Ammonium acetate catalyzed an efficient one-pot three component synthesis of pyrano[3,2-c]chromene derivatives

An efficient and simple procedure has been described using ammonium acetate as catalyst for the synthesis of 3,4-dihydropyrano[3,2-c]chromene derivatives by one-pot three component condensation of 4-hydroxycoumarin, various aryl/heteryl aldehydes and malononitrile. The attractive features of the present methodology are excellent yields, short reaction times and environmentally benign milder reaction conditions.