Cu-TEMPO catalyzed synthesis of benzo[a]acridines and their photophysical studies

Abstract

An efficient solvent-free synthesis of benzo[a]acridines 11 was achieved from 2-amino-5-chloro-benzhydrol 8, 1,2,3,4-tetrahydronaphthalen-2-ol 9, and benzyl alcohol 10 through Cu-TEMPO catalyzed dehydrogenative Friedlander annulation/C(sp³)–H functionalization utilizing DMU-based DESs. A plausible reaction mechanism was proposed based on control experiments and NMR studies. Additionally, the synthesized compounds’ absorption, emission, and synthetic utility studies were evaluated. Further examination revealed compound 11f exhibits acidochromic properties, resulting in noticeable colour changes.