A simple, green, and efficient procedure for the synthesis of 4-aza-podophyllotoxin derivatives by using a one-pot three-component reaction of benzaldehydes, 1,3-cyclohexanediones, and anilinolactones in the presence of catalytic amount of alum in 1-butyl-3-methylimidazolium triflate as green media is described. This reaction proceeded under mild conditions with the use of an inexpensive and readily available catalyst, high to excellent yields, and simple workup procedure.
One-pot multicomponent synthesis of unsymmetrical polyhydroquinoline derivatives with 1,1′-butylenebispyridinium hydrogen sulfate as an efficient, halogen-free and reusable Brönsted ionic liquid catalyst