Synthesis and conformational studies of peptides from new C-linked carbo-β-amino acids (β-Caas) with anomeric methylamino- and difluorophenyl moieties
作者:Gangavaram V. M. Sharma、Velaparthi Subash、Nelli Yella Reddy、Kongari Narsimulu、Rapolu Ravi、Vivekanand B. Jadhav、Upadhyayula S. N. Murthy、Kankipati Hara Kishore、Ajit C. Kunwar
DOI:10.1039/b810817j
日期:——
New C-linked carbo-β-amino acids (β-Caas), Cbz-(S)-β-Caa-(NHBoc)-OMe (1) and Cbz-(R)-β-Caa-(NHBoc)-OMe (2), with an additional amine group (methylamino group of NHBoc) at the C-1 position of the lyxofuranoside side chain and Boc-(S)-β-Caa-(diFP)-OMe (3) and Boc-(R)-β-Caa-(diFP)-OMe (4), with a C-difluorophenyl (diFP) moiety at the anomeric position of the lyxofuranoside side chain were prepared from D-mannose. β-Peptides [tetra- and hexapeptides] were synthesized from these β-Caas, âepimericâ [at the amine stereocentre (Cβ)], using the concept of âalternating chiralityâ to carry out their conformational studies [NMR (CDCl3), CD and MD]. In the monomer design, it was envisaged that the presence of an additional amine group in 1 or 2 would help in solubilizing the peptides in water, while, the C-difluorophenyl (diFP) moiety of 3 and 4 is expected to enhance the biological activity. The peptides having 1 and 2, though could not retain their 12â10-mixed helices in water, have shown moderate activity against Gram positive and Gram negative bacterial strains. The peptides prepared from 3 and 4, much against our expectations, did not display any biological activity.
新的 C 连接碳-β-氨基酸 (β-Caas)、Cbz-(S)-β-Caa-(NHBoc)-OMe (1) 和 Cbz-(R)-β-Caa-(NHBoc)-OMe (2),在 lyxofuranoside 侧链的 C-1 位置上有一个额外的胺基团(NHBoc 的甲基氨基)和 Boc-(S)-β-Caa-(diFP)-OMe (3) 和 Boc-(R )-β-Caa-(diFP)-OMe (4),在lyxofuranoside 侧链的异头位置具有C-二氟苯基(diFP) 部分,由D-甘露糖制备。 β-肽[四肽和六肽]是从这些β-Caas、“差向异构体”[在胺立构中心(Cβ)]合成的,使用“交替手性”的概念来进行构象研究[NMR (CDCl3)、CD 和 MD]。在单体设计中,预计1或2中额外胺基的存在将有助于将肽溶解在水中,而3和4中的C-二氟苯基(diFP)部分预计将增强生物活性。具有1和2的肽虽然不能在水中保留其12-10混合螺旋,但已显示出针对革兰氏阳性和革兰氏阴性细菌菌株的中等活性。由3和4制备的肽,与我们的预期非常不同,没有表现出任何生物活性。