反应详情

1-Ethyl-2-benzimidazolinone (100 g, 0.62 mol) was dissolved in phosphorus oxychloride (475 mL) with stirring and heated to reflux temperature. Hydrogen chloride gas was passed into the refluxing solution for 4 h. Excess phosphorous oxychloride was removed on a rotary evaporator at 70° C. The residue was poured into a stirred mixture of aqueous potassium carbonate solution and methylene chloride. The mixture was basified with 50% sodium hydroxide solution and the methylene chloride layer was separated, dried (Na2SO4), concentrated, and distilled to obtain 86 g (77%) of oil, bp 110°-115° C./2-0.3 mmHg, which crystallized on standing; mp 50°-52° C.

1. temperatureheated
2. temperatureto reflux temperature
3. customExcess phosphorous oxychloride was removed on a rotary evaporator at 70° C
4. additionThe residue was poured into a stirred mixture of aqueous potassium carbonate solution and methylene chloride
5. customthe methylene chloride layer was separated
6. dry with materialdried (Na2SO4)
7. concentrationconcentrated
8. distillationdistilled