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

, mandelonitrile is the

nitrile In organic chemistry, a nitrile is any organic compound that has a functional group. The name of the compound is composed of a base, which includes the carbon of the , suffixed with "nitrile", so for example is called " propionitrile" (or pr ...

of mandelic acid, 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. Cyanohyd ...

derivative of

benzaldehyde Benzaldehyde (C6H5CHO) is an organic compound consisting of a benzene ring with a formyl substituent. It is among the simplest aromatic aldehydes and one of the most industrially useful. It is a colorless liquid with a characteristic almond-li ...

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

Occurrence

Mandelonitrile is the

aglycone An aglycone (aglycon or genin) is the chemical 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 A steroid is an organic compoun ...

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. ...

s prunasin and

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

. Prunasin can be

hydrolyzed Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysi ...

by the enyzme prunase into

glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...

and mandelonitrile (for example, when an appleseed is digested in a

ruminant Ruminants are herbivorous grazing or browsing artiodactyls belonging to the suborder Ruminantia that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microb ...

's stomach). 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 In chemistry, cyanide () is an inorganic chemical compound that contains a functional group. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom. Ionic cyanides contain the cyanide anion . This a ...

and benzaldehyde, a reaction that can be catalyzed by the

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

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 a mixture that has equal amounts (50:50) 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 r ...

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

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 is not a real compound, but a mixture of salts that dissolve in water to give solutions compose ...

to give the corresponding adduct, which further reacts with aqueous

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 ...

to give the racemic product: :

References

{{Reflist Cyanohydrins