In accordance with a synthesis scheme shown in FIG. 3, a description will be made about one example of a process for the production of a compound of the formula (1) in which Q, Q??? and D3 are each a hydrogen atom, D4 is ???COOCH3, D1 and D2 are each a substituent group represented by the formula (3), D1 and D2 are the same, X is ???C6H12???NHCO???, Y is a PEG residual group, and Z is ???O??? {met