FIG 3.

Formation of AN6426-adenosine adduct. Proposed mechanism of formation of the adenosine adduct with the inhibitor AN6426. The reaction proceeds via a first step in which the 2′- or 3′-hydroxyl of the adenosine ribose reacts with the boron atom, followed by a second step in which the remaining hydroxyl, most probably stabilized by a water molecule (observed in the crystal structure), reacts with the boron atom, which adopts an sp3 tetrahedral hybridization, and forms the final pentyl cycle observed in the crystal structure.