反应详情

Heat a solution of 5-iodo-1,3-dihydro-benzimidazol-2-one (6.50 g, 25.0 mmol; Feitelson et al. (1952) J. Chem. Soc. 2389) and tetramethylammonium chloride (1.37 g, 12.5 mmol) to 100° C. in POCl3 (10 mL) for 18 hours. After cooling, remove the excess POCl3 in vacuo, and triturate the residue in ice-water (200 mL). After stirring for 30 minutes, filter the precipitate to obtain 2-chloro-5-iodo-1H-benzimidazole as a gray solid.

1. temperatureAfter cooling
2. customremove the excess POCl3 in vacuo
3. customtriturate the residue in ice-water (200 mL)
4. filtrationfilter the precipitate