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Understanding CAS No: 2374-03-0 — 4-Amino-3-Hydroxybenzoic Acid

In the world of organic chemistry, certain compounds quietly play indispensable roles in scientific research and industrial applications. One such compound is 4-Amino-3-hydroxybenzoic acid, identified by its unique CAS number 2374-03-0. Though it may not be a household name, this chemical’s distinctive structure and multifaceted utility make it significant in pharmaceuticals, materials science, and chemical synthesis.

Chemical Identity and Structure

4-Amino-3-hydroxybenzoic acid is an aromatic compound with the molecular formula C₇H₇NO₃ and a molecular weight of 153.14 g/mol. Its structure includes three key functional groups attached to a benzene ring:

• an amino group (-NH₂) at the 4-position,
  
  

• a hydroxyl group (-OH) at the 3-position, and
  
  

• a carboxylic acid group (-COOH).
  
  

This arrangement of substituents imparts unique chemical behavior. The amino and hydroxyl groups are electron-donating, while the carboxyl group is electron-withdrawing — a combination that influences reactivity, acidity, and interactions with other molecules.

Physically, the compound typically appears as a yellow-brown to brown crystalline powder. It has a melting point of about 211–215 °C and a high boiling point (~385 °C), underscoring its robust thermal stability compared with many small organic molecules.

Chemical Properties and Behavior

From a chemical perspective, the presence of both the –NH₂ and –OH groups enhances its hydrogen-bonding capabilities, making the compound reactive in both acid-base chemistry and nucleophilic substitution reactions. The compound is partially soluble in water, but shows greater solubility in organic solvents like chloroform, methanol, and ethanol. These solubility traits are important considerations for lab handling and formulation. 

Due to its mixed functionality, 4-Amino-3-hydroxybenzoic acid can participate in many types of reactions typical of aromatic compounds:

• Acylation and esterification involving the carboxyl group
  
  

• Diazonium coupling due to the amine
  
  

• Oxidation and reduction reactions involving the hydroxyl group
  
  

These characteristics make it a versatile building block in organic synthesis.

Applications in Pharmaceutical Chemistry

One of the most prominent areas where this compound finds use is pharmaceutical synthesis. It is frequently employed as an intermediate in the creation of more complex drug molecules. Its functional groups can be elaborated into diverse chemical frameworks that form the backbone of biologically active compounds. 

Specifically, derivatives of 4-Amino-3-hydroxybenzoic acid are used in the preparation of sphingosine kinase inhibitors, which are studied for potential roles in treating cancer and inflammatory diseases. By serving as a precursor that can be chemically manipulated, the compound contributes to medicinal chemistry programs focused on targeted disease therapies. 

Beyond inhibitors, its scaffold has been adaptable in synthesizing other therapeutic agents where aromatic substitution patterns are crucial for biological activity.

Organic Synthesis and Material Science

Outside pharmaceuticals, this benzoic acid derivative is also valued in organic synthesis more broadly. In research settings, it serves as a precursor for heterocyclic compounds and other functional materials. For example, some studies explore its incorporation into polymer precursors for high-performance materials, taking advantage of its ability to undergo cyclization and ring-forming transformations.

Because the compound’s structure combines both reactivity and rigidity (from the benzene ring), it is also useful in materials chemistry where stable yet modifiable aromatic intermediates are required.

Safety and Handling

Like many laboratory chemicals, 4-Amino-3-hydroxybenzoic acid must be handled with respect for safety. It is generally classified as an irritant — capable of causing irritation to the skin, eyes, and respiratory system. Ingestion may also be harmful. 

Standard laboratory safety practices should be observed when working with this compound:

• Wear appropriate protective equipment (gloves, eye protection).
  
  

• Work in a well-ventilated area or under a fume hood.
  
  

• Avoid inhalation of dust or prolonged skin contact.
  
  

• In case of exposure, rinse thoroughly and seek medical advice if necessary.
  
  

Conclusion

Although 4-Amino-3-hydroxybenzoic acid (CAS 2374-03-0) may not be as widely recognized as some other chemicals, its structural versatility and functional diversity make it important across multiple domains of chemistry. From pharmaceutical synthesis to materials science, this compound continues to prove its value as both a reagent and intermediate. Understanding its properties — chemical, physical, and safety-related — is essential for effectively incorporating it into research and industrial applications.