Ammonium Hydroxide → 2-chloro-4-[(2,3-dihydro-1H-indole-6-carbonyl)-amino]-benzoic acid methyl ester

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Reaction Conditions

Reaction Steps

Sodium cyanoborohydride (2.6 g, 41.6 mmol, 3 equiv.) was added to a stirred solution of 2-chloro-4-[(1H-indole-6-carbonyl)-amino]-benzoic acid methyl ester (1.4 g, 4.2 mmol, 1 equiv.) in acetic acid (25 mL) over 5 minutes at room temperature. The mixture was stirred for 30 minutes then cooled to 0° C. and poured onto concentrated ammonium hydroxide (78 mL, d=0.880) at 0° C. The mixture was diluted with water (25 mL) and dichloromethane (25 mL), the organic layer was separated and the aqueous layer extracted with dichloromethane (2×25 mL). The combined organic layers were dried over Na2SO4 and the solvent removed under vacuum to afford crude 2-chloro-4-[(2,3-dihydro-1H-indole-6-carbonyl)-amino]-benzoic acid methyl ester, 0.75 g, this material was taken onto the next step without further purification. LC @215 nm; Rt 1.04: 71%, m/z (ES+): 331 (M+H+.).

Provenance & Evidence