Isothiocyanate

Chemical group (–N=C=S)

General structure of an isothiocyanate.

In organic chemistry, isothiocyanate is a functional group as found in compounds with the formula R−N=C=S. Isothiocyanates are the more common isomers of thiocyanates, which have the formula R−S−C≡N.

## Occurrence

[edit]

Many isothiocyanates from plants are produced by enzymatic conversion of metabolites called glucosinolates. A prominent natural isothiocyanate is allyl isothiocyanate, also known as mustard oils.

Cruciferous vegetables, such as bok choy, broccoli, cabbage, cauliflower, kale, and others, are rich sources of glucosinolate precursors of isothiocyanates.[1]

## Structure

[edit]

The N=C and C=S distances are 117 and 158 pm.[2] By contrast, in methyl thiocyanate, N≡C and C−S distances are 116 and 176 pm.

Typical bond angles for C−N=C in aryl isothiocyanates are near 165°. Again, the thiocyanate isomers are quite different with C−S−C angle near 100°.[3] In both isomers the SCN angle approaches 180°.

## Synthesis

[edit]

Allyl thiocyanate isomerizes to the isothiocyanate:[4]

CH2=CHCH2SCN → CH2=CHCH2NCS

Isothiocyanates can be prepared by treating organic dithiocarbamate salts with lead nitrate or tosyl chloride.[5][6]

Synthesis of phenyl isothiocyanate

Isothiocyanates may also be accessed by the fragmentation reactions of 1,4,2-oxathiazoles.[7] This methodology has been applied to a polymer-supported synthesis of isothiocyanates.[8]

## Reactions

[edit]

Isothiocyanates are weak electrophiles, susceptible to hydrolysis. In general, nucleophiles attack at carbon:

The reaction of acetophenone enolate with phenyl isothiocyanate. In this one-pot synthesis[9] the ultimate reaction product is a Thiazolidine. This reaction is stereoselective with the formation of the Z-isomer only.

Electrochemical reduction gives thioformamides.[10]: 340

## Flavor research

[edit]

Isothiocyanates occur widely in nature and are of interest in food science and medical research.[1] Vegetable foods with characteristic flavors due to isothiocyanates include bok choy, broccoli, cabbage, cauliflower, kale, wasabi, horseradish, mustard, radish, Brussels sprouts, watercress, papaya seeds, nasturtiums, and capers.[1] These species generate isothiocyanates in different proportions, and so have different, but recognizably related, flavors. They are all members of the order Brassicales, which is characterized by the production of glucosinolates, and of the enzyme myrosinase, which acts on glucosinolates to release isothiocyanates.[1]

* Sinigrin is the precursor to allyl isothiocyanate
* Glucotropaeolin is the precursor to benzyl isothiocyanate
* Gluconasturtiin is the precursor to phenethyl isothiocyanate
* Glucoraphanin is the precursor to sulforaphane

## Uses

[edit]

Phenyl isothiocyanate, is used for amino acid sequencing in the Edman degradation.

## Coordination chemistry

[edit]

Isothiocyanate and its linkage isomer thiocyanate are ligands in coordination chemistry. Thiocyanate is a more common ligand.

## See also

[edit]

* Methyl isothiocyanate

## References

[edit]

