Oxazolones as Intermediates in Reactions of A-Alkoxycarbonylamino Acids

18 2-ALKOXY-5(4H)-OXAZOLONES AS INTERMEDIATES IN REACTIONS OF A/-ALKOXYCARBONYLAMINO ACIDS 

FIGURE 1.18 2-AI koxy-5(4/7)-oxazol ones as intermediates in reactions of IV-alkoxycarbo-nylamino acids.22 After removal of the symmetrical anhydride from a reaction mixture containing Boc-valine and ethyl-(3-dimethylaminopropyl)-carbodiimide hydrochloride, the filtrate contained a novel activated form of Boc-valine (20% yield) that was established to be the 2-alkoxy-5(4H)-oxazolone. Slow addition of Boc-valine to ethyl-(3-dimethylamino-propyl)-carbodiimide hydrochloride in dilute solution gave a 55% yield. Petrol = petroleum ether, bp 40-60°. 

M Miyoshi. Peptide synthesis via IV-acylated aziridinone. I. The synthesis of 3-substituted-l-benzylcarbonylaziridin-2-ones and related compounds. Bull Chem Soc Jpn 46, 212, 1973. 

JH Jones, MJ Witty. The formation of 2-benzyloxyoxazol-5(4/7)-ones from benzy-loxycarbonylamino-acids. J Chem Soc Perkin Trans 1 3203, 1979. 

NL Benoiton, FMF Chen. 2-Alkoxy-5(4/7)-oxazolones fromlV-alkoxycarbonylamino acids and their implication in carbodiimide-mediated reactions in peptide synthesis. Can J Chem 59, 384, 1981. 

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