Nitroalkene ring closure route to carbon-linked scaffolds for mimicking α-d-mannopyranosyl natural linkage

• Published in: Monatshefte für Chemie 2020-06, Vol.151 (6), p.925-933
• Main Authors: Pribulová, Božena, Kováčová, Hana, Jakubčinová, Jana, Baráth, Marek, Blahušiaková, Alexandra, Petrušová, Mária, Petruš, Ladislav
• Format: Article
• Language: English
• Subjects: Acetylation; Acidification; Aldehydes; Amines; Analytical Chemistry; Anion exchanging; Cation exchanging; Cationic polymerization; Chemisorption; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Chromatography; Dehydration; Dimethyl acetals; Direct reduction; Ferrous hydroxide; Formaldehyde; Inorganic Chemistry; Isomers; Mannose; Methanol; Organic Chemistry; Original Paper; Physical Chemistry; Resins; Ring structures; Scaffolds; Theoretical and Computational Chemistry
• ISSN: 0026-9247; 1434-4475
• DOI: 10.1007/s00706-020-02614-5

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 Ba 2+ 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