Cyanamide

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Cyanamide
Cyanamide.svg
Cyanamide (nitrile) 3D spacefill.png
Cyanamide (diimide) 3D spacefill.png
Names
IUPAC names
Cyanamide,
aminomethanenitrile
Other names
Amidocyanogen, carbamonitrile, carbimide, carbodiimide, cyanoamine, cyanoazane, N-cyanoamine, cyanogenamide, cyanogen amide, cyanogen nitride, diiminomethane, hydrogen cyanamide, methanediimine
Identifiers
3D model (JSmol)
3DMet
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.006.358 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 206-992-3
784
KEGG
PubChem CID
RTECS number
  • GS5950000
UNII
UN number 2811
  • InChI=1S/CH2N2/c2-1-3/h2H2 Yes check.svgY
    Key: XZMCDFZZKTWFGF-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/CH2N2/c2-1-3/h2H2
    Key: XZMCDFZZKTWFGF-UHFFFAOYAW
Properties
CH2N2
Molar mass 42.040 g/mol
AppearanceCrystalline solid
Density 1.28 g/cm3
Melting point 44 °C (111 °F; 317 K)
Boiling point 260 °C (500 °F; 533 K) (decomposes)
83 °C at 6.7 Pa
140 °C at 2.5 kPa
85 g/100 ml (25 °C)
Solubility in organic solventssoluble
log P -0.82
Acidity (pKa)10.3 [1]
Hazards
GHS labelling:
GHS-pictogram-acid.svg GHS-pictogram-skull.svg GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg
Danger
H301, H311, H314, H317, H351, H361, H373, H412
P201, P202, P260, P261, P264, P270, P272, P273, P280, P281, P301+P310, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P308+P313, P310, P312, P314, P321, P322, P330, P333+P313, P361, P363, P405, P501
NFPA 704 (fire diamond)
2
1
2
Flash point 141 °C (286 °F; 414 K)
NIOSH (US health exposure limits):
PEL (Permissible)
none [2]
REL (Recommended)
TWA 2 mg/m3
IDLH (Immediate danger)
N.D. [2]
Safety data sheet (SDS) ICSC 0424
Related compounds
Related compounds
 Calcium cyanamide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Cyanamide is an organic compound with the formula C N 2 H 2. This white solid is widely used in agriculture and the production of pharmaceuticals and other organic compounds. It is also used as an alcohol-deterrent drug. The molecule features a nitrile group attached to an amino group. Derivatives of this compound are also referred to as cyanamides, the most common being calcium cyanamide (CaCN2). [3]

Contents

Tautomers and self-condensations

Containing both a nucleophilic and electrophilic site within the same molecule, cyanamide undergoes various reactions with itself. Cyanamide exists as two tautomers, one with the connectivity N≡C–NH2 and the other with the formula HN=C=NH ("carbodiimide" tautomer). The N≡C–NH2 form dominates, but in a few reactions (e.g. silylation) the diimide form appears to be important. [3]

Cyanamide dimerizes to give 2-cyanoguanidine (dicyandiamide). This dimerization is disfavored by acids and is inhibited by low temperatures. The cyclic trimer is called melamine. [3]

Production

Cyanamide is produced by hydrolysis of calcium cyanamide, which in turn is prepared from calcium carbide via the Frank-Caro process. [4]

CaCN2 + H2O + CO2 → CaCO3 + H2NCN

The conversion is conducted on slurries.

Reactions and uses

Cyanamide can be regarded as a functional single carbon fragment which can react as an electrophile or nucleophile. The main reaction exhibited by cyanamide involves additions of compounds containing an acidic proton. Water, hydrogen sulfide, and hydrogen selenide react with cyanamide to give urea, thiourea, and selenourea, respectively:

H2NCN + H2E → H2NC(E)NH2 (E = O, S, Se)

In this way, cyanamide behaves as a dehydration agent and thus can induce condensation reactions. Alcohols, thiols, and amines react analogously to give alkylisoureas, "pseudothioureas", and guanidines. The anti-ulcer drug cimetidine is generated using such reactivity. Related reactions exploit the bifunctionality of cyanamide to give heterocycles, and this latter reactivity is the basis of several pharmaceutical syntheses such as the aminopyrimidine imatinib, and agrichemicals Amitrol and hexazinone. The hair-loss treatment minoxidil and the anthelmintics albendazole, flubendazole, and mebendazole feature 2-aminoimidazole substructures derived from cyanamide. [3] Cyanamide is also used in the synthesis of other pharmaceutical drugs including tirapazamine, etravirine, revaprazan, and dasantafil.

