3-Fluoro-4-(methylsulfonamido)benzoic Acid: Properties & Uses
3-Fluoro-4-(methylsulfonamido)benzoic Acid: Properties & Uses
3-Fluoro-4-(methylsulfonamido)benzoic acid is a fluorinated aromatic carboxylic acid bearing a methylsulfonamido substituent, widely employed as a versatile synthetic building block in medicinal chemistry and pharmaceutical research.
- Chemical Name
- 3-Fluoro-4-(methylsulfonamido)benzoic acid
- SKU
- F692728
- Functional Groups
- Carboxylic acid, sulfonamide (–NHSO₂CH₃), aryl fluoride
- Molecular Formula
- C₈H₈FNO₄S
- Primary Application
- Synthetic building block for drug discovery and medicinal chemistry
- Key Structural Features
- ortho-fluorine and para-carboxylic acid on a sulfonamide-substituted benzene ring
Chemical Structure and Properties
3-Fluoro-4-(methylsulfonamido)benzoic acid features a benzene ring substituted at the 3-position with a fluorine atom, at the 4-position with a methylsulfonamido group (–NHSO₂CH₃), and at the 1-position with a carboxylic acid moiety. This combination of electron-withdrawing groups confers distinct physicochemical characteristics to the molecule.
The fluorine substituent increases the lipophilicity profile and metabolic stability of derived compounds, while simultaneously influencing the acidity of the carboxylic acid through inductive effects. The methylsulfonamido group is a bioisostere frequently employed in drug design to improve aqueous solubility, hydrogen-bonding capacity, and membrane permeability of final drug candidates. Together, these functional groups make this compound a multifunctional scaffold for structure–activity relationship (SAR) studies.
The carboxylic acid functionality enables straightforward coupling reactions, including amide bond formation, esterification, and coordination chemistry, expanding its utility across a broad range of synthetic transformations.
Applications in Medicinal Chemistry and Drug Discovery
3-Fluoro-4-(methylsulfonamido)benzoic acid serves as a key intermediate and building block in the synthesis of biologically active molecules. Compounds incorporating both fluorinated aromatic and sulfonamide motifs are of significant interest in the pharmaceutical industry due to their demonstrated ability to modulate enzyme and receptor targets.
The carboxylic acid handle allows researchers to form amide bonds with amine-containing pharmacophores via standard coupling reagents such as EDC/HOBt, HATU, or thionyl chloride, enabling rapid library synthesis for high-throughput screening campaigns. The fluorine atom at the 3-position can also participate in directed metalation reactions, facilitating further functionalization of the aromatic ring.
Sulfonamide-containing benzoic acid derivatives are reported in the literature as scaffolds for inhibitors targeting carbonic anhydrases, kinases, and other therapeutically relevant enzymes. This compound's dual functionality makes it especially attractive for fragment-based drug discovery (FBDD) and lead optimization workflows.
Handling, Storage, and Safety Considerations
As with all aromatic sulfonamide and fluorinated carboxylic acid reagents, appropriate personal protective equipment (PPE) should be worn when handling 3-Fluoro-4-(methylsulfonamido)benzoic acid. This includes chemical-resistant gloves, safety goggles, and a lab coat. Operations should be performed in a well-ventilated fume hood to minimize inhalation exposure to fine particulates or aerosols.
The compound should be stored in a cool, dry location away from strong bases, strong oxidizing agents, and moisture to preserve its chemical integrity. A sealed container stored at room temperature or under refrigeration (2–8 °C) is recommended to prevent hydrolysis of the sulfonamide functionality and to maintain long-term stability.
Researchers should consult the Safety Data Sheet (SDS) provided by Aladdin Scientific for comprehensive hazard classifications, first-aid measures, and disposal guidance prior to use. Waste disposal must comply with applicable local regulations for chemical waste management.
Recommended Synthetic Protocols and Reaction Conditions
When employing 3-Fluoro-4-(methylsulfonamido)benzoic acid in amide coupling reactions, commonly used activating agents include HATU (1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate) and EDC·HCl in the presence of HOBt or HOAt. Reactions are typically conducted in polar aprotic solvents such as DMF or NMP, with a non-nucleophilic base (e.g., DIPEA or triethylamine) at 0 °C to room temperature for 1–16 hours.
For esterification, activation with thionyl chloride to generate the corresponding acid chloride, followed by reaction with the appropriate alcohol in the presence of a base, provides esters in good yield. Alternatively, Fischer esterification conditions (concentrated H₂SO₄ catalyst, reflux in alcohol solvent) may be applicable depending on the substrate scope.
Nucleophilic aromatic substitution (SNAr) reactions may exploit the activated aryl fluoride position under forcing conditions with strongly nucleophilic amines or thiolates, allowing further diversification of the aromatic scaffold. Researchers are advised to optimize reaction conditions based on the specific amine or nucleophile employed.
Frequently asked questions
What is the primary use of 3-Fluoro-4-(methylsulfonamido)benzoic acid in research?
It is primarily used as a synthetic building block and pharmaceutical intermediate in medicinal chemistry, enabling construction of sulfonamide- and fluorine-containing drug candidates through amide coupling, esterification, and nucleophilic aromatic substitution reactions.
How should 3-Fluoro-4-(methylsulfonamido)benzoic acid (SKU F692728) be stored to maintain stability?
The compound should be stored in a sealed container in a cool, dry place, away from moisture, strong bases, and oxidizing agents. Refrigeration at 2–8 °C is recommended for long-term storage to prevent degradation of the sulfonamide group.
Can the aryl fluoride in 3-Fluoro-4-(methylsulfonamido)benzoic acid undergo nucleophilic aromatic substitution?
Yes, the aryl fluoride at the 3-position is activated by the adjacent electron-withdrawing carboxylic acid and sulfonamide groups, making it susceptible to nucleophilic aromatic substitution (SNAr) under appropriate forcing conditions with strong nucleophiles such as amines or thiolates.
What coupling reagents are recommended for amide bond formation using this compound?
Commonly recommended coupling reagents include HATU, EDC·HCl (with HOBt or HOAt as additive), and thionyl chloride for acid chloride formation. Reactions are typically run in DMF or NMP with a non-nucleophilic base such as DIPEA or triethylamine.
References
- Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry, 2nd ed.; Oxford University Press: Oxford, 2012. (General reference for amide coupling and aromatic substitution reactions)
- Böhm, H.-J. et al. Fluorine in medicinal chemistry. ChemBioChem 2004, 5, 637–643. (General reference on fluorine in drug design) doi:10.1002/cbic.200301023
- Supuran, C. T. Carbonic anhydrases: novel therapeutic applications for inhibitors and activators. Nat. Rev. Drug Discov. 2008, 7, 168–181. (General reference on sulfonamide inhibitors) doi:10.1038/nrd2467
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