Green Synthesis of Mono, Bis and Tris Aminobenzochromenes and Benzopyranochromenes using FeO@Sio@ Vanillin/Vitamin B1 Nanoparticles: A New, Mild, Simple and Effective Bronsted Acid Catalyst for the Synthesis of Chromenes.

Objective: Vanillin/Vitamin B1 (Thiamine) supported FeO@Sio nanoparticles (FeO @SP@VT) were synthesized and thoroughly analyzed, and were used for the green and efficient synthesis of chromenes using the multicomponent reaction of aldehyde, malononitrile and 4-hydroxy coumarin, as well as the multicomponent reaction of aldehyde, α-naphthol or β-naphthol and 4-hydroxy coumarin.

Methods: The reaction was performed under grinding conditions, and at the end of the reaction, the catalyst was separated in the presence of a strong magnet and can be recovered 10 times.

Results: The advantages of this method are high purity of products, short times, higher yield, easy separation and cheap raw materials.