Stereoselective synthesis of [13C]methyl 2-[15N]amino-2-deoxy-β-d-glucopyranoside derivatives
作者:Fabien P Boulineau、Alexander Wei
DOI:10.1016/s0008-6215(01)00203-8
日期:2001.9
Efficient syntheses of three [13C]methyl 2-[15N]amino-2-deoxy-beta-D-glucopyranoside derivatives are described. Amination of the D-glucal with (saltmen)Mn(15N) proceeded with 11:1 stereoselectivity favoring the gluco configuration; subsequent methylation of the [15N]lactol using [13C]iodomethane and silver(I) oxide afforded the doubly labeled beta glucoside in high yield. This compound served as the
A Chemoenzymatic Approach to Glycopeptide Antibiotics
作者:Hening Lin、Christopher T. Walsh
DOI:10.1021/ja045147v
日期:2004.11.1
Many biologically active natural products are constrained by macrocyclization and modified with carbohydrates. These two types of modifications are essential for their biological activities. Here we report a chemoenzymatic approach to make carbohydrate-modified cyclic peptide antibiotics. Using a thioesterase domain from the decapeptide tyrocidine synthetase, 13 head-to-tail cyclized tyrocidine derivatives were obtained with one to three propargylglycines incorporated at positions 3-8. These cyclic peptides were then conjugated to 21 azido sugars via copper(I)-catalyzed cycloaddition. Antibacterial and hemolytic assays showed that the two best glycopeptides, Tyc4PG-14 and Tyc4PG-15, have a 6-fold better therapeutic index than the natural tyrocidine. We believe this method will also be useful for modifying other natural products to search for new therapeutics.
Design and Synthesis of Novel Scaffolds for Drug Discovery: Hybrids of β-<scp>d</scp>-Glucose with 1,2,3,4-Tetrahydrobenzo[<i>e</i>][1,4]diazepin-5-one, the Corresponding 1-Oxazepine, and 2- and 4-Pyridyldiazepines
作者:Leïla Abrous、John Hynes、Sarah R. Friedrich、Amos B. Smith、Ralph Hirschmann
DOI:10.1021/ol015698f
日期:2001.4.1
[GRAPHICS]We describe the syntheses of novel tricyclic scaffolds that incorporate a fusion of a substituted pyranose ring with the seven-membered rings of 1,2,3,4 tetrahydrobenzo[e][1,4]diazepin-5-one and the corresponding oxazepine and pyridyldiazepine to generate the benzodiazepines, and the related heterocycles. In each instance, the pyranose rings contain three protected hydroxyls, suitable for selective derivatization.
Novel Chimeric Scaffolds to Extend the Exploration of Receptor Space: Hybrid β-<scp>d</scp>-Glucose−Benzoheterodiazepine Structures for Broad Screening. Effect of Amide Alkylation on the Course of Cyclization Reactions
作者:Leïla Abrous、Patrick A. Jokiel、Sarah R. Friedrich、John Hynes,、Amos B. Smith、Ralph Hirschmann
DOI:10.1021/jo0352068
日期:2004.1.1
functionalized analogues (−)-96 and (−)-97 afforded the corresponding dimers (−)-98 and (−)-99, respectively, under a variety of reaction conditions, even at concentrations of only 0.001 N. Consideration of factors affecting the conformation of amide bonds and their effects on cyclization reactions led us to alkylate the amide bond. As expected, the cyclization of the N-methyl derivative (−)-110 afforded exclusively
Probing Synergy between Two Catalytic Strategies in the Glycoside Hydrolase <i>O</i>-GlcNAcase Using Multiple Linear Free Energy Relationships
作者:Ian R. Greig、Matthew S. Macauley、Ian H. Williams、David J. Vocadlo
DOI:10.1021/ja904506u
日期:2009.9.23
revealing changes in mechanism, transition state, and rate-determining step upon concomitant variation of both nucleophilic strength and leaving group abilities are observed. The observed changes in mechanism reflect the roles played by the enzymic general acid and the catalytic nucleophile. Significantly, these results illustrate how the enzyme synergistically harnesses both modes of catalysis; a feature that