Methyl isothiocyanate

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]

Methyl isothiocyanate
Names
Preferred IUPAC name
Isothiocyanatomethane
Other names
MITC, Trapex, Trapex, Vorlex, MITC-Fume, MIT, Morton EP-161E, WN 12
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.008.303
EC Number
  • 209-132-5
KEGG
UNII
UN number 2477
  • InChI=1S/C2H3NS/c1-3-2-4/h1H3 checkY
    Key: LGDSHSYDSCRFAB-UHFFFAOYSA-N checkY
  • InChI=1/C2H3NS/c1-3-2-4/h1H3
    Key: LGDSHSYDSCRFAB-UHFFFAOYAS
  • S=C=NC
Properties
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)
8.2g/l
Hazards
GHS labelling:
GHS05: CorrosiveGHS06: ToxicGHS07: Exclamation markGHS09: Environmental hazard
Danger
H301, H314, H317, H331, H410
P260, P261, P264, P270, P271, P272, P273, P280, P301+P310, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P311, P321, P330, P333+P313, P363, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamond
3
1
1
Safety data sheet (SDS) ACC# 07204
Structure
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).
☒N verify (what is checkY☒N ?)
Infobox references

Synthesis

It is prepared industrially by two routes. Annual production in 1993 was estimated to be 4,000 tonnes. 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 glucoside 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.[3]

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[4]), although the compound is question (Ex6) is with EITC.

Safety

MITC is a dangerous lachrymator as well as being poisonous.

See also

References
  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, vol. 3, p. 599
  3. Hartwig, Jürgen; Sommer, Herbert; Müller, Franz (2008). "Nematicides". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a17_125.pub2. ISBN 978-3527306732.
  4. U.S. Patent 3,417,085
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