反应详情

At 20° C., 5.28 g (0.02 mol) of 2-(3-hydroxyimino-3H-benzofuran-2-ylideneaminooxy)-ethyl acetate (XVI-1) in 20 ml of dimethylformamide are stirred with 4.24 g (0.048 mol) of 45% strength aqueous sodium hydroxide solution for 3 hours. The mixture is acidified with 2 N hydrochloric acid and extracted with ethyl acetate, the organic phase is dried over sodium sulphate and the solvent is distilled off under reduced pressure. According to HPLC analysis, the crude product contains 23.4% of the stereoisomer A and 4.1% of the stereoisomer B of benzofuran-2,3-dione 2-[O-(2-hydroxy-ethyl)-oxime] 3-oxime (X-1). Stirring the crude product with diethyl ether affords 1.4 g (28.5% of theory) of crystalline benzofuran-2,3-dione 2-[O-(2-hydroxy-ethyl)-oxime] 3-oxime (X-1) consisting of 84.7% of stereoisomer A and 6% of stereoisomer B (HPLC).

1. extractionextracted with ethyl acetate
2. dry with materialthe organic phase is dried over sodium sulphate
3. distillationthe solvent is distilled off under reduced pressure