Prodrugs of the Archetypal Dynamin Inhibitor Bis-T-22

The Bis-T series of compounds comprise some of the most potent inhibitors of dynamin GTPase activity yet reported, e. g., (2E,2'E)-N,N'-(propane-1,3-diyl)bis(2-cyano-3-(3,4-dihydroxyphenyl)acrylamide) (2), Bis-T-22. The catechol moieties are believed to limit cell permeability, rendering these compounds largely inactive in cells. To solve this problem, a prodrug strategy was envisaged and eight ester analogues were synthesised. The shortest and bulkiest esters (acetate and butyl/tert-butyl) were found to be insoluble under physiological conditions, whilst the remaining five were soluble and stable under these conditions. These five were analysed for plasma stability and half-lives ranged from ∼2.3 min (propionic ester 4), increasing with size and bulk, to greater than 24 hr (dimethyl carbamate 10). Similar profiles where observed with the rate of formation of Bis-T-22 with half-lives ranging from ∼25 mins (propionic ester 4). Propionic ester 4 was chosen to undergo further testing and was found to inhibit endocytosis in a dose-dependent manner with IC₅₀ ∼8 μM, suggesting this compound is able to effectively cross the cell membrane where it is rapidly hydrolysed to the desired Bis-T-22 parent compound.