反应详情

A mixture of 4-hydroxy-3-(2-hydroxy-1,1-dimethylethyl)phenyl methylsulphonate (10 parts) (from Example 1), 2,2-dimethoxypropane (17 parts) and p-toluenesulphonic acid (0.1 parts) was heated in toluene (90 parts) with distillation of low boiling fraction and slow addition of further 2,2-dimethoxypropane (17 parts) for 1 hour. The resulting solution was cooled, washed with aqueous sodium hydroxide solution and with water, dried over magnesium sulphate and the solvent evaporated off under reduced pressure. The crude product was distilled yielding 9 parts of 4,5-dihydro-2,2,5,5-tetramethyl-1,3-benzodioxepin-7-yl methanesulphonate, boiling point 130°-142° C./0.2 mm Hg. Recrystallisation from aqueous ethanol gave the pure product (4.8 parts), melting point 65°-67° C.

1. temperatureThe resulting solution was cooled
2. washwashed with aqueous sodium hydroxide solution and with water
3. dry with materialdried over magnesium sulphate
4. customthe solvent evaporated off under reduced pressure
5. distillationThe crude product was distilled