Diisopropylethylamine → 2-[(6-phenylethynyl-pyridine-2-carbonyl)-amino]-1H-benzoimidazole-4-carboxylic acid methyl ester

Participants

Reaction Steps

To a solution of 4.4 g (20 mmol) of 6-phenylethynyl-pyridine-2-carboxylic acid in DMF (30 mL) was added 7.6 g (20 mmol) of HBTU and DIEA (4 mL). The resulted mixture was stirred at room temperature for 10 min, then 4 g (21 mmol) of 2-amino-1H-benzoimidazole-4-carboxylic acid methyl ester (Intermediate A) was added, and stirred at room temperature for 1 h. After usual workup as described in general procedure A, 7 g (88%) of 2-[(6-phenylethynyl-pyridine-2-carbonyl)-amino]-1H-benzoimidazole-4-carboxylic acid methyl ester was obtained after column chromatography purification eluting with DCM/EtOAc. LCMS: 397 (M+1)+. 1H NMR (DMSO-d6, 400 MHz): δ 8.20 (dd, 1H), 8.13 (dd, 1H), 7.96 (d, 1H), 7.81 (d, 1H), 7.74 (d, 1H), 7.60 (m, 2H), 7.50 (m, 3H), 7.31 (t, 1H), 3.95 (s, 3H) ppm.

Provenance & Evidence