Definition: Esters of the hypothetical imidic acids. They react with amines or amino acids to form amidines and are therefore used to modify protein structures and as cross-linking agents.
methyl 4-mercaptobutyrimidate [ 2-iminothiolane,methyl 4-mercaptobutyrimidate hydrochloride ] used as a cross-linking agent to study ribosomal proteins, by making disulfide linkages; RN given refers to parent cpd; structure