Synthesis of S-Benzyl-N-carbobenzoxy-L-cysteinyl-L-tyrosyl- L-phenylalanyl-L-glutaminyl-L-asparagine, a Pentapeptide Derivative Related to Vasopressin1
Free-radical addition to di- and tripeptides containing dehydroalanine residues
作者:David Crich、John W. Davies
DOI:10.1016/s0040-4020(01)89507-7
日期:1989.1
Radical addition, by the alkylmercury halide/sodium borohydride method, to di-and tripeptidescontaining a dehydroalanine residue proceeds smoothly with good chemical yield, but low diastereoselectivity, to saturated di- and tripeptides.
molecular models reveals very low, if any, strain in the planar arrangements shown for the three donor groups of the ligan’d. Since resonance between the imine and aromatic ring would tend to keep the bonds adjacent to the imine nitrogens in the same plane, the planar arrangement for the ligands shown in B and C is favored over other possible structures. Additional evidence for the proposed chelate
分子模型显示,配体的三个供体组显示的平面排列中的应变非常低(如果有的话)。由于亚胺和芳环之间的共振倾向于将与亚胺氮相邻的键保持在同一平面上,因此 B 和 C 中所示配体的平面排列优于其他可能的结构。可以通过比较图 1 中的红外光谱获得所提出的螯合物结构的其他证据。在 2500-2600 cm 附近是否存在宽带。-l 表示 Cu(I1) 螯合物没有分子间氢键,而 Fe(II1) 和 Ni(I1) 螯合物的这种键合量增加。这些带的强度与无、一、和两个能够形成分子间氢键的吡啶鎓质子,分别如结构 A、B 和 C 所示。根据红外证据,对于 Fe(II1) 和 Ni(I1),不能排除水与金属配位且 3-吡啶醇基团参与分子间氢键的替代结构。另一方面,根据已知的金属离子与有机配体中各种类型的供体基团之间的亲和力,这种替代结构被认为是不可能的。
Amino Acid and Dipeptide Functionalized Polyolefins
作者:Timothy E. Hopkins、Kenneth B. Wagener
DOI:10.1021/ma021668w
日期:2003.4.1
N-protected aminoacid and dipeptide branched, chiralpolyolefins have been prepared using acyclic diene metathesis polycondensation chemistry. The polymerizations were performed in THF using Grubbs' second-generation catalyst. The polymers bearing CBz-protected aminoacids and dipeptides are semicrystalline with melt transitions of up to 150 °C, whereas the polymers bearing BOC-protected aminoacids and dipeptides
Peptidomimetics of the formula C-AMBA-X where C is cysteine, X is, for example, methionine or phenylalanine and AMBA is a hydrophobic spacer, notably 3-aminomethylbenzoic acid. These compounds are effective inhibitors of p21 ras farnesyltransferase. Other modifications including alternative spacers for AMBA, and replacement of the A.sub.1 A.sub.2 X component of known CA.sub.1 A.sub.2 X tetrapeptides by a non-peptide aryl or heterocyclic component are also disclosed as are various phosphonylated and arylated derivatives of peptides and peptidomimetics. Pro-drugs made by functionalizing terminal amino and carboxylic acid groups of peptides and peptidomimetics are also disclosed. Such functionalized derivatives demonstrate increased cell uptake. Other structural modifications are also referred to.
A golf ball comprises a core, an outer cover layer, and, optionally, an intermediate layer disposed between the core and the outer cover layer. The outer cover layer may comprise a polyurethane or polyurea composition. At least one portion of the golf ball comprises a composition that enhances physical properties and/or performance characteristics (e.g., coefficient of restitution) of the golf ball. Preferably, the coefficient of restitution of the core is 0.8 or greater.