1. ^ a b c d "Isothiocyanates". Micronutrient Information Center, Linus Pauling Institute, Oregon State University. 1 April 2017. Retrieved 14 April 2019.
2. ^ Majewska, Paulina; Rospenk, Maria; Czarnik-Matusewicz, Bogusława; Kochel, Andrzej; Sobczyk, Lucjan; Dąbrowski, Roman (2008). "Structure and polarized IR spectra of 4-isothiocyanatophenyl 4-heptylbenzoate (7TPB)". Chemical Physics. 354 (1–3): 186–195\. Bibcode:2008CP....354..186M. doi:10.1016/j.chemphys.2008.10.024.1–3&rft.pages=186-195&rft.date=2008&rft_id=info:doi/10.1016/j.chemphys.2008.10.024&rft_id=info:bibcode/2008CP....354..186M&rft.aulast=Majewska&rft.aufirst=Paulina&rft.au=Rospenk,+Maria&rft.au=Czarnik-Matusewicz,+Bogusława&rft.au=Kochel,+Andrzej&rft.au=Sobczyk,+Lucjan&rft.au=Dąbrowski,+Roman&rfr_id=info:sid/en.wikipedia.org:Isothiocyanate" class="Z3988">
3. ^ Erian, Ayman W.; Sherif, Sherif M. (1999). "The chemistry of thiocyanic esters". Tetrahedron. 55 (26): 7957–8024\. doi:10.1016/S0040-4020(99)00386-5.
4. ^ Emergon, David W. (1971). "The Preparation and Isomerization of Allyl Thiocyanate. An Organic Chemistry Experiment". Journal of Chemical Education. 48 (1): 81. Bibcode:1971JChEd..48...81E. doi:10.1021/ed048p81.
5. ^ Dains FB; Brewster RQ; Olander CP (1926). "Phenyl Isothiocyanate". Organic Syntheses. 6: 72. doi:10.15227/orgsyn.006.0072.
6. ^ Wong, R; Dolman, SJ (2007). "Isothiocyanates from tosyl chloride mediated decomposition of in situ generated dithiocarbamic acid salts". The Journal of Organic Chemistry. 72 (10): 3969–3971\. doi:10.1021/jo070246n. PMID 17444687.
7. ^ O'Reilly, RJ; Radom, L (2009). "Ab initio investigation of the fragmentation of 5,5-diamino-substituted 1,4,2-oxathiazoles". Organic Letters. 11 (6): 1325–1328\. doi:10.1021/ol900109b. PMID 19245242.
8. ^ Burkett, BA; Kane-Barber, JM; O'Reilly, RJ; Shi, L (2007). "Polymer-supported thiobenzophenone : a self-indicating traceless 'catch and release' linker for the synthesis of isothiocyanates". Tetrahedron Letters. 48 (31): 5355–5358\. doi:10.1016/j.tetlet.2007.06.025.
9. ^ Ortega-Alfaro, M. C.; López-Cortés, J. G.; Sánchez, H. R.; Toscano, R. A.; Carrillo, G. P.; Álvarez-Toledano, C. (2005). "Improved approaches in the synthesis of new 2-(1, 3-thiazolidin-2Z-ylidene)acetophenones". Arkivoc. 2005 (6): 356–365\. doi:10.3998/ark.5550190.0006.631. hdl:2027/spo.5550190.0006.631.
10. ^ Hammerich, Ole; Parke, Vernon D. (1977). "The electrochemistry of cyanates and related compounds". In Patai, Saul (ed.). The Chemistry of Cyanates and Their Thio Derivatives. Vol. Part 1. Chichester: Wiley. ISBN 0-471-99477-4. LCCN 75-6913.

* v
* t
* e

Salts and covalent derivatives of the cyanide ion

| HCN |  |  |  | He

|
|
|
|

LiCN | Be(CN)2 | B(CN)3 | C(CN)4
C2(CN)2 | NH4CN
ONCN
O2NCN
N3CN | OCN−
-NCO
O(CN)2 | FCN | Ne
NaCN | Mg(CN)2 | Al(CN)3 | Si(CN)4
(CH3)3SiCN | P(CN)3 | SCN−
-NCS
(SCN)2
S(CN)2 | ClCN | Ar
KCN | Ca(CN)2 |  | Sc(CN)3 | Ti  | V  | Cr(CN)63− | Mn  | Fe(CN)2
Fe(CN)64−
Fe(CN)63− | Co(CN)2
Co(CN)3−
5 | Ni(CN)2
Ni(CN)42−
Ni(CN)44− | CuCN | Zn(CN)2 | Ga(CN)3 | Ge(CN)2
Ge(CN)4 | As(CN)3
(CH3)2AsCN
(C6H5)2AsCN | SeCN−
(SeCN)2
Se(CN)2 | BrCN | Kr
RbCN | Sr(CN)2 |  | Y(CN)3 | Zr  | Nb  | Mo(CN)84− | Tc  | Ru  | Rh  | Pd(CN)2 | AgCN | Cd(CN)2 | In(CN)3 | Sn(CN)2 | Sb(CN)3 | Te(CN)2
Te(CN)4 | ICN | Xe
CsCN | Ba(CN)2 | *  | Lu(CN)3 | Hf  | Ta  | W(CN)84− | Re  | Os  | Ir  | Pt(CN)42-
Pt(CN)64-
| AuCN
Au(CN)2− | Hg2(CN)2
Hg(CN)2 | TlCN | Pb(CN)2 | Bi(CN)3 | Po  | At  | Rn
Fr  | Ra  | **  | Lr  | Rf  | Db  | Sg  | Bh  | Hs  | Mt  | Ds  | Rg  | Cn  | Nh  | Fl  | Mc  | Lv  | Ts  | Og

*  | La(CN)3 | Ce(CN)3
Ce(CN)4 | Pr(CN)3 | Nd  | Pm  | Sm(CN)3 | Eu(CN)3 | Gd(CN)3 | Tb  | Dy(CN)3 | Ho(CN)3 | Er  | Tm  | Yb(CN)3
**  | Ac(CN)3 | Th(CN)4 | Pa  | UO2(CN)2 | Np  | Pu  | Am  | Cm  | Bk  | Cf  | Es  | Fm  | Md  | No

* v
* t
* e

Nitrogen species

Hydrides|

* NH3
* NH4+
* NH2−
* N3−
* NH2OH
* N2H4
* HN3
* N3−
* NH5 (?)

