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.
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:
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.
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: