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121.
Golebiowski A Klopfenstein SR Shao X Chen JJ Colson AO Grieb AL Russell AF 《Organic letters》2000,2(17):2615-2617
[structure: see text]The solid-supported synthesis of a bicyclic diketopiperazine, a potential peptide beta-turn mimetic, is described. The Ugi reaction between the resin ester of alpha-N-Boc-diaminopropionic acid (an amine input), alpha-bromo acid, aldehyde, and isocyanide is the key step in the proposed protocol. 相似文献
122.
123.
The complexation of lanthanide(III) cations with 1,2-propanediaminetetraacetate (1,2-PDTA) in aqueous solution has been investigated by 10Na, 35Cl, 2H and 11O NMR shift measurements. It has been shown that the contact shifts are dominant for 17O, 16Cl and 2H (only for the heavier lanthanide series) and the pseudocontact shifts are dominant for 25Na. It is suggested that the 1,2-PDTA ligand is bound pentadentately via the two nitrogens and the three carboxylates for the lighter lanthanide complexes, hexdentately via the two nitrogens and the four carboxylates for the heavier ones. The numbers of the water coordinated were determined. The small amount of chloride anion in inner coordination sphere was observed. 相似文献
124.
Lesaicherre ML Lue RY Chen GY Zhu Q Yao SQ 《Journal of the American Chemical Society》2002,124(30):8768-8769
We report here the first example using an intein-mediated expression system to generate biotinylated proteins suitable for immobilization onto avidin-functionalized glass slides. With this novel array, proteins are site-specifically immobilized on the glass surface and are able to retain their native activity. The advantage of the avidin/biotin linkage over his-tag/Ni-NTA strategies for protein immobilization is highlighted by its ability to withstand a variety of chemical conditions, which makes this new protein array compatible with most biological assays. 相似文献
125.
126.
含硫希夫碱的合成研究 总被引:3,自引:0,他引:3
合成了一种含硫希夫碱—1,4-双[(2’-甲醛缩硫代氨基脲基)苯氧甲基]乙烷及其中间产物1,4-双[(2’-甲醛)苯氧甲基]乙烷.其结构经元素分析,IR和1H NMR表征。 相似文献
127.
Multimodal copolymer-encapsulated particles for liquid chromatography were prepared by bonding 1-octadecene and unsaturated carboxylic acids on silica particles (5 microm diameter, 300 A pores) for liquid chromatography of proteins. These multimodal copolymer-encapsulated particles can provide both hydrophobic and hydrogen bonding interactions with polar compounds. The chromatographic performance of these multimodal copolymer-encapsulated particles for peptide and protein separations was evaluated under reversed-phase conditions. Compared with typical C8-bonded silica, polymer-encapsulated particles were more stable in acidic mobile phases and provided better recoveries, especially for large proteins (Mr>0.5 x 10(6)). Totally hydrophobic polymer-encapsulated particles were found to produce broad peaks for proteins, and significant improvements were observed by introducing hydrophilic groups (-COOH) onto the polymer-encapsulated surface to form a multimodal phase. For the reversed-phase liquid chromatography of peptides and proteins, improved selectivity and increased solute retention were found using the multimodal polymer-encapsulated particles. More peaks were resolved for the separation of complex peptide mixtures such as protein digests using the multimodal polymer-encapsulated particles as compared to totally hydrophobic polymer-encapsulated particles. 相似文献
128.
De Feng XU Xiao Juan GUO Zhao Hui XU Shao Shun LI School of Pharmacy Shanghai Jiaotong University Shanghai 《中国化学快报》2006,(7)
Shikonin 1 was a key component isolated from the traditional Chinese herbal medicine, Zicao(Lithospermum erythrorhizon Sieb.et Zucc), which possesses multiple biological activities1. There have been many synthetic routes to shikonin, however, all these ro… 相似文献
129.
桑蚕丝素蛋白的结构、形态及其化学改性 总被引:4,自引:0,他引:4
通过对桑蚕吐丝机构的描述,着重从高分子科学的角度介绍桑蚕丝和蚕丝素蛋白大分子的组成、形态及各种化学、物理性质,讨论了蚕丝素蛋白的纤维化机理,并简述了丝索蛋白纤维的化学接枝改性及其应用。 相似文献
130.
高密度燃料HDF-1与橡胶的相容性研究 总被引:3,自引:0,他引:3
报道了在室温和70 ℃下橡胶材料G402氟硅胶、丁腈胶5171、丁腈胶4170、贮囊橡胶用合成的高密度燃料HDF-1浸泡后性能如伸长率、邵尔硬度、重量、面积体积的变化,并与采用3号喷气燃料(RP-3)实验结果进行对照。用红外光谱测定了燃料浸泡前后橡胶组成的变化。实验结果表明,G402氟硅胶和贮囊对于HDF-1和RP-3有相近的相容性,丁腈胶5171对HDF-1的相容性比对RP-3的相容性稍差,丁腈胶4170对HDF-1的相容性比对RP-3的相容性更差的结果。因此,丁腈胶5171和丁腈胶4170不能用于HDF-1储存和输送,原使用RP-3系统的橡胶密封件不能直接使用HDF-1。 相似文献