Thiophosgene is a red liquid with the formula . It is a molecule with trigonal planar geometry. There are two reactive C–Cl bonds that allow it to be used in diverse
organic syntheses
''Organic Syntheses'' is a peer-reviewed scientific journal that was established in 1921. It publishes detailed and checked procedures for the synthesis of organic compounds. A unique feature of the review process is that all of the data and ex ...
.
Preparation
is prepared in a two-step process from
carbon disulfide
Carbon disulfide (also spelled as carbon disulphide) is a neurotoxic, colorless, volatile liquid with the formula and structure . The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical n ...
. In the first step, carbon disulfide is chlorinated to give trichloromethanesulfenyl chloride (
perchloromethyl mercaptan), :
:
The chlorination must be controlled as excess chlorine converts trichloromethanesulfenyl chloride into
carbon tetrachloride. Steam distillation separates the trichloromethanesulfenyl chloride, a rare sulfenyl chloride, and hydrolyzes the sulfur monochloride. Reduction of trichloromethanesulfenyl chloride produces thiophosgene:
:
Tin
Tin is a chemical element with the symbol Sn (from la, stannum) and atomic number 50. Tin is a silvery-coloured metal.
Tin is soft enough to be cut with little force and a bar of tin can be bent by hand with little effort. When bent, t ...
and dihydroanthracene
have been used for the reducing agents.
Reactions
is mainly used to prepare compounds with the connectivity where X = OR,
NHR. Such reactions proceed via intermediate such as CSClX. Under certain conditions, one can convert primary amines into
isothiocyanate
In organic chemistry, isothiocyanate is the functional group , formed by substituting the oxygen in the isocyanate group with a sulfur. Many natural isothiocyanates from plants are produced by enzymatic conversion of metabolites called glucosi ...
s.
also serves as a
dienophile to give, after reduction 5-thiacyclohexene derivatives. Thiophosgene is also known as the appropriate reagent in
Corey-Winter synthesis for stereospecific conversion of 1,2-diols into olefins.
It forms a head-to-tail dimer upon irradiation with UV light:
:
Unlike thiophosgene monomer, a red liquid, the photodimer, an example of a 1,3-
dithietane
Dithietanes are saturated heterocyclic compounds that contain two divalent sulfur atoms and two sp3-hybridized carbon centers. Two isomers are possible for this class of organosulfur compounds:
1,2-Dithietanes
1,2-dithietanes, 4-membered rings ...
, is a colorless solid.
Safety considerations
is considered highly toxic.
References
Further reading
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{{Chemical agents
Inorganic carbon compounds
Inorganic sulfur compounds
Thiochlorides
Thiocarbonyl compounds
Lachrymatory agents