4-Aminothiophenol
[CAS# 1193-02-8]

Identification

• Classification: Chemical reagent >> Organic reagent >> Thiol/thiophenol
• Name: 4-Aminothiophenol
• Synonyms: 4-Aminobenzenethiol; 4-Mercaptoaniline
• Molecular Formula: C₆H₇NS
• Molecular Weight: 125.19
• CAS Registry Number: 1193-02-8
• EC Number: 214-763-4
• SMILES: C1=CC(=CC=C1N)S

Properties

• Melting point: 37-43 ºC
• Boiling point: 140-145 ºC (16 mmHg)
• Flash point: 113 ºC

Safety Data

• Hazard Symbols: GHS05;GHS07 Danger
• Hazard Statements: H301-H314
• Precautionary Statements: P260-P264-P270-P280-P301+P316-P301+P330+P331-P302+P361+P354-P304+P340-P305+P354+P338-P316-P321-P330-P363-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin corrosion	Skin Corr.	1B	H314
Acute toxicity	Acute Tox.	4	H302
Serious eye damage	Eye Dam.	1	H318
Skin corrosion	Skin Corr.	1C	H314

• Transport Information: UN 3263

Discovory and Applicatios

4-Aminothiophenol, also known as 4-mercaptoaniline, is a chemical compound with the molecular formula C6H7NS. It is characterized by its aromatic ring structure in which an amino group (-NH2) and a thiol group (-SH) are attached to a thiophene ring. 4-Aminothiophenol is a pale yellow to brown solid at room temperature and is slightly soluble in water, but soluble in organic solvents such as ethanol and acetone.

4-Aminothiophenol was first synthesized and characterized for its chemical properties and structure in organic chemistry research. Its discovery stemmed from the study of thiol-containing aromatic compounds and their reactivity in various chemical reactions.

4-Aminothiophenol is a widely used building block in organic synthesis, especially in the preparation of dyes, pharmaceuticals, and fine chemicals. Its amino and thiol functional groups enable it to participate in various reactions, including nucleophilic substitutions, redox reactions, and metal complex formation.

Due to its chemical reactivity and ability to form stable complexes with metals, 4-aminophenol is useful as a precursor in the synthesis of dyes and pigments. It aids in the production of colorants used in textiles, paints, and printing inks.

In biological and biomedical research, 4-aminophenol is used as a chemical probe and modifier due to its ability to bind and modify proteins and enzymes through its thiol group. This property makes it valuable in studies involving protein structure-function relationships and enzyme kinetics.

The thiol group of 4-aminophenol is used in analytical chemistry to detect and quantify metal ions. It forms stable complexes with metals such as mercury, lead, and copper, enabling sensitive detection methods such as colorimetric assays and electrochemical sensors.

4-Aminothiophenol is toxic when ingested, inhaled, or in contact with the skin and should therefore be handled with care. Appropriate safety precautions must be taken when handling this compound, including the use of gloves, goggles, and adequate ventilation.