Trichloromethylisocyanide Dichloride1

Cl3C-N=CCl2

[29164-55-4]  · C2Cl5N  · Trichloromethylisocyanide Dichloride  · (MW 215.28)

(strong chlorinating agent; used as a reagent in forming heterocycles and dehydrating amides1,2)

Physical Data: bp 59-60 °C/12 mmHg; d 1.698 g cm-3.

Solubility: sol most organic solvents.

Form Supplied in: liquid; must be synthesized.

Preparative Methods: synthesized by chlorinating triethylamine hydrochloride (in low yields)5 and, in better yields, with N,N-dimethylcarbamoyl chloride (1) at 250 °C (eq 1).5,6

Purification: redistil under reduced pressure.3

Handling, Storage, and Precautions: corrosive; moisture and air sensitive. Store under an inert atmosphere (see Aldrich safety index for phosphorus pentachloride4).

Chlorination of Functional Groups.

Trichloromethylisocyanide dichloride has been extensively used for the chlorination of functional groups.1 Alcohols, carboxylic and sulfonic acids, aldehydes, and phosphorus pentasulphide are converted to alkyl chlorides (2), acid and sulfonic chlorides (3,4), alkyl dichlorides (5), and phosphorus thiochloride (6),7 respectively (eqs 2-6).

Synthesis of Heterocycles.

Various heterocycles have been synthesized using trichloromethylisocyanide dichloride, normally involving a double nucleophilic attack from various substrates such as nitriles,8 hydrazines,9 and aromatic amines10 (eqs 7-10).

Heterocycles have also been formed by activating a carboxylic acid or amide towards cyclization with an amide by using trichloromethylisocyanide dichloride (eq 11).1

Dehydration of Amides.

Trichloromethylisocyanide dichloride has also been used to dehydrate amides in good yields (eq 12).1


1. Findeisen, K.; Wagner, K.; Holtschmidt, H. S 1972, 599.
2. FF 1974, 4, 523.
3. Harwood, L. M.; Moody, C. J. Experimental Organic Chemistry; Blackwell: Oxford, 1989; p 147.
4. Sigma-Aldrich Library of Chemical Safety Data, 2nd ed.; Lenga, R. E., Ed.; Sigma-Aldrich: Milwaukee, 1987; Vol. 2, p 2824A.
5. Holtschmidt, H.; Degener, E.; Schmelzer, H.-G.; Tarnow, H. AG(E) 1968, 7, 856.
6. Findeisen, K.; Holtschmidt, H.; Braden, R.; Schwarz, H. Ger. Patent 1 926 659, 1969 (CA 1973, 74, 8327d.)
7. Bunnenberg, R.; Jochims, J. C. CB 1981, 114, 1746.
8. Ischikawa, K.; Iida, N. Jpn. Patent 63 02 985 [88 02 985]. (CA 1988, 109, 92 989z). Findeisen, K.; Wagner, K. S 1978, 38. Findeisen, K.; Wagner, K. S 1978, 40.
9. Schmelzer, H.-G.; Degener, E.; Holtschmidt, H. AG(E) 1966, 5, 950.
10. Findeisen, K.; Holtschmidt, H.; Wagner, K. Ger. Patent 2 125 229, 1971 (CA 1975, 78, 43 508.)

Keith Jones

King's College London, UK



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