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

Syntheses of four N-Fmoc delta-amino acids with an ether linkage in the mai n chain and four different nucleobases on the side chain, Fmoc-NH-C*H(CH2-C H2-B)-CH2-O-CH2-COOH (B = thymine, uracil, N-4-benzoylcytosine, and N-2-iso butyrylguanine) are described. The delta-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). (C) 1999 Elsevier Science Ltd. All rights reserved.