反应详情

To a solution of crude methyl 1-[2-(4-bromophenyl)-2-oxoethyl]-1H-pyrrole-2-carboxylate (2.39 g, 2.47 mmol) in THF (30 mL) and water (20 mL) was added lithium hydroxide monohydrate (0.63 g, 15.1 mmol). The dark solution was stirred at room temperature. The outcome of the reaction was monitored by LCMS and after 1 h another portion of lithium hydroxide monohydrate (300 mg) was added to the reaction mixture. After 16 h the reaction mixture was diluted with a aqueous solution of NaOH (1M) (50 mL) then extracted with CH2Cl2 (100 mL). The pH of the aqueous fraction was adjusted to 1 with aqueous HCl (1M) and then extracted with CH2Cl2 containing 10% of propan-2-ol (3×75 mL). The organic extracts (from acidic aqueous) were combined, dried (MgSO4) and concentrated in vacuo to give crude (˜50% pure) 1-[2-(4-bromophenyl)-2-oxoethyl]-1H-pyrrole-2-carboxylic acid as a yellow solid (1.10 g, yield 72%) The crude material was used without purification.

1. extractionthen extracted with CH2Cl2 (100 mL)
2. extractionextracted with CH2Cl2 containing 10% of propan-2-ol (3×75 mL)
3. dry with materialdried (MgSO4)
4. concentrationconcentrated in vacuo