °C was described in good yield. The structures of all obtained products were characterized by FT-IR, 1H NMR, 13C NMR, and Mass spectrometry techniques. Anisole and 4-cyanobenzonitrile afforded both cyanated and brominated products. 1,3-Dimethoxybenzene yielded to two types of the cyanated products. 1,4-Dimethoxybenzene has done some unusual coupling reactions via new Beckmann-type rearrangement. No bromination of 1,4-dimethoxybenzene was observed under the same conditions. 1,3,5-Trimethoxybenzene and β-naphthol obtained both cyanated and brominated products which were analyzed by HPLC technique.

Keywords:

BrCN , Electron-rich aromatic compounds , Aluminum trichloride , solvent-free , Intramolecular hydrogen bond , Beckmann-type rearrangement