Immobilization of homogeneous oxidation catalysts

Sulfonated ethylenediamine functionalized magnetic nanoparticles as a highly efficient heterogeneous nanocatalyst for the green synthesis of 2,3-dihydroquinazolin-4(1H)-ones

Abstract:

In the present study, a new magnetically recyclable nanocatalyst, Fe3O4@SiO2@(CH2)3-en-SO3H/H2SO4, was prepared through the immobilization of sulfonated ethylenediamine on the silica-coated magnetite nanoparticles. The catalyst was fully characterized by several physicochemical techniques, including FT-IR, FESEM, TEM, EDS, VSM, XRD and TGA. The resultant nanocatalyst was then utilized in the green synthesis of 2,3-dihydroquinazolin-4(1H)-ones via the cyclocondensation reaction of various aldehydes and ketones with anthranilamide in refluxed EtOH. Short reaction times, high product yields, environmentally friendly reaction conditions, simple operation and reusability of the catalyst are important features of the present procedure. The catalyst can magnetically be recycled and reused several times without notable loss in activity.

Oxidation of N-heterocyclics: A green approach

chemical structure image Environmentally benign oxidation methods satisfy the postulates of green chemistry. Heterocyclic Noxides have applications in synthetic organic chemistry, chemotherapy and agrochemicals. Synthesis of Noxides using green oxidants will be attractive over the conventional methods. The presence of the N-oxide group in the azine ring makes it more subject to electrophilic and nucleophilic attack and substantially expands the synthetic approaches for the modification of nitrogen-containing heterocyclics. That is the reason for the increasing interest in the chemistry of heterocyclic N-oxides. Some reactions adopted for oxidation of N-heterocyclics have been discussed. Stereochemical and spectroscopic aspects have been mentioned. It will be advantageous if anchored catalysts are employed for industrial exploitation. Several physiochemical aspects of various methods have been discussed.