Nano-sized protonated ZSM–5 ( H-ZSM-5nanozeolite) was successfully synthesized by the hydrothermal method using the
bagasse ash (BGA) as a new silica source. Cultivated BGA in the south of the Caspian Sea (Mazandaran province, Iran) was
used for extracting silica powder. H-ZSM-5 was characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD),
scanning electronic microscopy (SEM) and Brunauer–Emmett–Teller (BET), Barrett-Joyner-Halenda (BJH) techniques. The
catalytic activity of H-ZSM-5 nanozeolite was evaluated for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones via one-pot threecomponent
reaction of aromatic aldehydes, 2-aminobenzothiazole or 2-aminobenzimidazole and isatoic anhydride under solventfree
conditions. Short reaction time, high yields, a simple experimental procedure in the absence of any toxic solvents and
recovery of catalyst are the advantages of this protocol.