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چکیده
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In this work, mesoporous KIT-6 was synthesized by a simple procedure using P123 and TEOS in n-butanol and HCl acidic conditions, followed by calcination at 550 °C. Then, the surface of KIT-6 was modified by 3-aminopropyl trimethoxysilane, and next it was functionalized by 2-aminobenzamide (ABA) using isatoic anhydride. Finally, immobilized ABA on KIT-6 became complex with ZrOCl2.8H2O (KIT-6-ABA-Zr). The prepared KIT-6-ABA-Zr was characterized by SEM, XRD, TGA, EDS, BET/BJH, FTIR, and WDX techniques. TGA and BET/BJH methods showed high thermal stability of this catalyst up to 250 °C and a high surface area for this catalyst up to 208.16 m2.g-1. Then, the catalytic usage of KIT-6-ABA-Zr was investigated in the selective and multicomponent synthesis of pyranopyrazoles and tetrahydrobenzo[b]pyrans. Various aldehydes (having electron-donating or electron-withdrawing functional groups) were investigated and all products of pyranopyrazoles and tetrahydrobenzo[b]pyrans were obtained with high yields. NMR spectroscopy was used to determine the synthesized pyranopyrazoles and tetrahydrobenzo[b]pyrans. KIT-6-ABA-Zr catalyst was shown to be reusable without significant loss in its performance in the synthesis of pyranopyrazoles and tetrahydrobenzo[b]pyrans.
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