反应详情

A solution of urea (6.00 g, 0.1000 mol) and 3,4-diaminotoluene (1) (12.20 g, 0.0999 mol) in pentan-1-ol (40 mL) was vigorously stirred and heated to reflux under a nitrogen atmosphere. After 2 hours the heating was discontinued and on cooling to room temperature a pink solid settled out. This was filtered off and recrystallised from boiling ethanol (17.98 g. in 400 mL) to give 2 crops of 5-methylbenzimidazol-2-one (2) as a pink powder. The total mass was recovered was 8.21 g (56% yield);

1. temperatureheated
2. temperatureto reflux under a nitrogen atmosphere
3. filtrationThis was filtered off
4. customrecrystallised