Studies on peptides. CXXXII. Evaluation of two .BETA.-carboxyl protecting groups of aspartic acid, cycloheptyl and cyclooctyl, for peptide synthesis.
作者:NOBUTAKA FUJII、MOTOYOSHI NOMIZU、SHIROH FUTAKI、AKIRA OTAKA、SUSUMU FUNAKOSHI、KENICHI AKAJI、KAZUHIDE WATANABE、HARUAKI YAJIMA
DOI:10.1248/cpb.34.864
日期:——
The properties of two aspartic acid β-esters (Asp(OR), R=cycloheptyl (Chp) and cyclooctyl(Coc)) were examined. These two protecting groups were found to be stable to trifluoroacetic acid(0°C, 2 h), but were cleaved by HF or 1 M trifluoromethanesulfonic acid-thioanisole in trifluoro-acetic acid (0°C, 60 min). Using a model peptide, Z(OMe)-Ala-Asp(OR)-Gly-OBzl, the behavior of the Asp(OR) residue with base or acid was examined. These esters were less susceptible to succinimide formation than the Bzl group in Et3N treatment. In acid deprotection, succinimide formation from these peptides was less than 7% in both cases.
对两种天冬氨酸β-酯(Asp(OR),R=环庚基(Chp)和环辛基(Coc))的性质进行了研究。发现这两种保护基在三氟醋酸(0°C,2小时)下是稳定的,但在HF或1 M三氟甲烷磺酸-硫醚苯的三氟醋酸中(0°C,60分钟)会被切割。使用模型肽Z(OMe)-Ala-Asp(OR)-Gly-OBzl,研究了Asp(OR)残基在碱或酸中的行为。这些酯对于succinimide的形成比Bzl基在Et3N处理下的敏感度低。在酸去保护过程中,这些肽中succinimide的形成在两种情况下均低于7%。