Methyl isothiocyanate

Methyl isothiocyanate
Names
	IUPAC name Methylisothiocyanate
	Other names MITC
Identifiers
CAS Number	556-61-6 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:78337 ;
ChEMBL	ChEMBL396000 ;
ChemSpider	10694 ;
ECHA InfoCard	100.008.303
KEGG	C18587 ;
PubChem CID	11167;
UNII	RWE2M5YDW1 ;
CompTox Dashboard (EPA)	DTXSID2027204 ;
	InChI InChI=1S/C2H3NS/c1-3-2-4/h1H3 Key: LGDSHSYDSCRFAB-UHFFFAOYSA-N ; InChI=1/C2H3NS/c1-3-2-4/h1H3 Key: LGDSHSYDSCRFAB-UHFFFAOYAS;
	SMILES S=C=NC;
Properties
Chemical formula	C2H3NS
Molar mass	73.12
Appearance	colourless solid
Density	1.07 g cm−3
Melting point	31 °C (88 °F; 304 K)
Boiling point	117 °C (243 °F; 390 K)
Solubility in water	8.2g/L
Hazards
Safety data sheet	ACC# 07204
NFPA 704 (fire diamond)	1 3 1
Structure
Dipole moment	3.528 D
Related compounds
Related compounds	Methyl isocyanate; Methyl thiocyanate
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Methyl isothiocyanate is the organosulfur compound with the formula CH₃N=C=S. This low melting colorless solid is a powerful lachrymator. As a precursor to a variety of valuable bioactive compounds, it is the most important organic isothiocyanate in industry.^[1]

Synthesis

It is prepared industrially by two routes. Annual production in 1993 was estimated to be 4M kg. The main method involves the thermal rearrangement of methyl thiocyanate:^[1]

CH₃S-C≡N → CH₃N=C=S

It is also prepared via with the reaction of methylamine with carbon disulfide followed by oxidation of the resulting dithiocarbamate with hydrogen peroxide. A related method is useful to prepare this compound in the laboratory.^[2]

MITC forms naturally upon the enzymatic degradation of glucocapparin, a modified sugar found in capers.

Reactions

A characteristic reaction is with amines to give methyl thioureas:

CH₃NCS + R₂NH → R₂NC(S)NHCH₃

Reaction scheme: MITC and secondary amine react to form a thiourea

Other nucleophiles add similarly.

Applications

Solutions of MITC are used in agriculture as soil fumigants, mainly for protection against fungi and nematodes.

MITC is a building block for the synthesis of 1,3,4-thiadiazoles, which are heterocyclic compounds used as herbicides. Commercial products include "Spike", "Ustilan," and "Erbotan."

Well known pharmaceuticals prepared using MITC include Zantac and Tagamet. Suritozole is a third example.

MITC is used in the Etasuline patent (Ex2^[3]), although the compound is question (Ex6) is with EITC.

Safety

MITC is a dangerous lachrymator as well as being poisonous.

References

^ ^a ^b Romanowski, F.; Klenk, H. "Thiocyanates and Isothiocyanates, Organic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a26_749.
^ Moore, M. L.; Crossley, F. S. (1941). "Methyl Isothiocyanate". Organic Syntheses. 21: 81.; Collective Volume, 3, p. 599
^ U.S. Patent 3,417,085

[Ullmann-1] Romanowski, F.; Klenk, H. "Thiocyanates and Isothiocyanates, Organic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a26_749.

[2] Moore, M. L.; Crossley, F. S. (1941). "Methyl Isothiocyanate". Organic Syntheses. 21: 81.; Collective Volume, 3, p. 599

[3] U.S. Patent 3,417,085

[1]

[2]