1H-Benzimidazole-1-carboxylic acid, 4-nitro-, 1,1-dimethylethyl ester synthesis

Yield:208772-95-6 93%

Reaction Conditions:

with triethylamine in dichloromethane at 20; for 16 h;

Steps:

29.B

Step B: Preparation of tert-butyl 4-nitro-1H-benzo[d]imidazole-1-carboxylate: Triethylamine (1.03 mL, 7.36 mmol) was added to a suspension of 4-nitro-1H-benzo[d]imidazole (1.0 g, 6.13 mmol) in dichloromethane (50 mL), followed by addition of Boc₂O (1.61 g, 7.36 mmol). The reaction was stirred at room temperature for 16 hours and then quenched with water (20 mL). The aqueous layer was extracted with dichloromethane (50 mL*3), and the combined organics were dried, filtered and concentrated. The crude product was purified by flash column chromatography, eluding with hexanes/ethyl acetate (4:1) to give the desired product (1.50 g, 93%).

References:

US2010/63066,2010,A1 Location in patent:Page/Page column 34