2) The acylation of the amine group of benzyl 2-amino-2-deoxy-4,6-O-isopropylidene-beta-D-glucopyranoside (IX) with 3(S)-hydroxytetradecanoic acid (II) by means of pivaloyl chloride in THF gives the corresponding amide (X), which is acylated with 9-phenylnonanoic acid (IV), 2-chloro-1-methylpyridinium iodide (CMPI) and dimethylaminopyridine to yield the fully esterified compound (XI). Elimination of the isopropylidene group of (XI) with acetic acid/water affords the dihydroxy compound (XII), which is treated with tert-butyldimethylsilyl chloride and DMAP to give (XIII) with the primary OH-group protected with a TBDMS group. Elimination of the benzyl protecting group of (XIII) by hydrogenation as before gives 2-deoxy-6-O-(tert-butyldimethylsilyl)-3-O-(9-phenylnonanoyl)-2-[3(S)-(9-phenylnonanoyloxy)tetradecanamido]-D-glucopyranose (XIV), which is sulfonated with SO3/pyridine complex in pyridine yielding the 4-O-sulfonated compound (XV). Finally, this compound is desilylated by means of acetic acid in methanol.
1) The reaction of benzyl 2-amino-4,6-O-benzylidene-2-deoxy-alpha-D-glucopyranoside (I) with 3(S)-hydroxytetradecanoic acid (II) by means of pivaloyl chloride in THF gives the corresponding amide (III), which is acylated with 9-phenylnonanoic acid (IV), dimethylaminopyridine (DMAP) and triethylamine (or tetramethylurea and oxalyl chloride) yielding the fully esterified compound (V). Elimination of the benzylidene group of (V) with HBF4/NaBF4 and the benzyl group by hydrogenolysis with H2 over Pd/C affords the trihydroxy compound (VI), which is treated with tert-butyldimethylsilyl chloride (TBDMS-Cl) and pyridine to give (VII) with the primary OH-group protected with a TBDMS group. The sulfonation of (VII) with SO3/pyridine complex affords the sulfonated compound (VIII), which is finally desilylated with acetic acid in ethanol.