合成路线1

The condensation of 3,4,6-O-tribenzyl-D-galactopyranose (I) with tridecyltriphenylphosphonium bromide (II) by treating first (I) with NaIO4 in aqueous ethanol, and then the resulting product with (II) and butyllithium in THF, gives the partially benzylated unsaturated tetraol (III), which is reduced with H2 over Pd/C in THF to the corresponding saturated compound (IV). The mesylation of (IV) with mesyl chloride and pyridine yields the mesylate (V), which by reaction with sodium azide in DMF is converted into the azido compound (VI). The reduction of (VI) with H2 over Pd/C in THF affords the corresponding amine (VII), which is acylated with hexacosanoic acid (VIII) by means of 2-chloro-1-methylpyridinium iodide (CMPI) in refluxing dichloromethane to give the amide (IX). The debenzylation of (IX) by hydrogenation with H2 over Pd/C in THF/propanol yields the trihydroxylated amide (X), which is selectively triphenylmethylated at the primary alcohol with trityl chloride and dimethylaminopyridine (DMAP) yielding the monotrityl derivative (XI). The subsequent protection of the secondary hydroxy groups with benzoyl chloride and DMAP affords the monotrityl dibenzoate derivative (XII), which is selectively deprotected with p-toluenesulfonic acid in methanol/water yielding the primary alcohol (XIII). The condensation of (XIII) with 2,3,4,6-O-tetrabenzyl-D-galactopyranosyl fluoride (XIV) by means of SnCl2 and AgClO4 in THF gives the fully protected final product (XV), which is first debenzylated by hydrogenation with H2 over Pd in ethyl acetate to the dibenzoate (XVI). Finally, this compound is debenzoylated by hydrolysis with sodium methoxide in methanol/THF.