Dehydrooligopeptides. III. Synthesis of (<i>Z</i>,<i>Z</i>)- and (<i>Z</i>,<i>E</i>)-Geometric Isomers of Dehydrodipeptides and Their Base-catalyzed Transformation to the Hydantoin Derivatives

Abstract

Abstract N-Benzyloxycarbonyl (Cbz)-(Z,E)-dehydrodipeptides, comprised of both (Z)- and (E)-α-dehydroamino acid residues, were first synthesized by dehydrochlorination of Cbz-(Z)-dehydrodipeptides containing an erythro-3-chloro-2-aminobutanoate moiety. Base-catalyzed transformation of the individual Cbz-(Z, Z)- and (Z, E)-dehydrodipeptides was carried out to give the corresponding new hydantoin derivatives. The NMR spectroscopic differences between the geometric isomers of both dehydrodipeptides and their hydantoin derivatives were elucidated.