PRODUCTION OF AROMATIC CARBOXYLIC ACID DERIVATIVE

摘要

PURPOSE: To simply obtain an aromatic carboxylic acid derivative useful as a synthetic intermediate of pyrazol derivatives useful as herbicides without requiring Grignard reaction process which is high in cost by oxidizing a sulfone compound using an oxidizing agent. CONSTITUTION: A sulfone compound of formula I (X<1> to X<4> are each a 1-4C alkyl) is reacted with an oxidizing agent (e.g. a halogen) in a solvent (e.g. dioxane) at a room temperature to a reducing temperature of a solvent for 3-24hr to provide an aromatic carboxylic acid derivative of formula II. A halogen as the oxidizing agent is preferably Cl or Br and when the halogen is used as the oxidizing agent, the halogen is used as a hypohalogenic acid salt together with an alkali hydroxide or a carbonic acid salt and used in an amount of >=3 equivalents based on the compound of formula I. The compound of formula I is obtained by reacting a thiochroman compound with an acetyl halide or acetic anhydride.