sAJM589

A green and rapid sonochem. research to preparation of the benzo[a]-pyrano[2,3-c]phenazines I [R = Ph, 4-(dimethylamino)phenyl, 2,3-dimethoxyphenyl, etc.] was carried out through a four-component reaction of 2-hydroxynaphthalene-1,4-dione, o-phenylenediamine, aldehydes RCHO, and malononitrile by using multisulfonic acid hyperbranched polyglycerol modified graphene oxide as an effective and recyclable catalyst.This procedure has a number of advantages such as: excellent yields, short reaction times and green conditions.In addition, the catalyst could be recovered easily and reused several times without any considerable loss of its catalytic activity.