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 4,000 tonnes.[citation needed] 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
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
- ^ 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. ISBN 978-3527306732.
- ^ Moore, M. L.; Crossley, F. S. (1941). "Methyl Isothiocyanate". Organic Syntheses. 21: 81; Collected Volumes, vol. 3, p. 599.
- ^ Hartwig, Jürgen; Sommer, Herbert; Müller, Franz (2008). "Nematicides". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a17_125.pub2. ISBN 978-3527306732.
- ^ U.S. patent 3,417,085
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