Cyanohydrin

Cyanohydrin-general-2D-skeletal

Cyanation of aldehyde with bisulfate

LiCN-from-acetone-cyanohydrin-2D-skeletal

Cyanohydrin synthesis

Amygdalin structure

Cyanohydrin refers to a class of organic compounds containing both a cyanide group (C≡N) and a hydroxyl group (-OH) attached to the same carbon atom. These compounds are important intermediates in organic synthesis, particularly in the production of amino acids, alpha-hydroxy acids, and other valuable chemical products. Cyanohydrins have the general formula R2C(OH)CN, where R can be hydrogen, alkyl, or aryl groups.

Formation

Cyanohydrins are typically formed through the reaction of aldehydes or ketones with hydrogen cyanide (HCN) in the presence of a base. This reaction is known as cyanohydrin formation. The base is required to generate the cyanide ion (CN−) from HCN, which then attacks the carbonyl carbon of the aldehyde or ketone, leading to the formation of the cyanohydrin.

Properties

Cyanohydrins are characterized by their functional groups: the hydroxyl group makes them somewhat polar and capable of forming hydrogen bonds, while the cyanide group introduces reactivity towards nucleophiles and electrophiles. This dual functionality makes cyanohydrins versatile intermediates in organic synthesis. They are usually stable under basic conditions but can be sensitive to acids, which can lead to hydrolysis of the cyanide group.

Applications

Cyanohydrins serve as key intermediates in the synthesis of various important compounds. For example, they can be converted into amino acids through hydrolysis followed by ammonolysis, or into alpha-hydroxy acids, which are useful in the pharmaceutical and cosmetic industries. Additionally, the cyanide group in cyanohydrins can be easily transformed into other functional groups, such as carboxylic acids, amides, and esters, further expanding their utility in organic synthesis.

Safety

Handling of cyanohydrins requires caution due to the presence of the toxic cyanide group. Proper safety measures, including the use of personal protective equipment (PPE) and adequate ventilation, are essential to prevent exposure to cyanide, which can be lethal in high concentrations.

See Also

• Nitrile
• Hydrogen cyanide
• Organic synthesis
• Aldehyde
• Ketone