Synthesis of 3,6-dideoxy-3-(methylamino)hexoses for g.l.c.-m.s. identification of Rhizobium lipopolysaccharide components.
A direct synthetic route from methyl alpha-D-glucopyranoside to 3,6-dideoxy-3-(methylamino)hexoses having the D-gluco, D-galacto, and D-manno configurations has been developed. Methyl alpha-D-glucoside was converted into the 4,6-O-benzylidene-2,3-di-O-tosyl derivative, which was then transformed into the 4-O-benzyl-6-deoxy 2,3-ditosylate (5) by successive reductive cleavage of the acetal ring, iodination, and reduction. The intermediate 5 was readily converted into the allo 2,3-epoxide, which yielded the pivotal intermediate methyl 4-O-benzyl-3,6-dideoxy-3-(methylamino)-alpha-D-glucopyranoside (7) by cleavage of the oxirane ring with methylamine. The amino compound 7 can be directly converted into the derivatized galacto and manno derivatives for mass-spectrometric identification by selective inversion at C-4 and C-2, respectively, followed by hydrolysis, reduction, and acetylation.
D000606:Amino Sugars / Q000138:chemical synthesis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006601:Hexoses / Q000138:chemical synthesis*; D007202:Indicators and Reagents; D008070:Lipopolysaccharides; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009904:Optical Rotation; D012231:Rhizobium / Q000032:analysis*
D000606:Amino Sugars; D006601:Hexoses; D007202:Indicators and Reagents; D008070:Lipopolysaccharides