Process for producing 4-substituted benzopyran derivatives

Abstract

The present invention relates to a first process for producing a 2,2-bis(fluoromethyl)-6-(perfluoroalkyl)-2H-1-benzopyran-4-carboxylic acid. The first process includes the steps of (a) reacting a 2,2-bis(fluoromethyl)-6-(perfluoroalkyl)-2H-1-benzopyran-4-one with a perfluoroalkanesulfonic acid anhydride in the presence of a base, thereby obtaining a perfluoroalkanesulfonic 2,2-bis(fluoromethyl)-6-(perfluoroalkyl)-2H- 1-benzopyran-4-yl ester; and (b) reacting the benzopyranyl ester with carbon monoxide in the presence of a palladium complex compound and a base, thereby obtaining the carboxylic acid. The present invention further relates to a second process for producing a 2-hydroxy-5-(perfluoroalkyl) acetophenone, which can be a raw material for producing the carboxylic acid. The second process includes the steps of (c) reacting a 4-(perfluoroalkyl)alkoxybenzene with acetic anhydride or an acyl halide in the presence of a Lewis acid, thereby obtaining a 2-alkoxy-5-(perfluoroalkyl)acetophenone; and (d) dealkylating the 2-alkoxy-5-(perfluoroalkyl) acetophenone by a dealkylating agent.