TABLE 1.

Structures, linker lengths, and antiviral activities of zanamivir dimers 4 to 12^a

^aIn the chemical structure, Ac represents acetyl.

^bFully extended length (in angstroms) (number of bonds) × 1.2 Å (average bond contribution).

^cThe decrease in activity observed with the longer dimers (dimers 11 and 12) may partially reflect the entropic penalty required to uncoil the polyethylene glycol linker.

^dAverage EC₅₀ (±standard deviations) are provided for assays performed three or more times (number in parentheses). No evidence of cytotoxicity was observed at concentrations up to 100 ng/ml for compounds 4 to 12 and at concentrations up to 1,000 ng/ml for compounds 2 and 2a.