[(EtO)3Si(CH2)3N+H3][CH3COO−] as Basic Ionic Liquid Catalyst Promoted Green Synthesis of Benzo[a]pyrano[2,3-c]phenazine Derivatives in Homogenous Solution

An efficient, one-pot quantitative procedure for the preparation of benzo[ a ]pyrano[2,3-c]phenazine derivatives from four-component condensation reaction of 2-hydroxynaphthalene-1,4-dione, benzene-1,2-diamine, aromatic aldehydes, and malononitrile in the presence of [(EtO) 3 Si(CH 2 ) 3 N + H 3 ][CH 3 COO − ] as basic ionic liquid as catalyst in homogenous solution under solvent-free conditions at 90 °C is described. Simple procedure, high yields, short reaction times, and an environmentally benign method are advantages of this protocol. The [(EtO) 3 Si(CH 2 ) 3 N + H 3 ][CH 3 COO − ] can be recovered and reused several times without loss of its activity.