93302-92-2Relevant academic research and scientific papers
Nitroalkene ring closure route to carbon-linked scaffolds for mimicking α-d-mannopyranosyl natural linkage
Baráth, Marek,Blahu?iaková, Alexandra,Jakub?inová, Jana,Ková?ová, Hana,Petru?, Ladislav,Petru?ová, Mária,Pribulová, Bo?ena
, (2020/06/02)
Abstract: Controlled treatment of 3,4,5,6,7-penta-O-acetyl-1,2-dideoxy-1-nitro-d-manno-hept-1-enitol with sodium methoxide in methanol was stopped by decationization at a point providing about equimolar mixture of α-d-mannopyranosyl and β-d-mannopyranosyl nitromethanes, from which the target α-anomer was isolated by chemisorption chromatography on a cation exchange resin in the Ba2+ form in a 36% yield. Direct reduction of the above mixture with ferrous hydroxide in situ to the corresponding amines, followed by the selective N-acetylation and the analogical chromatographic separation of both pertinent isomers with their stable ring structures gave N-acetyl-C-α-d-mannopyranosyl-methylamine. Alternative stopping of the initial ring forming reaction with acidified methanol at the above given product ratio initiated a subsequent Nef reaction and α-d-mannopyranosyl methanal dimethyl acetal was then chromatographically separated from its β-isomer on an anion exchange resin in the OH? form. Activations of two latter C-α-d-mannopyranosyl scaffolds by acid hydrolysis into respective reactive free amine or aldehyde forms were developed as well. Detailed reinvestigation of the classical method of preparation of d-mannosyl nitromethanes by thermal dehydration of a 1-deoxy-1-nitroalditol derived from d-mannose showed a maximum occurrence of only 18% of the required α-d-mannopyranosyl anomer. Graphic abstract: [Figure not available: see fulltext.].
STEREOCHEMISCHE ASPEKTE IN ZUSAMMENHANG MIT DER SYNTHESE VON 2,6-ANHYDRO-1-DESOXY-1-NITROALDITOLEN
Foertsch, Armin,Kogelberg, Heide,Koell, Peter
, p. 391 - 402 (2007/10/02)
2,6-Anhydro-1-deoxy-1-nitroalditols were prepared in good yields by known procedures via addition of nitromethane to D-glucose, D-mannose, D-galactose, D-xylose, D-lyxose and L-arabinose, followed by a cyclization step in boiling water.In the case of D-ribose, a mixture of pyranoid and furanoid anhydroalditols was isolated by different methods in relatively poor yields, at variance with recent reports by other authors.Establishment of the stereochemical relations of the products from 1H-n.m.r. spectra of their acetates gave further insight into the diasteroselectivity of the cyclization step.
