Hydrochloric Acid → 6-Methoxy-1H-indole-3-carboxaldehyde

Participants

Reaction Conditions

Reaction Steps

A mixture of DMF (7 mL, 90 mm) and POCl3 (2.25 mL, 24.5 mmol) which had been cooled to 5° C., was treated with known 6-methoxy-1H-indole. After stirring at room temperature for 1 hour, the mixture was heated at 45° C. for 1 hour, then allowed to cool to room temperature overnight. The reaction mixture was poured into ice (100 mL), and stirred for 30 minutes at which time a solution of KOH (9.6 g, 171 mm) in H2O (20 mL) was added dropwise. After stirring for 30 minutes, then heating for 1 hour at 60° C., the reaction was cooled to 30° C., and the pH adjusted to 7 with 1N HCl. The mixture was extracted with EtOAc(50 mL×3), the organic fractions were combined, dried over MgSO4, filtered and evaporated. The residue was purified by crystallization from methanol to afford 6-methoxy-1H-indole-3-carboxaldehyde (1.65 g, 69%).

Provenance & Evidence