反应详情

At 80° C., 10.1 g (0.05 mol) of benzofuran-2,3-dione 2-[O-(2-hydroxy-ethyl)-oxime] (VII-1) in 50 ml of N-methyl-2-pyrrolidinone are stirred with 3.5 g of hydroxylamine hydrochloride for 2 hours. The reaction mixture is poured into water and the resulting mixture is extracted with ethyl acetate, the organic phase is dried over sodium sulphate and the solvent is distilled off under reduced pressure. The residue is then chromatographed over silica gel using tert-butyl methyl ether/petroleum ether (1:1). The eluent is distilled off under reduced pressure, affording 4.2 g (29.6% of theory) of benzofuran-2,3-dione 2-[O-(2-hydroxy-ethyl)-oxime] 3-oxime consisting of 62.4% of isomer A and 15.8% of isomer B (HPLC).

1. extractionthe resulting mixture is extracted with ethyl acetate
2. dry with materialthe organic phase is dried over sodium sulphate
3. distillationthe solvent is distilled off under reduced pressure
4. customThe residue is then chromatographed over silica gel
5. distillationThe eluent is distilled off under reduced pressure