Occurrence
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
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
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]
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
Isothiocyanates are weak electrophiles, susceptible to hydrolysis. In general, nucleophiles attack at carbon:
Electrochemical reduction gives thioformamides.[10]: 340
Flavor research
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
References
- 1 2 3 4 "Isothiocyanates". Micronutrient Information Center, Linus Pauling Institute, Oregon State University. 1 April 2017. Retrieved 14 April 2019.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ Dains FB; Brewster RQ; Olander CP (1926). "Phenyl Isothiocyanate". Organic Syntheses. 6: 72. doi:10.15227/orgsyn.006.0072.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 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.
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 |
|
|
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Hydrides | |
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Organic | |
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Oxides | |
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Halides |
- NF
- NF2
- NF3
- NF5 (?)
- NCl3
- NBr3
- NI3
- FN3
- ClN3
- BrN3
- IN3
- NH2F
- N2F2
- NH2Cl
- NHF2
- NHCl2
- NHBr2
- NHI2
|
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Oxidation states | |
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|
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Hydrocarbons (only C and H) | |
---|
Only carbon, hydrogen, and oxygen (only C, H and O) | |
---|
Only one element, not being carbon, hydrogen, or oxygen (one element, not C, H or O) | |
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Other | |
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|
Cruciferous biochemistry |
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Types of compounds | |
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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
|
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Bioactive metabolites |
- Goitrin
- Indole-3-carbinol
|
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- Brassicaceae (Cruciferous vegetables): Brassica
- Cruciferous Biochemistry
- genera (list)
|
|
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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
|
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|
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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
|
---|
|
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TRPML | Activators |
- EVP21
- MK6-83
- ML-SA1
- ML2-SA1
- PI(3,5)P2
- SF-22
- SN-2
|
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Blockers | |
---|
|
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TRPP | Activators |
- Triptolide (Tripterygium wilfordii)
|
---|
Blockers | |
---|
|
---|
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
|
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See also: Receptor/signaling modulators • Ion channel modulators |
Authority control databases: National | |
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