| abstract |
The invention relates to a new process for the stereoselective preparation of Gal-α(1-3)/Gal-β(1-4)/GlcNac trisaccharides of the formula ##STR1## and of β(1-3)-linked oligolactosamines of the formula ##STR2## via partially alkylated glycals of the formula ##STR3## and other new intermediate products, wherein, depending on the formula, R is H, R'CH 2 --, or allyl, n R 1 is H, R'CH 2 --, allyl or R'CO--, n R' is H, C 1 to C 3 -alkyl or (un)substituted phenyl, n S is a spacer, preferably of the formula --(CH 2 ) n --COOR'', n R'' is alkyl having 1 to 4 C atoms, n X is N 3 or --NHCOCH 3 , n X is N 3 or --NHCOCH 3 , n Y is β-OSiR 2 3 or α-OC(═NH)CCl 3 , n R 2 is C 1 or C 4 -alkyl or phenyl and n m and n are integers from 1 to 4 or 4 to 12 respectively. |