Functionalized polymers

1. A method of making 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 is O;

Z 2 is O;

L is selected from the group consisting of: a divalent radical of a nucleoside, alkylene, alkyleneoxyalkylene, oligomeric alkyleneoxyalkylene, and unsubstituted and substituted arylene;

M is a protected group that when deprotected is reactive with a biologically active molecule, a group reactive with a biologically active molecule;

R is absent or selected from the group consisting of: hydrogen, a protecting group, a hydrophobic separation handle, or an activating group;

R 1 is absent or a hydrophobic separation handle;

wherein when M is a protected group that when deprotected is reactive with a biologically active molecule, then R is a protecting group or a hydrophobic separation handle;

wherein when M is a group reactive with a biologically active molecule, R is absent, hydrogen, or an activating group; and

wherein only one of R, R 1 , and G can be a hydrophobic separation handle,

said method comprising:

a) contacting a water-soluble, non-peptidic, and non-nucleotidic polymer, in a water-free solvent, with a reagent of formula (4):

wherein:

R 5 and R 6 independently from each other represent C 1 -C 6 -alkyl or R 5 and R 6 jointly form a 5- or 6-membered ring with the N to which they are bonded; and

K, G, Z 1 , Z 2 , L, M, R, and R 1 are as defined for formula (1);

b) adding an activating reagent; and

c) adding an oxidizing reagent, wherein the P is oxidized from P +3 to P +5 ,

to obtain the compound comprising the water-soluble, non-peptidic, and non-nucleotidic polymer backbone having at least one terminus covalently bonded to the structure of formula (1).

2. The method of claim 1 , wherein R is a protecting group.

3. The method of claim 2 , wherein the method further comprises purifying the protected polymer by chromatography.

4. The method of claim 3 , wherein the method further comprises removing the protecting group.

5. The method of claim 1 , wherein said activating reagent is selected from the group consisting of: tetrazole, 2-ethylthiotetrazole, 2-bezylthiotetrazole, 4,5-dicyanoimidazole, Activator 42, pyridinium hydrochloride, and pyridinium trifluoroacetate.

6. The method of claim 1 , wherein said oxidizing reagent is selected from a group consisting of: iodine, hydrogen peroxide, t-butyl hydrogen peroxide, acetone peroxide, sulfur, and thiuram disulfide.

7. The method of claim 1 , wherein the ratio of the polymer to the compound of formula (4) is from about 1:10 to about 10:1.

8. The method of claim 1 , wherein said polymer backbone is selected from the group consisting of poly(alkylene glycol), poly(oxyethylated polyol), poly(olefinic alcohol), poly(α-hydroxy acid), poly(vinyl alcohol), polyoxazoline, and copolymers.

9. The method of claim 8 , wherein said polymer backbone is poly(ethylene glycol).

10. The method of claim 9 , wherein said poly(ethylene glycol) has an average molecular weight from about 500 Da to about 100,000 Da.

11. The method of claim 1 , wherein said group reactive with a biologically active molecule is selected from the group consisting of: hydroxyl, amine, thiol, carboxyl, aldehyde, glyoxal, dione, alkenyl, alkynyl, alkedienyl, azide, acrylamide, vinyl sulfone, hydrazide, aminoxy, maleimide, dithiopyridine, iodoacetamide.

12. The method of claim 1 , wherein K is selected from the group consisting of: methylene, ethylene, propylene, isopropylene, butylene, isobutylene, sec-butylene, tert-butylene, and hexylene, or a residue from diethylene glycol, triethylene glycol, tetraethylene glycol or hexaethylene glycol.

13. The method of claim 1 , wherein G is a substituted or unsubstituted trityloxy.

14. The method of claim 1 , wherein L is a substituted or unsubstituted C 1 -C 12 alkylene.

15. The method of claim 1 , wherein R is selected from the group consisting of: trityl, monoalkoxytrityl, dialkoxytrityl, pixyl, alkoxypixyl, fluorenylmethyloxycarbonyl, trifluoroacetyl, acetal, and cyclic acetal.

16. The method of claim 1 , wherein said group reactive with a biologically active molecule is carboxyl and R is absent or selected from the group consisting of: chlorotrityl, trityl, N-hydroxysuccinimidyl, p-nitrophenyl, pentachlorophenyl, and an unsubstituted C 1 -C 18 alkyl.