tBuO-Ste-Glu(AEEA-AEEA-OH)-OtBu is a specialized chemical side-chain intermediate crucial for the synthesis of the anti-diabetic drug Semaglutide.

Basic Chemical Information
Item Information
CAS Number 1118767-16-0
Common Names Semaglutide Side Chain, Semaglutide Carboxylic Acid Modifier
Molecular Formula C₄₃H₇₉N₃O₁₃ (Note: Slight variations may exist between sources)
Molecular Weight Approximately 846.10 g/mol
Key Structural Features tBuO- (tert-butoxy) and -OtBu (tert-butyl ester): Act as protecting groups for the carboxyl and hydroxyl groups during synthesis to prevent unwanted side reactions.
-Ste- (Stearoyl): A long hydrophobic fatty acid chain that helps the drug bind to serum albumin, thereby prolonging its duration of action in the body.
-Glu- (Glutamic acid) and AEEA units (Aminoethoxyethoxyacetic acid): Provide linkage sites and enhance the molecule's water solubility and stability.
Storage Conditions Recommended to be sealed, stored dry, protected from light at -20°C.
Primary Use Used as a pharmaceutical intermediate specifically for the chemical synthesis of the peptide drug Semaglutide.

Function and Significance
This side chain is the core design element that gives Semaglutide its unique long-acting properties:

Extends Efficacy: The long fatty acid chain (stearoyl) within its structure allows for reversible binding to albumin in the bloodstream, significantly slowing the drug's clearance from the body. This enables Semaglutide to be administered just once a week, greatly improving patient convenience.

Key Synthetic Building Block: In the drug manufacturing process, this side chain is a pre-designed functional module. Chemists attach it precisely to the main peptide chain of Semaglutide via specific reactions, thereby imparting the desired long-acting characteristic to the final drug molecule.