Method for inhibiting sialidase activity

A method for inhibiting sialidase activity comprising contacting sialidase with a compound of Formula I ##STR8## wherein R is H or C.sub.1 to C.sub.20 hydrocarbyl or substituted hydrocarbyl;

• R.sup.1 is H, a C.sub.1 to C.sub.20 alkyl, a mono, di or polyvalent cation of an alkali metal, alkaline earth metal or transition metal, or an ammonium or substituted ammonium ion;
• X is O, S, CR.sup.4 R.sup.5 or NR.sup.6, wherein R.sup.4, R.sup.5, R.sup.6 are each independently H or a C.sub.1 to C.sub.20 hydrocarbyl or substituted hydrocarbyl;
• R.sup.2 is a C.sub.1 to C.sub.20 hydrocarbyl or substituted hydrocarbyl;
• R.sup.3 and R.sup.3' are H, OH, a C.sub.1 to C.sub.20 alkoxy or substituted alkoxy, a mono, di or oligosaccharide, or a C.sub.1 to C.sub.20 alkylideneoxy taken together with R.sup.7' when R.sup.7' is not H;
• provided that one of R.sup.3 or R.sup.3' must be H but R.sup.3 and R.sup.3' may not both be H;
• R.sup.7 and R.sup.7' are independently H, a C.sub.1 to C.sub.20 acyl, a C.sub.1 to C.sub.20 alkyl, or a C.sub.1 to C.sub.20 alkylidene taken together with an adjacent R.sup.3', R.sup.7 or R7';
• and
• R.sup.8 is H, a C.sub.1 to C.sub.20 acyl, or a C.sub.1 to C.sub.20 alkyl.