排序方式: 共有19条查询结果,搜索用时 15 毫秒
1.
2.
Lars Kröger 《Journal of carbohydrate chemistry》2013,32(7):717-722
Natural O‐glycoproteins such as the Thomsen‐Friedenreich antigen or gangliosides contain the motif Galβ1‐3GalNAc as an important disaccharide with significant biologic activity. The arrangement of spatial functionalities in this structure are of particular interest with regard to the development of potential leads en route to pharmaceuticals. Therefore, it was desired to obtain access to a range of modified derivatives of the aforementioned motif paying particular attention to introducing specific deoxy functions instead of hydroxyl groups. 相似文献
3.
4.
5.
Some advantages, disadvantages, and anomalies of various donors in glycosidations are discussed. By studying several two‐component donor/acceptor‐diol reactions, it is shown that regiopreferences are not very sensitive to the type of donor used. However, in competitive glycosidations within a given type of donor and between different types of donor, it is shown that regio‐ and chemoselectivities must be indexed to donor reactivity. 相似文献
6.
Fabian Pfrengle Dipl.‐Chem. Dieter Lentz Prof. Dr. Hans‐Ulrich Reißig Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(17):3165-3169
Well concealed : 1,2‐oxazines such as 1 rearrange under Lewis acidic conditions to bicyclic products of type 2 , which can be incorporated into oligosaccharides as protected amino sugar equivalents. Subsequent reductive steps provide unusual oligosaccharides 3 having C2‐branched 4‐amino sugar units. Most of the reactions proceed with excellent stereocontrol and allow the synthesis of a collection of stereoisomers.
7.
8.
9.
Williams TI Saggese DA Toups KL Frahm JL An HJ Li B Lebrilla CB Muddiman DC 《Journal of mass spectrometry : JMS》2008,43(9):1215-1223
Posttranslational modifications such as glycosylation can play a fundamental role in signaling pathways that transform an ordinary cell into a malignant one. The development of a protocol to detect these changes in the preliminary stages of disease can lead to a sensitive and specific diagnostic for the early detection of malignancies such as ovarian cancer in which differential glycan patterns are linked to etiology and progression. Small variations in instrument parameters and sample preparation techniques are known to have significant influence on the outcome of an experiment. For an experiment to be effective and reproducible, these parameters must be optimized for the analyte(s) under study. We present a detailed examination of sample preparation and matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FT-ICR-MS) analysis of O-linked glycans globally cleaved from mucin glycoproteins. Experiments with stable isotope-labeled biomolecules allowed for the establishment of appropriate acquisition times and excitation voltages for MALDI-FT-ICR-MS of oligosaccharides. Quadrupole ion guide optimization studies with mucin glycans identified conditions for the comprehensive analysis of the entire mass range of O-linked carbohydrates in this glycoprotein. Separately optimized experimental parameters were integrated in a method that allowed for the effective study of O-linked glycans. Copyright (c) 2008 John Wiley & Sons, Ltd. 相似文献
10.