Methyl isothiocyanate

Methyl isothiocyanate
IUPAC name Methylisothiocyanate
Other names MITC
Identifiers
CAS number	556-61-6 Y
PubChem	11167
ChemSpider	10694 Y
KEGG	C18587 N
ChEMBL	CHEMBL396000 Y
Jmol-3D images	Image 1
SMILES S=C=NC
InChI InChI=1S/C2H3NS/c1-3-2-4/h1H3 Y Key: LGDSHSYDSCRFAB-UHFFFAOYSA-N Y InChI=1/C2H3NS/c1-3-2-4/h1H3 Key: LGDSHSYDSCRFAB-UHFFFAOYAS
Properties
Molecular formula	C2H3NS
Molar mass	73.12 g mol−1
Appearance	colourless solid
Density	1.07 g cm–3
Melting point	31 °C, 304 K, 88 °F
Boiling point	117 °C, 390 K, 243 °F
Solubility in water	8.2g/L
Hazards
MSDS	ACC# 07204
NFPA 704	1 3 1 W
Structure
Dipole moment	3.528 D
Related compounds
Related compounds	Methyl isocyanate Methyl thiocyanate
N isothiocyanate (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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

Other nucleophiles add similarly.

Applications

Solutions of MITC is used in agriculture as a soil fumigant, 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.

Safety

MITC is a dangerous lachrymator as well as being poisonous.

References

1. ^ ^{a b} F. Romanowski, H. Klenk "Thiocyanates and Isothiocyanates, Organic" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH: Weinheim.
2. ^ Moore, M. L.; Crossley, F. S. (1955), "Methyl Isothiocyanate", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV3P0599 ; Coll. Vol. 3: 599