Cyanohydrin


Cyanohydrin
The structure of a general cyanohydrin.

A cyanohydrin is a functional group found in organic compounds. Cyanohydrins have the formula R2C(OH)CN, where R is H, alkyl, or aryl. Cyanohydrins are industrially important precursors to carboxylic acids and some amino acids. Cyanohydrins can be formed by the cyanohydrin reaction, which involves treating a ketone or an aldehyde with hydrogen cyanide (HCN) in the presence of excess amounts of sodium cyanide (NaCN) as a catalyst:

RR’C=O + HCN → RR’C(OH)CN

In this reaction, the nucleophilic CN ion attacks the electrophilic carbonyl carbon in the ketone, followed by protonation by HCN, thereby regenerating the cyanide anion. Cyanohydrins are also prepared by displacement of sulfite by cyanide salts:[1]

Cyanation of aldehyde with bisulfate.svg

Cyanohydrins are intermediates in the Strecker amino acid synthesis.

Contents

Acetone cyanohydrins

Acetone cyanohydrin, (CH3)2C(OH)CN is the cyanohydrin of acetone. It is generated as an intermediate in the industrial production of methyl methacrylate.[2] In the laboratory, this liquid serves as a source of HCN, which is inconveniently volatile.[3] Thus, acetone cyanohydrin can be used for the preparation other cyanohydrins, for of HCN to Michael acceptors, and for the formylation of arenes. Treatment of this cyanohydrin with lithium hydride affords anhydrous lithium cyanide:

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

Other cyanohydrins

Mandelonitrile, with the formula C6H5CH(OH)CN, occurs in small amounts in the pits of some fruits.[1] Related cyanogenic glycosides are known, such as amygdalin.

Glycolonitrile, also called hydroxyacetonitrile or formaldehyde cyanohydrin, is the organic compound with the formula HOCH2CN. It is the simplest cyanohydrin, being derived from formaldehyde.[4]

Glycolonitrile-2D-skeletal.png
Acetone cyanohydrin.svg
Mandelonitrile-2D-skeletal.png
glycolonitrile
acetone cyanohydrin
mandelonitrile

References

  1. ^ a b Corson, B. B.; Dodge, R. A.; Harris, S. A.; Yeaw, J. S. (1941), "Mandelic Acid", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1p0336 ; Coll. Vol. 1: 336 
  2. ^ William Bauer, Jr. "Methacrylic Acid and Derivatives" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. DOI: 10.1002/14356007.a16_441. Article Online Posting Date: June 15, 2000
  3. ^ Haroutounian, S. A. ”Acetone Cyanohydrin” Encyclopedia of Reagents for Organic Synthesis 2001, John Wiley & Sons. DOI: 10.1002/047084289X.ra014
  4. ^ Gaudry, R. (1955), "Glycolonitrile", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv3p0436 ; Coll. Vol. 3: 436 

External links

  • IUPACs Gold Book definition of cyanohydrins [1]

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Look at other dictionaries:

  • cyanohydrin — [sī΄ə nō hī′drin] n. [ CYANO + HYDR(O) + IN1] any of a class of organic chemical compounds containing the CN and OH radicals …   English World dictionary

  • cyanohydrin — cianhidrinas statusas T sritis chemija formulė HORCN atitikmenys: angl. cyanohydrin rus. циангидрин …   Chemijos terminų aiškinamasis žodynas

  • cyanohydrin — noun Etymology: International Scientific Vocabulary, from cyan + hydr + 1 in Date: 1925 any of various compounds containing both cyano and hydroxyl groups …   New Collegiate Dictionary

  • cyanohydrin — /suy euh noh huy drin, suy an oh /, n. any of a class of organic chemical compounds that contains both the CN and the OH group, usually linked to the same carbon atom. [1920 25; CYANO 3 + HYDR 2 + IN2] * * * …   Universalium

  • cyanohydrin — noun Any compound having both a hydroxy and a cyanide functional group, especially one having these groups attached to the same carbon atom …   Wiktionary

  • cyanohydrin — cy·a·no·hy·drin (si″ə no hiґdrin) a compound containing a cyano and a hydroxyl group; formed by the addition of hydrocyanic acid to an aldehyde group; called also cyanalcohol …   Medical dictionary

  • cyanohydrin — n. organic compound (Chemistry) …   English contemporary dictionary

  • cyanohydrin — [ˌsʌɪənə(ʊ) hʌɪdrɪn] noun Chemistry an organic compound containing a carbon atom linked to both cyanide and hydroxyl groups …   English new terms dictionary

  • cyanohydrin — cy·a·no·hy·drin …   English syllables

  • cyanohydrin — cy•a•no•hy•drin [[t]ˌsaɪ ə noʊˈhaɪ drɪn, saɪˌæn oʊ [/t]] n. chem. an organic compound containing both the cyanogen and hydroxyl groups • Etymology: 1920–25 …   From formal English to slang