[(EtO) 3 Si(CH 2 ) 3 N + H 3 ][CH 3 COO - ] as basic ionic liquid catalyst promoted green synthesis of benzo[a]pyrano[2,3-c]phenazine derivatives

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 under solvent-free conditions 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.