Method for producing maleimide polyethylene glycol lipid

1 . A method for producing a maleimide polyethylene glycol lipid represented by the following general formula (2), the method comprising:

a reaction step of deprotecting a maleimide polyethylene glycol lipid having a protective group, which is represented by the following general formula (1), by heating the maleimide polyethylene glycol lipid having a protective group in a solvent in the presence of silica gel,

wherein R 1 , R 2 , R 3 , and R 4 are each independently a group selected from a hydrogen atom, an alkyl group, a halogen, a cyano group, a formyl group, an acyl group, a carboxy group, an acyloxy group, and an alkylcarbonyloxymethyl group, n is an integer of 2 to 10 which represents a repeating unit number of a methylene group, m is an integer of 10 to 2000 which represents a repeating unit number of polyethylene glycol, Z represents a group selected from an ether group, a methylene group, and a dimethylvinylidene group, Y is any group represented by the following general formulas (3) to (6):

wherein M represents Na or K, and 1 represents an integer of 1 to 5 which represents a repeating unit number of a methylene group, and

A is a group represented by the following general formula (7) or (8):

wherein R 5 and R 6 are each independently a group selected from a hydrogen atom, a saturated or unsaturated acyl group having 8 to 24 carbon atoms, or a saturated or unsaturated alkyl group having 8 to 24 carbon atoms.

2 . The production method according to claim 1 , wherein R 1 , R 2 , R 3 , and R 4 in the general formula (1) are each independently a hydrogen atom or an alkyl group.

3 . The production method according to claim 1 , wherein A in the general formulas (1) and (2) is a group represented by the formula (7), and R 5 and R 6 are each independently selected from a saturated or unsaturated acyl group having 8 to 24 carbon atoms or a saturated or unsaturated alkyl group having 8 to 24 carbon atoms.

4 . The production method according to claim 1 , wherein Y in the general formulas (1) and (2) is a group represented by the formula (3).

5 . The production method according to claim 1 , wherein n in the general formulas (1) and (2) is an integer of 2 to 6.

6 . The production method according to claim 1 , wherein n in the general formulas (1) and (2) is 2.

7 . The production method according to claim 1 , wherein m in the general formulas (1) and (2) is an integer of 20 to 150.