Browse
Submit Data
Databases
API
Help

Dataset Information

27 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Ring-opening of aziridine-2-carboxamides with carbohydrate C1-O-nucleophiles. Stereoselective preparation of alpha- and beta-O-glycosyl serine conjugates.

ABSTRACT: The stereoselective formation of the alpha-GalNAc-Ser linkage via the ring opening of aziridine-2-carboxamides with pyranose C1-O-nucleophiles is described. The process is tolerant to the native C2-NHAc group, can be modulated to provide either the alpha- or beta-glycoside through judicious choice of solvent and metal counterion, and is amenable to other classes of O-glycosyl-Ser constructs such as the beta-GlcNAc-Ser and alpha-Man-Ser linkages. This coupling reaction also led to the development of the o-allylbenzyl (ABn) moiety as a new C-terminus carboxyl protective group, which allows for the use of novel methods for N- and C-terminus extension of amino acids following carbohydrate conjugation.

SUBMITTER: Ryan DA

PROVIDER: S-EPMC2648612 | biostudies-literature | 2008 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Ring-opening of aziridine-2-carboxamides with carbohydrate C1-O-nucleophiles. Stereoselective preparation of alpha- and beta-O-glycosyl serine conjugates.

Ryan Daniel A DA Gin David Y DY

Journal of the American Chemical Society 20081025 46

The stereoselective formation of the alpha-GalNAc-Ser linkage via the ring opening of aziridine-2-carboxamides with pyranose C1-O-nucleophiles is described. The process is tolerant to the native C2-NHAc group, can be modulated to provide either the alpha- or beta-glycoside through judicious choice of solvent and metal counterion, and is amenable to other classes of O-glycosyl-Ser constructs such as the beta-GlcNAc-Ser and alpha-Man-Ser linkages. This coupling reaction also led to the development ...[more]

PMID: 18950157

Similar Datasets

Aziridine Ring Opening as Regio- and Stereoselective Access to C-Glycosyl-Aminoethyl Sulfide Derivatives.

Project description:A short synthetic route to stereoselective access to C-glycosyl-aminoethyl sulfide derivatives has been developed through the reaction of tributhyltin derivatives of glycals with aziridinecarboaldehyde and the regioselective ring opening of a chiral aziridine with thiophenol. The absolute configurations of the resulting diastereoisomers were determined by 1H NMR spectroscopy.

| S-EPMC8952378 | biostudies-literature

Alkylative Aziridine Ring-Opening Reactions.

Project description:In this study, the highly strained three-membered aziridine ring was successfully activated as the aziridinium ion by alkylation of the ring nitrogen with a methyl, ethyl or allyl group, which was followed by ring opening with external nucleophiles such as acetate and azide. Such alkylative aziridine ring opening provides an easy route for the synthesis of various N-alkylated amine-containing molecules with concomitant introduction of an external nucleophile at either its α- or β-position.

| S-EPMC8003214 | biostudies-literature

Stereoselective oxidative glycosylation of anomeric nucleophiles with alcohols and carboxylic acids.

Project description:Oligosaccharides, one of the most abundant biopolymers, are involved in numerous biological processes. Although many efforts have been put in preparative carbohydrate chemistry, achieving optimal anomeric and regioselectivities remains challenging. Herein we describe an oxidative glycosylation method between anomeric stannanes and oxygen nucleophiles resulting in the formation of a C-O bond with consistently high anomeric control for glycosyl donors bearing a free C2-hydroxyl group. These reactions are promoted by hypervalent iodine reagents with catalytic or stoichiometric amounts of Cu or Zn salts. The generality of this transformation is demonstrated in 42 examples. Mechanistic studies indicate that the oxidative glycosylation is initiated by the hydroxyl-guided delivery of the hypervalent iodine and tosylate into the anomeric position, and results in excellent 1,2-trans selectivity. The unique mechanistic paradigm, high selectivities, and mild reaction conditions make this method suitable for the synthesis of oligosaccharides and for integration with other methodologies such as automated synthesis.

| S-EPMC6128909 | biostudies-other

Stereoselective Multicomponent Reactions Using Zincate Nucleophiles: ?-Dicarbonyl Synthesis and Functionalization.

Project description:A general strategy for conjugate addition-C-acylation that enables the synthesis of enantioenriched ?-dicarbonyl compounds is described. A novel method for derivatizing these adducts by stereo- and site-selective zinc-catalyzed addition of alkyllithium reagents is also reported. These reactions can be performed in tandem to achieve an enantio- and diastereoselective four-component coupling. The in situ generation of weakly basic lithium zincate species is central to the success of all three transformations.

| S-EPMC7000105 | biostudies-literature

Aziridine Opening via a Phenonium Ion Enables Synthesis of Complex Phenethylamine Derivatives.

