Triethylamine → 1H-Benzimidazole-5-carboxylic acid, 7-bromo-2,3-dihydro-2-oxo-, methyl ester

A solution of 3,4-diamino-5-bromobenzoate (1 g, 4.0 mmol) and triethylamine (0.4 g, 4.0 mmol) in dichloromethane (6 mL) was cooled to 0° C. A solution of triphosgene (1.2 g, 4.08 mmol) in dichloromethane (15 mL) was added to this solution. The reaction mixture was allowed to warm to ambient temperature and maintained for 18 hours. The reaction mass was quenched with water (3 mL) and extracted with ethyl acetate (3×10 mL). The combined organic layers were washed with aqueous saturated sodium chloride (50 mL), dried over anhydrous sodium sulfate and concentrated to obtain methyl 7-bromo-2-oxo-2,3-dihydro-1H-benzo[d]imidazole-5-carboxylate as an off-white solid (500 mg, 45%). 1HNMR (CDCl3+DMSO-d6): δ 11.35 (s, 1H), 11.05 (s, 1H), 7.75 (s, 1H), 7.52 (s, 1H) and 3.85 (s, 3H).

1. temperaturemaintained for 18 hours
2. customThe reaction mass was quenched with water (3 mL)
3. extractionextracted with ethyl acetate (3×10 mL)
4. washThe combined organic layers were washed with aqueous saturated sodium chloride (50 mL)
5. dry with materialdried over anhydrous sodium sulfate
6. concentrationconcentrated

ORD record

ord-8db1b3f214d143d3bafdc731febab0b6

Source dataset

uspto-grants-2013_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08507681B2