In a 1 L four-reaction vessel, 326.7 g of tetrahydrofuran and 132.9 g of glacial acetic acid were added, stirred for 30 min,Adding 110.0g 2.3-difluoro-4-ethoxybenzeneboronic acid crude, stirring for half an hour, the control temperature between 15 ~ 25 ° C,Dropping 111. 1 g of hydrogen peroxide, stirring was added dropwise insulation lh, sample testing, raw material residue 0.15%To the vessel was added water 200.0g and 15. lg sodium sulfite treatment, stratification, the upper organic phase rejection rate was 2.3-difluoro-4-ethoxy phenol crude 85.0g, distilled product 64.8g, GC purity: 99 ? 96 %, Two-step yield 69 ? 8%
