Synthesis of Novel Nucleo‐β‐Amino Acids and Nucleobase‐Functionalized β‐Peptides

Abstract

Abstract Four novel β‐amino acids bearing the canonical nucleobases guanine, cytosine, adenine, and thymine in the side chain, are synthesized starting from Boc‐ L ‐aspartic acid 4‐benzyl ester. The syntheses are accomplished in six steps by the nucleophilic substitution of ( S )‐β‐( tert ‐butoxycarbonylamino)‐δ‐bromopentanoic acid benzyl ester with the corresponding nucleobase derivative as the key step. The guaninyl and cytosinyl β‐amino acids were built into β‐peptides that were studied by temperature‐dependent CD and UV spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)