Hydroxy-PEG-Propionic acid t-butyl ester

Hydroxy-PEG-Propionic acid t-butyl ester is a heterobifunctional reagent featuring a hydroxyl group and a protected tert-butyl ester with an extended spacer, primarily used as an intermediate in multi-step organic synthesis where the ester requires subsequent acidic deprotection to a carboxylic acid for conjugation. Its key advantages include reduced steric hindrance due to the elongated chain, tunable spacer length (n), and protection of the carboxyl group during synthetic steps, though deprotection is necessary for final functionalization.