RESUMEN
Synephrine is a natural small-molecule alkaloid found in Aurantii fructus immaturus with versatile biological activities, but its derivatives have been rarely studied so far. Based on the multi-target drug design strategy, the phenolic hydroxyl and secondary amino group of synephrine were modified structurally by the molecular splicing method in this study and thus five intermediates and fifteen target molecules were designed and synthesized. These compounds were evaluated with certain human pathogenic bacteria and fungi, and found that the inhibitory activities of IM4 and IM5 against E.coli are comparable to those of eight fluoroquinolones; TM1n showed stronger inhibitory activity against drug-resistant C. trobicans and drug-resistant C. albicans than the positive control drug fluconazole. TM1d and TM1f against C. albicans ATCC90023, TM1o and TM1f against drug-resistant C. albicans, and TM1f against C. parapsilosis ATCC22019 are all comparable to fluconazole, all of which have the potential for in-depth research. In this study, synephrine derivatives with strong inhibitory activities against human pathogenic fungi were discovered for the first time, which provided a new idea for the further study of synephrine.