silica gel has been used for synthesis of biscoumarin derivatives starting from 4-hydroxycoumarin and aryl aldehydes. the reaction conditions are completely in agreement with green chemistry principles including sing water as media and a recyclable and safe catalyst. this method is also simple and inexpensive and leads to high yield of products in short reaction times.

A simplistic green and neat procedure was developed for the synthesis of arylmethyl and heteroaryl phosphonates or phosphinates by silica gel supported Lewis acid catalyst, CeCl3.7H2O-SiO2 through Michaelis-Arbuzov reaction under conventional as well as microwave irradiation methods. Herein, tetraalkyl 1,4phenylenebis(methylene)diphosphonates 5(a-d)/dimethyl 1,4-phenylenebis(methylene)bis (phen...

The challenge in DNA-based asymmetric catalysis is to perform a reaction in the vicinity of the helix by incorporating a small-molecule catalyst anchored to the DNA in a covalent, dative, or non-covalent yet stable fashion in order to ensure high levels of enantio-discrimination. Here, we report the first generation of a DNA-based catalyst bound to a cellulose matrix. The chiral biomaterial is ...

Annulation of internal alkynes with functionalized aryl halides is a versatile and useful method for the synthesis of a wide variety of carboand heterocycles (Fig. 1). To date, many homogeneous transition metal-based catalytic systems have been developed for this transformation. Although homogeneous catalysis have many advantages, difficulties in separation and recovery of the catalyst and prod...

A magnetic recyclable Cu/ZnFe2O4 composite material was successfully prepared with easy-to-obtain raw materials. This obtained copper could be employed as efficient catalyst for both degradation of aromatic nitro compounds and C-N bond formation reactions without extra ligands. The reaction accomplished in 4 min high selectivity. variety N-aryl nitrogen-containing heterocycles products achieved...

In this study, Mn (III) salen complex was synthesized and immobilized onto the graphene oxide, which is modified by 3-chloropropyltrimethoxy silane. Heterogeneous catalyst was characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, fourier transform infrared spectra, nitrogen adsorption−desorption isotherm and atomic absorption spectroscopy. The catalyt...

Recyclable aggregates of mesoporous titania with different anatase-rutile ratios have been prepared by thermal treatments of either amorphous or peptized precursors. These last two have been obtained by hydrolysis of either Ti(OC₂H₅)₄ or of Ti(OC₂H₅)₄ in mixture with 5 mol % Zr(OC₃H₇)₄ at room temperature in the presence of NH₄OH as a catalyzing agent. The anatase-rutile ratio, the recyclable a...

the one-pot, multi-component synthesis of 4,4′-(arylmethylene)bis(1h-pyrazol-5-ols) by tandem knoevenagel-michael reaction of phenylhydrazine, ethyl acetoacetate and aldehydes in the presence of silica-bonded n-propylpiperazine sulfamic acid (sbppsa) as a recyclable solid acid catalyst was reported. sbppsa showed much the same efficiency when used in consecutive reaction runs.

in this research an effective and appropriate method has been developed for one-pot synthesis of new n-phenyl fulleroisoxazoline using fe3o4@sio2 nanoparticles as a green magnetically recyclable catalyst. the prepared catalytic samples were characterized by xrd, sem, ft-ir and vsm. the products have been characterized by physical and spectroscopic data such as ir, 1h nmr, 13c nmr, and ms analyses.

Chemically Recyclable Plastics In article number 2210154, Ting-Han Lee, George Kraus, Eric Cochran, and co-workers report dihydroxyterephthalate (DHTE) as a “Trojan horse” co-unit in poly(ethylene terephthalate) to produce highly recyclable plastics. The DHTE enables chemical recycling via hydrolysis monomers pure water by acting an internal catalyst through neighboring group participation.