Preparation of 6-amino-6-deoxy-D-altronic acid and their derivatives

Abstract

Methyl 6-azido-3,5-di-O-benzoyl-6-deoxy-α- and -β-D-glucofuranosides (IIIandIV), obtained by methanolysis of 1,2-O-isopropylidene derivative II were converted via 2-O-methanesulfonyl esters V and VI to methyl 2,3-anhydro-6-azido-6-deoxy-α- and -β-D-mannofuranosides (VII or VIII, respectively). Epoxide VII when submitted to alkaline hydrolysis gave methyl 6-azido-6-deoxy-α-D-altrofuranoside (IX) exclusively, while epoxide VIII afforded a mixture of methyl 6-azido-6-deoxy-β-D-furanosides of altro (X) and gluco(XI) configuration in a 5 : 4 ratio. Altrofuranosides IX and X were converted to 6-azido-6-deoxy-D-altrose (XII) the oxidation of which with bromine and catalytic reduction with hydrogen afforded amorphous amino acid XIV, characterized as its tetraacetyllactam XVI. The structural changes of the compounds from individual steps of the synthesis were checked by IR and 1H NMR spectra which are discussed.