72858-55-0Relevant academic research and scientific papers
Glycosidic linkage, N-acetyl side-chain, and other structural properties of methyl 2-acetamido-2-deoxy-β-d-glucopyranosyl-(1→4)-β-d-mannopyranoside monohydrate and related compounds
Carmichael, Ian,Meredith, Reagan J.,Oliver, Allen G.,Serianni, Anthony S.,Zhang, Wenhui
, p. 287 - 297 (2020/03/17)
The crystal structure of methyl 2-acetamido-2-deoxy-β-d-glycopyranosyl-(1→4)-β-d-mannopyranoside monohydrate, C15H27NO11·H2O, was determined and its structural properties compared to those in a set of mono- and disaccharides bearing N-acetyl side-chains in βGlcNAc aldohexopyranosyl rings. Valence bond angles and torsion angles in these side chains are relatively uniform, but C - N (amide) and C - O (carbonyl) bond lengths depend on the state of hydrogen bonding to the carbonyl O atom and N - H hydrogen. Relative to N-acetyl side chains devoid of hydrogen bonding, those in which the carbonyl O atom serves as a hydrogen-bond acceptor display elongated C - O and shortened C - N bonds. This behavior is reproduced by density functional theory (DFT) calculations, indicating that the relative contributions of amide resonance forms to experimental C - N and C - O bond lengths depend on the solvation state, leading to expectations that activation barriers to amide cis-trans isomerization will depend on the polarity of the environment. DFT calculations also revealed useful predictive information on the dependencies of inter-residue hydrogen bonding and some bond angles in or proximal to β-(1→4) O-glycosidic linkages on linkage torsion angles φ and ψ. Hypersurfaces correlating φ and ψ with the linkage C - O - C bond angle and total energy are sufficiently similar to render the former a proxy of the latter.
Asymmetric Total Synthesis of Brasilicardins
Yoshimura, Fumihiko,Itoh, Ryusei,Torizuka, Makoto,Mori, Genki,Tanino, Keiji
, p. 17161 - 17167 (2018/12/11)
Brasilicardins, bacterial diterpenoid natural products that display highly potent immunosuppressive activity, are promising immunosuppressant drug candidates. Structurally, they can be described as hybrids of terpenoids, amino acids, and saccharides, and share a characteristic highly strained anti-syn-anti-fused perhydrophenanthrene terpenoid scaffold (ABC-ring system) with two quaternary asymmetric carbon atoms. A unified and stereoselective total synthesis of all four brasilicardins has been designed based on the strategic use of an intramolecular conjugate addition. The ABC-ring system was initially constructed with high stereocontrol by novel intramolecular conjugate additions of Weinreb amides and in situ generated (Z)-vinyl copper species. The late-stage common intermediate was subjected to stereoselective installation of the amino acid component, followed by introduction of the saccharide unit via glycosylation to accomplish the total synthesis of brasilicardins A–D. Our synthesis offers opportunities to synthesize various brasilicardin analogues for biological and pharmacological investigations.
Synthesis of building blocks for an iterative approach towards oligomers of the Streptococcus pneumoniae type 1 zwitterionic capsular polysaccharide repeating unit
Ní Cheallaigh, Aisling,Oscarson, Stefan
, p. 940 - 960 (2016/11/17)
Zwitterionic capsular polysaccharide extracts, 8 kDa in mass, from Streptococcus pneumoniae type 1 (Spt1) have shown unique T-cell activating properties. Oligomers of the trisaccharide repeating unit of the Spt1 capsular polysaccharide [3)-4-NH2-α-d-QuipNAc-(14)-α-d-GalpA-(13)-α-d-GalpA-(1-]n of defined length are needed to further investigate this response. An approach towards iteratively extendable trisaccharide building blocks of the zwitterionic capsular polysaccharides of Spt1 is described. Key elements include the comparison of pre-glycosylation oxidation and post-glycosylation oxidation approaches using thioglycoside donors to the target trisaccharide, the optimisation of the post-glycosylation oxidation approach, and the conversion of the trisaccharide to building blocks tailored for iterative glycosylation. The construction and evaluation of stereotunable 2-N-3-O-oxazolidinone donors for the common bacterial 2-acetamido-4-amino-2,4,6-trideoxy-α-d-galactopyranoside motif is also described, as is a key intermediate for their efficient synthesis.
Synthesis and selective anticancer activity of steroidal glycoconjugates
Fernandez-Herrera, Maria A.,Lopez-Munoz, Hugo,Hernandez-Vazquez, Jose M.V.,Sanchez-Sanchez, Luis,Escobar-Sanchez, Maria L.,Pinto, B. Mario,Sandoval-Ramirez, Jesus
, p. 721 - 727 (2012/09/21)
The synthesis of glucosamine derivatives of the steroidal sapogenins diosgenin and hecogenin using the N-phthaloyl protected trichloroacetimidate of d-glucosamine as donor and TMSOTf as promoter is reported. The corresponding glycoconjugates were transformed into their acetamido derivatives and the hydrochloride salt (from diosgenin) and tested against HeLa, CaSki, and ViBo cervicouterine cancer cells. These compounds showed low cytotoxicity values on tumor cells and human lymphocytes, indicating that the main cell death process is presumably not necrosis. Significantly, the antiproliferative activity of these compounds on tumor cells did not affect the proliferative potential of peripheral blood lymphocytes.
An efficient synthesis of the protected carbohydrate moiety of Brasilicardin A
Jung, Michael E.,Koch, Pierre
, p. 3710 - 3713 (2011/09/14)
A synthesis of the protected carbohydrate moiety 2 of Brasilicardin A starting from l-rhamnose and d-glucosamine is described. The disaccharide was synthesized using a TMSOTf-mediated glycosylation of the 2-phthalimido-2- deoxyglucose donor 5 and the 3-hydroxyl group of the protected l-rhamnose derivative 4, which already bears the 3-hydroxybenzoate unit. The imidate 2 was coupled via TMSOTf-mediated glycosidation with cholesterol as a model aglycone followed by the selective cleavage of all the acetate groups to give the Brasilicardin A analogue 16.
Solid-phase synthesis of thioether-linked glycopeptide mimics for application to glycoprotein semisynthesis.
Macmillan, Derek,Daines, Alison M,Bayrhuber, Monika,Flitsch, Sabine L
, p. 1467 - 1470 (2007/10/03)
[reaction: see text]. Glycoproteins are particularly suited to protein semisynthesis since homogeneous samples for biological analyses are not readily available using traditional recombinant techniques. Here we apply glycosyl iodoacetamides, normally used for the modification of bacterially derived proteins, to solid-phase glycopeptide synthesis. This provides access to glycopeptide alpha-thioesters, which may lend themselves to the semisynthesis of homogeneous N-linked glycoprotein mimics and novel glycopeptide libraries.
A convenient synthetic route to the disaccharide repeating-unit of peptidoglycan.
Kantoci,Keglevic,Derome
, p. 227 - 235 (2007/10/02)
Glycosylation of the readily accessible benzyl 2-acetamido-6-O-benzyl-2-deoxy-3-O-[(R)-1-(methoxycarbonyl)ethyl]-alpha- D- glucopyranoside with 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-beta-D-glucopyranosyl chloride (2), using the silver triflate method i
