metaansulfonüülkloriidi

metaansulfonüülkloriid is a chemical compound with the formula CH3SO2Cl. It is a colorless liquid with a pungent odor. The compound is an organosulfur compound and a derivative of methanesulfonic acid. It is a reactive chemical intermediate used in organic synthesis.

The primary application of metaansulfonüülkloriid is as a mesylating agent. This means it is used to introduce the methanesulfonyl group (CH3SO2-, often abbreviated as Ms or Mes) onto other molecules, typically alcohols or amines. This mesylation process converts hydroxyl groups (-OH) into mesyloxy groups (-OSO2CH3) and amino groups (-NH2) into mesylamide groups (-NHSO2CH3). The mesyloxy group is an excellent leaving group, making it useful for subsequent nucleophilic substitution reactions. This property is exploited in the synthesis of various pharmaceuticals and fine chemicals.

Metaansulfonüülkloriid is typically prepared by the reaction of methanesulfonyl chloride with thionyl chloride or phosphorus pentachloride. It is sensitive to moisture and should be handled with care in dry conditions. Due to its reactivity, it is considered an irritant and appropriate personal protective equipment should be used when handling it.