The cyanamide anion has the character of a pseudo chalcogen, cyanamide can therefore be regarded as analogue to water or hydrogen sulfide.

A convenient method for the preparation of secondary amines which are not contaminated with primary or tertiary amines is the reaction of cyanamide with alkyl halides to N,N-dialkylcyanamides which can easily be hydrolyzed to dialkylamines and then decarboxylated. [5] Cyanamide adds itself in the presence of N-bromosuccinimide to olefinic double bonds. The addition product is converted by bases to N-Cyanaziridine, [6] cyclized in the presence of acids to imidazolines, which can be further reacted to vicinal diamines by alkaline cleavage. [7]

Cyanamide is also a versatile synthetic building block for heterocycles: it forms 2-aminobenzimidazole with 1,2-diaminobenzene [8] and it forms with the readily available cyclic enamine 4-(1-cyclohexenyl)morpholine [9] and with elemental sulfur a 2-aminothiazole in good yields. [10]

Sodium dicyanamide is available in good yield and high purity from cyanamid and cyanogen chloride, [11] [12] which is suitable as an intermediate for the synthesis of active pharmaceutical ingredients. [13] A guanidino group is introduced by reaction of cyanamide with sarcosine In the industrial synthesis of creatine: [14]

reaction equation Creatine synthesis.svg
reaction equation

This synthesis route mostly avoids problematic impurities like chloroacetic acid, iminodiacetic acid, or dihydrotriazine that occur in other routes. The physiological precursor guanidinoacetic is obtained analogously by reacting cyanamide with glycine.

Methods to stabilize cyanamidefmel make it available on an industrial scale. Due to the strong affinity towards self-condensation in alkaline media (see above) solutions of cyanamide are stabilized by the addition of 0.5 wt% of monosodium phosphate as buffer. Solid cyanamide is produced by careful evaporation of the solvent and subsequent addition of a hydrolysis-labile ester of formic acid. The ester absorbs traces of moisture (suppression of urea formation), neutralizes alkalinity (ammonia) and continually releases small amounts of formic acid. [15]

Agricultural use

Cyanamide, under the trade name Dormex, is a common agricultural rest-breaking agent applied in spring to stimulate uniform opening of buds, early foliation and bloom. Cyanamide can effectively compensate for the moderate lack of chilling units accumulated in the previous autumn and save the harvest that would otherwise be lost. It is particularly effective for woody plants such as blueberries, grapes, apples, peaches and kiwifruit. Most recently the product was approved for use on almonds and pistachios in the USA. Overdosage, high concentration and error in timing of application can damage the buds (especially of peach trees). [16] Growers may avoid damage by applying 30 days prior to bud break according to the label.

A 50% aqueous solution of cyanamide is also used as a biocide (disinfectant) particularly in pig farming, because it effectively kills salmonella and shigella and fights flies in all stages of development. [17]

Environmental aspects

Cyanamide degrades via hydrolysis to urea, an excellent fertilizer. Fungi, like Myrothecium verrucaria , accelerate this process utilizing the enzyme cyanamide hydratase. [18]

Cyanamide functional group

Cyanamide is the name for a functional group with the formula NCNRR' where R and R' can be a variety of groups. These compounds are called cyanamides. One example is naphthylcyanamide, C10H7N(H)CN [19] Some cyanamides are prepared by alkylation of calcium cyanamide. Others, such as the naphthyl derivative, are produced indirectly. [11]

Cyanamide in space

Due to its high permanent dipole moment (i.e., 4.32 ± 0.08 D), [20] cyanamide was detected by spectral emissions coming from the Sgr B2 molecular cloud (T < 100 K) through its microwave transitions as the first known interstellar molecule containing the NCN frame. [21]

Safety

It is used as an alcohol-deterrent drug in Canada, Europe, and Japan. [3]

Cyanamide has a modest toxicity in humans. [22] Workplace exposure to hydrogen cyanamide sprays or exposure in people living in the vicinity of spraying have been reported as causing respiratory irritation, contact dermatitis, headache, and gastrointestinal symptoms of nausea, vomiting, or diarrhea. [22]

Related Research Articles

Hydrazone Organic compounds - Hydrazones

Hydrazones are a class of organic compounds with the structure R1R2C=N−NH2. They are related to ketones and aldehydes by the replacement of the oxygen =O with the =N−NH2 functional group. They are formed usually by the action of hydrazine on ketones or aldehydes.

