2- Thiophenecarboxyhc acid

The need for low levels of 3-isomer in 2-thiophenecarboxyhc acid [527-72-0] which is produced by oxidation of 2-acetylthiophene [88-15-3] and used in dmg appHcations, has been the driving force to find improved acylation catalysts. The most widely used oxidant is sodium hypochlorite, which produces a quantity of chloroform as by-product, a consequence that detracts from its simplicity. Separation of the phases and acidification of the aqueous phase precipitate the product which is filtered off. Alternative oxidants have included sodium nitrite in acid solution, which has some advantages, but, like the hypochlorite method, also involves very dilute solutions and low throughput volumes. 

The principal source of 2-thiophenecarboxaldehyde is Great Lakes Fine Chemicals Ltd. in the United Kingdom, whereas 2-acetylthiophene is produced by a number of manufacturers. Some of the 2-acetylthiophene producers continue derivatization to 2-thiophenecarboxyhc acid and 2-thiopheneacetic acid. 

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