Document Type : Full Paper
Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad
Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad 91775-1436, Iran.
Cobalt hydrogensulfate is an efficient catalyst for the condensation of β-naphthol, aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione at 120 °C to afford 9,9-dimethyl-12-phenyl-8,10,11,12-tetrahydro-9-H-benzo[a]xanthen-11-one derivatives in high yields. Also, polycondensation reactions of phenols with phthalic anhydride were carried out in the presence of cobalt hydrogensulphate under solvent-free conditions. Simple and convenient procedure, high conversion, reusability of catalyst, easy purification and short reaction time are the advantageous features of this method.