Azido and diazarinyl analogues of bis-tyrphostin as asymmetrical inhibitors of dynamin GTPase

Probing the Dynamin binding site: Bis-tyrphostin (1, Bis-T), is a potent inhibitor of the phospholipid-stimulated GTPase activity of Dynamin I. Analogues of Bis-T have significant potential as a biological probes for the dissection of endocytic pathways. Bis-T-derived compounds were synthesised and evaluated for their ability to inhibit the GTPase activity of Dynamin I. Two analogues (23 and 24) represent the first asymmetrically substituted Bis-T analogues to retain Dynamin inhibition.Two azidobenzyl amide (4 and 23) and one 3-trifluoromethyl-3H-diazirin-3-ylphenyl (24) analogues of bis-tyrphostin (1, Bis-T) were synthesised as potential photoaffinity labels for the elucidation of the binding site of compound 1 in Dynamin I. Of the two azidobenzyl amide analogues (4 and 23), the terminally substituted 23 retained Dynamin I GTPase inhibition (IC(50)=6.4+/-2.8 microM) whilst 4, which was substituted on the central carbon of the amide linker, displayed no activity. Analogue 24 also retained inhibitory activity (IC(50)=36+/-9 microM). Photoaffinity labelling experiments did not unequivocally elucidate the binding pocket of compound 1. However, compounds 23 and 24 represent the first asymmetrically substituted Bis-T analogues to retain Dynamin inhibitory activity, providing a new direction for analogue synthesis.