Sodium Carbonate → 5-Chloro-4-nitro-1,3-dihydro-2H-benzimidazol-2-one

Participants

Reaction Steps

A solution of 5-chloro-4-nitro-2,1,3-benzoselenadiazole from Step B (650 mg, 2.47 mmol) in conc. HCl (4 mL) and 48% aqueous HI (2 mL) was stirred at ambient temperature for 2 h. The reaction was diluted with a 1:1 saturated aqueous solution of NaHSO4 and Na2CO3 (20 mL) and then adjusted to pH 10 using 10 M aqueous NaOH. The mixture was extracted with EtOAc (3×10 mL) and the organic extracts dried over Na2SO4, filtered, and concentrated in vacuo. The resulting dark red solid was dissolved in CH3CN (4 mL) and phosgene was added (20% solution in toluene, 1.5 mL, 3.2 mmol). The reaction mixture was stirred for 1 h, then diluted with toluene. Filtration of the resultant solid gave the title compound. MS: m/z=214 (M+1).

Provenance & Evidence