Design of Supported Organocatalysts from Carboxylic Acids for the Mannich-Type Synthesis of β-Amino Carbonyl Compounds

Abstract

New supported acidic organocatalysts were prepared by the impregnation of three carboxylic acids (CF₃COOH, CCl₃COOH, and CH₃COOH) on silica support at room temperature in diethyl ether. The catalysts were characterized by scanning electron microscopy, energy dispersion X-ray analysis (EDX), Brunauer-Emmett-Teller-surface-area-analysis (BET), thermogravitational analysis, Fourier transform infrared, and powder X-ray diffractometry analysis. These solid acids were observed as highly efficient reusable catalysts at room temperature for the selective synthesis of β-amino carbonyl compounds via Mannich-type reactions of acetophenone, arylamine and arylaldehydes using two different conditions in CH₂Cl₂ solution and solvent-free grinding within a short time. The more acidic two catalysts could be recycled for up to five cycles with a small loss in catalytic activity.

GRAPHICAL ABSTRACT

Keywords:

• Mannich-type reaction
• organocatalysts
• reusable solid acid
• silica support

ACKNOWLEDGMENT

The authors are thankful to Sophisticated Analytical Instrumentation Centre, T.U., for analyses of various samples for this work.

SUPPLEMENTAL MATERIAL

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