Polyamide based nucleic acid analogs - Synthesis of delta-amino acids with nucleic acid bases bearing side chains

Nucleoamino acids of type I - III have been synthesized, which can serve as building blocks for novel polyamide based nucleic acid analogs. Key steps in the syntheses are the alkylation of serinol I and homoserinol 18 with tert-butyl bromoacetate or tert-butyl bromopropionate under phase transfer conditions and the introduction of thymine or uracil into the amino acid side chains by way of a Mitsunobu reaction. Cytosine derivatives were prepared through uracil --> cytosine base conversion at the stage of N-delta-BOC protected amino acid tert-butyl esters. (C) 1997 Elsevier Science Ltd.