N,N-disulfo-1,1,3,3-tetramethylguanidinium carboxylate ionic liquids as reusable homogeneous catalysts for multicomponent synthesis of tetrahydrobenzo[ a ]xanthene and tetrahydrobenzo[ a ]acridine derivatives
carboxylate ionic liquids [DSTMG][CX3COO], ( where X = H, Cl, F) were prepared as viscous liquids from the reaction of [DSTMG][Cl] with equimolar amount of three carboxylic acids (AcOH, CCl3COOH and CF3COOH) for the first time at 60 °C in 1 h. Their structures were confirmed from IR, NMR and elemental analyses data. The Hammett acidity and TGA analysis were also investigated. The two ionic liquids