Dimethylcarbamoyl chloride

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Dimethylcarbamoyl chloride
Names
Preferred IUPAC name
Dimethylcarbamoyl chloride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.001.099 Edit this at Wikidata
UNII
  • InChI=1S/C3H6ClNO/c1-5(2)3(4)6/h1-2H3
    Key: YIIMEMSDCNDGTB-UHFFFAOYSA-N
  • CN(C)C(=O)Cl
Properties
C3H6ClNO
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Dimethylcarbamoyl chloride (DMCC) is a reagent for transferring a dimethylcarbamoyl group to alcoholic or phenolic hydroxyl groups forming dimethyl carbamates, usually having pharmacological or pesticidal activities. Because of its high toxicity and its carcinogenic properties shown in animal experiments and presumably also in humans,[1] dimethylcarbamoyl chloride can only be used under stringent safety precautions.

The production of dimethylcarbamoyl chloride from phosgene and dimethylamine was reported as early as 1879 (reported as "Dimethylharnstoffchlorid" – dimethylurea chloride).[2]

Synthesis of dimethylcarbamoyl chloride with dimethylamine
Synthesis of dimethylcarbamoyl chloride with dimethylamine

DMCC can be produced in high yields (90%) at 275 °C by reacting phosgene with gaseous dimethylamine in a flow reactor.[3] To suppress the formation of ureas, excess phosgene is used (in a 3:1 ratio).

The reaction can also be carried out at the laboratory scale with diphosgene or triphosgene and an aqueous dimethylamine solution in the two-phase system of benzenexylene and water in a stirred reactor with sodium hydroxide as an acid scavenger. However, considerably lower yields (56%) are achieved due to the hydrolysis sensitivity of DMCC.[4]

Dimethylcarbamoyl chloride is also formed (together with methyl chloride) when reacting phosgene with trimethylamine.[5]

Synthesis of dimethylcarbamoyl chloride with trimethylamine
Synthesis of dimethylcarbamoyl chloride with trimethylamine

A more recent process is based on chlorodimethylamine, which is converted practically quantitatively to dimethylcarbamoyl chloride on a palladium catalyst under pressure with carbon monoxide at room temperature.[6]

Synthesis of dimethylcarbamoyl chloride from chloramine
Synthesis of dimethylcarbamoyl chloride from chloramine

DMCC can also be formed in small amounts (up to 20 ppm) from dimethylformamide (DMF) in the Vilsmeier–Haack reaction[7] or when DMF is used as a catalyst in the reaction of carboxylic acids with thionyl chloride to the corresponding acyl chloride.[8]

Synthesis of dimethylcarbamoyl chloride with dimethylformamide
Synthesis of dimethylcarbamoyl chloride with dimethylformamide

The tendency towards DMCC formation depends on the chlorination reagent (thionyl chloride > oxalyl chloride > phosphorus oxychloride) and is higher in the presence of a base. However, dicarbamoyl chloride hydrolyses very quickly to dimethylamine, hydrochloric acid and carbon dioxide (with a half-life of about 6 minutes at 0 °C) so that less than 3 ppm of dicarbamoyl chloride is found in the Vilsmeier product after aqueous workup.[9]

Properties

See also

References

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