New aldehyde and vinylsulfone proteasome inhibitors for targeted melanoma therapy

► Synthesis of aldehyde and vinylsulfone proteasome inhibitors. ► Proteasome inhibitors conjugated to the melanin-targeting ligand to target melanoma. ► Influence on the cytotoxicity of the benzamide alkyl side chain length. ► Influence on the cytotoxicity of the composition of the amino acid sequence. ► Cytotoxicity persisted in the presence of a melanin-targeting ligand.