Synthesis of p-trifluoroacetamidophenyl 2-acetamido-4-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-2-deoxy- beta-D-mannopyranosiduronic acid, an artificial antigen corresponding to a disaccharide repeating unit of the capsular polysaccharide of Haemophilus influenzae type e.
