Synthesis of pyridino[2,1-b]quinazolinones via a visible light-induced functionalization of alkynes/nitrile insertion/cyclization tandem sequences in continuous-flow technology

We successfully developed an unprecedented route to pyridino[2,1-b]quinazolinone synthesis through a visible light-induced functionalization of alkynes/nitrile insertion/cyclization tandem sequences in a microchannel reactor. The yield of the template reaction under optimized conditions is 91%. This photocatalytic reaction provides rapid, facile, and practical access to valuable polycyclic quinazolinone, and is amenable to the gram scale. In addition, a reasonable reaction mechanism is proposed based on controlled experiments.