Natural product to modern discovery of their active ingredients and eventually to the development of new drugs. A large number of currently prescribed drugs have been either directly derived from or inspired by natural products. A few representative examples are listed below. Some of the oldest natural product based drugs are analgesics. The bark of the willow tree has been known from antiquity to have pain relieving properties. This is due to presence of the natural product salicin which in turn may be hydrolyzed into salicylic acid. A synthetic derivative acetylsalicylic acid better known as aspirin is a widely used pain reliever.
Tetrolic acid (water, ethanol) and may be recrystallized from non polar solvents (such as heptane, toluene). The compound is a white crystalline solid which can exist in two polymorphous crystalline forms. The proton nuclear magnetic resonance (H-NMR) spectrum in deuterated dimethyl sulfoxide shows a characteristic singlet peak at 1.99 ppm corresponding to the -CH protons. 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