<span class="mw-page-title-main">Imine</span> Organic compound or functional group containing a C=N bond

In organic chemistry, an imine is a functional group or organic compound containing a carbon–nitrogen double bond. The nitrogen atom can be attached to a hydrogen or an organic group (R). The carbon atom has two additional single bonds. Imines are common in synthetic and naturally occurring compounds and they participate in many reactions.

In organic chemistry, a nitrile is any organic compound that has a −C≡N functional group. The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, including methyl cyanoacrylate, used in super glue, and nitrile rubber, a nitrile-containing polymer used in latex-free laboratory and medical gloves. Nitrile rubber is also widely used as automotive and other seals since it is resistant to fuels and oils. Organic compounds containing multiple nitrile groups are known as cyanocarbons.

Acyl halide Chemical compound

An acyl halide is a chemical compound derived from an oxoacid by replacing a hydroxyl group with a halide group.

Diazomethane Simplest diazo compound and methylating agent

Diazomethane is the chemical compound CH2N2, discovered by German chemist Hans von Pechmann in 1894. It is the simplest diazo compound. In the pure form at room temperature, it is an extremely sensitive explosive yellow gas; thus, it is almost universally used as a solution in diethyl ether. The compound is a popular methylating agent in the laboratory, but it is too hazardous to be employed on an industrial scale without special precautions. Use of diazomethane has been significantly reduced by the introduction of the safer and equivalent reagent trimethylsilyldiazomethane.

Cyclohexene is a hydrocarbon with the formula C6H10. This cycloalkene is a colorless liquid with a sharp smell. It is an intermediate in various industrial processes. Cyclohexene is not very stable upon long term storage with exposure to light and air because it forms peroxides.

<span class="mw-page-title-main">Aluminium chloride</span> Chemical compound

Aluminium chloride, also known as aluminium trichloride, is an inorganic compound with the formula AlCl3. It forms hexahydrate with the formula [Al(H2O)6]Cl3, containing six water molecules of hydration. Both are colourless crystals, but samples are often contaminated with iron(III) chloride, giving a yellow color.

<i>N</i>,<i>N</i>-Dicyclohexylcarbodiimide Chemical compound

N,N′-Dicyclohexylcarbodiimide (DCC or DCCD) is an organic compound with the chemical formula (C6H11N)2C. It is a waxy white solid with a sweet odor. Its primary use is to couple amino acids during artificial peptide synthesis. The low melting point of this material allows it to be melted for easy handling. It is highly soluble in dichloromethane, tetrahydrofuran, acetonitrile and dimethylformamide, but insoluble in water.

<i>tert</i>-Butyl alcohol Chemical compound

tert-Butyl alcohol is the simplest tertiary alcohol, with a formula of (CH3)3COH (sometimes represented as t-BuOH). Its isomers are 1-butanol, isobutanol, and butan-2-ol. tert-Butyl alcohol is a colorless solid, which melts near room temperature and has a camphor-like odor. It is miscible with water, ethanol and diethyl ether.

Copper chromite Chemical compound

Copper chromite is an inorganic compound with the formula Cu2Cr2O5. It is a black solid that is used to catalyze reactions in organic synthesis.

<span class="mw-page-title-main">1,4-Benzoquinone</span> Chemical compound

1,4-Benzoquinone, commonly known as para-quinone, is a chemical compound with the formula C6H4O2. In a pure state, it forms bright-yellow crystals with a characteristic irritating odor, resembling that of chlorine, bleach, and hot plastic or formaldehyde. This six-membered ring compound is the oxidized derivative of 1,4-hydroquinone. The molecule is multifunctional: it exhibits properties of a ketone, being able to form oximes; an oxidant, forming the dihydroxy derivative; and an alkene, undergoing addition reactions, especially those typical for α,β-unsaturated ketones. 1,4-Benzoquinone is sensitive toward both strong mineral acids and alkali, which cause condensation and decomposition of the compound.

