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

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).

1. extractionThe mixture was extracted with EtOAc (3×10 mL)
2. dry with materialthe organic extracts dried over Na2SO4
3. filtrationfiltered
4. concentrationconcentrated in vacuo
5. dissolutionThe resulting dark red solid was dissolved in CH3CN (4 mL)
6. additionphosgene was added (20% solution in toluene, 1.5 mL, 3.2 mmol)
7. additiondiluted with toluene
8. filtrationFiltration of the resultant solid

ORD record

ord-00e11412809143f3a5adf7ee9ae9eb5d

Source dataset

uspto-grants-2012_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08163752B2