Methyl indole-6-carboxylate → Methyl indoline-6-carboxylate

Participants

Reaction Conditions

Reaction Steps

A solution of indole-6-carboxylic acid methyl ester (534 mg, 3.05 mmol) in acetic acid (7.5 ml) was cooled to 0° C. Sodium cyanoborohydride (580 mg, 9.2 mmol, 3 equiv.) was added and the mixture stirred at 15° C. for 40 min. A further aliquot of sodium cyanoborohydride (193 mg, 3.05 mmol, 1 equiv.) was added, and the reaction mixture was stirred for 30 min. at room temperature. The solvent was then evaporated, and the residue dissolved in dichloromethane and washed with 1N NaOH. The organic phase was dried with Na2SO4 and evaporated, yielding 2,3-dihydro-1H-indole-6-carboxylic acid methyl ester as a light yellow solid, 494 mg (77%). This was used as such in the following reaction.

Provenance & Evidence