Amino Acids and Peptides. XLIX. Synthesis of .GAMMA.-2-Adamantylglutamate and Its Evaluation for Peptide Synthesis.
作者:Yoshio OKADA、Yu MU
DOI:10.1248/cpb.45.88
日期:——
2-Adamantyl ester was examined for the selective protection of the γ-carboxyl function of the Glu residue, with the aim of preventing side reactions during peptide synthesis and increasing the solubility in organic solvents of peptide intermediates containing the Glu residue. Z-Glu(O-2-Ada)-OBzl was synthesized from Z-Glu-OBzl and admantan-2-ol with the aid of dicyclohexylcarbodiimide (DCC) and 4-N, N-dimethylaminopyridine (DMAP) in AcOEt. The 2-adamantyl ester group was stable to TFA, 20% piperidine/DMF and 10% Et3N/DMF up to 24 h and was easily removed by MSA, 1 M TFMSA-thioanisole in TFA, and HF. Therefore, H-Glu-(O-2-Ada)-OH could be applied for peptide synthesis in both solution and solid phase methods in combination with a Boc or Fmoc group as the Nα-protecting group. Boc-Glu(O-2-Ada)-OH was successfully employed for the synthesis of Bz-Ile-Glu-Gly-Arg-CH2Cl, an irreversible inhibitor of factor Xa.
2-亚氟烷酯被用于选择性保护谷氨酸残基的γ-羧基功能,以防止在肽合成过程中发生副反应,并提高含有谷氨酸残基的肽中间体在有机溶剂中的溶解度。从Z-Glu-OBzl和二氟烷醇在醋酸乙酯中通过二环己基碳二亚胺(DCC)和4-N,N-二甲基氨基吡啶(DMAP)的帮助下合成了Z-Glu(O-2-Ada)-OBzl。2-亚氟烷酯基团在TFA、20%哌啶/DMF和10% Et3N/DMF中稳定长达24小时,并且可以通过MSA、1 M TFMSA-硫醚醇和HF轻松去除。因此,H-Glu-(O-2-Ada)-OH可以应用于肽合成,无论是在溶液法还是固相法中,并结合Boc或Fmoc基团作为Nα保护基团。Boc-Glu(O-2-Ada)-OH成功应用于合成Bz-Ile-Glu-Gly-Arg-CH2Cl,这是Xa因子的不可逆抑制剂。