Pyridine → Benzimidazole

Temperature

5 °C

Into 500 ml of acetonitrile was suspended 40 g (0.217 mol) of N-phenylenediamine in an atmosphere of nitrogen. The suspension was cooled with ice to 5° C. or lower where it was then kept. To the suspension was then added 37 ml (0.477 mol) of pyridine. To the reaction mixture was then added dropwise 25 g (0.217 mol) of thiophosgene while the temperature of the reaction system was being controlled to lower than 10° C. After completion of the dropwise addition, the temperature of the reaction solution was gradually returned to room temperature. The reaction solution was then allowed to undergo at the same temperature for 2 hours. To the reaction solution was then added water. The resulting precipitate was withdrawn by filtration, washed with water, dried, and then recrystallized from methanol to obtain 30.9 g (0.137 mol) of benzimidazole as the target compound (yield: 63%).

1. customlower than 10° C
2. additionAfter completion of the dropwise addition
3. customwas gradually returned to room temperature
4. customThe resulting precipitate was withdrawn by filtration
5. washwashed with water
6. customdried
7. customrecrystallized from methanol

ORD record

ord-7ef90f863c95438fa03e79cdbbd339e2

Source dataset

uspto-grants-2000_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06074813