3-Amino-4-methylphenol: Properties, Uses & Lab Guide

3-Amino-4-methylphenol is a bifunctional aromatic compound bearing both an amino group and a hydroxyl group on a methyl-substituted benzene ring, making it a valuable intermediate in organic synthesis, dye chemistry, and pharmaceutical research.

IUPAC Name

3-amino-4-methylphenol

Molecular Formula

C₇H₉NO

Molecular Weight

123.15 g/mol

CAS Number

2836-00-2

Functional Groups

Primary aromatic amine (–NH₂) and phenol (–OH)

SKU (Aladdin Scientific)

A183421

Chemical Structure and Physical Properties

3-Amino-4-methylphenol (CAS 2836-00-2) is an aromatic compound with the molecular formula C₇H₉NO and a molecular weight of approximately 123.15 g/mol. Its structure consists of a benzene ring substituted with a hydroxyl group at position 1, an amino group at position 3, and a methyl group at position 4. The simultaneous presence of the electron-donating amino (–NH₂) and hydroxyl (–OH) groups imparts high reactivity toward electrophilic aromatic substitution and condensation reactions.

The compound typically appears as a solid at room temperature. Both the amino and hydroxyl functionalities allow this molecule to engage in hydrogen bonding, influencing its solubility in polar solvents such as water, ethanol, and methanol. The methyl substituent at position 4 introduces steric and electronic effects that can direct regioselectivity in downstream reactions, distinguishing it from related isomers such as 2-amino-4-methylphenol or 4-amino-3-methylphenol.

Synthesis Relevance and Reactivity

The bifunctional nature of 3-Amino-4-methylphenol makes it an important building block in organic synthesis. The amino group can participate in diazotization reactions to form diazonium salts, which are key intermediates in the synthesis of azo dyes and coupling products. The hydroxyl group can undergo O-alkylation or O-acylation under appropriate conditions, enabling diversification of the molecular scaffold.

This compound can also serve as a starting material or intermediate for the preparation of benzoxazole and benzimidazole heterocyclic frameworks, which are pharmacologically relevant scaffolds found in numerous bioactive molecules. Additionally, the presence of both nucleophilic sites makes it useful in condensation reactions with carbonyl compounds, anhydrides, and acid chlorides to produce amide, ester, or Schiff base derivatives.

Researchers working in medicinal chemistry, materials science, or dye synthesis should consider the reactivity of both functional groups when designing reaction sequences, ensuring appropriate protection or selective activation strategies are employed.

Laboratory Applications and Research Uses

3-Amino-4-methylphenol finds application across several research domains. In the dye and pigment industry, it serves as a coupling component or intermediate in the manufacture of azo dyes, where the amino group participates in diazo coupling reactions to produce colored products with defined spectral properties.

In pharmaceutical and medicinal chemistry research, this aminophenol derivative is used as a synthetic precursor for the preparation of heterocyclic compounds, including benzoxazoles and related nitrogen-containing ring systems with potential biological activity. The compound's dual reactive sites offer chemists flexibility in constructing complex molecular architectures.

In materials science and polymer chemistry, aminophenol derivatives like 3-Amino-4-methylphenol have been investigated as monomers or chain extenders in the synthesis of polyamides, epoxy resin curing agents, and conducting polymer precursors. Researchers in analytical chemistry may also use it as a reference standard or reagent in colorimetric assays and sensor development.

Handling, Storage, and Safety Considerations

As with most aromatic amine and phenol-containing compounds, 3-Amino-4-methylphenol should be handled with appropriate laboratory precautions. Personnel should wear suitable personal protective equipment (PPE) including chemical-resistant gloves, safety goggles, and a laboratory coat when handling this reagent. Operations that may generate dust or aerosols should be conducted in a well-ventilated fume hood.

The compound should be stored in a tightly sealed container, away from strong oxidizing agents, strong acids, and strong bases, which can react with both the amino and hydroxyl functionalities. Storage in a cool, dry location away from direct light is recommended to maintain reagent integrity over time. Users should consult the current Safety Data Sheet (SDS) provided by Aladdin Scientific for comprehensive hazard information, first-aid measures, and disposal guidelines before use.

Waste disposal must comply with local and institutional regulations governing aromatic amines and phenolic compounds. Avoid release to drains or the environment.

Frequently asked questions

What is 3-Amino-4-methylphenol used for in research?

3-Amino-4-methylphenol is primarily used as a synthetic intermediate in organic chemistry, including the preparation of azo dyes, heterocyclic compounds such as benzoxazoles, and pharmaceutical building blocks. It is also investigated in materials science as a monomer or chain extender in polymer synthesis.

How should 3-Amino-4-methylphenol be stored to maintain its stability?

The compound should be stored in a tightly sealed container in a cool, dry location away from direct light, strong oxidizing agents, strong acids, and strong bases. These precautions help prevent degradation of the amino and hydroxyl functional groups over time.

What makes 3-Amino-4-methylphenol different from other aminomethylphenol isomers?

The specific arrangement of the amino group at position 3 and the methyl group at position 4, relative to the hydroxyl group at position 1, gives 3-Amino-4-methylphenol a unique electronic and steric profile. This distinct substitution pattern influences its regioselectivity in reactions and its physicochemical properties compared to isomers such as 2-amino-4-methylphenol or 4-amino-3-methylphenol.

Is 3-Amino-4-methylphenol soluble in common laboratory solvents?

Due to its amino and hydroxyl groups, 3-Amino-4-methylphenol is expected to show good solubility in polar protic solvents such as water, ethanol, and methanol. Solubility in less polar organic solvents may be limited. Users should verify solubility experimentally under their specific conditions.

References

1. March, J. Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, 4th ed.; Wiley-Interscience: New York, 1992.
2. Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry, 2nd ed.; Oxford University Press: Oxford, 2012.
3. Aladdin Scientific. Product Page: 3-Amino-4-methylphenol, SKU A183421. Aladdin Scientific, 2024.

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