Microwave Assisted Amidation of 5-Aminoisophtalic Acid Dimethyl Ester Catalyzed by Imidazolium Ionic Liquids

Abstract

Amide functionalities present in living system as peptides and possess various biological role. Many synthetic amides also possess biological activities due to the possibility of interaction with cellular liquids such as those compounds useful as a contrast agent in radiographic method. Synthesis of amides from the carboxylic acid or derivatives normally require heating and catalyst. In this report, an environmentally benign synthesis of amide was carried out utilizing microwave radiation and catalyzed by imidazolium ionic liquids (BMIMCl). Microwave radiation provided efficient heating through activation of chemical bonds instead of conventional conductivity methods hence increasing the rate of reactions. Ionic liquids were suitable material in this synthesis due to non-volatile nature as well as stability under high temperature and microwave heating. Furthermore, ionic liquids are tunable material that can be designed for the specific synthesis and functioned as a catalyst. The optimum condition for coupling of 5-Amino-isophthalic acid dimethyl ester with an amino diol was found at 80 °C, 90 minutes, under radiation of microwave at the power of 300 Watt. The product was obtained at 38.46% yield. Furthermore, the methodology was applied to synthesis radiographic material and was successful to obtain product with 48.78% yield. The products were characterized by NMR spectroscopy.