2-Phenylethylamine Hydroiodide
[CAS# 151059-43-7]

Identification

• Classification: Chemical reagent >> Organic reagent >> Amine salt (ammonium salt)
• Name: 2-Phenylethylamine Hydroiodide
• Synonyms: 2-phenylethan-1-amine hydroiodide
• Molecular Formula: C₈H₁₂IN
• Molecular Weight: 249.09
• CAS Registry Number: 151059-43-7
• EC Number: 808-198-8
• SMILES: C1=CC=C(C=C1)CCN.I

Properties

• Melting point: 283 ºC (Expl.)

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H302-H315-H319-H335
• Precautionary Statements: P261-P264-P264+P265-P270-P271-P280-P301+P317-P302+P352-P304+P340-P305+P351+P338-P319-P321-P330-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

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

Discovory and Applicatios

2-Phenylethylamine hydroiodide (C₈H₁₂NI) is a crystalline salt formed from 2-phenylethylamine, a naturally occurring biogenic amine, and hydroiodic acid. The compound consists of the protonated amine cation (C₆H₅CH₂CH₂NH₃⁺) and the iodide anion (I⁻). While the free base 2-phenylethylamine has attracted considerable attention as a trace amine in biological systems and as a chemical building block, its hydroiodide salt is mainly studied in the context of pharmaceutical chemistry, crystallography, and synthetic applications.

The discovery of 2-phenylethylamine dates back to the early 20th century, when it was first identified as a naturally occurring trace amine in the central nervous system. Its salt forms, including hydroiodide, were prepared to stabilize the otherwise volatile free amine, facilitating laboratory handling and storage. The hydroiodide salt exhibits higher crystallinity and stability compared to the free base, which is typically oily and sensitive to atmospheric conditions.

In pharmaceutical and medicinal chemistry, 2-phenylethylamine hydroiodide has been used as a convenient form of the parent amine for synthesis and biological testing. The amine backbone serves as a precursor for numerous derivatives, including sympathomimetic agents, psychoactive compounds, and other bioactive molecules. By isolating it as the hydroiodide salt, researchers gained a reliable solid material that could be weighed and purified more easily than the free amine.

Crystallographic studies of 2-phenylethylamine hydroiodide have provided insight into hydrogen bonding networks, cation–anion interactions, and molecular packing in organic salts. The compound has been examined as part of systematic research into the structural properties of substituted phenylethylamines and their halide salts. Such studies not only clarified the molecular geometry but also helped in understanding solid-state stabilization mechanisms in organic–inorganic salts.

In synthetic organic chemistry, the hydroiodide salt functions as a reagent or intermediate in the preparation of substituted phenylethylamines and related analogues. Its solubility in polar solvents, such as ethanol and water, makes it suitable for reactions where controlled release of the amine under mildly basic conditions is required. Moreover, the presence of iodide as a counterion can sometimes influence reactivity and crystallization behavior in multicomponent systems.

The role of 2-phenylethylamine and its derivatives in biochemistry has further stimulated interest in its stable salts. While the free amine acts as a neuromodulator with affinities for trace amine-associated receptors, its salts, including hydroiodide, provide practical laboratory forms for research. Studies have examined its involvement in neurotransmitter pathways, metabolism by monoamine oxidase, and its structural relationships with more complex biogenic amines such as dopamine.

Applications of 2-phenylethylamine hydroiodide remain largely specialized to research contexts. It is not widely used in industrial processes, but it serves as a model compound in structural chemistry and as a precursor in the synthesis of pharmacologically relevant molecules. Its significance lies less in direct applications and more in its role as a stable, crystalline, and manageable form of a fundamental chemical scaffold with wide-ranging biological and synthetic relevance.

In summary, 2-phenylethylamine hydroiodide represents a useful salt derivative of a biologically important amine. While not itself a widely used drug or industrial reagent, it has contributed to advances in structural chemistry, organic synthesis, and biochemical research through its role as a stable source of 2-phenylethylamine.

References

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2024. Efficient tin-based perovskite solar cells with trans-isomeric fulleropyrrolidine additives. Nature Photonics.
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