organic chemistry Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, ...

, mandelonitrile is the nitrile of

mandelic acid Mandelic acid is an aromatic alpha hydroxy acid with the molecular formula C6H5CH(OH)CO2H. It is a white crystalline solid that is soluble in water and polar organic solvents. It is a useful precursor to various drugs. The molecule is chiral. T ...

, or the

cyanohydrin In organic chemistry, a cyanohydrin or hydroxynitrile is a functional group found in organic compounds in which a cyano and a hydroxy group are attached to the same carbon atom. The general formula is , where R is H, alkyl, or aryl. Cyanohydr ...

derivative of benzaldehyde. Small amounts of mandelonitrile occur in the pits of some fruits.

Occurrence

Mandelonitrile is the

aglycone An aglycone (aglycon or genin) is the compound remaining after the glycosyl group on a glycoside is replaced by a hydrogen atom. For example, the aglycone of a cardiac glycoside would be a steroid molecule. Detection A way to identify aglycone ...

part of the

cyanogenic glycoside In chemistry, a glycoside is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. ...

prunasin (''R'')-prunasin is a cyanogenic glycoside related to amygdalin. Chemically, it is the glucoside of (''R'')- mandelonitrile. Natural occurrences Prunasin is found in species in the genus ''Prunus'' such as '' Prunus japonica'' or '' P. maximow ...

and

amygdalin Amygdalin (from Ancient Greek: ' "almond") is a naturally occurring chemical compound found in many plants, most notably in the seeds (kernels) of apricots, bitter almonds, apples, peaches, cherries, and plums. Amygdalin is classified as a cy ...

. The naturally occurring (''R'')-(+) enantiomer finds use as an intermediate in the preparation of optically active α-hydroxy carboxylic acids, α-hydroxy aldehydes, α-hydroxy ketones, and 2-amino alcohols.Kruse, C.G. In Collins, A.N. Sheldrake, G.N. Crosby, J., Eds. ''Chirality in Industry Chichester'', UK , (1992), 279 Mandelonitrile can break down into

cyanide Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of ...

and benzaldehyde, a reaction that can be

catalyzed Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

by the

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

mandelonitrile lyase The enzyme (''R'')-mandelonitrile lyase (, ''(R)-HNL'', ''(R)-oxynitrilase'', ''(R)-hydroxynitrile lyase'') catalyzes the chemical reaction :mandelonitrile \rightleftharpoons hydrogen cyanide + benzaldehyde This enzyme belongs to the family of ...

Preparation

Racemic In chemistry, a racemic mixture, or racemate (), is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as racemates. ...

mandelonitrile may be prepared similar to many other cyanohydrins. In a one pot reaction, benzaldehyde is reacted with

sodium bisulfite Sodium bisulfite (or sodium bisulphite, sodium hydrogen sulfite) is a chemical mixture with the approximate chemical formula NaHSO3. Sodium bisulfite in fact is not a real compound, but a mixture of salts that dissolve in water to give solutions ...

to give the corresponding adduct, which further reacts with aqueous

sodium cyanide Sodium cyanide is a poisonous compound with the formula Na C N. 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 exploits its hi ...

to give the racemic product: :

References

{{Reflist Cyanohydrins