208644-75-1Relevant academic research and scientific papers
Towards a Synthetic Strategy for the Ten Canonical Carrageenan Oligosaccharides – Synthesis of a Protected γ-Carrageenan Tetrasaccharide
Kinnaert, Christine,Clausen, Mads H.
supporting information, p. 3236 - 3243 (2019/06/08)
Herein, we report a synthetic strategy aiming at synthesizing the ten canonical carrageenan oligosaccharides from one single precursor. The key β-(1→4)-linked disaccharide was synthesized from commercially available galactose pentaacetate. The notoriously difficult formation of β-(1→4)-d-galactan linkages was successfully optimized on the differentially substituted monosaccharides to afford the desired disaccharide in 55 % yield. Following a convergent strategy, two disaccharides were then glycosylated to form the fully protected α-(1→4)-linked tetrasaccharide backbone of the carrageenans. The careful selection of protecting groups provides the opportunity to access all ten carrageenan substructures identified in polysaccharides isolated from red algae. Here, we demonstrate how one such target oligosaccharide can be obtained in a protected form.
Conformational Distortion Using a Molecular Lever: Synthesis and Conformational Studies of Galactoside Derivatives
H?ner, Markus,Herrstedt Hammelev, Christian,Pedersen, Christian Marcus
supporting information, p. 5532 - 5537 (2018/10/24)
Novel bicyclic d-galactose derivatives containing a molecular lever were synthesized and their conformations studied by 1H-NMR and crystallography. Increasing the bulkiness in the alkylidene ring in combination with introducing bulky O-protective groups on the pyranoside ring, causes a ring flip from a 4C1 into the axial rich 1C4 conformation. With less bulky protective groups, the pyranoside ring resides in the 4C1 conformation despite distortion of the external alkylidene ring.
Total synthesis of LewisX using a late-stage crystalline intermediate
Munneke, Stefan,Painter, Gavin F.,Gainsford, Graeme J.,Stocker, Bridget L.,Timmer, Mattie S.M.
, p. 1 - 7 (2015/07/15)
Abstract Herein, we report on a highly efficient synthesis of a crystalline protected LewisX trisaccharide that was converted to LewisX following global deprotection. The trisaccharide was prepared in a highly convergent synthesis (seven steps, longest linear sequence) and in a 38% overall yield using a strategy that involved the regioselective glycosylation of a GlcNAc acceptor with a galactose thioglycoside donor, followed by fucosylation of the remaining free GlcNAc hydroxyl as key steps. The core trisaccharide also has the potential to be converted to other members of the Type-2 Lewis family of antigens due to the orthogonal nature of the protecting groups employed.
Acylation of carbohydrates over Al2O3: Preparation of partially and fully acylated carbohydrate derivatives and acetylated glycosyl chlorides
Tiwari, Pallavi,Misra, Anup Kumar
, p. 339 - 350 (2007/10/03)
Selective and per-O-acylation of carbohydrate derivatives using acyl chlorides and Al2O3, a solid support reagent, is reported. This protocol does not require the addition of any base or activator. This methodology has been further extended to the selective acylation of carbohydrate diols and the one-pot preparation of acetylated glycosyl chlorides direct from free reducing sugars. The yields obtained in most of the cases are excellent.
Nickel(II) chloride-mediated regioselective benzylation and benzoylation of diequatorial vicinal diols
Gangadharmath, Umesh B.,Demchenko, Alexei V.
, p. 2191 - 2193 (2007/10/03)
Ni(II)-chelates of monosaccharide vicinal diols were found to be useful intermediates in regioselective monobenzylation and monobenzoylation. It was observed that the substitution occurs exclusively at the position adjacent to the axially oriented substit
Chemical synthesis of (4,6-Pyr)-Gal β1→4GlcNacβ1→3Fucβ1→OMe: A pyruvated trisaccharide related to the cell aggregation of the sponge Microciona prolifera
Deng, Shaojiang,Yu, Biao,Guo, Zhongwu,Hui, Yongzheng
, p. 439 - 452 (2007/10/03)
4,6-O-[(R)-1-carboxylethylidene] Galβ1→4GlcNAcβ1→3Fucβ1→OMe, a pyruvated trisaccharide unit involved in the aggregation factor of the marine sponge Microciona prolifera, was synthesized stereospecifically and unambiguously employing thioglycosides as glycosyl donors to construct glycosidic bonds.
