Nanosilica molybdic acid: synthesis, characterization and application as a green and reusable catalyst for the Pechmann condensation

Recyclable cellulose nanocrystal supported Palladium nanoparticles as an efficient heterogeneous catalyst for the solvent‐free synthesis of coumarin derivatives via von Pechmann condensation

“…The catalyst is easily recycled and reused without loss of the catalytic activity. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] Traditional methods for synthesis of coumarins have disadvantages such as rough conditions, long reaction time, creation problems related to corrosion, using of precious and noxious reactant or organic solvents, large amounts of catalyst, and production of products with low yield. Coumarin and its derivatives are essentially main and structural units of a few natural products and display unique applications in pharmacologic, pharmaceutics, agricultural and perfume industry.…”

“…From the different methods on hand for the synthesizing of coumarin derivatives, [9][10][11][12][13][14] the most important is the Pechmann reaction as a particularly preciousness method, begins from condensation of phenol derivatives with alkyl acetoacetates and obtains fine products of many coumarin derivatives. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] Traditional methods for synthesis of coumarins have disadvantages such as rough conditions, long reaction time, creation problems related to corrosion, using of precious and noxious reactant or organic solvents, large amounts of catalyst, and production of products with low yield. Till now, many catalysts, like Zr-TMS-TFA-25, [30] [31] Fe 3 O 4 @SiO 2 @Et-PhSO 3 H, [32] mesoporous zirconium phosphate, [33] trifluoroacetic acid, [34] nanocrystalline sulfated tin oxide, [35] InCl 3 [36] and ZrCl 4 [37] have been applied for catalyzing of the Pechmann reaction.…”