A facile microwave-assisted Knoevenagel condensation of various aldehydes and ketones using amine-functionalized metal organic frameworks

Pyrrole-Based Conjugated Microporous Polymers as Efficient Heterogeneous Catalysts for Knoevenagel Condensation

“…Various reaction substrates were used to test the catalytic activities of the CMP catalysts under classical reaction conditions ( Wang et al, 2015 ; Taher et al, 2020 ). In addition, the reaction temperature, solvent and reaction temperature were investigated in details to find the best conditions for the reaction ( Supplementary Table S2 , ESI).…”

Post-synthesis modification of metal–organic frameworks: synthesis, characteristics, and applications

“…The enhanced catalytic activity of modied MOFs as nanoenzymes was promising to be applied in various catalysis reactions 95,96 such as coupling reactions, 58,97-99 photocatalytic reaction, [100][101][102][103] analytes conversion, 2,73,104 organic transformation, [105][106][107][108] synthesis, [109][110][111][112][113] oxygen evolution, 114,115 and condensation. 83,116,117 Also, a large number of post-synthesis modied MOFs were used as catalysts for CO 2 conversion, 82,118 including but not limited to photocatalytic reduction, 81,[119][120][121] thermo-catalysis conversion, 4 co-catalyst free cycloaddition, 122,123 and chemical xation. [124][125][126] Typical applications of post-synthesis modied MOFs as catalysts are discussed as follows.…”

“…Various functional groups were able to be incorporated into MOFs through PSM to improve catalytic activity, 81–84 water stability, 85 mechanical strength, 86 and gas adsorption properties. 31,87–89 PSM of MOFs was successfully applied in synthesizing chiral stationary phases (CSPs), 70 tailoring surface-anchored and highly crystalline MOFs, 90 removing harmful metal ions from wastewater, 91 enriching glycopeptides from human serum for glycoproteomic analysis, 92,93 and developing biomedical materials.…”

Nitrogen-Enriched Biguanidine-Functionalized Cobalt Ferrite Nanoparticles as a Heterogeneous Base Catalyst for Knoevenagel Condensation under Solvent-Free Conditions

“…The Knoevenagel condensation, a well-known reaction involving aldehydes and activated methylene group-containing molecules, has gained immense significance and widespread adoption as a highly influential and beneficial approach in organic chemistry for the synthesis of C–C bond formation to generate substituted electrophilic alkenes. , The alkenes thus formed act as versatile intermediates in various organic synthesis applications. These applications encompass a wide range of fields, including the production of fine chemicals, formation of heterocyclic compounds, carbohydrates, and synthesis of drug intermediates, natural products, fluorescent dyes, and functional polymers. − …”

“…This condensation reaction is frequently carried out using a basic catalyst, as the basic sites present over the catalyst attract protons from the adsorbed active methylene molecules such as malononitrile in order to generate carbanion intermediates. In order to catalyze this Knoevenagel condensation reaction, several homogeneous and heterogeneous (several different types of) catalysts such as zeolites, ionic liquids, Lewis acids, basic catalysts (urea, thiourea, and piperidine), ammonium salts, amino acids, aliphatic amines, metal oxides, metal–organic frameworks (MOFs), carbon materials, graphene-supported Pd and Ni nanoparticles, and covalent organic frameworks (COFs) have been employed. ,,,,, However, the applicability of these catalysts is limited owing to various environmental issues, such as post-treatment of the generated waste liquid, severe reaction conditions, elevated temperature, use of additives, costly metals, insufficient yields, extensive reaction period, harmful solvents, corrosion of equipment, and tedious workup procedure. , Also, some of these reported procedures suffer from various other serious problems including the formation of unwanted side products and the production of waste due to self-condensation, addition, and polymerization reactions …”