Design and synthesis of novel fucosylated chondroitin sulfate derivatives as intrinsic FXase inhibitors and evaluation of their antithrombotic activities.

Thrombotic disease is a major threat to human health, underscoring the urgent need for novel anticoagulants. Fucosylated chondroitin sulfate (FuCS) oligosaccharides, have emerged as promising anticoagulant drug candidates owing to their selective inhibition of the intrinsic factor Xase complex (iFXase). However, elucidation of their structure-activity relationship (SAR) has been hindered by structural complexity and synthetic challenges. This work aims to fill this gap by systematically investigating the effects of terminal modifications on their anticoagulant properties. Here, we established a modular synthetic platform that enables the preparation of sixteen FuCS nonasaccharide derivatives via click chemistry-mediated terminal. All FuCS derivatives exhibited significant and selective intrinsic anticoagulant activity. Among them, compounds A-3 and B-1 demonstrated the highest potency and pronounced selectivity toward iFXase, while showing minimal effects on FXa and thrombin (FIIa). Both compounds further displayed favorable pharmacodynamic properties, characterized by rapid onset of action (Tmax = 30 min) and sustained anticoagulant effects. In vitro and in vivo tests further revealed that selective iFXase inhibition by FuCS oligosaccharide derivatives effectively suppressed thrombus formation, validating iFXase as a promising antithrombotic target. Collectively, this work provides a practical framework for the rational design and evaluation of FuCS oligosaccharide-based anticoagulants.