Nitrile

Information about Nitrile

The structure of the nitrile group

A nitrile is any organic compound which has a -C≡N functional group. The -C≡N functional group is called a nitrile group. In the -CN group, the carbon atom and the nitrogen atom are triple bonded together. The prefix cyano is used in chemical nomenclature to indicate the presence of a nitrile group in a molecule. A cyanide ion is a negative ion with the formula CN⁻. The -CN group is sometimes, less properly, referred to as a cyanide group or cyano group and compounds with them are sometimes referred to as cyanides.

Nitriles sometimes release the highly toxic CN⁻ cyanide ion. See the article on cyanide for a discussion of biological effects and toxicity.

History

Hydrogen cyanide was first synthesized by K.W. Scheele in 1782 and he was killed in an attempt to get the anhydrous compound ^[1]. J. L. Gay-Lussac was the first to prepare the pure acid in 1811 and Friedrich Wohler and Justus von Liebig were the first to prepare the first nitriles benzoyl cyanide and benzonitrile in 1832. Théophile-Jules Pelouze synthesized propionitrile in 1834.

Synthesis of nitriles

Nitriles can be prepared in organic synthesis by the following methods:

Nucleophilic aliphatic substitution reactions of alkyl halides with metal cyanides.
dehydration of primary amides. Many reagents are available, the combination of ethyl dichlorophosphate and DBU just one of them in this conversion of benzamide to benzonitrile:^[2]

Amide dehydration

Two intermediates in this reaction are amide tautomer A and its phosphate adduct B.

dehydration of secondary amides (von Braun amide degradation)
dehydration of aldoximes with triethylamine/sulfur dioxide, zeolites, or sulfuryl chloride
One-pot synthesis of aldehyde with hydroxylamine and sodium sulfate.

one-pot synthesis from aldehyde

In one study ^[3] an aromatic or aliphatic aldehyde is reacted with hydroxylamine and anhydrous sodium sulfate in a dry media reaction for a very small amount of time under microwave irradiation through an intermediate aldoxime.

reaction of metal cyanides with aldehydes in the cyanohydrin reaction
from aryl carboxylic acids (Letts nitrile synthesis)
aromatic nitriles from diazonium compounds in the Sandmeyer reaction
from alkenes and alkynes in hydrocyanation
A commercial source for the cyanide group is diethylaluminum cyanide Et₂AlCN which can be prepared from triethylaluminium and HCN ^[4]. It has been used in nucleophilic addition to ketones.^[5] For an example of its use see: Kuwajima Taxol total synthesis
cyanide ions facilitate the coupling of dibromides. Reaction of α,α'-dibromo adipic acid with sodium cyanide in ethanol yields the cyano cyclobutane:^[6]

In the so-called Franchimont Reaction (A. P. N. Franchimont, 1872) an α-bromocarboxylic acid is dimerized after hydrolysis of the cyanogroup and decarboxylation ^[7]

Reactions of nitriles

Nitrile groups in organic compounds can undergo various reactions when subject to certain reactants or conditions. A nitrile group can be hydrolyzed, reduced, or ejected from a molecule as a cyanide ion.

In hydrolysis the nitrile is reacted with an acid and water at a high temperature, or with a base and water. The acid hydrolysis forms a carboxylic acid, the alkali hydrolysis forms a carboxylate.
In organic reduction the nitrile is reduced by reacting it with hydrogen with a nickel catalyst; an amine is formed in this reaction. Reduction to the imine followed by hydrolysis to the aldehyde takes place in the Stephen aldehyde synthesis
A nitrile is an electrophile at the carbon atom in a nucleophilic addition reactions:
with an organozinc compound in the Blaise reaction
and with alcohols in the Pinner reaction.
likewise, the reaction of the amine sarcosine with cyanamide yields creatine ^[8]
In reductive decyanation the nitrile group is replaced by a proton ^[9]. An effective decyanation is by a dissolving metal reduction with HMPA and potassium metal in tert-butyl alcohol. α-Amino-nitriles can be decyanated with lithium aluminium hydride.
Nitriles self-react in presence of base in the Thorpe reaction in a nucleophilic addition
In organometallic chemistry nitriles are known to add to alkynes in carbocyanation:^[10]

Carbocyanation Nakao 2007

External links

International Union of Pure and Applied Chemistry. "nitrile". Compendium of Chemical Terminology Internet edition.
International Union of Pure and Applied Chemistry. "cyanide". Compendium of Chemical Terminology Internet edition.

