Phosphonic Acid Functionalized Ordered Mesoporous Material: A New and Ecofriendly Catalyst for One-Pot Multicomponent Biginelli Reaction under Solvent-Free Conditions

Abstract

We report a new ordered 2D hexagonal mesoporous organosilica material (PAFMS-1) bearing phosphonic acid functionality at the surface. This hybrid material showed high Brunauer-Emmett-Teller surface area (565 m(2) g(-1)) and ordered assembly of mesoporoes with an average pore diameter of ca. 2.1 nm. This novel hybrid mesoporous material has been synthesized via cocondensation of (triethoxysilyl)(propyliminomethyl)biphenylmethyl phosphoester (PEFOS) and tetraethyl orthosilicate (TEOS) in the presence of cationic surfactant cetyltrimethylammonium bromide (CTAB) at 373 K. The phosphoester-functionalized organosilane (PEFOS) precursor has been synthesized for the first time by a simple SN2 reaction followed by Suzuki coupling and a Mannich reaction. The material has been characterized by powder X-ray diffraction, N2 sorption, and transmission electron microscopy image analysis, whereas the presence of organic moieties (an aromatic biphenyl ring and an aliphatic side chain), phosphrous, and silicon in the pore wall of the material have been characterized by solid-state magic-angle-spinning NMR, X-ray photoelectron, and Fourier transform infrared (FT-IR) spectroscopic tools. Further, the surface acid strength of the hybrid material has been determined by FT-IR analysis of the samples via temperature-programmed pyridine adsorption studies. The material has been utilized as a reusable heterogeneous catalyst for the synthesis of biologically important and value added multifunctionalized 3,4-dihydropyridin-2-1H-(ones)/3,4-dihydropyridin-2-1H-(thiones) (DHPMs) through a multicomponent Biginelli condensation reaction under solvent-free conditions at 333 K. The phosphonic acid functionalized 2D hexagonal mesoporous material showed much higher catalytic activity in this multicomponent condensation reaction over sulfonic acid functionalized mesoporous silica (MCM-41-SO3H) bearing an aliphatic chain in the hybrid framework.

Surface-Functionalized Porous Lignin for Fast and Efficient Lead Removal from Aqueous Solution

“…In the second step, the amine groups are reacted with carbon disulfide to produce SFPL with dithiocarbamate groups (as shown in Scheme 1). Both reactions are facile reactions [28][29] . In our efforts to develop a modified lignin with high efficiency for adsorption of lead ions, we selected branched PEI as grafting agent both for its high content of reactive primary/secondary amine groups and high-branched structure 21 .…”

12‐Tungstosilicic Acid H4[W12SiO40] Over Natural Bentonite as a Heterogeneous Catalyst for the Synthesis of 3,4‐dihydropyrimidin‐2(1H)‐Ones

“…Patil et al recently extensively reviewed usage of different kind of supports as a heterogeneous catalyst for this reaction . A notable solid acid catalysts such as silica sulfuric acid, MCM‐41‐SO 3 H, PS‐PEG‐SO 3 H, Al 2 O 3 /MeSO 3 H, bio‐glycerol‐SO 3 H, Fe 3 O 4 @SBA‐15‐COOH, PPF‐SO 3 H, Fe 3 O 4 /PAA‐SO 3 H, BPMO‐IL‐SO 3 H, SiO 2 ‐Pr‐SO 3 H, nano‐γ‐Fe 2 O 3 ‐SO 3 H, perlite‐SO 3 H, nano‐ZrO 2 ‐SO 3 H, Fe 3 O 4 @SiO 2 ‐PhSO 3 H, SiO 2 ‐phosphonicacid, β‐cyclodextrin‐propylsulfonicacid, ZrO 2 ‐SO 3 H, GO‐SO 3 H, halogenated macroporous sulfonic resin and Fe 3 O 4 @meglumine‐SO 3 H that delivered DHPMs in high yields with good reusability. In spite of exploring the different type of material as a catalyst for this one‐pot condensation reaction, there is still scope to find a novel catalyst system which is easily available and can mitigate the above mentioned problems.…”

Cu(II) immobilized on mesoporous organosilica as an efficient and reusable nanocatalyst for one‐pot Biginelli reaction under solvent‐free conditions

“…This method is based on one‐pot condensation of an aldehyde, urea, and a β ‐ketoester that proceeds under strongly acidic conditions . Due to the importance of the Biginelli reaction products (DHPMs), numerous improvements have been developed with different types of catalysts such as ionic liquids or supported ionic liquids, dodecyl sulfonic acid (DSA), NbCl 5 , Gly(NO 3 ), Cu(NO 3 ) 2 ·3H 2 O, mesoporous SiO 2 ‐H 2 PO 3 , Fe 3 O 4 @Nb 2 O 5 , β ‐Cyclodextrin‐propyl sulfonic acid, Lanthanide Triflate, hydrotalcite, ZrO 2 –Al 2 O 3 –Fe 3 O 4 , ErCl 3 , nano‐γ‐Fe 2 O 3 ‐SO 3 H, Fe 3 O 4 @mesoporous SBA‐15, and various conditions such as solvent‐free, ultrasound, microwave synthesis, and the grindstone technique . However, there is scope for further improvement toward milder reaction conditions, and better yields.…”