Evaluation of a New Proline-Based Polymer Monolith as Catalyst in Mannich-Type Reaction

Dipti      Garg; Lok      Raj; Rohini      Dharela; Ghanshyam      S. Chauhan

Abstract

A series of proline-based heterogeneous polymeric organocatalysts was synthesized as monoliths via the chemo-enzymatic route. These were characterized by various techniques and the one that was synthesized with 1% crosslinker was used as the candidate catalyst in the three-component one pot reaction, i.e., Mannich-type reaction to synthesize 3-substituted 2,6-diarylpiperidin-4-ones and 4-aryldihydropyrimidinones. The merits of the monolith catalyst, the mild reaction conditions, simple protocol, and clean reaction makes the synthetic protocol practical and economically attractive. The catalyst exhibited high efficiency, easy recyclability, reusability and selectivity, especially, with the aromatic substrates having electron withdrawing substituents which resulted in high conversion.

Keywords: Asymmetric catalysis, Mannich reaction, Organocatalyst, Proline, Polymer catalyst, Reusability, Supported catalysts, Reusability, Supported catalysts, piperidines, ChemNMR Pro, polarimete, FTIR, Ps values, dihydropyrimidinones, imine, aldehydes