S-acetyl-PEG4-t-butyl ester

S-acetyl-PEG4-t-butyl ester is a PEG linker containing a sulfur acetyl group and a t-butyl ester. The sulfur acetyl group can be deprotected to form a thiol group. The t-butyl ester can be removed under acidic conditions. The hydrophilic PEG linker increases the water solubility of compounds in aqueous media.