Efficient Synthesis of Symmetrical Bisamides from Aldehydes and Amides Catalyzed by Silica-Bonded S-Sulfonic Acid Nanoparticles

Abstract

Silica-bonded S-sulfonic acid nanoparticles (SBSSANPs) were easily synthesized from silica nanoparticles and showed to be an efficient catalyst in the synthesis the symmetrical N,N′-alkylidene bisamides. Reaction of aldehydes and amides in the presence of the catalyst afforded the corresponding bisamides in good to excellent yields. The extensive range of substrates suggests general applicability of the method. Reusability of the catalyst, simple workup procedure, and short reaction times are other advantages of this protocol.

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GRAPHICAL ABSTRACT

Keywords:

• Aldehydes
• amides
• bisamides
• silica-bonded S-sulfonic acid nanoparticles
• supported catalyst

ACKNOWLEDGMENT

We are thankful to the Research Council of Mazandaran University for the partial support of this work.

Notes

^a Isolated yield.

^b SiO₂ with 12.6-nm average particle size.

^c Non-nanoparticle silica-bonded S-sulfonic acid.

^a The reaction was carried out in 7 mL of solvent at reflux.

^b Isolated yield.

^c The reaction was carried out at 100 °C.

^a Optimized conditions: aldehyde (1 mmol), amide (2 mmol), SBSSANPs (0.08 g), and toluene at reflux temperature.

^b Isolated yield.

^a Reaction conditions: aldehyde (1 mmol), acetamide (1 mmol), benzmide (1 mmol), SBSSANPs (0.08 g), and toluene at reflux.

^b Ratio determined by ¹H NMR analysis.