Peptide Enolates.C-Alkylation of Glycine Residues in linear tri-, tetra-, and pentapeptidesvia dilithium azadienediolates
作者:Hans G. Bossler、Dieter Seebach
DOI:10.1002/hlca.19940770424
日期:1994.6.29
has (R)-configuration (i.e. a D-amino-acid residue is incorporated in the peptide chain). Electrophiles which can be employed with the highly reactive azadienediolate moiety are: MeI, EtI, i-PrI, allyl and benzyl bromide, ethyl bromoacetate, CO2, and Me2S2 (Schemes 11–13). No epimerizations of the starting materials (racemization of the amino-acid residues) are observed under the strongly basic conditions
Boc保护的三肽Boc-Val-Gly-Leu-OH(1),Boc-Leu-Sar-Leu-OH(2),Boc-Leu-Gly-MeLeu-OH(3)和Boc-Val-BzlGly -Leu-OMe(64),四肽Boc-Leu-Gly-Pro-Leu-OH(9)和五肽Boc-Val-Leu-Gly-Abu-Ile-OH(4),Boc-Val-Leu-Sar -MeAbu-Ile-OH(5),Boc-Val-Leu-Gly-MeAbu-Ile-OH(6),Boc-Val-Leu-BzlGly-BzlAbu-Ile-OH(7)和Boc-Val-Leu -Gly-BzlAbu-Ile-OH(8)通过常规方法(方案4-7)或相应前体的直接苄基化(方案8)制备。THF中的多锂化反应使Li消失6个含有甘氨酸,肌氨酸或N-苄基甘氨酸烯醇酸部分(AH)的衍生物。最好用t -BuLi处理生成具有氮杂二烯丙二