2-Thiophenecarboxylic acid
[CAS# 527-72-0]

Identification

• Classification: Pharmaceutical intermediate >> Heterocyclic compound intermediate >> Thiophene compound
• Name: 2-Thiophenecarboxylic acid
• Synonyms: Thiophene-2-carboxylic acid; 2-Thenoic acid
• Molecular Formula: C₅H₄O₂S
• Molecular Weight: 128.14
• CAS Registry Number: 527-72-0
• EC Number: 208-423-4
• SMILES: C1=CSC(=C1)C(=O)O

Properties

• Melting point: 126-130 °C
• Boiling point: 260 °C
• Water solubility: 80 g/L (20 °C)

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319-H335
• Safety Statements: P261-P264-P270-P271-P280-P301+P312-P302+P352-P304+P340-P305+P351+P338-P330-P332+P313-P337+P313-P362-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2	H319
Eye irritation	Eye Irrit.	2A	H319
Acute toxicity	Acute Tox.	4	H302
Skin corrosion	Skin Corr.	1B	H314

Discovery and Applications

2-Thiophenecarboxylic acid, with the chemical formula C6H5O2S, is an aromatic carboxylic acid featuring a thiophene ring. This compound is distinguished by its carboxyl group (-COOH) attached to the second carbon of the thiophene ring, which positions it as a versatile building block in organic synthesis and materials science.

The discovery of 2-thiophenecarboxylic acid is rooted in the broader exploration of thiophene derivatives and their applications. Thiophene, a five-membered aromatic heterocycle with a sulfur atom, has been known for its distinct chemical properties and is a key component in various chemical reactions. The introduction of a carboxyl group into the thiophene ring enhances its reactivity and opens new avenues for chemical transformations. The synthesis of 2-thiophenecarboxylic acid typically involves the carboxylation of thiophene using carbon dioxide and a suitable catalyst, or through other methods such as oxidation of thiophene derivatives.

In organic synthesis, 2-thiophenecarboxylic acid serves as an important intermediate for the preparation of various thiophene-based compounds. Its carboxyl group allows for further functionalization, making it useful in the synthesis of esters, amides, and other derivatives. This versatility is particularly valuable in the development of pharmaceuticals, agrochemicals, and other specialty chemicals. For instance, 2-thiophenecarboxylic acid can be converted into 2-thiophenecarboxamides, which have applications in medicinal chemistry as potential drug candidates.

Additionally, 2-thiophenecarboxylic acid finds applications in materials science. Its ability to participate in polymerization reactions makes it useful in the synthesis of thiophene-based polymers and copolymers. These materials are of interest due to their electronic properties, which are beneficial for applications in organic electronics, including organic semiconductors and conductive polymers. The incorporation of thiophene rings into polymer structures can enhance their electrical conductivity and stability, making them suitable for various electronic devices.

In summary, 2-thiophenecarboxylic acid is a valuable compound in organic synthesis and materials science. Its role as an intermediate in the preparation of thiophene-based derivatives and its applications in polymer chemistry highlight its significance in both chemical and material research.

References

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DOI: 10.1107/s1600536806039158

2013. Mass spectrometry contamination from Tinuvin 770, a common additive in laboratory plastics. Journal of biomolecular techniques : JBT, 24(2).
DOI: 10.7171/jbt.13-2402-004

1994. Inhibition of nicotinic acetylcholine receptors by bis (2,2,6,6-tetramethyl- 4-piperidinyl) sebacate (Tinuvin 770), an additive to medical plastics. The Journal of Pharmacology and Experimental Therapeutics, 268(2).
DOI: 10.1016/s0022-3565(25)39002-6