Application of the Benzoyl O-Protecting Group in the Synthesis of α,β-Dehydrotyrosine-containing Amides and Imidazolones

Abstract The use of O-benzoyl protection in the synthesis of N-benzoyl-α,β-dehydrotyrosine benzylamide, and the corresponding 4-imidazolone was studied. The reaction of 4-(4-benzoyloxybenzylidene)oxazol-5(4H)-one with benzylamine proceeds with the retention of the O-benzoyl protecting group. The latter is removed with 2-(dimethylamino)-1-ethylamine or 3-(dimethylamino)-1-propylamine. In the case of the cyclization of N,O-dibenzoyl-α,β-dehydrotyrosine benzylamide with 1,1,1,3,3,3-hexamethyldisilazane into (Z)-3-benzyl-5-(4-hydroxybenzylidene)-2-phenyl-3,5-dihydro-4H-imidazol-4-one leads to elimination of the O-benzoyl protection. The antiradical and anticholinesterase properties of the synthesized compounds were studied.