Oligosaccharide-protein conjugates

A method of preparing a compound having the Formula VII:

• wherein:
• R1 is chosen from hydrogen, hydroxyl, optionally substituted lower alkyl, phosphate, sulfate, —OR7, a protecting group, and a saccharide;
• R2, R3, R4, and R5 are each independently chosen from hydrogen, sulfate, hydroxyl, —OR8, a protecting group and a saccharide;
• R6 is chosen from hydroxyl, carboxyl, alkoxycarbonyl, amino, amide, alkyamino, aminoalkyl, aminoxy, hydrazide, hydrazine, and optionally substituted C2-C6 alkyl;
• R7 and R8 are each independently chosen from acetyl and optionally substituted lower alkyl;
• and
• n is an integer from 1 to 10;
• comprising:
• a) treating a compound having the Formula VIII:
• wherein:
• R1 through R5 are as defined above;
• and
• R9 and R10 are chosen from hydrogen and hydroxyl, such that when one of R9 and R10 is hydroxyl, the other is hydrogen;
• with a compound having the Formula R11R12(Sn═O) to form a compound having the Formula IX:
• wherein:
• R1 through R5 are as defined above;
• and
• R11 and R12 are each independently chosen from unsubstituted alkyl, or R11 and R12, taken together, are chosen from unsubstituted alkylene;
• and
• b) treating the compound of Formula IX, optionally in the presence of a metal halide, with a compound having the Formula R6—(CH2)n-L,
• wherein:
• R6 and n are as defined above;
• and
• L is a halogen;
• to form the compound of Formula VII.