反应详情

A mixture of 730 mg 2,8-dimethyl-1-oxa-8-azaspiro[4,5]-decan-3-one, 2.25 ml ethylene glycol, 836 mg p-toluenesulfonic acid monohydrate and 30 ml toluene was heated under reflux for 3 hours with a Dean-Strak azeotropic dehydration apparatus, and the reaction mixture was poured into 30 ml of an aqueous solution containing 1.26 g sodium becarbonate. The resulting mixture was extracted with chloroform. The extract was dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography on silica gel eluted with a mixted solvent of chloroform/methanol/conc. ammonia (20:1:0.1 by volume) to give 640 mg of 10,14-dimethyl-1,4, 13-trioxa-10-azasprio[4.1.5.2]tetradecane as oil. It was dissolved in isopropanol, and a solution of maleic acid in isopropanol was added to convert it to the corresponding maleate, which was recrystallized from dichloromethane/ether.

1. temperaturewas heated
2. temperatureunder reflux for 3 hours with a Dean-Strak azeotropic dehydration apparatus
3. extractionThe resulting mixture was extracted with chloroform
4. dry with materialThe extract was dried over anhydrous magnesium sulfate
5. concentrationconcentrated under reduced pressure
6. customThe residue was purified by silica gel column chromatography on silica gel
7. washeluted with a mixted solvent of chloroform/methanol/conc