Amino-protecting reagents for t-butoxycarbonylation and benxyloxycarbonylation of amino acids and amines

Abstract

tert-Butyl benzotriazol-l-yl carbonate is conveniently prepared by the reaction of 1-benzotriazolyl chloroformate, generated from phosgene and 1-hydroxybenzotriazole in the presence of pyridine, with equimolar amounts of tert-butanol in the presence of pyridine in methylene chloride at room temperature. It is very effective in the tert-butoxycarbonylation of amino acids and amines. Similarly, benzyl benzotriazol-1-yl carbonate is also applicable to the benzyloxycarbonylation of amino acids and amines. Furthermore, tert-butyl S-(benzothiazol-2-yl) thiocarbonate and benzyl S-(benzothiazol-2-yl) thiocarbonate were prepare and their effectiveness in the tertbutoxycarbonylation and benzyloxycarbonylation of amines was examined.