Spiro sugar-isoxazolidine scaffold as useful polyfunctional building block for peptidomimetics design.

Spiro sugar-isoxazolidines obtained by 1,3-dipolar cycloaddition of activated exo-glycals and nitrones were efficiently functionalized at two sites, i.e. C-4 and C-7, with arginine, arginine mimetics and guanidylated appendages. Two bicyclic sugar derivatives differing by the configuration at C-7 were chosen as model compounds. The small library of peptidomimetics was evaluated toward inhibition of VEGF-A165/neuropilin-1 binding. Unexpected cleavage of C3-C4 bond of isoxazolidine moiety was observed during hydrogenolysis and opened thus a new way toward hemiketal structures which could also find interesting applications as less constrained scaffold.