Patent ID: 8846941

Claim:
A compound comprising a water-soluble, non-peptidic, and non-nucleotidic polymer backbone having at least one terminus covalently bonded to a structure of formula (1): or a salt thereof, wherein: A is the point of covalent bonding to the terminus of the polymer backbone; E is O; K is selected from the group consisting of: alkylene, alkyleneoxyalkylene, and oligomeric alkyleneoxyalkylene; G is selected from the group consisting of: hydrogen, alkoxy, and a hydrophobic separation handle; Z 1 and Z 2 are independently O; L is a divalent radical of an alkylene; M is a protected carboxyl moiety; R is selected from the group consisting of: a protecting group and a hydrophobic separation handle; R 1 is absent or a hydrophobic separation handle; and wherein no more than one of R, R 1 , and G is a hydrophobic separation handle.