Diisopropylethylamine → 2-chloro-4-[(1H-indole-6-carbonyl)-amino]-benzoic acid methyl ester

Participants

Reaction Steps

Bromo-tris-pyrrolidino-phosphonium hexafluorophosphate (8.3 g, 17.8 mmol, 1.1 equiv.) and diisopropyl ethyl amine (4.4 ml, 33.9 mmol, 2.1 equiv.) were added to 1H-indole-6-carboxylic acid (2.6 g, 16.2 mmol, 1 equiv.) in tetrahydrofuran (30 mL) and the mixture was shaken for 5 minutes at room temperature. 4-Amino-2-chlorobenzoic acid methyl ester (3.3 g, 17.9 mmol, 1.1 equiv.) was added and the resultant mixture was shaken at room temperature for 16 hours. The solvent was removed under vacuum and the residue triturated with dichloromethane (10 mL). The solid was filtered to afford 2-chloro-4-[(1H-indole-6-carbonyl)-amino]-benzoic acid methyl ester, 1.4 g (26% yield). LC @215 nm; Rt 1.36: 90%, m/z (ES+): 329 (M+H+.); δH (400 MHz; d6-DMSO) 11.65 (1H, s), 10.59 (1H, s), 8.16 (1H, s), 8.10 (1H, s), 7.93 (2H, m), 7.65 (2H, s), 7.59 (1H, m), 6.62 (1H, s), 3.85 (3H, s).

Provenance & Evidence