Methyl 3,4-dibromo-2,5-dioxo-2,5-dihydro-1H-pyrrole-1-carboxylate

Methyl 3,4-dibromo-2,5-dioxo-2,5-dihydro-1H-pyrrole-1-carboxylate is a small pyrrolidone molecule which features two bromine atoms and a methyl ester. The unsaturated dibromo motif is a covalent ligand for thiol groups, and may be used to label cysteine residues in proteins. The presence of two leaving groups on this molecule allows this linker to bind two thiols at a time. The methyl ester can be saponified to link this molecule to amines to form larger structures.