Allyl isothiocyanate

Allyl isothiocyanate (AITC) is a naturally occurring unsaturated isothiocyanate. The colorless oil is responsible for the pungent taste of cruciferous vegetables such as mustard, radish, horseradish, and wasabi. This pungency and the lachrymatory effect of AITC are mediated through the TRPA1 and TRPV1 ion channels.^[1][2][3] It is slightly soluble in water, but more soluble in most organic solvents.^[4]

Allyl isothiocyanate

Allyl isothiocyanate
Space-filling model of allyl isothiocyanate
Names
Preferred IUPAC name 3-Isothiocyanatoprop-1-ene
Other names Synthetic mustard oil
Identifiers
CAS Number	57-06-7 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:73224 N
ChEMBL	ChEMBL233248 Y
ChemSpider	21105854 Y
ECHA InfoCard	100.000.281
EC Number	200-309-2
IUPHAR/BPS	2420
KEGG	D02818 Y C19317
PubChem CID	5971
RTECS number	NX8225000
UNII	BN34FX42G3 Y
UN number	1545
CompTox Dashboard (EPA)	DTXSID3020047
InChI InChI=1S/C4H5NS/c1-2-3-5-4-6/h2H,1,3H2 Y Key: ZOJBYZNEUISWFT-UHFFFAOYSA-N Y InChI=1/C4H5NS/c1-2-3-5-4-6/h2H,1,3H2 Key: ZOJBYZNEUISWFT-UHFFFAOYAS
SMILES C=CCN=C=S
Properties
Chemical formula	C4H5NS
Molar mass	99.15 g·mol−1
Density	1.013–1.020 g/cm3
Melting point	−102 °C (−152 °F; 171 K)
Boiling point	148 to 154 °C (298 to 309 °F; 421 to 427 K)
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H226, H301, H310, H315, H319, H330, H335, H410
Precautionary statements	P210, P233, P240, P241, P242, P243, P260, P261, P262, P264, P270, P271, P273, P280, P284, P301+P310, P302+P350, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P320, P321, P322, P330, P332+P313, P337+P313, P361, P362, P363, P370+P378, P391, P403+P233, P403+P235, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Biosynthesis and biological functions

Allyl isothiocyanate can be obtained from the seeds of black mustard (Rhamphospermum nigrum) or brown Indian mustard (Brassica juncea). When these mustard seeds are broken, the enzyme myrosinase is released and acts on a glucosinolate known as sinigrin to give allyl isothiocyanate.^[5] This serves the plant as a defense against herbivores; since it is harmful to the plant itself,^[6] it is stored in the harmless form of the glucosinolate, separate from the myrosinase enzyme. When an animal chews the plant, the allyl isothiocyanate is released, repelling the animal. Human appreciation of the pungency is learned.^[7]: 105

The compound has been shown to strongly repel fire ants (Solenopsis invicta).^[8] AITC vapor is also used as an antimicrobial and shelf life extender in food packaging.^{[7]: 118–120}

Production and applications

Allyl isothiocyanate is produced commercially by the reaction of allyl chloride and potassium thiocyanate:^[4]

CH₂=CHCH₂Cl + KSCN → CH₂=CHCH₂NCS + KCl

The product obtained in this fashion is sometimes known as synthetic mustard oil. Allyl thiocyanate isomerizes to the isothiocyanate:^[9]

CH₂=CHCH₂SCN → CH₂=CHCH₂NCS

Allyl isothiocyanate can also be liberated by dry distillation of the seeds. The product obtained in this fashion is known as volatile oil of mustard.

It is used principally as a flavoring agent in foods. Synthetic allyl isothiocyanate is used as an insecticide, as an anti-mold agent ^[10] bacteriocide,^[11] and nematicide, and is used in certain cases for crop protection.^[4] It is also used in fire alarms for the deaf.^[12][13]

Hydrolysis of allyl isothiocyanate gives allylamine.^[14]

Safety

Allyl isothiocyanate has an LD₅₀ of 151 mg/kg and is a lachrymator (similar to tear gas or mace).^[4]

Oncology

Based on in vitro experiments and animal models, allyl isothiocyanate exhibits many of the desirable attributes of a cancer chemopreventive agent.^[15]

See also

• Mustard plaster, traditional home remedy
• Piperine, the piquant chemical in black pepper
• Capsaicin, the piquant chemical in chili peppers
• Allicin, the piquant flavor chemical in raw garlic