Synthesis of caffeic acid ester morpholines and their activation effects on tyrosinase

•A simple method was proposed for the synthesis of caffeic acid derivatives.•Caffeic acid derivatives synthesized in this research have an activation effect on tyrosinase.•The activation effect of caffeic acid derivatives on tyrosinase was further verified at the cellular level.•Caffeic acid derivatives show potential development value in cosmetics and pharmaceutical ingredients.