Acetic Acid → 3-methyl-4,5,6,7-tetrahydro-1H-indol-4-one

Participants

Reaction Steps

The subtitle compound was prepared according to the literature procedure (Hauptmann, S. et al., Z. Chem., 1966, 3, 107. Ravina, E. et al., Bio. Med. Chem. Lett., 1995, 5, 579.). A mixture of anti-pyruvic aldehyde 1-oxime (1.3 g, 15 mmol), 1,3-cyclohexanedione (1.7 g, 15 mmol), glacial acetic acid (12 mL) and water (3.0 mL) was stirred vigorously at room temperature. Zinc dust (3 g) was added slowly keeping the temperature below 60° C. After addition, this resulting brown solution was heated under reflux temperature for 2 hours. After cooling, the reaction mixture was basified by an addition of 1 M aqueous KOH. The whole was extracted with CH2Cl2 (50 mL×3), and the combined organic layers were dried over MgSO4, and concentrated in vaciio. The residue was purified by flash chromatography eluting with hexane-ethyl acetate (3:1→EtOAc only) to afford the subtitle compound (1.0 g, 46% yield) of as a yellow solid.

Provenance & Evidence