Synthesis of tetrazole analogs of amino acids using Fmoc chemistry: isolation of amino free tetrazoles and their incorporation into peptides

摘要

An efficient synthesis of tetrazole analogs of amino acids starting from Nα-​Fmoc amino acid (Fmoc = 9-​fluorenylmethoxycarbonyl) in a three-​step protocol is reported. The free amino tetrazoles were obtained in good yields and with excellent purity after removal of the Fmoc group. The synthesis of analogs of aspartic and glutamic acids in which the 5-​tetrazolyl moiety is inserted at the β​/γ carboxyl group starting from Fmoc-​Asn and Fmoc-​Gln and the incorporation of these tetrazoles into peptides are also described.