Fluorooleic acid is a naturally occurring, unsaturated, and fluorinated

fatty acid In chemistry, in particular in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated and unsaturated compounds#Organic chemistry, saturated or unsaturated. Most naturally occurring fatty acids have an ...

. The Delta notation is 18-F-18:1-delta-9c.

Natural occurrence

Fluoroleic acid, along with some other ω-fluoro-substituted fatty acids, occurs at about 10–20% in the seed oil of ''

Dichapetalum toxicarium ''Dichapetalum'' is a genus in the plant family Dichapetalaceae. The plants are tropical lianas native mainly to tropical regions of Africa, Asia, Malesia, the West Indies, Australia and Latin America. Some species are known to be poisonous due t ...

'', a plant native to

Sierra Leone Sierra Leone, officially the Republic of Sierra Leone, is a country on the southwest coast of West Africa. It is bordered to the southeast by Liberia and by Guinea to the north. Sierra Leone's land area is . It has a tropical climate and envi ...

West Africa West Africa, also known as Western Africa, is the westernmost region of Africa. The United Nations geoscheme for Africa#Western Africa, United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Gha ...

Biosynthesis

Unlike many other plants, ''Dichapetalum toxicarium'' can accumulate much more fluoride, even when the soil content is not particularly high. In young leaves, this is converted into

monofluoroacetate Fluoroacetic acid is an organofluorine compound with the chemical formula . It is a colorless solid that is noted for its relatively high toxicity. The conjugate base, fluoroacetate occurs naturally in at least 40 plants in Australia, Brazil, and ...

, which is stored in the leaves around the flowers. During seed formation, the

fluoroacetate Fluoroacetate may refer to: * Salts of fluoroacetic acid such as sodium fluoroacetate * Fluoroacetate anion (), a conjugate base of fluoroacetic acid * Esters In chemistry, an ester is a chemical compound, compound derived from an acid (either ...

is transferred there and converted into long-chain fluorinated fatty acids, including fluorooleic acid.

Synthesis

One method starts with 8-fluorooctanol, which is first reacted with

phosphorus tribromide Phosphorus tribromide is a colourless liquid with the formula P Br3. The liquid fumes in moist air due to hydrolysis and has a penetrating odour. It is used in the laboratory for the conversion of alcohols to alkyl bromides. Preparation PBr3 ...

. The product of this reaction is then reacted with sodium acetylide in

xylene In organic chemistry, xylene or xylol (; IUPAC name: dimethylbenzene) are any of three organic compounds with the formula . They are derived from the substitution of two hydrogen atoms with methyl groups in a benzene ring; which hydrogens are su ...

/ DMF. Then, the reaction takes place with 1-chloro-7-iodoheptane and metallic lithium in

liquid ammonia Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the formula . A stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pungent smell. It is widely used in fertilizers, ...

and finally with

sodium cyanide Sodium cyanide is a compound with the formula Na C N and the structure . It is a white, water-soluble solid. Cyanide has a high affinity for metals, which leads to the high toxicity of this salt. Its main application, in gold mining, also expl ...

DMSO Dimethyl sulfoxide (DMSO) is an organosulfur compound with the formula . This colorless liquid is the sulfoxide most widely used commercially. It is an important polar aprotic solvent that dissolves both polar and nonpolar compounds and is ...

, yielding the nitrile of fluorooleic acid. This reacts with

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usua ...

and

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...

in acetone to form the amide, and then with

in ethanol to form the carboxylic acid. The

triple bond A triple bond in chemistry is a chemical bond between two atoms involving six Electron pair bond, bonding electrons instead of the usual two in a covalent bond, covalent single bond. Triple bonds are stronger than the equivalent covalent bond, sin ...

can be converted into a (''Z'')-double bond by

Lindlar catalyst A Lindlar catalyst is a heterogeneous catalyst consisting of palladium deposited on calcium carbonate or barium sulfate then poisoned with various forms of lead or sulfur. It is used for the hydrogenation of alkynes to alkenes (i.e. without furth ...

. Fluoroleic acid can also be isolated from ''Dichapetalum toxicarium''. A chromatography method optimized for the separation of fluorinated fatty acids has been published.

Toxicology

Fluorooleic acid is responsible for the toxicity of ''Dichapetalum toxicariumthe'' fruits, which have been used as

rat poison Rodenticides are chemicals made and sold for the purpose of killing rodents. While commonly referred to as "rat poison", rodenticides are also used to kill mice, groundhog, woodchucks, chipmunks, porcupines, nutria, beavers, and voles. Some rod ...

. Oral LD₅₀ values of fluorooleic acid for various animals have been determined; these are 6 mg/kg for rats, 1.5 mg/kg for guinea pigs, 2.5 mg/kg for pigeons, 0.5 mg/kg for rabbits, and 2 mg/kg for sheep. In many cases, death was delayed and sudden, presumably due to

cardiac arrest Cardiac arrest (also known as sudden cardiac arrest CA is when the heart suddenly and unexpectedly stops beating. When the heart stops beating, blood cannot properly Circulatory system, circulate around the body and the blood flow to the ...

References

{{Fatty acids Fatty acids Fluorine-containing natural products Rodenticides Toxicology Organofluorides Fluorinated carboxylic acids

Natural occurrence

Biosynthesis

Synthesis

Toxicology

See also

References