FACILE PREPARATION AND UTILIZATION OF A NOVEL BETA-D-MANNACA-DONOR - METHYL 2-BENZOYLOXYIMINO-1-BROMO-2-DEOXY-ALPHA-D-ARABINO-HEXOPYRANURONATE

The title beta-D-ManNAcA-donor, the alpha-bromide of methyl 2-benzoyloxyimino-2-deoxy-D-arabino-hexopyranuronate 9, has been prepared from D-glucuronolactone in an overall yield of 21% for the seven steps required, all intermediates being securable in crystalline form. Key compounds were the 2-acetoxy-D-glucuronal ester 6 and its hydroxylaminolysis product, the 1,5-anhydro-D-fructuronate oxime 7, the latter elaborating 9 on O-benzoylation (-->8) and photobromination. -The utility of 9 as a suitable beta-D-ManNAcA donor rests on two ensuing reactions: first, Koenigs-Knorr type glycosidations, with N-blocked 2-aminoethanols as spacer substrates, or with the 6-OH of an otherwise protected glucoside (16), produce beta-selectivities of 20:1 or better, and second, the oxime reduction of the beta-glycosides, thus obtained, proceeds in an essentially stereospecific manner to yield, upon N-acetylation, the 2-acetamido-2-deoxy-beta-D-mannosiduronates. -The methodology elaborated was used to prepare some novel artificial glycolipids, e.g. the (myristoylamino)ethyl 6-O-(2-acetamido-2-deoXy-beta-D-mannopyranosyluronic acid)-alpha-D-glucopyranoside (25) and its (stearoylamino)ethyl analog (26), that are being evaluated as recognition markers for liposomes.