Preparation of Protected?2- and?3-Homocysteine,?2- and?3-Homohistidine, and?2-Homoserine for Solid-Phase Syntheses
作者:G�rald Lelais、Peter Micuch、Delphine Josien-Lefebvre、Francesco Rossi、Dieter Seebach
DOI:10.1002/hlca.200490280
日期:2004.12
The Ser, Cys, and His side chains play decisive roles in the syntheses, structures, and functions of proteins and enzymes. For our structural and biomedical investigations of β-peptides consisting of amino acids with proteinogenic side chains, we needed to have reliable preparative access to the title compounds. The two β3-homoamino acid derivatives were obtained by Arndt–Eistert methodology from Boc-His(Ts)-OH
Ser,Cys和His的侧链在蛋白质和酶的合成,结构和功能中起决定性作用。为了进行由具有蛋白原性侧链的氨基酸组成的β肽的结构和生物医学研究,我们需要可靠地制备标题化合物。两个β 3 -homoamino酸衍生物是通过获得阿恩特-艾斯特方法由Boc-他(TS)-OH和Fmoc-半胱氨酸(PMB)-OH(方案2-4),与侧链官能团的反应性,需要特殊预防措施。该β 2在手性恶唑烷酮辅助DIOZ的帮助下,通过向非对映体选择性地向甲醛(由三恶烷原位生成)中添加合适的Ti-烯醇盐,并随后进行官能团操作,制备高纯氨基酸。这些包括OHO吨卜醚化(对于β 2 hSer;方案5和6),OHSTrt更换(对于β 2个hCys;方案7),和CH 2 OHCH 2 Ñ 3 CH 2 NH 2个变换(对于β 2 hHis;方案9 –11)。包括保护/脱保护/再保护反应在内,从商业前体中获得对映体纯的目标化合物需要多达