| abstract |
Sialic acid derivs., having an active carbonyl gp. of formula (I), amino-cpd. coupled sialic acid derivs. of formula (II), biological half-life extending agents for physiologically active materials comprising (I), and binder for affinity chromatography coupling gels comprising (I), are new, where R1 = H or Ac; R2 = H, a metal or lower alkyl; R2' = H, Na or lower alkyl; R3 = H, OH or active ester alcohol residue; X = residue of an amino cpd. having m reacted NH2 gps.; m = 1-60; and n = 1-20. Pref. X = residue of an amino acid, peptide or protein, or conjugated protein also contg. a prosthetic gp. |