| 摘要 |
PROBLEM TO BE SOLVED: To industrially advantageously obtain the subject compound useful as a production intermediate for medicines, etc., by esterifying a benzoic acid derivative under specific reaction conditions. SOLUTION: An 3-alkylsulfonylbenzoic acid derivative represented by formula I (R1 and R2 are each a 1-5C alkyl) is esterified in an acid catalyst (e.g. sulfuric acid) and a solvent (e.g. toluene) in the presence of an esterifying agent to provide the objective compound of formula II (e.g. 3-methylsulfonyl-4- isopropylbenzoic acid). Furthermore, it is preferable that a 1-5C aliphatic alcohol is used as the esterifying agent and especially, the solvent is the same as the esterifying agent and water produced by esterifying reaction is forcibly distilled away out of the system, and e.g. the reaction is preferably carried out at a reaction temperature which is a boiling point of the solvent, namely under reflux. |
