Methyl 3-phenylpropionate
[CAS# 103-25-3]

Identification

• Classification: Flavors and spices >> Synthetic spice >> Aromatic cinnamic acid, esters and derivatives
• Name: Methyl 3-phenylpropionate
• Synonyms: 3-Phenylpropionic acid methyl ester; Methyl b-phenylpropionate
• Molecular Formula: C₁₀H₁₂O₂
• Molecular Weight: 164.20
• CAS Registry Number: 103-25-3
• EC Number: 203-092-2
• FEMA: 2741
• SMILES: COC(=O)CCC1=CC=CC=C1

Properties

• Density: 1.0±0.1 g/cm³ Calc.^*, 1.045 g/mL (Expl.)
• Boiling point: 238.5 °C 760 mmHg (Calc.)^*, 236 - 239 °C (Expl.)
• Flash point: 100.0 °C (Calc.)^*, 100 °C (Expl.)
• Index of refraction: 1.502 (Calc.)^*, 1.499 - 1.505 (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: S24/25

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2A	H319

Discovery and Applications

Methyl 3-phenylpropionate is an organic ester formed from methanol and 3-phenylpropionic acid. It belongs to the class of aromatic esters characterized by a phenyl-substituted aliphatic chain linked to a methyl ester group. This compound is a colorless to pale yellow liquid with a sweet, floral odor, making it of interest in both chemical research and applied industries such as flavor and fragrance formulation.

The compound was first identified during studies of natural plant-derived volatile substances, as it occurs in certain essential oils and contributes to the pleasant scent of flowers and fruits. In the fragrance industry, methyl 3-phenylpropionate is valued for its resemblance to floral and honey-like aromas, often being used in perfumery compositions and cosmetic products to enhance sweetness and depth of scent. It is also applied in flavoring, imparting fruity and balsamic notes that are used in beverages, confectionery, and baked goods.

In chemical synthesis, methyl 3-phenylpropionate serves as a useful intermediate. Its ester group makes it amenable to hydrolysis, reduction, and transesterification reactions, while the phenylpropyl moiety can undergo a wide range of aromatic substitutions or oxidations. This dual reactivity provides versatility for constructing more complex organic molecules, including pharmaceuticals and agrochemicals. The ester is often employed as a model substrate in studies involving ester hydrolysis and catalytic hydrogenation due to its balance of stability and reactivity.

From a synthetic perspective, methyl 3-phenylpropionate is most commonly prepared by Fischer esterification, in which 3-phenylpropionic acid is refluxed with methanol in the presence of an acid catalyst such as sulfuric acid or p-toluenesulfonic acid. Alternative synthesis routes include transesterification reactions from other esters of 3-phenylpropionic acid, or catalytic esterification using solid acid catalysts, which offer more environmentally benign processes.

Applications extend into material science and chemical research. The compound’s aromatic and ester functionalities make it suitable for mechanistic studies of catalytic processes, as well as for exploring new methodologies in organic synthesis. Furthermore, its natural occurrence in plants and its pleasant odor profile have led to investigations into its ecological roles, particularly as a volatile organic compound contributing to plant–insect interactions and pollinator attraction.

Toxicological evaluations indicate that methyl 3-phenylpropionate has relatively low acute toxicity and is generally considered safe for controlled use in fragrances and flavorings. Nevertheless, as with many esters, its handling requires adherence to standard laboratory safety protocols, including avoidance of prolonged inhalation exposure and direct skin contact.

Methyl 3-phenylpropionate thus holds significance both as a naturally occurring aromatic ester and as a practical synthetic intermediate. Its role in perfumery, food flavoring, and organic chemistry reflects its multifaceted utility, while ongoing research continues to explore its reactivity and potential new applications in chemical and biological systems.

References

2017. Hydrogenation with Palladium Nanoparticles Supported on Magnetic Carbon-Coated Cobalt Nanobeads. Science of Synthesis.
URL: SD-226-00035

2019. Cobalt-Catalyzed Hydrogenation of Olefins in Water. Synfacts.
DOI: 10.1055/s-0039-1690251

2023. The LOTUS Initiative for Open Natural Products Research: frozen dataset union wikidata (with metadata).
DOI: 10.5281/zenodo.5794106