Sustainable Synthesis of p-Hydroxycinnamic Diacids through Proline-Mediated Knoevenagel Condensation in Ethanol: An Access to Potent Phenolic UV Filters and Radical Scavengers

Benjamin Rioux (1, 2) , Cédric Peyrot (1, 2) , Matthieu Mention (1, 2) , Fanny Brunissen (1, 2) , Florent Allais (1, 2)

1 ABI - Agro-Biotechnologies Industrielles
2 CEBB - Centre Européen de Biotechnologies et Bioéconomie

p-Hydroxycinnamic diacids are reaction intermediates of the classical Knoevenagel-Doebner condensation between malonic acid and benzaldehydes. As they are generally obtained in low yields, they remain relatively under-studied and under-exploited. Herein, we developed and optimized a sustainable synthetic procedure allowing the production of these compounds in good to high yields (60-80%) using proline as the catalyst and ethanol as the solvent. Study of their antioxidant and anti-UV activities revealed that these p-hydroxycinnamic diacids were not only potent radical scavengers but also efficient UV filters exhibiting high photostability.

Keywords: Knoevenagel condensation; L-proline; p-hydroxycinnamic diacids; ferulic diacid; coumaric diacid; caffeic diacid; anti-UV; antioxidant

Domains: Organic chemistry

Benjamin Rioux, Cédric Peyrot, Matthieu Mention, Fanny Brunissen, Florent Allais. Sustainable Synthesis of p-Hydroxycinnamic Diacids through Proline-Mediated Knoevenagel Condensation in Ethanol: An Access to Potent Phenolic UV Filters and Radical Scavengers. Antioxidants , 2020, 9 (4), pp.331. ⟨10.3390/antiox9040331⟩. ⟨hal-03630946⟩