Organic|

* NR3
* >C=NR
* −CONR2
* −CN
* HCN
* CN−
* (CN)2
* H2NCN
* HOCN
* HNCO
* HNCS
* CH2N2
* -NO
* -NO2

Oxides|

* NO / (NO)2
* N2O3
* HNO2 / NO−
2 / NO+
* NO2 / (NO2)2
* N2O5
* HNO3 / NO−
3 / NO+

* NO3
* HNO / (HON)2 / N2O2−
2 / N2O
* H2NNO2
* HO2NO / ONOO−
* HO2NO2 / O2NOO−
* NO3−

* H4N2O4 / N2O2−

Halides|

* NF
* NF2
* NF3
* NF5 (?)
* NCl3
* NBr3
* NI3
* FN3
* ClN3
* BrN3
* IN3
* NH2F
* N2F2
* NH2Cl
* NHF2
* NHCl2
* NHBr2
* NHI2

Oxidation states|

−3, −2, −1, 0, +1, +2, +3, +4, +5 (a strongly acidic oxide)

* v
* t
* e

Functional groups

Hydrocarbons
(only C and H)|

* Alkyl
* Methyl
* Ethyl
* Propyl
* Cyclopropyl
* Butyl
* Pentyl
* Methylene
* Bridge
* Methine
* Alkene
* Vinyl
* Allyl
* 1-Propenyl
* Crotyl
* Allene
* Cumulene
* Aryl
* Phenyl
* Benzyl
* Alkyne
* Carbene

Only carbon,
hydrogen,
and oxygen
(only C, H and O)|

| R-O-R|

* Acetal
* Alcohol
* Alkoxy
* Methoxy
* Ether
* Enol ether
* Epoxide
* Peroxy
* Hydroperoxy
* Dioxiranes
* Ethylenedioxy
* Methylenedioxy

|

carbonyl|

* Acyl
* Acetyl
* Acryloyl
* Benzoyl
* Aldehyde
* Ketene
* Ketone
* Ynone
* Reductone

carboxy|

* Carboxyl
* Acetoxy
* Anhydride
* Ester
* Orthoester

Only one
element,
not being
carbon,
hydrogen,
or oxygen
(one element,
not C, H or O)|

| Nitrogen|

* Amine
* Enamine
* Ammonium
* Hydrazo
* Nitrene
* Imine
* Oxime
* Hydrazone
* Azo
* Amide
* Imidate
* Amidine
* Carbamate
* Imide
* Nitrile
* Isonitrile
* Cyanate
* Isocyanate
* Nitrate
* Nitrite
* Nitro
* Nitroso
* NONOate
* Triazole
* Tetrazole

|

Silicon|

* Silane
* Hydrosilane
* Chlorosilane
* Silene
* Silanol
* Siloxide
* Siloxane
* Silanone
* Silether
* Silole
* Silatrane
* Silicate

Phosphorus|

* Phosphate
* Phosphodiester
* Phosphonate
* Phosphite
* Phosphonous
* Phosphinate
* Phosphine oxide
* Phosphine
* Phosphonium
* Phosphaalkene
* Phosphaalkyne
* Phosphaallene

Sulfur|

* Thiol
* Thioether
* Sulfonium
* Thia-crown ether
* Persulfide
* Disulfide
* Sulfenic acid
* Thiosulfinate
* Sulfoxide
* Thiosulfonate
* Sulfinic acid
* Sulfone
* Sulfonic acid
* Thioketone
* Thial
* Thioester
* Thionoester
* Thioxanthate
* Xanthate

Boron|

* Boronic acid
* Borinic acid

Selenium|

* Selenol
* Selenonic acid
* Seleninic acid
* Selenenic acid
* Selone
* Selenoether

Tellurium|

* Tellurol
* Telluroketone
* telluroether

Polonium|

* Polonol
* Polonoether

Halo|

* Haloalkane
* Fluoroethyl
* Trifluoromethyl
* Trichloromethyl
* Trifluoromethoxy
* Hypervalent iodine
* Vinyl halide
* Iodide
* Acyl halide
* Chloride
* Perchlorate

