NaCl as an eco-friendly and efficient promoter for Knoevenagel condensation at room temperature

Abstract

Knoevenagel condensation was optimized through the eco-friendly condition as a binary mixture of ethanol:water (3:7, v/v) associated with NaCl salt as the promoter of the reaction between different aldehydes or isatins and malononitrile at room temperature. Due to its high efficiency and low toxicity, the proposed system provides easy isolation of products by simple filtration and optimal yields ranging between 83 and 97% in a short-time reaction at room temperature.

Graphical Abstract

The use of NaCl as a catalyst associated with the use of the ethanol:water mixture (3:7) (v/v) as an attractive ecological strategy in the synthesis of Knoevenagel adducts at room temperature, with high yield, short reaction time, and isolation more easy of the final product.

Keywords:

• Binary mixture solvent
• catalyst
• green approach
• Knoevenagel condensation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Capes and CNPq for financial support and Unical (Unidade da Central Analítica) of the IPeFarM-UFPB (Instituto de Pesquisa em Fármacos e Medicamentos da UFPB) for assistance with the NMR analysis. Financial support from Projeto Produtividade em Pesquisa (PROPESQ/PRPG/UFPB, PVA13317-2020).