反应详情

温度

100 °C

Polyphosphoric acid which had been newly prepared from diphosphorus pentaoxide (50 g) and phosphoric acid (50 ml) was heated at 100° C. With stirring, 2-(3,4-dimethoxyphenyl)-4,5-dimethoxybenzoic acid (7.5 g) was added thereto as it is (in the crystal form) in several portions. After stirring at 100 to 120° C. for 2 hours, the reaction solution was poured into water (1.5 liter) and extracted with chloroform. The extract was washed with 2% aqueous sodium hydroxide solution, water and a saturated saline solution, then dried over sodium sulfate. The solvent was distilled off, and the residue was purified by silica gel column chromatography (eluent: chloroform) and recrystallized from ethyl acetate-n-hexane to give 5.0 g of 2,3,6,7-tetramethoxyfluorenone as an orange needle-like crystal.

1. stirringAfter stirring at 100 to 120° C. for 2 hours
2. extractionextracted with chloroform
3. washThe extract was washed with 2% aqueous sodium hydroxide solution, water
4. dry with materiala saturated saline solution, then dried over sodium sulfate
5. distillationThe solvent was distilled off
6. customthe residue was purified by silica gel column chromatography (eluent: chloroform)
7. customrecrystallized from ethyl acetate-n-hexane