Brønsted acid-promoted facile synthesis of N-fused angular imidazoquinolines

Bronsted acid-promoted straightforward synthesis of Nfused tricyclic angular imidazoquinolines in high yields is realized through a succinct 1,3-hydride shift. The protocol is operationally simple, scalable, and features broad scope. A photophysical study revealed that these π-extended imidazoquinolines display large Stokes shifts (up to 158 nm) and high fluorescent quantum yields.