Sodium Chloride → Indoxyl

Participants

Reaction Conditions

Reaction Steps

Indoxyl 1,3-diacetate (Sigma Chemical Co., St. Louis, Mo.) (10.0 g; 46.05 mmole) was suspended with stirring in thoroughly deoxygenated H2O (200 mL), maintained under an inert gas atmosphere. NaOH (16 g) was added at once and the reaction mixture was heated at ca. 85° C. for 15 min. The reaction was cooled in an ice/salt bath to <5° C., then dropwise treated with a thoroughly deoxygenated solution of citric acid monohydrate (30.63 g) in H2O (30 mL) at a rate that kept the reaction temperature <5° C. NaCl (30 g) was then added and the reaction stirred in the cold for 1 h. The greenish yellow solid product was collected by filtration with suction, washed with a minimum amount of deoxygenated, ice-cold aq 0.5 N citric acid and dried in vacuo overnight to give 3-hydroxyindole (4.94 g; 80%). This product was used without further purification.

Provenance & Evidence