Ethyl Bromide → Methyl 9-ethylxanthene-9-carboxylate

참여 물질

반응 단계

10.0 g (0.042 mol) of methyl 9-xanthenecarboxylate (obtainable according to step 1.1.a) are dissolved in 100 mL of tetrahydrofuran and combined batchwise with 5.16 g (0.044 mol) of potassium tert-butoxide while cooling. Then at about 18° C. to 22° C., 6.296 mL (0.083 mol) of bromoethane are added dropwise; after it has all been added, the mixture is stirred for about 1.5 hours at ambient temperature. The precipitate formed is suction filtered and the solvent is removed by distillation. The residue remaining is taken up in diethyl ether and extracted with water. The organic phase is dried over magnesium sulfate and the solvent is removed by distillation. The crude product obtained is used in the next step without any further purification. Yield: 7.92 g of yellow oil (70% of theoretical yield).

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