References

1. ^ David T. Mowry (1948). "The Preparation of Nitriles". Chem. Rev. 42 (2): 189 - 283. DOI:10.1021/cr60132a001.
2. ^ Chun-Wei Kuo, Jia-Liang Zhu, Jen-Dar Wu, Cheng-Ming Chu, Ching-Fa Yao and Kak-Shan Shia (2007). "A convenient new procedure for converting primary amides into nitriles". Chem. Commun. 2007: 301 - 303. DOI:10.1039/b614061k.
3. ^ Sharwan K, Dewan, Ravinder Singh, and Anil Kumar (2006). "One pot synthesis of nitriles from aldehydes and hydroxylamine hydrochloride using sodium sulphate (anhyd) and sodium bicarbonate in dry media under microwave irradiation" (open access). Arkivoc: (ii) 41-44.Arkivoc&rft.date=2006&rft.au=Sharwan%20K,%20Dewan,%20Ravinder%20Singh,%20and%20Anil%20Kumar&rft.pages=%28ii%29%2041-44&rft_id=http%3A%2F%2Fwww.arkat-usa.org%2Fark%2Fjournal%2F2006%2FI02_General%2F1646%2F05-1646D%2520as%2520published%2520mainmanuscript.pdf">
4. ^ W. Nagata and M. Yoshioka (1988). "Diethylaluminum cyanide". Org. Synth.; Coll. Vol. 6: 436.
5. ^ W. Nagata, M. Yoshioka, and M. Murakami (1988). "PREPARATION OF CYANO COMPOUNDS USING ALKYLALUMINUM INTERMEDIATES: 1-CYANO-6-METHOXY-3,4-DIHYDRONAPHTHALENE". Org. Synth.; Coll. Vol. 6: 307.
6. ^ Reynold C. Fuson, Oscar R. Kreimeier, and Gilbert L. Nimmo (1930). "RING CLOSURES IN THE CYCLOBUTANE SERIES. II. CYCLIZATION OF α,α′-DIBROMO-ADIPIC ESTERS". J. Am. Chem. Soc. 52 (10): 4074 - 4076. DOI:10.1021/ja01373a046.
7. ^ [1]
8. ^ Smith, Andri L.; Tan, Paula (2006). "Creatine Synthesis: An Undergraduate Organic Chemistry Laboratory Experiment". J. Chem. Educ. 83: 1654.
9. ^ The reductive decyanation reaction: chemical methods and synthetic applications Jean-Marc Mattalia, Caroline Marchi-Delapierre, Hassan Hazimeh, and Michel Chanon Arkivoc (AL-1755FR) pp 90-118 2006 Article
10. ^ Yoshiaki Nakao, Akira Yada, Shiro Ebata, and Tamejiro Hiyama (2007). "A Dramatic Effect of Lewis-Acid Catalysts on Nickel-Catalyzed Carbocyanation of Alkynes" (Communication). J. Am. Chem. Soc. 129 (9): 2428 - 2429. DOI:10.1021/ja067364x.

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Functional group

Chemical class: Alcohol • Aldehyde • Alkane • Alkene • Alkyne • Amide • Amine • Azo compound • Benzene derivative • Carboxylic acid • Cyanate • Disulfide • Ester • Ether • Haloalkane • Imine • Isocyanide • Isocyanate • Ketone • Nitrile • Nitro compound • Nitroso compound • Peroxide • Phosphoric acid • Pyridine derivative • Sulfone • Sulfonic acid • Sulfoxide • Thioester • Thioether • Thiol

organic compounds]] An organic compound is any member of a large class of chemical compounds whose molecules contain carbon; for historical reasons discussed below, a few types of compounds such as carbonates, carbon oxides and cyanides, as well as elemental carbon are
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4, 2
(mildly acidic oxide)
Electronegativity 2.55 (Pauling scale)
Ionization energies
(more) 1st: 1086.5 kJmol⁻¹
2nd: 2352.6 kJmol⁻¹
3rd: 4620.5 kJmol⁻¹

