Increase the degree of activity Single benzene ring, Metabolized easierEGreatly reduce the O-methylation of the catechol hydroxyl groupEntacapone

Entacapone Nitro group-electron withdrawing, stabilize the ionized catechol-COMT complexEntacapone @$#^88…Greatly reduce the extent of O-methylation of the catechol hydroxyl groupMore active than Tolcapone-ethyl groupEntacapone

Nitro group, stabilizing the ionized catechol-COMT complexTolcaponeDifficult to be metabolized, increase toxicity2 benzene ring, extend level of toxicityResponsible for the degree of activityElectron withdrawing,Strongly stabilized the ionized catechol-COMT complex