反应详情

48.05 g (0.2 mol) methyl xanthene-9-carboxylate are dissolved in 1200 mL of tetrahydrofuran and at 0° C. combined with 23.63 g (0.2 mol) of potassium tert-butoxide. Oxygen is the piped in for 2 hours at −10° C. to −5° C., then the mixture is acidified with 2 N aqueous hydrochloric acid and the majority of the solvent is distilled off. The residue remaining is extracted with ethyl acetate and water, the organic phase is extracted with aqueous Na2S2O5 solution, washed with water, and dried, and the solvent is distilled off. The product is purified by crystallization from diisopropylether and cyclohexane. Yield: 11.10 g white crystals (22% of theoretical yield)

1. customin for 2 hours
2. customat −10° C. to −5° C.
3. distillationthe majority of the solvent is distilled off
4. extractionThe residue remaining is extracted with ethyl acetate and water
5. extractionthe organic phase is extracted with aqueous Na2S2O5 solution
6. washwashed with water
7. customdried
8. distillationthe solvent is distilled off
9. customThe product is purified by crystallization from diisopropylether and cyclohexane