m-(Trifluoromethyl)phenylacetic acid
[CAS 351-35-9]

Identification

• Classification: Chemical reagent >> Organic reagent >> Aromatic acid
• Name: m-(Trifluoromethyl)phenylacetic acid
• Synonyms: 3-(Trifluoromethyl)phenylacetic acid
• Molecular Formula: C₉H₇F₃O₂
• Molecular Weight: 204.15
• CAS Registry Number: 351-35-9
• EC Number: 206-511-7
• SMILES: C1=CC(=CC(=C1)C(F)(F)F)CC(=O)O

Properties

• Density: 1.4±0.1 g/cm³ Calc.^*
• Melting point: 76 - 79 °C (Expl.)
• Boiling point: 251.8±35.0 °C 760 mmHg (Calc.)^*
• Flash point: 106.1±25.9 °C (Calc.)^*
• Index of refraction: 1.475 (Calc.)^*

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

Safety Data

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

Hazard Classification

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

chemBlink Chemical Story

m-(Trifluoromethyl)phenylacetic acid, CAS 351-35-9, is more systematically named 2-[3-(trifluoromethyl)phenyl]acetic acid. PubChem records the formula C9H7F3O2 and molecular weight 204.15. Structurally, it combines a phenylacetic-acid side chain with a strongly electron-withdrawing CF3 group at the meta position.

Phenylacetic acids are useful synthetic intermediates because the carboxylic acid can be converted into esters, amides, acid chlorides and other derivatives, while the methylene between aromatic ring and carbonyl provides a different electronic environment from that of benzoic acids. The molecule therefore offers a familiar carboxylic-acid reaction handle attached to a fluorinated aromatic building block.

The trifluoromethyl group is one of the most important motifs in medicinal and agrochemical chemistry. Three fluorine atoms create a strongly electron-withdrawing, lipophilic substituent with high C-F bond stability. Installing CF3 on an aromatic ring can change acidity, membrane partitioning, metabolic behavior and binding interactions. The meta placement in CAS 351-35-9 gives a defined substitution geometry for analogue synthesis.

This compound can consequently serve as an intermediate when chemists want to introduce the 3-(trifluoromethyl)phenethyl/carboxymethyl aromatic motif into a larger structure. Amide formation is especially straightforward conceptually: activate the carboxyl group and couple it with an amine, while the CF3-substituted ring remains intact.

Public sources strongly establish identity and structure but do not justify assigning one dominant end product to this CAS number. Its chemical story is instead that of modular fluorinated synthesis. A carboxylic acid supplies the reaction point; the aromatic CF3 group supplies an electronic and lipophilic design element. Combining the two gives medicinal and fine-chemical chemists a ready-made fragment for building fluorinated analogues.

References:
1. PubChem, 3-(Trifluoromethyl)benzeneacetic acid, CID 67695, CAS 351-35-9.
2. CAS Common Chemistry, CAS 351-35-9.
3. Purser S et al. Fluorine in medicinal chemistry. Chem Soc Rev. 2008;37:320-330.

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