Microwave-assisted multicomponent reaction for the synthesis of phthalhydrazide derivatives using FeCl3 as a catalyst

Nitrogen-containing heterocycles have wide range of biologically activities such as antibiotics, fungicides, antibiotics agents, anti-cancer, anti-inflammatory, anti-allergic, analgesic, glucagon receptor antagonism, herbicides, and insecticides. Phthalazine derivatives have attracted much attention owing to their biological activities such as anticonvulsant, cardiotonic, vasorelaxant, pharmacological properties, and many other applications are well documented. Due to their importance, some methods have been reported for synthesis of phthalazine derivatives [1,2]. FeCl3 is a ‘green’ and efficient Lewis acid catalyst is potentially attractive in current organic synthesis by forming carbonecarbon and carboneheteroatom bonds. In recent years there have been many reports unraveling the utility of FeCl3 in a wide variety of organic transformations. Moreover, FeCl3 is inexpensive, easy to handle, and are environmentally friendly [3-5]. An efficient, inexpensive, environmentally friendly one-pot route to phthalhydrazide derivatives has been developed, involving three-component reaction of phthalhydrazide, aldehydes, and barbituric acid catalyzed by FeCl3 in solvent free condition under microwave irradiation (scheme 1). This method should provide high yields, shorter reaction time, easy work-up and cleaner reaction. It is a new strategy for N-fused heterocycles synthesis, which has wider application in organic and medicinal chemistry.