反应详情

温度

20 °C

5-(2'-Hydroxy-3',4',6'-trimethylbenzoyl)pentanoic acid (formula II-1 wherein R=H3C, X=H, Y=OH, n=4, in the free form) (0.048 part) was dissolved in 0.5% NaOH (3.3 volume parts) and, while the solution was stirred at 20° C., potassium nitrosodisulfonate (0.4 part) was added. The mixture was stirred for 10 minutes. Then, under cooling with ice, the reaction mixture was diluted with water (100 volume parts) and rendered acidic with dilute hydrochloric acid. It was then extracted with diethyl ether and the extract was washed with water and dried. The solvent was distilled off under reduced pressure and the residue was then recrystallized from hexane-ethyl acetate (2:1). The procedure provided 2,3,5-trimethyl-6-(5'-carboxy-1'-oxopentyl)-1,4-benzoquinone (formula I-1 wherein R=H3C, n=4, in the free form) (0.042 part) as yellow needles melting at 96.5°-98.5° C.

1. stirringThe mixture was stirred for 10 minutes
2. temperatureThen, under cooling with ice
3. extractionIt was then extracted with diethyl ether
4. washthe extract was washed with water
5. customdried
6. distillationThe solvent was distilled off under reduced pressure
7. customthe residue was then recrystallized from hexane-ethyl acetate (2:1)