18854-19-8Relevant articles and documents
Isothiourea-Catalyzed Acylative Kinetic Resolution of Tertiary α-Hydroxy Esters
Greenhalgh, Mark D.,Laina-Martín, Víctor,Neyyappadath, Rifahath M.,Qu, Shen,Smith, Andrew D.,Smith, Samuel M.
supporting information, p. 16572 - 16578 (2020/09/09)
A highly enantioselective isothiourea-catalyzed acylative kinetic resolution (KR) of acyclic tertiary alcohols has been developed. Selectivity factors of up to 200 were achieved for the KR of tertiary alcohols bearing an adjacent ester substituent, with both reaction conversion and enantioselectivity found to be sensitive to the steric and electronic environment at the stereogenic tertiary carbinol centre. For more sterically congested alcohols, the use of a recently-developed isoselenourea catalyst was optimal, with equivalent enantioselectivity but higher conversion achieved in comparison to the isothiourea HyperBTM. Diastereomeric acylation transition state models are proposed to rationalize the origins of enantiodiscrimination in this process. This KR procedure was also translated to a continuous-flow process using a polymer-supported variant of the catalyst.
FACTOR XI ACTIVATION INHIBITORS
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Paragraph 26, (2020/12/11)
The present invention provides a compound of Formula (I) and pharmaceutical compositions comprising one or more said compounds, and methods for using said compounds for treating or preventing thromboses, embolisms, hypercoagulability or fibrotic changes. The compounds are selective Factor XI activation inhibitors.
4,6- O-Pyruvyl Ketal Modified N-Acetylmannosamine of the Secondary Cell Wall Polysaccharide of Bacillus anthracis Is the Anchoring Residue for Its Surface Layer Proteins
Chapman, Robert N.,Liu, Lin,Boons, Geert-Jan
supporting information, p. 17079 - 17085 (2018/12/14)
The secondary cell wall polysaccharide (SCWP) of Bacillus anthracis plays a key role in the organization of the cell envelope of vegetative cells and is intimately involved in host-guest interactions. Genetic studies have indicated that it anchors S-layer and S-layer-associated proteins, which are involved in multiple vital biological functions, to the cell surface of B. anthracis. Phenotypic observations indicate that specific functional groups of the terminal unit of SCWP, including 4,6-O-pyruvyl ketal and acetyl esters, are important for binding of these proteins. These observations are based on genetic manipulations and have not been corroborated by direct binding studies. To address this issue, a synthetic strategy was developed that could provide a range of pyruvylated oligosaccharides derived from B. anthracis SCWP bearing base-labile acetyl esters and free amino groups. The resulting oligosaccharides were used in binding studies with a panel of S-layer and S-layer-associated proteins, which identified structural features of SCWP important for binding. A single pyruvylated ManNAc monosaccharide exhibited strong binding to all proteins, making it a promising structure for S-layer protein manipulation. The acetyl esters and free amine of SCWP did not significantly impact binding, and this observation is contrary to a proposed model in which SCWP acetylation is a prerequisite for association of some but not all S-layer and S-layer-associated proteins.
