An efficient four-component domino protocol for the rapid and green synthesis of functionalized benzo[a]pyrano[2,3-c]phenazine derivatives using caffeine as a homogeneous catalyst

摘要

A one-pot, two-step procedure has been used to synthesize functionalized benzo[a]pyrano[2,3-c]phenazine derivatives from a four-component condensation reaction of 2-hydroxynaphthalene-1,4-dione, o-phenylenediamine, aldehydes, and malononitrile in the presence of 1,3,7-trimethylpurine-2,6-dione (caffeine) as an expedient and reusable solid base catalyst. This new procedure has the following advantages: operational simplicity, short reaction times, environmentally friendly, easy work-up, and all the products were obtained in excellent yields.