VERFAHREN ZUR HERSTELLUNG VON DIFLUORBENZO-(1,3)- DIOXOL-5-CARBONSÄUREDERIVATEN

Preparation of difluorobenzo-[1,3]-dioxol-5-carbonic acid and its derivatives comprises reacting difluorobenzo-[1,3]-dioxol compound (II) in the presence of boron trifluoride and hydrogen fluoride to give difluoro-benzo[1,3]dioxol-5-carbonic acid-2-hydroxy-phenylester compound (III), optionally at least partially distilling boron trifluoride and/or hydrogen fluoride, and hydrolysing in aqueous acid or in alkaline medium to give (I). Preparation of difluorobenzo-[1,3]-dioxol-5-carbonic acid and its derivatives comprises reacting difluorobenzo-[1,3]-dioxol compound of formula (II) in the presence of boron trifluoride and hydrogen fluoride to give difluoro-benzo[1,3]dioxol-5-carbonic acid-2-hydroxy-phenylester compound of formula (III), optionally at least partially distilling boron trifluoride and/or hydrogen fluoride, and hydrolysing in aqueous acid or in alkaline medium to give (I). R 1>1-12C alkyl, 1-12C fluoroalkyl, 1-12C alkoxy, 1-12C fluoroalkoxy, Br, Cl or F; and n : 0-3. Independent claims are also included for: (1) New difluoro-benzo[1,3]dioxol-5-carbonic acid-2-hydroxy-phenylester compounds (III) and its phenolate salts; and (2) preparation of difluorobenzo-[1,3]-dioxol-chloride compounds of formula (IV) comprising preparing (I) and reacting (I) with chlorinating agents. [Image] [Image].