Post synthesis alumination of KIT-6 materials with Ia3d symmetry and their catalytic efficiency towards multicomponent synthesis of 1H-pyrazolo[1,2-]phthalazine-5,10-dione carbonitriles and carboxylates

Alumination of Si-KIT-6 materials with ordered three-dimensional (3D) structure were prepared by post-synthesis method with various Si/Al ratios. The catalysts were characterized by X-ray diffraction analysis (XRD), N2 porosimetry and FT-IR spectra. The presence of framework and extra framework aluminium was predicted by Aluminium MAS NMR. The strength of the acid sites of the catalysts was studied by NH3-TPD acidity measurements. The morphology of mesoporous materials was studied by SEM and TEM observation. The metal content of the samples was investigated by ICP-OES. The prepared solid acid catalysts were applied for the multi-component synthesis of 1H-pyrazolo[1,2-]phthalazine-5,10-diones from the reaction of phthalhydrazide, malononitrile/ethylcyano acetate and aromatic aldehyde in ethanol under liquid phase conditions. Activities of the catalysts follow the order: Al-KIT-6 (33) > Al-KIT-6 (56) > Al-KIT-6 (81) > Al-KIT-6 (110) > Nafion-H > Amberlyst-15 ≫ HM (12) > Hβ (8) > HY (4). The effects of reaction conditions and different catalysts have been studied. Various advantages associated with these protocols include effective catalysis, simple work-up procedure, short reaction times, high product yields, easy recovery and reusability of the catalysts.

Mesoporous aluminosilicates with ordered three-dimensional (3D) structure were prepared by post synthetic hydrothermal method of various Si/Al ratios. The catalysts were characterized by X-ray diffraction analysis (XRD), N2 porosimetry, 27Al MAS NMR, NH3-TPD acidity measurements, ICP-OES, EDX analysis and TEM technique. The prepared solid acid catalysts were applied for the multi-component synthesis of 1H-pyrazolo[1,2-]phthalazine-5,10-diones from the reaction of phthalhydrazide, malononitrile/ethylcyano acetate and aromatic aldehyde in ethanol under liquid phase conditions.Figure optionsDownload high-quality image (79 K)Download as PowerPoint slideHighlights
► Synthesis of mesoporous aluminosilicates (Al-KIT-6) by post synthetic method.
► The materials possess uniform ordered large pores with Ia3d symmetry.
► Surface acidity measurements shows that the catalysts possess strong acid sites.
► Synthesis of 1H-pyrazolo[1,2-]phthalazine-5,10-dione over Al-KIT-6 catalysts.
► The solid acid catalysts were active for several cycles.