Regioselective and Diastereoselective Amination of Polybenzyl Ethers Using Chlorosulfonyl Isocyanate: Total Syntheses of 1,4-Dideoxy-1,4-imino-<scp>d</scp>-arabinitol and (−)-Lentiginosine
作者:In Su Kim、Ok Pyo Zee、Young Hoon Jung
DOI:10.1021/ol061614x
日期:2006.8.1
The total syntheses of DAB1 (1) and (-)-lentiginosine (2) were concisely accomplished from D-lyxose via regioselective and diastereoselective NHCbz introduction using CSI, chemoselective removal of the Cbz protection, and ring-closing metathesis as key steps.
Stereoselective <i>C</i>-Glycosylation Reactions of Pyranoses: The Conformational Preference and Reactions of the Mannosyl Cation
作者:Claudia G. Lucero、K. A. Woerpel
DOI:10.1021/jo0522963
日期:2006.3.31
mannose, the high α selectivity observed with C-mannosylation was reversed to high β selectivity if the C-5 alkoxyalkyl group were removed. An analysis of the conformationalpreferences of the intermediate oxocarbenium ions, including the mannosyl cation, as well as consideration of steric effects that develop in the transition states for nucleophilic attack provide explanations for these phenomena.
Direct Experimental Evidence for the High Chemical Reactivity of α‐ and β‐Xylopyranosides Adopting a<sup>2,5</sup><i>B</i>Conformation in Glycosyl Transfer
conformation on xyloside reactivity has been investigated by studying the hydrolysis and glycosylation of a series of synthetic xyloside analogues based on a 2‐oxabicyclo[2.2.2]octane framework, which forces the xylose analogue to adopt a 2,5B conformation. The locked β‐xylosides were found to hydrolyze 100–1200 times faster than methyl β‐D‐xylopyranoside, whereas the locked α‐xylosides hydrolyzed up
Synthesis and Antibacterial Activity of Doxycycline Neoglycosides
作者:Jianjun Zhang、Larissa V. Ponomareva、Karen Marchillo、Maoquan Zhou、David R. Andes、Jon S. Thorson
DOI:10.1021/np4003096
日期:2013.9.27
A set of 37 doxycycline neoglycosides were prepared, mediated via a C-9 alkoxyamino-glycyl-based spacer reminiscent of that of tigecycline. Subsequent in vitro antibacterial assays against representative drug-resistant Gram negative and Gram positive strains revealed a sugar-dependent activity profile and one doxycycline neoglycoside, the 2'-amino-alpha-D-glucoside conjugate, to rival that of the parent pharmacophore. In contrast, the representative tetracycline-susceptible strain E. coli 25922 was found to be relatively responsive to a range of doxycycline neoglycosides. This study also extends the use of aminosugars in the context of neoglycosylation via a simple two-step strategy anticipated to be broadly applicable for neoglycorandomization.
McGeary, Ross P.; Rasoul Amini, Sara; Tang, Vincent W. S., Journal of Organic Chemistry, 2004, vol. 69, # 8, p. 2727 - 2730
作者:McGeary, Ross P.、Rasoul Amini, Sara、Tang, Vincent W. S.、Toth, Istvan