Other|

* Isothiocyanate
* Phosphoramides
* Sulfenyl chloride
* Sulfonamide
* Thiocyanate
* Sulfinylamines

See also
chemical classification
chemical nomenclature

inorganic
organic

* v
* t
* e

Cruciferous biochemistry

Types of compounds|

* Phenylthiocarbamide (PTC/PTU)
* Thiocyanates
* Nitriles
* Indoles
* Gibberellin

Glucosinolates|

* Glucobrassicin
* Glucocapparin
* Glucoraphanin
* Gluconasturtiin
* Glucotropaeolin
* Progoitrin
* Sinigrin
* Sinalbin

Isothiocyanates (ITC, mustard oils)|

* Sulforaphane (SFN)
* Raphanin
* Allyl isothiocyanate (AITC)
* Methyl isothiocyanate (MITC)
* Benzyl isothiocyanate (BITC)
* Fluorescein isothiocyanate (FITC)
* Phenyl isothiocyanate (PITC)
* Phenethyl isothiocyanate (PEITC)
* 6-MITC
* Erucin

Bioactive metabolites|

* Goitrin
* Indole-3-carbinol

* Brassicaceae (Cruciferous vegetables): Brassica
* Cruciferous Biochemistry
* genera (list)

* v
* t
* e

TRP channel modulators

TRPA|

| Activators|

* 4-Hydroxynonenal
* 4-Oxo-2-nonenal
* 5,6-EET
* 12S-HpETE
* 15-Deoxy-Δ12,14-prostaglandin J2
* α-Sanshool (ginger, Sichuan and melegueta peppers)
* Acrolein
* Allicin (garlic)
* Allyl isothiocyanate (mustard, radish, horseradish, wasabi)
* AM404
* ASP-7663
* Bradykinin
* Cannabichromene (cannabis)
* Cannabidiol (cannabis)
* Cannabigerol (cannabis)
* Cinnamaldehyde (cinnamon)
* CR gas (dibenzoxazepine; DBO)
* CS gas (2-chlorobenzal malononitrile)
* Cuminaldehyde (cumin)
* Curcumin (turmeric)
* Dehydroligustilide (celery)
* Diallyl disulfide
* Dicentrine (Lindera spp.)
* Farnesyl thiosalicylic acid
* Formalin
* Gingerols (ginger)
* Hepoxilin A3
* Hepoxilin B3
* Hydrogen peroxide
* Icilin
* Isothiocyanate
* JT-010
* Ligustilide (celery, Angelica acutiloba)
* Linalool (Sichuan pepper, thyme)
* Methylglyoxal
* Methyl salicylate (wintergreen)
* N-Methylmaleimide
* Nicotine (tobacco)
* Oleocanthal (olive oil)
* Paclitaxel (Pacific yew)
* Paracetamol (acetaminophen)
* PF-4840154
* Phenacyl chloride
* Polygodial (Dorrigo pepper)
* Shogaols (ginger, Sichuan and melegueta peppers)
* Tear gases
* Tetrahydrocannabinol (cannabis)
* Tetrahydrocannabiorcol
* Thiopropanal S-oxide (onion)
* Umbellulone (Umbellularia californica)
* WIN 55,212-2

|

Blockers|

* A-967079
* AM-0902
* Dehydroligustilide (celery)
* HC-030031
* Nicotine (tobacco)
* PF-04745637
* Ruthenium red

TRPC|

| Activators|

* Adhyperforin (St John's wort)
* Diacyl glycerol
* GSK1702934A
* Hyperforin (St John's wort)
* Substance P

|

Blockers|

* DCDPC
* DHEA-S
* Flufenamic acid
* GSK417651A
* GSK2293017A
* Meclofenamic acid
* N-(p-Amylcinnamoyl)anthranilic acid
* Niflumic acid
* Pregnenolone sulfate
* Progesterone
* Pyr3
* Tolfenamic acid

