合成了几种前手性NCN-钳夹钯(II),具有半不稳定的配体和长的脂肪族链,并进行了光谱表征。在某些配合物中,N个供体原子上存在两个不同的取代基,使它们具有立体异构性,因此它们被分离为非对映异构体的混合物,可以区分为11 H NMR光谱。理论上通过分子对接模拟研究了其中一些复合物通过在其内腔中插入而与牛β-乳球蛋白的结合,并通过CD光谱法进行了实验证实。配体骨架上的H键供体取代基的结合产生了更稳定的超分子蛋白质-复合物组装体。这些构建物显示出在水性介质中催化羟醛缩合反应,在某些情况下提供了不利的顺式产物。由于相应的复合物在不存在β-乳球蛋白的情况下专门提供了反式产物,因此这种异常的非对映选择性是由蛋白质宿主带来的第二个配位域产生的。
Selective Synthesis and Structural Elucidation of <i>S</i>-Acyl- and <i>N</i>-Acylcysteines
作者:Alan R. Katritzky、Srinivasa R. Tala、Nader E. Abo-Dya、Kapil Gyanda、Bahaa El-Dien M. El-Gendy、Zakaria K. Abdel-Samii、Peter J. Steel
DOI:10.1021/jo900853s
日期:2009.9.18
N-(Acyl)-1H-benzotriazoles 6a−f react with l-cysteine 5 at 20 °C to give exclusively (i) N-acyl-l-cysteines 8a−e in the presence of triethylamine in CH3CN−H2O (3:1), but (ii) S-acyl-l-cysteines 7a−e in CH3CN−H2O (5:1) in the absence of base. Structures 7b, 7d and 8b, 8d are supported by 2D NMR spectroscopic methods including gDQCOSY, gHMQC, gHMBC, and 1H−15N CIGAR-gHMBC experiments. The structure of
N-(酰基)-1 H-苯并三唑6a - f在20°C下与1-半胱氨酸5反应,仅在CH 3 CN-H中存在三乙胺的情况下仅生成(i)N-酰基-1-半胱氨酸8a - e 2 O(3:1),但(ii)CH 3 CN-H 2 O(5:1)中在不存在碱的情况下的S-酰基-1-半胱氨酸7a - e。结构7b,7d和8b,8d支持2D NMR光谱方法,包括gDQCOSY,gHMQC,gHMBC和1 H - 15 N CIGAR-gHMBC实验。化合物8d的结构也通过单晶X射线衍射来支撑。
Chemical modification of recombinant hirudin with palmitic acid in mixed aqueous-organic solutions
chromatography. Three mono-PAL-HV2 isomers were obtained and retained 36%, 4% and 89% of the in vitro anticoagulantactivity of unmodified HV2, respectively. One of the mono-PAL-HV2 isomers, namely, mono-PAL-HV2-3, was isolated with the highest selectivity and exhibited the highest in vitro anticoagulant bioactivity. Modification site analysis of mono-PAL-HV2-3 revealed that a single PAL molecule was conjugated
A method of selectively acylating an insulin, an insulin analogue or a precursor thereof having a free .epsilon.-amino group of a Lys residue contained therein and at least one free .alpha.-amino group which method comprises reacting the .epsilon.-amino group with an activated amide in a polar solvent in the presence of a base.