Mandelonitrile

Mandelonitrile is the cyanohydrin derived from benzaldehyde. Its chemical formula is C8H7NO, and its structure is Ph-CH(OH)-CN, with Ph representing a phenyl group. The molecule contains a chiral benzylic carbon and exists as two enantiomers (R and S) or as a racemate. Mandelonitrile is typically a colorless solid or viscous liquid and is soluble in many organic solvents.

In the laboratory, mandelonitrile can be prepared by the addition of hydrogen cyanide to benzaldehyde, often generated in situ from a cyanide source under suitable conditions. The reaction is reversible and tends to favor the cyanohydrin under appropriate parameters.

In nature mandelonitrile is an intermediate in plant cyanogenesis. It is produced in seeds of many Prunus species (including almonds and apricots) as part of cyanogenic glycosides such as amygdalin, which release mandelonitrile upon enzymatic hydrolysis. Mandelonitrile lyase cleaves it to benzaldehyde and hydrogen cyanide, a key step in the plant defense mechanism.

Reactions of mandelonitrile include hydrolysis or hydration of the nitrile to form mandelic acid (Ph-CH(OH)-CO2H). Enzymatic cleavage by mandelonitrile lyase yields benzaldehyde and HCN. Safety considerations are important, as mandelonitrile can release toxic hydrogen cyanide under acidic or enzymatic conditions; handling requires appropriate precautions.