Synthesis of Novel Cross-Linked Amino Acid Derivatives

Abstract

Reactions of the derivatives of cysteine (6), serine (7) and lysine (8a), with the bromide (1), afforded the corresponding cross-linked amino acid derivatives (11), (12) and (13). Of the linked species (11)-(13), the cysteine derivative (11) was found to be the most stable under a variety of conditions. A mixture of the cross-linked serine derivative (12) and the cysteine derivative (6) in chloroform containing triethylamine reacted to give the cross-linked cysteine derivative (11) and the serine derivative (7). Similarly, a mixture of (13) and (6) in chloroform reacted to give (11).