反应详情

To a solution of 300 mg of 22-(2-hydroxy-3,4-dimethoxy-6-methylphenyl)docosanoic acid (IV:n=21, R=H) in 20 ml of N,N-dimethylformamide is added 50 mg of bis(salicylidene)ethylenediiminocobalt(II) and the mixture is stirred in oxygen gas stream at room temperature for 24 hours. The insolubles are filtered off and the filtrate is concentrated under reduced pressure. The residue is dissolved in ethyl acetate, washed with water and dried. The solvent is distilled off and the residue is dissolved in chloroform and column-chromatographed on silica gel, elution being carried out with chloroform. The eluate is recrystallized from ethanol to obtain 6-(21-carboxyheneicosyl)-2,3-dimethoxy-5-methyl-1,4-benzoquinone (I:n=21, R=H) as orange-yellow needles melting at 86° C.-87° C.

1. filtrationThe insolubles are filtered off
2. concentrationthe filtrate is concentrated under reduced pressure
3. dissolutionThe residue is dissolved in ethyl acetate
4. washwashed with water
5. customdried
6. distillationThe solvent is distilled off
7. dissolutionthe residue is dissolved in chloroform
8. customcolumn-chromatographed on silica gel, elution
9. customThe eluate is recrystallized from ethanol