Synthesis of β-aminoacrylated betulin derivatives by a spontaneous amino-yne reaction for antifungal applications.

Betulin, a lupane-based pentacyclic triterpenoid, is renowned for its sustainability and potent antifungal properties. By leveraging a spontaneous amino-yne reaction in conjunction with betulin, novel biomolecules representing a diverse library of triterpenoid derivatives are designed and synthesized for potential antifungal development. In this work, betulin was initially transformed into 28-propynoylbetulin via a traditional DCC coupling reaction. Subsequently, mono- and di-β-aminoacrylated betulin derivatives were synthesized by reacting betulin with various secondary (di)amines via an amino-yne chemistry. All the compounds were identified by 1H, 13C NMR, HR-MS, and FT-IR analyses, and their antifungal properties were evaluated. The versatility of these betulin derivatives in accommodating a wide range of N-substituents has identified them as promising antifungal agents. These findings illustrate an innovative approach for enhancing the antifungal properties of betulin through β-aminoacrylation, thereby enriching its utility in biomedical applications and promoting the sustainable utilization of bioresources. This study demonstrates that combining an amino-yne reaction with biocompounds facilitates the development of novel biomolecules, indicating their potential for application in the biomedical field and advancing the sustainable development of antimicrobial compounds.