Willow active extract of the bark, called salicin, was isolated to its crystalline form in 1828 by Henri Leroux, a French pharmacist, and Raffaele Piria, an Italian chemist, who then succeeded in separating out the compound in its pure state. In 1897, Felix Hoffmann created a synthetically altered version of salicin (in his case derived from the "Spiraea" plant), which caused less digestive upset than pure salicylic acid. The new drug, formally acetylsalicylic acid, was named Aspirin by Hoffmann's employer Bayer AG. This gave rise to the hugely important class of drugs known as nonsteroidal anti-inflammatory drugs (NSAIDs). Some of humans'
Tetrolic acid Tetrolic acid Tetrolic acid (2-butynoic acid) is a short-chain unsaturated carboxylic acid, described by the formula CH-C≡C-COH. Salts and esters of tetrolic acid are known as tetrolates. The first reported synthesis of tetrolic acid is believed to be by German chemist Johann Georg Anton Geuther in 1871 as part of his work investigating the derivatives of ethyl acetoacetate. Tetrolic acid is manufactured on a commercial scale by treatment of propyne with a strong base (to form an acetylide), followed by carbon dioxide: Strong bases such as "n"-BuLi and NaNH can be used. Tetrolic acid is highly soluble in polar solvents