Oxygen → Fluoreneone

Into a 150 ml three-necked flask, 6.5 g of the thus obtained fluorene compound and 100 ml of pyridine were introduced. The mixture was cooled with ice and then 0.5 ml of a 40% methanol solution of benzyltrimethylammonium hydroxide was added thereto. The resulting mixture was stirred for one hour in an oxygen stream. After completion of the reaction, the contents were poured into 100 ml of water, resulting in a yellow precipitate. This precipitate was filtered off, washed with diluted hydrochloric acid and then with water, and dissolved in methylene chloride. This solution was dried with Na2SO4 and then purified with a silica gel short column (methylene chloride/hexane=1/1). Subsequently, the solvent was removed by evaporation under reduced pressure, and then the residue was recrystallized from a mixture of ethyl acetate and ethanol. Thus, 6.5 g (yield 94%) of a fluorenone compound having the following structural formula was obtained as orangish yellow needle crystals. The melting point of this compound was 172°-173.5° C. ##STR6##

1. temperatureThe mixture was cooled with ice
2. customAfter completion of the reaction
3. customresulting in a yellow precipitate
4. filtrationThis precipitate was filtered off
5. washwashed with diluted hydrochloric acid
6. dissolutionwith water, and dissolved in methylene chloride
7. dry with materialThis solution was dried with Na2SO4
8. custompurified with a silica gel short column (methylene chloride/hexane=1/1)
9. customSubsequently, the solvent was removed by evaporation under reduced pressure
10. customthe residue was recrystallized from a mixture of ethyl acetate and ethanol

ORD record

ord-b974a1721569495a8cdcae6b68d8adf0

Source dataset

uspto-grants-1991_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05075487