Microwave Assisted Multi-component Synthesis of 4Hchromene Derivatives by Nano-coconut Shell-BF3 as a New Heterogeneous Catalyst

Microwave assisted reactions have gained considerable attention, due to versatility and reduction of solvent and reaction time. The reaction of a nano-coconut shell and boron tri-fluoride in diethyl ether solvent resulted in preparation of nano-coconut shell-BF3 as a catalyst. The nano-coconut shell-BF3 catalyst has been characterized by fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Nano-coconut shell-BF3 has been applied as a new heterogeneous catalyst for synthesis of 4Hchromene derivatives from the simple one-pot reaction between aryl aldehydes, cyclic 1,3-diketone and, malononitrile under microwave reaction. Cleanliness, simple methodology, short time, and excellent yields of products are some advantages of this method.