Fondaparinux structure

The most representative example utilizing this approach is the synthesis of the ultralow molecular weight (ULMW) heparin construct 27 (Scheme 9.2), a heptasac-charide that has a very similar structure to the FDA-approved anticoagulant drug fondaparinux. Fondaparinux is currently synthesized chemically through 50 steps... 

The direct thrombin inhibitors, as their name implies, interact directly with the thrombin molecule" (Fig. 19-6). The agents in this class differ in terms of their molecular weight, chemical structure, and binding to the thrombin molecule. Unlike the UFH, the LMWHs, and fondaparinux, DTIs do not require antithrombin to have antithrombotic activity. They are capable of inhibiting both circulating and clot-bound thrombin, a potential advantage over UFH and the LMWHs. Eurther, DTIs have not been shown to induce immune-mediated thrombocytopenia and have been used widely for the treatment of HIT. 

Fig. 45.8. A. Structure of fondaparinux. B. Mechanism of fondaparinux action. The drug (shown in blue) binds to ATIIl, which induces a conformational change such that Factor Xa can now bind to ATIIL Once Factor Xa binds, and is inactivated, the drug is released and can activate another molecule of ATIIl.

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