Dopamine (C₈H₁₁NO₂) — Properties, Uses & Safety

Overview

Dopamine (C8H11NO2) is a neurotransmitter and catecholamine with a molar mass of 153.18 g/mol. Its IUPAC name, 4-(2-aminoethyl)benzene-1,2-diol, describes its structure: a catechol ring (a benzene ring with two adjacent hydroxyl groups) attached to an ethylamine side chain. At standard conditions, dopamine is a white to off-white crystalline solid. In the human body, dopamine is synthesized from the amino acid tyrosine through a two-step enzymatic process and functions as one of the most important neurotransmitters in the brain. It plays central roles in reward and motivation (the feeling of pleasure when achieving a goal), motor control (coordinating smooth, purposeful movements), learning and memory, and attention and focus. Dopamine dysfunction is implicated in several major neurological and psychiatric conditions. Parkinson's disease results from the progressive loss of dopamine-producing neurons in the substantia nigra, leading to tremors, rigidity, and difficulty initiating movement. Schizophrenia is associated with excessive dopamine signaling in certain brain pathways. Addiction involves the hijacking of dopamine reward circuits by drugs, alcohol, or compulsive behaviors. The GHS hazard code H302 (harmful if swallowed) applies to dopamine as a chemical reagent. Dopamine itself cannot cross the blood-brain barrier, so L-DOPA (its biosynthetic precursor) is used as a medication for Parkinson's disease. For chemistry students, dopamine is an engaging molecule that bridges organic chemistry and neuroscience. Its catechol and amine functional groups connect to lessons on aromatic chemistry, hydrogen bonding, and acid-base behavior (dopamine is amphoteric). The biosynthesis of dopamine from tyrosine illustrates enzymatic reactions and the role of cofactors. Understanding how dopamine's molecular structure enables it to bind to specific receptors introduces concepts of molecular recognition, lock-and-key models, and the chemical basis of behavior and emotion.

IUPAC Name

4-(2-aminoethyl)benzene-1,2-diol

CAS Number

51-61-6

PubChem CID

681

Molecular Formula

C₈H₁₁NO₂

Molar Mass

153.179 g/mol

State at STP

solid

Appearance

White to off-white crystalline solid