Characterization and application of pyrazinium di(hydrogen sulfate) as a highly efficient catalyst for synthesis of 14-aryl-14H-dibenzo[aj]xanthenes, 9-aryl-1,8-dioxo-octahydroxanthenes and 1-amidoalkyl/carbamatoalkyl-2-naphthols

In this work, characterization of Brønsted acidic ionic liquid namely pyrazinium di(hydrogen sulfate){PyH2(HSO42} using 1H and 13C NMR, mass, thermogravimetry(TG) and derivative thermogravimetry(DTG) data is achieved. Afterward, it is used as a highly efficient, green and homogeneous catalyst to promote the following organic transformations under solvent-free conditions: (i) the synthesis of 14-aryl-14H-dibenzo[aj]xanthenesfrom2-naphthol and arylaldehydes, (ii) the preparation of 9-aryl-1,8-dioxo-octahydroxanthenes by the reaction of dimedone (5,5-dimethyl-1,3-cyclohexanedione)with arylaldehydes, (iii) the synthesis of 1-amidoalkyl/carbamatoalkyl-2-naphthols by the condensation of 2-naphthol with aromatic aldehydes and amide derivatives/alkyl carbamates.