Sodium 3-(N-ethyl-3-methylanilino)propanesulfonate
[CAS 40567-80-4]

Identification

• Classification: Biochemical >> Biochemical reagent >> Biological dye
• Name: Sodium 3-(N-ethyl-3-methylanilino)propanesulfonate
• Synonyms: TOPS; 3-(N-Ethyl-3-methylanilino)propanesulfonic acid sodium salt; TOPS
• Molecular Formula: C₁₂H₁₈NNaO₃S
• Molecular Weight: 279.33
• CAS Registry Number: 40567-80-4
• SMILES: CCN(CCCS(=O)(=O)[O-])C1=CC=CC(=C1)C.[Na+]

Properties

• Solubility: DMSO: 42mg/mL (Expl.)

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319-H332-H335
• Safety Statements: P261-P280-P305+P351+P338

Discovery and Applications

Sodium 3-(N-ethyl-3-methylanilino)propanesulfonate is an organic sulfonate salt composed of a substituted anilino group linked through a three-carbon propanesulfonate chain, present as a sodium salt. The molecule combines an aromatic amine-derived structure with a strongly ionic sulfonate functionality, resulting in a compound with pronounced polarity and water solubility.

The core aromatic portion is a substituted aniline system, consisting of a benzene ring bearing an amino substituent that has been further alkylated. In this case, the nitrogen atom is part of an N-ethyl-3-methylaniline fragment. The benzene ring provides a delocalized π-electron system, while the methyl substituent at the 3-position modifies the electron density and steric environment of the aromatic ring. The ethyl group attached to the nitrogen increases hydrophobic character and reduces the basicity of the amine relative to unsubstituted aniline.

The nitrogen atom is directly bonded to the aromatic ring, forming a tertiary aniline-type structure (N-ethyl-N-aryl amine). The lone pair on nitrogen is partially delocalized into the aromatic ring through resonance, increasing electron density at certain positions of the benzene system and influencing its electronic behavior. However, substitution on the nitrogen reduces the extent of hydrogen bonding compared with primary or secondary anilines.

Attached to the nitrogen through a propyl chain is a sulfonate group at the terminal position, forming a propanesulfonate moiety (–CH₂–CH₂–CH₂–SO₃⁻). The sulfonate group is strongly electron-withdrawing and exists in a fully ionized state under normal conditions. It consists of a sulfur atom bonded to three oxygen atoms in a tetrahedral arrangement, with resonance stabilization distributing negative charge across the oxygen atoms.

The sodium ion acts as a counterion to balance the negative charge of the sulfonate group. In aqueous solution, sodium typically dissociates from the organic anion, resulting in free ions that are solvated by water molecules. The presence of the ionic sulfonate group is the dominant factor governing solubility and intermolecular interactions.

Structurally, the molecule contains both hydrophobic and hydrophilic regions. The aromatic ring and ethyl substituent contribute hydrophobic character, while the sulfonate group provides strong hydrophilicity and ionic character. This amphiphilic nature influences aggregation behavior in solution and interactions with other molecules.

The propyl linker between the aromatic nitrogen and sulfonate group provides flexibility, allowing rotational freedom and spatial separation between the aromatic and ionic domains. This structural feature reduces direct electronic interaction between the sulfonate group and the aromatic ring, meaning their effects on reactivity are largely independent.

From an electronic standpoint, the molecule contains a combination of electron-rich aromatic and amine components and a strongly electron-withdrawing sulfonate group. The nitrogen lone pair participates in resonance donation into the aromatic ring, while the sulfonate group stabilizes negative charge through delocalization across oxygen atoms.

Chemically, the sulfonate group is generally stable and unreactive under mild conditions, serving primarily as a solubilizing and ionic functionality. The aromatic amine portion is more chemically active and can participate in electrophilic aromatic substitution reactions under appropriate conditions, although steric and electronic effects from substitution influence its reactivity.

Overall, sodium 3-(N-ethyl-3-methylanilino)propanesulfonate is a highly functionalized organic sulfonate salt consisting of a substituted tertiary aniline connected via a flexible propyl linker to a strongly ionic sulfonate group. Its structure integrates hydrophobic aromatic character with hydrophilic ionic functionality, resulting in a compound with distinct physicochemical and electronic properties.

References

2024. A free fatty acid determination kit Publication Number: CN-119592659-A Priority Date: 2024-12-26
URL: https://patents.google.com/patent/CN119592659A