Thiophenol Chemical compound

Thiophenol is an organosulfur compound with the formula C6H5SH, sometimes abbreviated as PhSH. This foul-smelling colorless liquid is the simplest aromatic thiol. The chemical structures of thiophenol and its derivatives are analogous to phenols except the oxygen atom in the hydroxyl group (-OH) bonded to the aromatic ring is replaced by a sulfur atom. The prefix thio- implies a sulfur-containing compound and when used before a root word name for a compound which would normally contain an oxygen atom, in the case of 'thiol' that the alcohol oxygen atom is replaced by a sulfur atom.

Dakin oxidation

The Dakin oxidation is an organic redox reaction in which an ortho- or para-hydroxylated phenyl aldehyde or ketone reacts with hydrogen peroxide in base to form a benzenediol and a carboxylate. Overall, the carbonyl group is oxidized, and the hydrogen peroxide is reduced.

<span class="mw-page-title-main">Mercury(II) acetate</span> Chemical compound

Mercury(II) acetate is the chemical compound with the formula Hg(O2CCH3)2. Commonly abbreviated Hg(OAc)2, this compound is employed as a reagent to generate organomercury compounds from unsaturated organic precursors. It is a white water-soluble solid, but samples appear yellowish with time owing to decomposition.

Meerwein arylation

The Meerwein arylation is an organic reaction involving the addition of an aryl diazonium salt (ArN2X) to an electron-poor alkene usually supported by a metal salt. The reaction product is an alkylated arene compound. The reaction is named after Hans Meerwein, one of its inventors who first published it in 1939.

Acetone cyanohydrin (ACH) is an organic compound used in the production of methyl methacrylate, the monomer of the transparent plastic polymethyl methacrylate (PMMA), also known as acrylic. It liberates hydrogen cyanide easily, so it is used as a source of such. For this reason, this cyanohydrin is also highly toxic.

2-Cyanoguanidine is a nitrile derived from guanidine. It is a dimer of cyanamide, from which it can be prepared. 2-Cyanoguanidine is a colourless solid that is soluble in water, acetone, and alcohol, but not nonpolar organic solvents.

4-Nitroaniline Chemical compound

4-Nitroaniline, p-nitroaniline or 1-amino-4-nitrobenzene is an organic compound with the formula C6H6N2O2. A yellow solid, it is one of three isomers of nitroaniline. It is an intermediate in the production of dyes, antioxidants, pharmaceuticals, gasoline, gum inhibitors, poultry medicines, and as a corrosion inhibitor.

In nitrile reduction a nitrile is reduced to either an amine or an aldehyde with a suitable chemical reagent.

Ureas

In chemistry, ureas are a class of organic compounds with the formula (R2N)2CO where R = H, alkyl, aryl, etc. Thus, in addition to describing the specific chemical compound urea ((H2N)2CO), urea is the name of a functional group that is found in many compounds and materials of both practical and theoretical interest. Generally ureas are colorless crystalline solids, which, owing to the presence of fewer hydrogen bonds, exhibit melting points lower than that of urea itself.

