PyBOP® and PyBroP: Two reagents for the difficult coupling of the α,α-dialkyl amino acid, Aib.
摘要:
The difficult coupling of alpha-aminoisobutyric acid (Aib) was carried out using PyBOP(R) and PyBroP in a comparative study with BOP and BroP. These reagents gave good results under simple conditions (one pot, r.t., 1 h). Coded amino acids could be coupled with Aib using PyBOP under standard conditions of peptide synthesis without racemization whereas the coupling of two Aib residues required PyBroP/DMAP. A fragment containing an Aib C-terminal could be coupled without epimerization of the penultimate residue.
Copper-mediated oxidative C-terminal N-dealkylation of peptide-derived ligands. A possible model for enzymatic generation of desglycine peptide amides
作者:K. Veera Reddy、Shiow Jen Jin、Pramod K. Arora、David S. Sfeir、S. C. Feke Maloney、F. L. Urbach、Lawrence M. Sayre
DOI:10.1021/ja00162a038
日期:1990.3
A number of Cu(II) complexes of peptide derivatives that coordinate via N-deprotonation at the C-terminal amino acid residue have been characterized by titrimetry and the Cu(III)-Cu(II) electrochemical potentials. Reaction of these complexes with persulfate induces oxidative decarboxylation and hydrolysis of the resulting N-acylimines to carboxamide and either HCHO, CH 3 CHO, or acetone depending on
已经通过滴定法和 Cu(III)-Cu(II) 电化学电位表征了许多肽衍生物的 Cu(II) 复合物,它们通过 C 端氨基酸残基的 N-去质子化进行了配位。这些复合物与过硫酸盐的反应会诱导产生的 N-酰基亚胺氧化脱羧和水解为甲酰胺和 HCHO、CH 3 CHO 或丙酮,具体取决于 C 末端残基的身份
Synthese von 2-methylalanin-peptiden, die pH-Abhängiggkeit ihrer 13C-NMR-spektren und eine neue methode zur auswertung über CS-diagramme
The uncommon amino-acid 2-methylalanine (α-aminoisobutyric acid, Aib) was investigated by 13C-NMR. The chemical shifts of amino- or carboxy-protected derivatives of Aib and of protected oligopeptides are discussed with respect to neighbouring groups and amino acids. The pH-dependence of the 13C-NMR spectra of Aib, Aib-Ala, Ala-Aib, Aib-Ala-Aib and Aib-Ala-Aib-Ala-Aib was studied. Using these examples
Total Synthesis of the α-Helical Eicosapeptide Antibiotic Alamethicin
作者:Heribert Schmitt、Günther Jung
DOI:10.1002/jlac.198519850210
日期:1985.2.12
identical with the main component F 30 of the microheterogeneous antibiotic metabolite isolated from Trichoderma viride. The antibiotic activities of synthetic alamethicin (1) and the stimulating effect on calcium/calmodulin-dependent guanylate cyclase of Paramecium are identical with those of natural alamethicin. – The uniform synthetic alamethicin (1) shows perfectly homogeneous conductance states of single
电压依赖性膜成孔多肽抗生素alamethicin F 30(Ac-Aib-Pro-Aib-Ala-Aib-Ala-Gln-Aib-Val-Aib-Gly-Leu-Aib-Pro-Val-Aib-Aib- Glu-Gln-Phl,1)是通过链段缩合合成的。使用二环己基碳二亚胺/ 1-羟基苯并三唑和混合酸酐法,可通过链段2-11(4a)和12-20(3a)获得不含外消旋物(<0.8%D组分)的化合物。通过色谱和物理方法(包括13 C NMR,圆二色性和手性气相色谱法)明确表征了中间体。段2–6(5a)和12–20(3)也通过X射线结构确定得到了证明。—在不进行HPLC分离的情况下,获得了非常高的纯度和结晶形式的最终产物1(150 mg)。根据所有分析数据以及通过光谱法和色谱分析法(HPLC,DC)进行的比较,产物1与从木霉属木霉分离的微异质抗生素代谢产物的主要成分F 30相同。合成的alame
Development of a New Family of Conformationally Restricted Peptides as Potent Nucleators of β-Turns. Design, Synthesis, Structure, and Biological Evaluation of a β-Lactam Peptide Analogue of Melanostatin
作者:Claudio Palomo、Jesus M. Aizpurua、Ana Benito、José Ignacio Miranda、Raluca M. Fratila、Carlos Matute、Maria Domercq、Federico Gago、Sonsoles Martin-Santamaria、Anthony Linden
DOI:10.1021/ja038180a
日期:2003.12.1
annealing techniques, showing a strong tendency to form stable type II or type II' beta-turns either in the solidstate or in highly coordinating DMSO solutions. Tetrapeptide models containing syn- or anti-alpha,beta-dialkyl-alpha-amino-beta-lactam rings have also been synthesized and their conformations analyzed, revealing that alpha-alkyl substitution is essential for beta-turn stabilization. A beta-lactam
新型对映体纯 (i)-(β-内酰胺)-(Gly)-(i+3) 肽模型,定义为存在中心 α-烷基-α-氨基-β-内酰胺环,放置为 (i+1 ) 残基,通过合适的 N-[双(三甲基甲硅烷基)甲基]-β-内酰胺的α-烷基化以完全立体控制的方式合成。这些 β-内酰胺假肽的结构特性已经通过 X 射线晶体学、分子动力学模拟和 NOESY 抑制 NMR 模拟退火技术进行了研究,显示出形成稳定的 II 型或 II 型'β-转角的强烈趋势。固态或高度协调的 DMSO 溶液。还合成了含有顺式或反式 α,β-二烷基-α-氨基-β-内酰胺环的四肽模型并分析了它们的构象,揭示α-烷基取代对于β-转角稳定是必不可少的。还制备了黑色素抑制素的 β-内酰胺类似物(PLG 酰胺),在 DMSO-d6 溶液中表征为 II 型β-转角,并通过竞争性结合试验作为大鼠神经元培养细胞中的多巴胺能 D2 调节剂进行测试,显示出中等微摩
Synthesis and characterization of an unsymmetrical cobalt(III) active site analogue of nitrile hydratase
作者:Jennifer K. Angelosante、Lauren M. Schopp、Breia J. Lewis、Amber D. Vitalo、Dustin T. Titus、Rebecca A. Swanson、April N. Stanley、Brendan P. Abolins、Michelle J. Frome、Lisa E. Cooper、David L. Tierney、Curtis Moore、Arnold L. Rheingold、Christopher J. A. Daley
DOI:10.1007/s00775-011-0794-7
日期:2011.8
protocol established in our laboratory that includes two peptide couples using O-(1H-benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate as the coupling agent. The ligand and all precursors were characterized by NMR spectroscopy and elemental analysis. The cobalt nitrile hydratase synthetic analogue complex [NBu(4)][Co(1)] was prepared on deprotonating ligand H(4) 1 to [1](4-) on addition