The first total synthesis of marine bioactive cyclic heptapeptide Leucamide A has been accomplished, including a simple method for construction of the 4,2-bisheterocycle tandem pair substructure that employs a DAST-mediated cyclization of beta-hydroxy amide and final HBTU-promoted ring closing.
Oxidation of Oxazolines and Thiazolines to Oxazoles and Thiazoles. Application of the Kharasch−Sosnovsky Reaction
作者:A. I. Meyers、Francis X. Tavares
DOI:10.1021/jo9613491
日期:1996.11.15
Kharasch-Sosnovsky reaction, the oxidation of oxazolines and thiazolines bearing a variety of 2-alkyl substituents (chiral and achiral) were smoothly oxidized to their corresponding oxazoles and thiazoles, respectively. The key feature involved in the successful implementation of this important oxidation was the use of a mixture of Cu(I) and Cu(II) salts to enhance the oxidation of the intermediate captodative
Design, synthesis and anticancer mechanistic studies of linked azoles
作者:Md. Amirul Islam、Yuqi Zhang、Yao Wang、Shelli R. McAlpine
DOI:10.1039/c4md00387j
日期:——
Herein we report the synthesis and biological activity evaluation of 2,4 linked azole-containing molecules.
在此,我们报告了2,4-偶联咪唑含有分子的合成和生物活性评估。
Oxazole-modified glycopeptides that target arthritis-associated class II MHC Aq and DR4 proteins
作者:Ida E. Andersson、Tsvetelina Batsalova、Balik Dzhambazov、Lotta Edvinsson、Rikard Holmdahl、Jan Kihlberg、Anna Linusson
DOI:10.1039/c003640d
日期:——
The glycopeptide CII259-273, a fragment from type II collagen (CII), can induce tolerance in mice susceptible to collagen-induced arthritis (CIA), which is a validated disease model for rheumatoid arthritis (RA). Here, we describe the design and synthesis of a small series of modified CII259-273 glycopeptides with oxazole heterocycles replacing three potentially labile peptide bonds. These glycopeptidomimetics were evaluated for binding to murine CIA-associated Aq and human RA-associated DR4 class II major histocompatibility complex (MHC) proteins. The oxazole modifications drastically reduced or completely abolished binding to Aq. Two of the glycopeptidomimetics were, however, well tolerated in binding to DR4 and they also induced strong responses by one or two DR4-restricted T-cell hybridomas. This work contributes to the development of an altered glycopeptide for inducing immunological tolerance in CIA, with the long-term goal of developing a therapeutic vaccine for treatment of RA.
糖肽 CII259-273 是 II 型胶原蛋白(CII)的一个片段,它能诱导易患胶原诱导性关节炎(CIA)的小鼠产生耐受性,CIA 是类风湿性关节炎(RA)的一种有效疾病模型。在这里,我们描述了设计和合成一小系列改性 CII259-273 糖肽的过程,这些糖肽用噁唑杂环取代了三个潜在的易变肽键。我们评估了这些拟糖肽与小鼠 CIA 相关 Aq 和人类 RA 相关 DR4 II 类主要组织相容性复合体 (MHC) 蛋白的结合情况。草唑修饰可显著减少或完全消除与 Aq 的结合。不过,其中两种拟糖肽类药物与 DR4 的结合耐受性很好,它们还能诱导一两种 DR4 限制性 T 细胞杂交瘤产生强烈反应。这项工作有助于开发一种可诱导CIA免疫耐受的改变糖肽,其长远目标是开发一种治疗RA的疫苗。
Total synthesis and assignment of stereochemistry of raocyclamide cyclopeptides from cyanobacterium Oscillatoria raoi
作者:David J Freeman、Gerald Pattenden
DOI:10.1016/s0040-4039(98)00404-3
日期:1998.5
Total synthesis demonstrates that the structures and stereochemistries of the cyclopeptides raocyclamide A and B isolated from a cyanobacterium should be altered to those shown in formulae 13 and 14 respectively.
全合成表明,从蓝细菌分离的环肽饶环酰胺A和B的结构和立体化学应分别改变为式13和14所示。
Peptide-Embedded Heterocycles by Mild Single and Multiple Aza-Wittig Ring Closures