Efficient bromination of polyaniline base to poly(2-bromoaniline)-bromide salt and its application as a recyclable catalyst for the synthesis of 2-methyl-4-anilino-1,2,3,4-tetrahydroquinolines

•Polyaniline base is effectively brominated by BDMS.•Highly conducting poly(2-bromoaniline) salt — (2.5 S/cm)•Poly(2-bromoaniline) salt with non-hygroscopic nature•Heterogeneous catalyst for tetrahydroquinolines•Reusable, easily handled and environmentally friendly catalyst

Efficient bromination of polyaniline base to poly(2-bromoaniline)-bromide is successfully carried out using bromodimethylsulfonium bromide. Poly(2-bromoaniline)-bromide salt was obtained in a dry amorphous nature, having high conductivity (2.5 S/cm) with agglomerated spherical morphology. Poly(2-bromoaniline)-bromide salt was proved to be a novel, efficient, reusable, cheaper and eco-friendly polymer-based solid acid catalyst in the reaction between aromatic amines and N-vinyl lactam under solvent-free conditions to provide 2-methyl-4-anilino-1,2,3,4-tetrahydroquinolines. These 2,4-disubstituted tetrahydroquinolines were synthesized with trans selectivity.

Graphical abstractSynthesized brominated polyaniline and acts as novel reusable polymeric catalyst in organic synthesis. This methodology is economic, very simple, green benign and energy efficient.Figure optionsDownload full-size imageDownload as PowerPoint slide