Synthesis of δ-amino acids with an ether linkage in the main chain and nucleobases on the side chain as monomer units for oxy-peptide nucleic acids

Abstract

Syntheses of four N-Fmoc δ-amino acids with an ether linkage in the main chain and four different nucleobases on the side chain, Fmoc-NH-C ∗H(CH 2-CH 2-B)-CH 2-O-CH 2-COOH (B =thymine, uracil, N 4-benzoylcytosine, and N 2-isobutyrylguanine) are described. The δ-amino acids were prepared through 8–12 step synthesis starting from l-homoserine and could be linked together to form novel peptide nucleic acids (oxy-PNAs = OPNAs).