Thiophene-2-carboxylic acid is an organic compound with the formula SC4H3CO2H. It is one of two monocarboxylic acids of thiophene, the other being thiophene-3-carboxylic acid. Copper(I) thiophene-2-carboxylate is a catalyst for Ullmann coupling reactions.
Synthesis It can be prepared by the oxidation of thiophene-2-carboxaldehyde or, more practically, 2-acetylthiophene.
Applications and reactions
Upon treatment with LDA, thiophene-2-carboxylic acid undergoes double deprotonation to give the 5-lithio derivative, a precursor to many 5-substituted derivatives. Thiophene-2-carboxylic acid has been widely studied as a substrate in coupling reactions and olefinations.
References


![Thiophene-2-carboxylic acid: Suprofen, which is produced from thiophene-2-carboxylic acid, is the active ingredient in some eye drops.[2]](https://upload.wikimedia.org/wikipedia/commons/thumb/c/c3/Suprofen.svg/500px-Suprofen.svg.png?utm_source=en.wikipedia.org&utm_campaign=parser&utm_content=thumbnail)
