Amide-1,2,3-triazole bioisosterism: the glycogen phosphorylase case
摘要:
Per-O-acetylated beta-D-glucopyranosyl azide was transformed into an intermediate iminophosphorane by PMe3 which was then acylated to N-acyl-beta-D-glucopyranosylamines. The same azide and substituted acetylenes gave 1-(beta-D-glucopyranosyl)-4-substituted-1,2,3-triazoles in Cu(I)-catalyzed azide-alkyne cycloadditions. Deprotection of these products by the Zemplen method furnished beta-D-Glc(p)-NHCO-R derivatives as well as 1-(beta-D-Glc(p))-4-R-1,2,3-triazoles which were evaluated as inhibitors of rabbit muscle glycogen phosphorylase b. Pairs of amides versus triazoles with the same R group displayed similar inhibition constants. X-ray crystallographic studies on the enzyme-inhibitor complexes revealed high similarities in the binding of pairs with R = 2-naphthyl and hydroxymethyl, while for the R = Ph and 1-naphthyl compounds a different orientation of the aromatic part and changes in the conformation of the 280s loop were observed. By this study new examples of amide-1,2,3-triazole bioisosteric relationship have been provided. (C) 2009 Elsevier Ltd. All rights reserved.
2,3,4,6-Tetra-O-acetyl-beta-D-glucopyranosyl- and 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-beta-D-glucopyranosyl azides were transformed into the corresponding per-O-acetylated N-(beta-D-glycopyranosyl) amides via a PMe3 mediated Staudinger protocol (generation of N-(beta-D-glycopyranosyl)imino-trimethylphosphoranes followed by acylation with carboxylic acids, acid chlorides or anhydrides). The deprotected compounds obtained by Zemplen deacetylation were evaluated as inhibitors of rabbit muscle glycogen phosphorylase b. The best inhibitor of this series has been N-(beta-D-glucopyranosyl) 3-(2-naphthyl)-propenoic amide (K-i = 3.5 muM). (C) 2004 Elsevier Ltd. All rights reserved.
Application of bis(diphenylphosphino)ethane (DPPE) in Staudinger-type N-glycopyranosyl amide synthesis
作者:David P. Temelkoff、Craig R. Smith、Daniel A. Kibler、Shawn McKee、Sara J. Duncan、Matthias Zeller、Mo Hunsen、Peter Norris
DOI:10.1016/j.carres.2006.02.001
日期:2006.7
Bis(diphenylphosphino)ethane (DPPE) reacts with pyranosyl azides derived from D-glucose and D-glucuronic acid in the presence of acid chlorides to yield the corresponding glycosyl amides. Reaction rates are comparable to those with triphenylphosphine, however, the byproduct phosphine oxide is easily removed from reaction mixtures using column chromatography. The simple and clean workup allows for the formation of collections of related compounds by parallel synthesis, and the method is also applicable to scaled-up reactions. The beta-stereochemistry of the glycosyl azide precursor is retained in all cases, which is supported by X-ray crystallography in several cases. (c) 2006 Elsevier Ltd. All rights reserved.