Multi-arm polyethylene glycol derivative, intermediate thereof, and method for producing same

A multi-arm polyethylene glycol derivative represented by the following formula (1):

• m[Z—YnCH2CH2OX—O-L-O—XOCH2CH2nY—Z]m (1)
• wherein L represents a group selected from a linear or branched alkylene, arylene, or cycloalkylene group having two or more carbon atoms and combinations thereof, which may have an ether bond in a chain;
• X represents a dehydroxylation residue of a linear sugar alcohol having 5 or 7 carbon atoms;
• m is the number of polyethylene glycol chains bonded to X and represents 4 or 6;
• n is the average addition molar number of oxyethylene groups and n represents an integer of 3 to 600;
• Y represents a single bond or an alkylene group which may have an ester bond, a urethane bond, an amide bond, an ether bond, a carbonate bond, a secondary amino group, a urea bond, a thioether bond or a thioester bond in a chain or at an end;
• and Z is independently selected from the group consisting of the following formula (a), formula (b), formula (c), formula (d), formula (e), formula (f), formula (g), formula (h), formula (i), formula (j), formula (k), formula (l), formula (m), formula (n), formula (o), and formula (p):
• wherein R represents a hydrocarbon group having 1 to 10 carbon atoms, which may contain a fluorine atom.