TRPM|

| Activators|

* ADP-ribose
* BCTC
* Calcium (intracellular)
* CIM-0216
* Cold
* Coolact P
* Cooling Agent 10
* Eucalyptol (eucalyptus)
* Frescolat MGA
* Frescolat ML
* Geraniol
* Hydroxycitronellal
* Icilin
* Linalool
* Menthol (mint)
* PMD 38
* Pregnenolone sulfate
* Rutamarin (Ruta graveolens)
* Steviol glycosides (e.g., stevioside) (Stevia rebaudiana)
* Sweet tastants (e.g., glucose, fructose, sucrose; indirectly)
* Thio-BCTC
* WS-12

|

Blockers|

* AMG-333
* Capsazepine
* Clotrimazole
* DCDPC
* Elismetrep
* Flufenamic acid
* Meclofenamic acid
* Mefenamic acid
* N-(p-Amylcinnamoyl)anthranilic acid
* Nicotine (tobacco)
* Niflumic acid
* Ononetin
* PF-05105679
* RQ-00203078
* Ruthenium red
* Rutamarin (Ruta graveolens)
* Tolfenamic acid
* TPPO
* TRPM4-IN-5

TRPML|

| Activators|

* EVP21
* MK6-83
* ML-SA1
* ML2-SA1
* PI(3,5)P2
* SF-22
* SN-2

|

Blockers|

* ML-SI3
* PI(4,5)P2

TRPP|

| Activators|

* Triptolide (Tripterygium wilfordii)

|

Blockers|

* Ruthenium red

TRPV|

| Activators|

* 2-APB
* 5,6-EET
* 9-HODE
* 9-oxoODE
* 12S-HETE
* 12S-HpETE
* 13-HODE
* 13-oxoODE
* 20-HETE
* α-Sanshool (ginger, Sichuan and melegueta peppers)
* Allicin (garlic)
* AM404
* Anandamide
* Bisandrographolide (Andrographis paniculata)
* Camphor (camphor laurel, rosemary, camphorweed, African blue basil, camphor basil)
* Cannabidiol (cannabis)
* Cannabidivarin (cannabis)
* Capsaicin (chili pepper)
* Carvacrol (oregano, thyme, pepperwort, wild bergamot, others)
* DHEA
* Diacyl glycerol
* Dihydrocapsaicin (chili pepper)
* Estradiol
* Eugenol (basil, clove)
* Evodiamine (Euodia ruticarpa)
* Gingerols (ginger)
* GSK1016790A
* Heat
* Hepoxilin A3
* Hepoxilin B3
* Homocapsaicin (chili pepper)
* Homodihydrocapsaicin (chili pepper)
* Incensole (incense)
* Lysophosphatidic acid
* Low pH (acidic conditions)
* Menthol (mint)
* N-Arachidonoyl dopamine
* N-Oleoyldopamine
* N-Oleoylethanolamide
* Nonivamide (PAVA) (PAVA spray)
* Nordihydrocapsaicin (chili pepper)
* Paclitaxel (Pacific yew)
* Paracetamol (acetaminophen)
* Phenylacetylrinvanil
* Phorbol esters (e.g., 4α-PDD)
* Piperine (black pepper, long pepper)
* Polygodial (Dorrigo pepper)
* Probenecid
* Protons
* RhTx
* Rutamarin (Ruta graveolens)
* Resiniferatoxin (RTX) (Euphorbia resinifera/pooissonii)
* Shogaols (ginger, Sichuan and melegueta peppers)
* Tetrahydrocannabivarin (cannabis)
* Thymol (thyme, oregano)
* Tinyatoxin (Euphorbia resinifera/pooissonii)
* Tramadol
* Vanillin (vanilla)
* Zucapsaicin

|

Blockers|

* α-Spinasterol (Vernonia tweediana)
* AMG-517
* AMG-9810
* Asivatrep
* BCTC
* Cannabigerol (cannabis)
* Cannabigerolic acid (cannabis)
* Cannabigerovarin (cannabis)
* Cannabinol (cannabis)
* Capsazepine
* DCDPC
* DHEA
* DHEA-S
* Flufenamic acid
* GRC-6211
* HC-067047
* Lanthanum
* Mavatrep
* Meclofenamic acid
* N-(p-Amylcinnamoyl)anthranilic acid
* NGD-8243
* Niflumic acid
* Pregnenolone sulfate
* RN-1734
* RN-9893
* Ruthenium red
* SB-366791
* SB-705498
* Tivanisiran
* Tolfenamic acid
* TRPV3-74a

See also: Receptor/signaling modulators • Ion channel modulators

Authority control databases: National |

* Germany

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*[v]: View this template
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*[TRP]: Transient receptor potential
*[TRPA]: Transient receptor potential ankyrin channel
*[TRPC]: Transient receptor potential canonical channel
*[TRPM]: Transient receptor potential melastatin channel
*[TRPML]: Transient receptor potential mucolipin channel
*[TRPP]: Transient receptor potential polycystin channel
*[TRPV]: Transient receptor potential vanilloid channel