Atomic radius 70 pm
Atomic radius (calc.
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3, 5, 4, 2
(strongly acidic oxide)
Electronegativity 3.04 (Pauling scale)
Ionization energies
(more) 1st: 1402.3 kJmol⁻¹
2nd: 2856 kJmol⁻¹
3rd: 4578.1 kJmol⁻¹

Atomic radius 65 pm
Atomic radius (calc.
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In organic chemistry, functional groups (or moieties) are specific groups of atoms within molecules, that are responsible for the characteristic chemical reactions of those molecules.
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Covalent bonding is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms, or between atoms and other covalent bonds.
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cyanide ion, CN⁻.
From the top:
1. Valence-bond structure
2. Space-filling model
3. Electrostatic potential surface
4. 'Carbon lone pair' HOMO]] A cyanide
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Hydrogen cyanide is a chemical compound with chemical formula HCN. A solution of hydrogen cyanide in water is called hydrocyanic acid. Hydrogen cyanide is a colorless, very poisonous, and highly volatile liquid that boils slightly above room temperature at 26 °C (78.8 °F).
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Carl Wilhelm Scheele (December 9,1742 - May 21, 1786) a German-Swedish pharmaceutical chemist, born in Stralsund, Western Pomerania, Germany (at the time under Swedish rule), was the discoverer of many chemical substances, most notably discovering oxygen before Joseph Priestley and
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As a general term, a substance is said to be anhydrous if it contains no water. The way of achieving the anhydrous form differs from one substance to another.

Solvents

In many cases, the presence of water can prevent a reaction from happening, or form undesirable products.
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Joseph Louis Gay-Lussac (December 6, 1778 – May 9, 1850) was a French chemist and physicist. He is known mostly for two laws related to gases, and for his work on alcohol-water mixtures, which led to the degrees Gay-Lussac used to measure alcoholic beverages in many countries.
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Friedrich Wöhler

German chemist
Born July 31 1800
Eschersheim, Frankfurt am Main, Germany
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Justus von Liebig

Justus von Liebig-chemist
Born 12 May 1803
Darmstadt, Grand Duchy of Hesse
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Benzonitrile is the chemical compound with the formula C₆H₅CN, abbreviated PhCN. This aromatic organic compound is colourless, with a sweet almond odour.
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Théophile-Jules Pelouze (also known as Jules Pelouze, Théophile Pelouze, Theo Pelouze, or TJ Pelouze, February 26, 1807 - 1867) was a French chemist. He was born at Valognes, and died in Paris.
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Propionitrile, or ethyl cyanide, is a low-molecular weight nitrile with the molecular formula C₂H₅CN. It is a clear liquid with an etherial, sweet odor.
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Organic synthesis is the construction of organic molecules via chemical processes. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has developed into one of the most important aspects of
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In organic and inorganic chemistry, nucleophilic substitution is a fundamental class of substitution reaction in which an "electron rich" nucleophile selectively bonds with or attacks the positive charge of a group or atom called the leaving group; rarely referred to as an
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haloalkanes (also known as halogenoalkanes or alkyl halides) are a group of chemical compounds, consisting of alkanes, such as methane or ethane, with one or more halogens linked, such as chlorine or fluorine, making them a type of organic halide.
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dehydration reaction is usually defined as a chemical reaction that involves the loss of water from the reacting molecule. Dehydration reactions are a subset of elimination reactions.
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amide is one of two kinds of compounds:

the organic functional group characterized by a carbonyl group (C=O) linked to a nitrogen atom (N), or a compound that contains this functional group (pictured to the right); or
a particular kind of nitrogen anion.

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1,8-Diazabicyclo[5.4.0]undec-7-ene, or more commonly DBU, is a chemical compound and belongs to the class of amidine compounds. It is used in chemistry as a catalyst and complexing ligand and non-nucleophilic base.

Benzamides

Benzamides are a class of amides of benzoic acid.
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Tautomers are organic compounds that are interconvertible by a chemical reaction called tautomerization. As most commonly encountered, this reaction results in the formal migration of a hydrogen atom or proton, accompanied by a switch of a single bond and adjacent
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An organophosphate (sometimes abbreviated OP) is the general name for esters of phosphoric acid. Phosphates are probably the most pervasive organophosphorus compounds.
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