Chloroiodomethane

Chloroiodomethane is an organohalogen compound with the formula CH2ClI. It is a dihalomethyl derivative of methane, containing one chlorine and one iodine substituent on a methyl group. Physically, it is a colorless, volatile liquid at room temperature and is soluble in many organic solvents. It is reactive toward nucleophiles and radicals, making it useful as a halomethylating agent in organic synthesis.

Preparation: It can be prepared by halogen exchange starting from chloromethyl derivatives or from iodination of chloromethyl precursors; it is generally handled under inert atmosphere due to its reactivity and tendency to hydrolyze in moisture.

Reactions and applications: In synthesis, chloroiodomethane serves as a source of halomethyl groups, enabling introduction of CH2Cl or CH2I fragments into substrates via nucleophilic substitution or radical pathways. It is employed in the preparation of more complex halomethyl reagents and as an intermediate in the synthesis of pharmaceuticals, agrochemicals, and natural products. It can participate in various transformations including alkylation and carbenoid-type reactions under appropriate conditions.

Safety: Chloroiodomethane is toxic and can be irritating to the skin, eyes, and mucous membranes. It should be handled in a well-ventilated fume hood with appropriate protective equipment, stored in tightly closed containers away from moisture and incompatible reagents.

See also: Methyl iodide, chloromethyl methyl ether, halomethylating agents.