反应详情

To the mixture of 3-Bromo-5-(3-methyl-butyryl)-1H-indole-2-carboxylic acid ethyl ester (408 mg, 1.1 mmol), ammonium formate (10 mg, 1.7 mmol), and 10% Pd/C (200 mg) was added DMF (5 mL) and water (0.625 mL). The mixture was slightly shaked at room temperature for 70 minutes and then filtered through celite. The solvent was evaporated under vacuum to give 5-(3-Methyl-butyryl)-1H-indole-2-carboxylic acid ethyl ester as light yellow liquid as crude product with the purity of 90%; E1-MS m/z 274.1 (M++H). The crude ethyl ester was dissolved in dioxane (10 mL), Then a solution of LiOH.H2O (195 mg, 4.6 mmol) in water (5 mL) was added to the flask. The mixture was stirred at room temperature for 2 days. Dioxane was stripped under vacuum. 10 mL water was added and extracted with CH2Cl2. Then the aqueous phase was acidified with 6N HCl and extracted with CH2Cl2. The CH2Cl2 phase was then washed with saturated brine and dried over anhydrous Na2SO4. Solvent was removed under vacuum to give 5-(3-Methyl-butyryl)-1H-indole-2-carboxylic acid (250 mg, 88% for two steps) as white solid. EIMS m/z 246.1 (M++H) (lab-ref: YS-053-141).

1. filtrationfiltered through celite
2. customThe solvent was evaporated under vacuum