2-Nitro-4-methylsulfonylbenzoic acid
[CAS# 110964-79-9]

Identification

• Classification: Organic raw materials >> Hydrocarbon compounds and their derivatives >> Hydrocarbon nitrite
• Name: 2-Nitro-4-methylsulfonylbenzoic acid
• Synonyms: 4-Methylsulfonyl-2-nitrobenzoic acid
• Molecular Formula: C₈H₇NO₆S
• Molecular Weight: 245.21
• CAS Registry Number: 110964-79-9
• EC Number: 601-017-1
• SMILES: CS(=O)(=O)C1=CC(=C(C=C1)C(=O)O)[N+](=O)[O-]

Properties

• Density: 1.6±0.1 g/cm³, Calc.^*
• Melting point: 211-212 °C (Expl.)
• Index of Refraction: 1.59, Calc.^*
• Boiling Point: 497.8±45.0 °C (760 mmHg), Calc.^*
• Flash Point: 254.9±28.7 °C, Calc.^*

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

Safety Data

• Hazard Symbols: GHS08 Warning
• Risk Statements: H317-H319
• Safety Statements: P261-P264+P265-P272-P273-P280-P302+P352-P305+P351+P338-P321-P333+P317-P337+P317-P362+P364-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Skin sensitization	Skin Sens.	1	H317
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335

Discovery and Applications

2-Nitro-4-methylsulfonylbenzoic acid is an aromatic organic compound with the molecular formula C₈H₇NO₆S. It consists of a benzoic acid core substituted with a nitro group at the 2-position and a methylsulfonyl group at the 4-position of the aromatic ring. The nitro and sulfonyl functionalities significantly influence the compound’s reactivity and chemical behavior, particularly in electrophilic aromatic substitution and nucleophilic aromatic substitution reactions.

The synthesis of 2-nitro-4-methylsulfonylbenzoic acid has been well-documented in the literature. It can be prepared through the sulfonation of 2-nitro-4-methylbenzoic acid followed by oxidation of the methylsulfinyl intermediate to the corresponding methylsulfonyl derivative. This transformation is achieved using strong oxidizing agents such as hydrogen peroxide or peracids under controlled conditions to ensure complete conversion to the sulfone. The nitro group in the ortho position to the carboxylic acid contributes to the overall electron-withdrawing character of the molecule, enhancing its reactivity in further synthetic applications.

2-Nitro-4-methylsulfonylbenzoic acid serves as an important intermediate in pharmaceutical and agrochemical synthesis. The combination of electron-withdrawing groups in its structure allows for selective functionalization and incorporation into more complex molecular frameworks. The nitro group provides a convenient handle for reduction to the corresponding amine, facilitating the formation of aniline derivatives that are commonly used as precursors in drug development. The sulfonyl group is known to enhance aqueous solubility and metabolic stability when incorporated into bioactive molecules.

In medicinal chemistry, sulfonyl-substituted benzoic acids, including derivatives such as 2-nitro-4-methylsulfonylbenzoic acid, are frequently explored for their potential as pharmacophores or building blocks in the design of enzyme inhibitors, anti-inflammatory agents, and antimicrobial compounds. Their role is not necessarily as active agents themselves but as precursors or structural components of more biologically active molecules. Their incorporation can influence the potency, selectivity, and pharmacokinetic properties of the final compounds.

The compound has also been utilized in studies focused on the synthesis of substituted benzoxazoles, benzimidazoles, and other heterocyclic systems. The presence of both a nitro group and a carboxylic acid group on the aromatic ring allows for cyclization reactions under suitable conditions to generate heteroaromatic systems with diverse applications. These heterocycles are known for their wide range of biological activities and have attracted considerable interest in drug discovery and development.

In the context of materials science, sulfonyl-substituted aromatic compounds such as 2-nitro-4-methylsulfonylbenzoic acid have been examined as monomers or functional additives in the development of advanced polymeric materials. The strong electron-withdrawing character of the nitro and sulfonyl groups imparts specific electronic properties to the resulting polymers, which may be of interest in applications such as organic electronics or membrane technologies.

Safety considerations for handling 2-nitro-4-methylsulfonylbenzoic acid are consistent with those for aromatic nitro compounds and sulfonic acid derivatives. It should be managed in accordance with standard laboratory safety protocols, including the use of personal protective equipment and proper waste disposal. Although the compound is stable under normal conditions, the nitro functionality can present risks associated with reduction reactions or high-temperature processing.

2-Nitro-4-methylsulfonylbenzoic acid is therefore recognized in the scientific literature as a valuable intermediate with diverse applications in organic synthesis, particularly in the preparation of functionalized aromatic compounds, heterocycles, and potential pharmacologically active structures. Its role in synthetic organic chemistry is supported by its stability, reactivity, and ability to introduce multiple functional groups into molecular frameworks.

References

2022. Highly selective electrochemical oxidation of 2-nitro-4-methylsulfonyltoluene to 2-nitro-4-methylsulfonylbenzoic acid enabled by molybdate. Journal of Applied Electrochemistry, 53(4), 705-714.
DOI: 10.1007/s10800-022-01805-8

2022. Metal-free catalyzed aerobic oxidation of 2-nitro-4-methylsulfone toluene to 2-nitro-4-methylsulfonylbenzoic acid using a continuous-flow reactor. Journal of Flow Chemistry, 12(3), 275-282.
DOI: 10.1007/s41981-022-00225-1

2017. Iron(II) and copper(II) phthalocyanine-catalyzed synthesis of 2-nitro-4-methylsulfonylbenzoic acid under mild conditions. Journal of Chemical Sciences, 129(10), 1625-1632.
DOI: 10.1007/s12039-017-1373-4