References

  1. ↑ "Cyanamide_msds".
  2. 1 2 NIOSH Pocket Guide to Chemical Hazards. "#0160". National Institute for Occupational Safety and Health (NIOSH).
  3. 1 2 3 4 5 Thomas Güthner; Bernd Mertschenk (2006). Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a08_139.pub2.
  4. ↑ Kurzer, Frederick; Lawson, Alexander (1954). "Methylisourea Hydrochloride". Organic Syntheses. 34: 67. doi:10.15227/orgsyn.034.0067.
  5. ↑ Jonczyk A, Ochal Z, Makosza M (1978). "Reactions of Organic Anions; LXXXV1. Catalytic Two-Phase Alkylation of Cyanamide". Synthesis . 1978 (12): 882–883. doi:10.1055/s-1978-24922.
  6. ↑ Ponsold K, Ihn W (1970). "Die Addition von cyanamid und Halogen an Olefine ein neues Verfahren zur Darstellung von vic.-Halogencyanaminen und Aziridinen". Tetrahedron Lett. 11 (13): 1125–1128. doi:10.1016/S0040-4039(01)97925-0. PMID   5439242.
  7. ↑ Kohn, Harold; Jung, Sang Hun (1983). "New stereoselective method for the preparation of vicinal diamines from olefins and cyanamide". Journal of the American Chemical Society. 105 (12): 4106–4108. doi:10.1021/ja00350a068..
  8. ↑ Weiss, Stefan; Michaud, Horst; Prietzel, Horst; Krommer, Helmut (1973). "A New, Simple Synthesis of 2-Aminobenzimidazole". Angewandte Chemie International Edition in English. 12 (10): 841. doi:10.1002/anie.197308411..
  9. ↑ S. Hünig, E. Lücke, and W. Brenninger (1961). "1-Morpholino-1-Cyclohexene". Organic Syntheses : 65. doi:10.15227/orgsyn.041.0065.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  10. ↑ Gewald, K.; Spies, H.; Mayer, R. (1970). "Zur Reaktion von Enaminen mit Schwefel und Cyanamid" [On the Reaction of Enamines with Sulfur and Cyanamide]. Journal für Praktische Chemie. 312 (5): 776–779. doi:10.1002/prac.19703120507..
  11. 1 2 E. B. Vliet (1925). "Diallylcyanamide". Organic Syntheses. 5: 45. doi:10.15227/orgsyn.005.0045.
  12. ↑ Verfahren zur Herstellung von Natrium-Dicyanamid, veröffentlicht am 10. August 2000, Anmelder: SKW Trostberg AG.
  13. ↑ "Sodium dicyanamide (Na-dicyanamide)". lonza.com. Archived from the original on 2013-05-23. Retrieved 2019-07-01.
  14. ↑ Deutsche Offenlegungsschrift DE-OS 10 2006 016 227 A1, Offenlegungsdatum: 11. Oktober 2007, Anmelder: Degussa GmbH.
  15. ↑ Wehrstedt, Klaus-Dieter; Wildner, Werner; Güthner, Thomas; Holzrichter, Klaus; Mertschenk, Bernd; Ulrich, Armin (2009-10-30). "Safe transport of cyanamide". Journal of Hazardous Materials. 170 (2–3): 829–835. doi:10.1016/j.jhazmat.2009.05.043. ISSN   0304-3894. PMID   19505756.
  16. ↑ Powell, A. (1999). "Action Program for Dormex Application on Peaches". Auburn University. Archived from the original on 2018-06-20.
  17. ↑ "ALZOGUR®". AlzChem (in German). Retrieved 2019-07-01.
  18. ↑ Stransky H, Amberger A (1973). "Isolierung und eigenschaften einer Cyanamid-hydratase (E.C.-Gruppe 4. 2.1.) aus Myrothecium verrucaria Alb. u. Schw" [Isolation and properties of a cyanamide hydratase (EC 4.2.1) from Myrothecium verrucaria]. Z. Pflanzenphysiol. 70: 74–87. doi:10.1016/S0044-328X(73)80049-2.
  19. ↑ Homer W. J. Cressman (1947). "N-Methyl-1-Naphthylcyanamide". Organic Syntheses. 27: 56. doi:10.15227/orgsyn.027.0056.
  20. ↑ Tyler, J.K.; Sheridan, J.; Costain, C.C. (August 1972). "The microwave spectra of cyanamide". Journal of Molecular Spectroscopy. 43 (2): 248–261. doi:10.1016/0022-2852(72)90021-5.
  21. ↑ Turner, B. E.; Liszt, H. S.; Kaifu, N.; Kisliakov, A. G. (November 1975). "Microwave detection of interstellar cyanamide". The Astrophysical Journal. 201: L149. Bibcode:1975ApJ...201L.149T. doi:10.1086/181963.
  22. 1 2 Schep L, Temple W, Beasley M (January 2009). "The adverse effects of hydrogen cyanamide on human health: an evaluation of inquiries to the New Zealand National Poisons Centre". Clinical Toxicology . Philadelphia, PA. 47 (1): 58–60. doi:10.1080/15563650802459254. PMID   18951270. S2CID   6961576.
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