Multi-arm single molecular weight polyethylene glycol active derivative and application thereof

A multi-arm single molecular weight polyethylene glycol active derivative having the following structure:

• wherein A is a core structure, and is a polyol group selected from the group consisting of pentaerythritol, oligo-pentaerythritol, glycerol and oligoglycerol, or a glyceryl ether group thereof,
• X1 is a linking group selected from any one or a combination of two or more of the group consisting of —(CH2)i—, —(CH2)iO—, —(CH2)iNHCO—, —(CH2)iCONH—, —(CH2)iOCO—, and —(CH2)iCOO—, and i is an integer from 1 to 10,
• R is a linking group selected from any one or a combination of two or more of the group consisting of —NHCO—, —CONH—, —OCO—, —COO—, and —O—,
• X2 is a linking group selected from any one or a combination of two or more of the group consisting of —(CH2)j—, —(CH2)jO—, —(CH2)jCO—, —(CH2)jNH—, —(CH2)jNHCO—, —(CH2)jCONH—, —(CH2)jOCO— and —(CH2)jCOO—, and j is an integer from 0 to 10,
• PEG has the following structure:
• —(CH2CH2O)m—, m is an integer from 8 to 200, and
• F is the same or different —X3—Z type structure,
• X3 is a linking group selected from any one or a combination of two or more of the group consisting of —(CH2)k—, —(CH2)kO—, —(CH2)kCO—, —(CH2)kNH—, —(CH2)kNHCO—, —(CH2)kCONH—, —(CH2)kNHCONH—, —(CH2)kOCO—, —(CH2)kCOO—, —(CH2)kOCOO— and —(CH2)kOCONH—, and k is an integer from 0 to 10,
• Z is an active terminal group selected from any one of the group consisting of —H and
• and
• n is an integer from 3 to 24.