7-hydroxy-2,2-dimethyl-1-benzofuran-3-one

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: 25 mmol 7-Hydroxy-2,2-dimethyl-benzofuran-3-one and 30 g silica gel are stirred in 200 ml chloroform. A solution of 25 mmol N-chloro-diisopropylamine in 100 ml chloroform (prepared from diisopropylamine and aqueous sodium hypochlorite solution, extracted in chloroform, concentration determined iodometrically) is added dropwise. After stirring for 10 hours it is filtered and the filtrate is shaken out with water. The solution is dried over sodium sulfate. The solvent is removed by distillation at 300 mbar. The residue is separated by column chromatography (silica gel: ethyl acetate). extracted in chloroform concentration determined iodometrically) is added dropwise is filtered the filtrate is shaken out with water The solution is dried over sodium sulfate The solvent is removed by distillation at 300 mbar The residue is separated by column chromatography (silica gel: ethyl acetate)

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: 7-Hydroxy-2,3-dihydro-2,2-dimethylbenzofurane is dissolved in 100 ml pyridine. 0.5 mol benzoyl chloride is added dropwise at 0° C. within 4 h. Subsequently it is stirred for 10 h at room temperature. It is poured onto 200 ml ice water and aspirated. The residue is washed with 500 ml 2 M hydrochloric acid and then with 1000 ml water and dried in air. A solution of 0.906 mol chromium trioxide in 370 ml glacial acetic acid is added dropwise to a solution of this crude product (0.45 mol) in 600 ml glacial acetic acid in such a way that the temperature of the mixture does not exceed 20° C. After the dropwise addition is completed it is stirred for a further 1 hour at 40° C. and subsequently poured onto 2 l water. It is suction filtered. The residue is washed with 1 l water and recrystallized from ethanol/water 3:1. The benzoyl compound is fed into 400 ml 10% ethanolic potassium hydroxide solution and the mixture is heated for 1 hour to 70° C. It is admixed with 3 l water and suction filtered. The residue is recrystallized from 2 l water. The residue is washed with 500 ml 2 M hydrochloric acid with 1000 ml water and dried in air does not exceed 20° C After the dropwise addition is stirred for a further 1 hour at 40° C. filtered The residue is washed with 1 l water recrystallized from ethanol/water 3:1 the mixture is heated for 1 hour to 70° C filtered The residue is recrystallized from 2 l water