Scope of the DMC mediated glycosylation of unprotected sugars with phenols in aqueous solution
作者:Xin Qiu、Antony J. Fairbanks
DOI:10.1039/d0ob01727b
日期:——
sugars in aqueous solution using 2-chloro-1,3-dimethylimidazolinium chloride (DMC) and triethylamine in the presence of para-nitrophenol allows direct stereoselective conversion to the corresponding 1,2-trans para-nitrophenyl glycosides without the need for any protecting groups. The reaction is applicable to sulfated and phosphorylated sugars, but not to ketoses or uronic acids or their derivatives
在对硝基苯酚存在下,使用 2-氯-1,3-二甲基咪唑啉 (DMC) 和三乙胺在水溶液中活化还原糖,可以直接立体选择性转化为相应的 1,2-反式对硝基苯基糖苷,而无需任何保护基团。该反应适用于硫酸化和磷酸化的糖,但不适用于酮糖或糖醛酸或其衍生物。当应用于其他酚类时,发现产物产率取决于 p K a添加的苯酚,并且该方法不太广泛适用于2-乙酰氨基糖。对于 2-乙酰氨基底物,另一种方法是预先形成糖基恶唑啉,将反应混合物冷冻干燥,然后粗产物与添加的苯酚在极性非质子溶剂系统中与微波辐射反应证明是一种有用的简化.
Synthesis and utility of sulfated chromogenic carbohydrate model substrates for measuring activities of mucin-desulfating enzymes
作者:Keith Clinch、Gary B Evans、Richard H Furneaux、Phillip M Rendle、Phillippa L Rhodes、Anthony M Roberton、Douglas I Rosendale、Peter C Tyler、Damian P Wright
DOI:10.1016/s0008-6215(02)00104-0
日期:2002.6
from monosaccharide precursors by two different methods, the shorter requiring just six steps from 4-nitrophenyl 2-acetamido-2-deoxy-beta-D-glucopyranoside and giving an overall yield of 26.4%. The syntheses of 4-nitrophenyl beta-D-galactopyranoside 3-triethylammonium sulfate and 6-triethylammonium sulfate and their use in combination with beta-galactosidase as chromogenicsubstrates for detecting Bacteroides
The present invention relates generally to compositions and methods comprising abiotic, synthetic polymers with affinity and specificity to proteins. The synthetic polymers are an improvement over biological agents by providing a simpler, less expensive, and customizable platform for binding to proteins. In one embodiment, the compositions and methods relate to synthetic polymers with affinity and specificity to vascular endothelial growth factor (VEGF). In one embodiment, the compositions are useful for treating diseases and disorders related to the overexpression of VEGF. In one embodiment, the compositions are useful for treating cancer. In one embodiment, the compositions are useful for detecting VEGF levels from biological samples. In one embodiment, the compositions are useful for detecting overexpression of VEGF from biological samples. In one embodiment, the compositions are used to diagnose cancer.
Biological activity of N-acetyl-6-SUIfO-beta-D-glucosaminides (6-sulfo-GlcNAc 1) having a structural homology to N-acetylneuraminic acid (Neu5Ac 2) and 2-deoxy-2,3-dehydro-N-acetylneuraminic acid (Neu5Ac2en 3) was examined in terms of inhibitory activity against influenza virus sialidase (influenza, A/Memphis/l/71 H3N2). pNP 6-Sulfo-GlcNAc la was proved to show substantial activity to inhibit the virus sialidaSe IC50 2.8 mM), though p-nitrophenyl (pNP) GlcNAc without 6-sulfo group and pNP 6-sulfo-GlcNH(3)(+) 1b without 2-NHAc showed little activity IC50 > 50 mM). The activity was enhanced nearly 100-fold when the pNP group of la was converted to p-acetamidophenyl one 5 (IC50 = 30 muM) or replaced with 1-naphthyl 6 IC50 = 10 muM) or n-propyl one 8 (IC50 = 11 muM) (C) 2004 Elsevier Ltd. All rights reserved.
Substrate specificity of N-acetylhexosaminidase from Aspergillus oryzae to artificial glycosyl acceptors having various substituents at the reducing ends
The substrate specificity of N-acetylhexosaminidase (E.C. 3.2.1.51) from Aspergillus oryzae was examined using p-nitrophenyl 6-O-sulfo-N-acetyl-beta-D-glucosaminide (6-O-sulfo-GlcNAc-O-pNP) as the glycosyl donor and a series of beta-D-glucopyranosides and N-acetyl-beta-D-glucosaminides with variable aglycons at the anomeric positions as the acceptors. When beta-D-glucopyranosides with methyl (CH3) allyl (CH2CH=CH2), and phenyl (C6H5) groups at the reducing end were used as the acceptors, this enzyme transferred the 6-O-sulfo-GlcNAc moiety in the donor to the location of O-4 in these glycosyl acceptors with a high regioselectivity, producing the corresponding 6-O-sulfo-N-acetylglucosaminyl beta-D-glucopyranosides. However, beta-D-glucopyranose lacking aglycon was a poor substrate for transglycosylation. This A. oryzae enzyme could also accept various N-acetyl-beta-D-glucosaminides carrying hydroxyl (OH), methyl (CH3) propyl (CH2CH2CH3), allyl (CH2CH=CH2) and p-nitrophenyl (PNP; C6H4-NO2) groups at their aglycons, yielding 6-O-sulfo-N-acetylglucosaminyl-beta(1 -> 4)-disaccharide products. (c) 2006 Elsevier Ltd. All rights reserved.