Total Synthesis and Structure Elucidation of JBIR-39: A Linear Hexapeptide Possessing Piperazic Acid and γ-Hydroxypiperazic Acid Residues
作者:Masahito Yoshida、Naoki Sekioka、Miho Izumikawa、Ikuko Kozone、Motoki Takagi、Kazuo Shin-ya、Takayuki Doi
DOI:10.1002/chem.201406020
日期:2015.2.9
The total synthesis and stereochemical structural elucidation of JBIR‐39, containing four nonproteinogenic piperazic acid (Piz) residues, is reported. The synthesis includes Sc(OTf)3‐catalyzed acylation of a Piz(γ‐OTBS) derivative with piperazic acid chloride, providing the desired Piz‐Piz(γ‐OTBS) dipeptide in high yield without epimerization. After assembling two additional Piz moieties and (S)‐isoleucic
据报道,JBIR-39的总合成和立体化学结构阐明了四个非蛋白生成的哌嗪酸(Piz)残基。合成过程包括Sc(OTf)3催化Piz(γ-OTBS)衍生物与哌嗪酰氯的酰化反应,以高收率提供所需的Piz-Piz(γ-OTBS)二肽,而无需差向异构化。在N端组装两个额外的Piz部分和(S)-异亮氨酸后,在C端与(R)-α-甲基丝氨酸酯酰胺化,然后脱保护得到所需的(2 R,8 S)-六肽,这是JBIR‐39的假定结构。尽管(2 R,8 S)-六肽与JBIR-39不同,进一步合成三种立体异构体证实JBIR-39的立体化学结构为(2 S,6 S,8 S,11 R,16 S,21 R,26 S,27 S)。