Phenethylamine hydrobromide
[CAS# 53916-94-2]

Identification

• Classification: Chemical reagent >> Organic reagent >> Amine salt (ammonium salt)
• Name: Phenethylamine hydrobromide
• Synonyms: 2-phenylethanamine hydrobromide
• Molecular Formula: C₈H₁₂BrN
• Molecular Weight: 202.09
• CAS Registry Number: 53916-94-2
• EC Number: 811-843-6
• SMILES: C1=CC=C(C=C1)CCN.Br

Properties

• Melting point: 270 ºC (Expl.)

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H315-H319
• Precautionary Statements: P264-P264+P265-P280-P302+P352-P305+P351+P338-P321-P332+P317-P337+P317-P362+P364

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319

Discovory and Applicatios

Phenethylamine hydrobromide (C₈H₁₂NBr) is the hydrobromide salt of phenethylamine, a naturally occurring trace amine found in the central nervous system and in certain plants and foods. The free base phenethylamine is a volatile, oily liquid, but its salt forms, including hydrobromide, provide crystalline solids with enhanced stability and easier handling in laboratory and research contexts. The hydrobromide salt consists of the protonated amine cation (C₆H₅CH₂CH₂NH₃⁺) paired with the bromide anion (Br⁻).

Phenethylamine itself was first identified in the early 20th century as a natural constituent of mammalian tissues. Since then, it has been recognized as a trace amine that plays a modulatory role in the nervous system, particularly through interaction with trace amine-associated receptors. Its physiological role is linked to mood, attention, and stimulation, though in very small concentrations compared to classical neurotransmitters. The preparation of phenethylamine hydrobromide emerged as a practical way to stabilize and crystallize the otherwise unstable free amine for experimental studies.

The hydrobromide salt form is commonly used in chemical and pharmacological research. Its crystalline nature makes it easier to weigh, store, and transport than the free base. This stability has allowed its use as a starting material in the synthesis of numerous derivatives, including sympathomimetic amines, psychoactive compounds, and other structurally related bioactive molecules. Because the phenethylamine backbone is a fundamental chemical scaffold, the salt has been employed to generate a wide range of analogues for medicinal chemistry research.

Crystallographic investigations of phenethylamine hydrobromide have shed light on hydrogen bonding, molecular packing, and cation–anion interactions in organic salts. These studies contribute to a broader understanding of how simple amine salts crystallize, which is relevant to pharmaceutical solid-state chemistry. The hydrobromide salt often serves as a reference compound in comparative studies involving substituted phenethylamines, where structural modifications influence both pharmacological activity and solid-state properties.

In organic synthesis, phenethylamine hydrobromide functions as a precursor for more complex molecules. Its solubility in polar solvents, such as ethanol and water, allows it to be incorporated into various synthetic transformations where controlled release of the amine under basic conditions is desired. Additionally, the presence of bromide as a counterion can affect crystallization behavior, providing advantages in purification and characterization.

From a biochemical perspective, phenethylamine itself is metabolized rapidly in vivo, primarily by monoamine oxidase-B. While the hydrobromide form is not directly used therapeutically, it has been employed in laboratory studies as a stable source of the parent amine. Research into its biological role has highlighted its potential involvement in mood regulation and its structural similarity to more potent neurotransmitters and psychostimulants.

Applications of phenethylamine hydrobromide remain mainly within research and laboratory settings. It does not have widespread industrial or pharmaceutical use in its salt form, but its importance lies in being a manageable, crystalline derivative of a biologically significant amine. By providing a convenient entry point for the study and synthesis of phenethylamine-based compounds, it has contributed to developments in neurochemistry, synthetic organic chemistry, and structural studies.

In summary, phenethylamine hydrobromide is a stable salt form of phenethylamine that has been used primarily in research to facilitate the handling, synthesis, and structural investigation of this key biochemical scaffold. While not itself a therapeutic or industrial product, it plays an enabling role in both chemical and biological research contexts.

References

2022. High-Performance Quasi-Two-Dimensional CsPbBr2.1Cl0.9:PEABr Perovskite Sky-Blue LEDs with an Interface Modification Layer. Nanoscale Research Letters.
DOI: 10.1186/s11671-022-03703-6

2023. 2-Phenethylamines in Medicinal Chemistry: A Review. Molecules (Basel, Switzerland).
DOI: 10.3390/molecules28020855

2024. Gut microbiota-derived tryptamine and phenethylamine impair insulin sensitivity in metabolic syndrome and irritable bowel syndrome. Nature Communications.
DOI: 10.1038/s41467-023-40552-y