Citric acid has been used as a green and efficient catalyst for one-pot, multi-component synthesis of linear naphtho[2,3-b]-furan-4,9-dione derivatives by condensation of 2-hydroxy-1,4naphthoquinone with cyclohexyle isocyanides and variety of aldehydes at ambient temperature under aqueous-ethanol media. This method has several advantages including use of a nonhazardous and inexpensive catalyst, easy work-up, clean reaction conditions, and high yields.
