Propargyl-PEG4-CH2CH2-Boc is a non-cleavable ADC linker that can be used to synthesize ADC inhibitors of Galectin-3. Propargyl-PEG4-CH2CH2-Boc is a PEG- and Alkyl/ether-based PROTAC linker that can be used in the synthesis of PROTACs.In Vitro: ADCs are comprised of an antibody to which is attached an ADC cytotoxin through an ADC linker.