Project description:We report that the treatment of unsymmetrical 2,3-disubstituted aziridines with TiCl4 yields β-phenethylamine products via the intermediacy of a phenonium ion. Derivatization of the products obtained via this method is demonstrated. Computational analysis of the reaction pathway provides insight into the reaction mechanism, including the selectivity of the phenonium opening.

| S-EPMC8796817 | biostudies-literature

β-amino esters from the reductive ring opening of aziridine-2-carboxylates.

Project description:A general study is undertaken to examine the scope of the reductive ring opening of aziridine-2-carboxylates with samarium diiodide. The competition between C-C and C-N bond cleavage is examined as a function of the nature of the N-substituent of the aziridine, the nature of the substituent in the 3-position of the aziridine, and whether the substituent in the 3-position is in a cis or trans relationship with the carboxylate in the 2-position. The desired C-N bond cleavage leads to β-amino esters that are the predominant products for most aziridines with an N-activating group. However, C-C cleavage products are observed with an aryl group in the 3-position; this can be particularly pronounced with cis-aziridines where a nearly equal mixture of the two is observed. Exclusive formation of the C-N cleavage product is observed for all aziridines with the strongly N-activating p-toluene sulfonate group. Similarly high selectivity is observed for the 2-trimethylsilylethyl sulfonate group (SES), which is easier to remove. The utility of these methods is illustrated in the synthesis of protected forms of (R)-β(3)-DOPA and L-DOPA from the same aziridine, the former by SmI2-mediated reductive opening at C-2 and the latter by palladium-mediated reductive opening at C-3.

| S-EPMC4227569 | biostudies-literature

Expanding the scope of stereoselective α-galactosylation using glycosyl chlorides.

Project description:Recently, we reported that silver(I) oxide mediated Koenigs-Knorr glycosylation reaction can be dramatically accelerated in the presence of catalytic acid additives. We have also investigated how well this reaction works in application to differentially protected galactosyl bromides. Reported herein is the stereoselective synthesis of α-galactosides with galactosyl chlorides as glycosyl donors. Chlorides are easily accessible, stable, and can be efficiently activated for glycosylation. In this application, the most favorable reactions conditions comprised cooperative Ag2SO4 and Bi(OTf)3 promoter system.

| S-EPMC9677435 | biostudies-literature

Stereoselective photoredox ring-opening polymerization of O-carboxyanhydrides.

Project description:Biodegradable polyesters with various tacticities have been synthesized by means of stereoselective ring-opening polymerization of racemic lactide and ?-lactones but with limited side-chain groups. However, stereoselective synthesis of functional polyesters remains challenging from O-carboxyanhydrides that have abundant pendant side-chain functional groups. Herein we report a powerful strategy to synthesize stereoblock polyesters by stereoselective ring-opening polymerization of racemic O-carboxyanhydrides with the use of photoredox Ni/Ir catalysts and a selected Zn complex with an achiral ligand. The obtained stereoblock copolymers are highly isotactic with high molecular weights (?>?70?kDa) and narrow molecular weight distributions (Mw/Mn?<?1.1), and they display distinct melting temperatures that are similar to their stereocomplex counterparts. Furthermore, in one-pot photoredox copolymerization of two different O-carboxyanhydrides, the use of such Zn complex mediates kinetic resolution of the comonomers during enchainment and shows a chirality preference that allows for the synthesis of gradient copolymers.

| S-EPMC5908805 | biostudies-other

Catalytic activation of glycosyl phosphates for stereoselective coupling reactions.

Project description:Glycosyl phosphates are shown to be activated to stereospecific nucleophilic substitution reactions by precisely tailored bis-thiourea catalysts. Enhanced reactivity and scope is observed with phosphate relative to chloride leaving groups. Stronger binding (Km) to the H-bond donor and enhanced reactivity of the complex (kcat) enables efficient catalysis with broad functional group compatibility under mild, neutral conditions.

| S-EPMC6320501 | biostudies-other

Stereoselective Synthesis of ?- and ?-l-Ara4N Glycosyl H-Phosphonates and a Neoglycoconjugate Comprising Glycosyl Phosphodiester Linked ?-l-Ara4N.

Project description:Stereoselective synthesis of variably protected ?- and ?-l-Ara4N glycosyl H-phosphonates as key intermediates in the syntheses of ?-l-Ara4N-modified LPS structures and ?-l-Ara4N-containing biosynthetic precursors is reported. A facile one-pot approach toward ?-l-Ara4N glycosyl H-phosphonates includes anomeric deallylation of protected 4-azido ?-l-Ara4N via terminal olefin isomerization followed by ozonolysis and methanolysis of formyl groups to furnish exclusively ?-configured lactols that are phosphitylated with retention of configuration. The carbohydrate epitope of ?-l-Ara4N-modified Lipid A, ?GlcN(1?6)?GlcN(1?P?1)?-l-Ara4N, was stereoselectively synthesized and linked to maleimide-activated bovine serum albumin.

| S-EPMC5223274 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data