Applications of a novel nano magnetic catalyst in the synthesis of 1,8-dioxo-octahydroxanthene and dihydropyrano[2,3-c]pyrazole derivatives

Abstract

Imidazole-based ionic liquid-stabilized on silica coated Fe 3 O 4 magnetic nano particles [nano-Fe 3 O 4 @SiO 2 @(CH 2) 3-Imidazole-SO 3 H]Cl as a novel heterogeneous acidic catalyst was designed, synthesized and fully characterized by FT-IR, thermo gravimetric analysis (TGA), differential thermal analysis (DTA), energy-dispersive x-ray spectroscopy (EDX), X-ray diffraction patterns (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), Brunauer-Emmett-Teller (BET) and inductively coupled plasma (ICP) analysis. The nano-structured organo solid catalyst as a novel, mild and full-fledged catalyst was used for the cascade synthesis of 1,8-dioxo-octahydroxanthene derivatives by the condensation reaction between dimedone and various aldehydes at 80 o C under solvent-free conditions. Similarly, dihydropyrano[2,3-c]pyrazole derivatives were synthesized by the one-pot three-component condensation reaction of aldehydes, malononitrile and 3-methyl-1-phenyl-2-pyrazoline-5-one under solvent-free conditions at room temperature. To the knowledge of our science, this is the main investigation on the synthesis of [nano-Fe 3 O 4 @SiO 2 @(CH 2) 3-Imidazole-SO 3 H]Cl as a worthy heterogeneous nano magnetic solid acid for acid catalyzed organic reactions.

1,10‐Phenanthrolin‐1‐ium Trinitromethanide (1,10‐PHTNM) as a Nano Molten Salt Catalyst With Y‐Aromatic Counter Ion: Applications for Synthesis of Organic Compounds

“…The synthesis of organic compounds include 1,4‐dihydropyrano[2,3‐ c ]pyrazoles, tetrahydrobenzo[ b ]pyran, pyrano[4,3‐ b ]pyrans, bispyrazole, 1 H ‐pyrazolo[3,4‐ b ]quinolones, hexahydroacridine‐1,8‐diones and methylenebis(3‐hydroxy‐5,5‐dimethylcyclohex‐2‐enones) has been considerable attention of organic chemists due to their broad range of pharmaceutical and biological properties include arisugacins, anti‐multidrug‐resistant, anti‐inflammatory, photodynamic therapy, inhibitors of human Chk1 kinase, spasmolytic and anti‐filarial agents . Literature survey shows that various processes and catalysts for the synthesis of these compounds include {[HIM]C(CN) 3 }, {[HMIM]C(CN) 3 },, [nano‐Fe 3 O 4 @SiO 2 @(CH 2 ) 3 ‐Imidazole‐SO 3 H]Cl, 2‐carbamoylhydrazine‐1‐sulfonic acid or carbamoylsulfamic acid, L ‐proline, eggshell (ES)‐supported Cu(OH) 2 nanoribbons, triethylbenzylammonium chloride, [2‐MPyH]OTf, ZnCl 2 , hexadecyltrimethylammonium bromide, phosphomolybdic acid and sodium acetate trihydrate urea …”

Preparation, characterization and catalytic application of molybdenum Schiff‐base complex immobilized on silica‐coated Fe3O4 as a reusable catalyst for the synthesis of pyranopyrazole derivatives

“…Recently, the expansions of green protocols in pollution‐free type of these reactions have received substantial levels of consideration. The synthesis of pyranopyrazoles by using nanoparticles has been already reported in the presence of various catalysts such as MgO, Ni(0), SnO 2, [nano‐Fe 3 O 4 @SiO 2 @(CH 2 ) 3 ‐Imidazole‐SO 3 H] Cl and ZrO 2. …”

Caffeinium Hydrogen Sulfate: A Green Solid Acid Catalyst for Selective One‐Pot Domino Knoevenagel‐Michael Transformations

“…Xanthenes derivatives have attracted the attention of various organic synthetic chemists as they are frequently occurring motifs in a scaffold of natural products with various biological and pharmaceutical properties . Furthermore they serve as valuable precursors for dyes, pH sensitive fluorescent materials for visualization of biomolecules, laser technologies and photodynamic therapy . Bis‐cyclohexenone compounds and their derivatives also exhibit various biological activities such as antioxidant, antibacterial and inflammatory problems .…”

“…Numerous methodologies have been reported for the creation of xanthenes which include trapping of benzynes by phenols, cycloacylation of carbamates and coupling reaction of benzaldehydes and acetophenones . Among all, the most typical route is the condensation of aromatic aldehydes with cyclic 1,3 dicarbonyl compounds for which various acidic catalysts are reported such as NaHSO 4 .SiO 2, Amberlyst‐15, TMSCl, Fe 3+ ‐montmorillonite and SbCl 3 /SiO 2 ,.…”