反应详情

To 73 parts of hot (70° C.) polyphosphoric acid were added 27 parts of 1-(phenylmethyl)-4-piperidineacetic acid hydrochloride: temperature rose to 100° C. When the addition was complete, there were added portionwise 14 parts of 1,2-benzenediamine and stirring and heating was continued for 50 minutes at 170° C. The hot reaction mixture was poured into 300 parts of warm water. The acid solution was alkalized with a potassium hydroxide solution. The precipitated free base was filtered off, washed with water and extracted with trichloromethane. The extract was dried and evaporated. The solid residue was recrystallized from a mixture of 2-propanone and methanol, yielding 17 parts of 2-[[1-(phenylmethyl)-4-piperidinyl]-methyl]-1H-benzimidazole; mp. 221.5°-222° C. (compound 1).

1. customrose to 100° C
2. additionWhen the addition
3. temperatureheating
4. filtrationThe precipitated free base was filtered off
5. washwashed with water
6. extractionextracted with trichloromethane
7. customThe extract was dried
8. customevaporated
9. customThe solid residue was recrystallized from a mixture of 2-propanone and methanol