Reaction #65494

Reaction equation

4-[1-(1H-imidazol-1-yl)-2-methylpropyl]-1,2-benzenediamine

ethyl ethanimidate hydrochloride

→

5-[1-(1H-imidazol-1yl)-2-methylpropyl]-2-methyl-1H-benzimidazole dihydrochloride

Yield 44.0%

Solvents

ethanol

Conditions

Workup

1. 1
   Temperatureat reflux temperature
2. 2
   OtherAfter evaporation
3. 3
   Otherto dry
4. 4
   ExtractionThe product was extracted three times with 120 parts of trichloromethane
5. 5
   OtherThe combined extracts were dried
6. 6
   Filtrationfiltered
7. 7
   Otherevaporated
8. 8
   OtherThe residue was purified by column chromatography over silica gel using
9. 9
   workup.ADDITIONa mixture of trichloromethane and methanol (95:5 by volume) as eluent
10. 10
    OtherThe pure fractions were collected
11. 11
    Otherthe eluent was evaporated
12. 12
    workup.ADDITIONThe residue was convened into the hydrochloride salt in a mixture of 2-propanone and ethanol
13. 13
    FiltrationThe salt was filtered off
14. 14
    Othercrystallized from a mixture of ethanol and 2-propanone
15. 15
    FiltrationThe product was filtered off
16. 16
    Otherdried

Procedure

A mixture of 6.2 parts of 4-[1-(1H-imidazol-1-yl)-2-methylpropyl]-1,2-benzenediamine, 6.5 parts of ethyl ethanimidate hydrochloride and 80 parts of ethanol was stirred for 3 hours at reflux temperature. After evaporation to dry, the residue was taken up in water and sodium carbonate. The product was extracted three times with 120 parts of trichloromethane. The combined extracts were dried, filtered and evaporated. The residue was purified by column chromatography over silica gel using a mixture of trichloromethane and methanol (95:5 by volume) as eluent. The pure fractions were collected and the eluent was evaporated. The residue was convened into the hydrochloride salt in a mixture of 2-propanone and ethanol. The salt was filtered off and crystallized from a mixture of ethanol and 2-propanone. The product was filtered off and dried, yielding 4 parts (44% ) of 5-[1-(1H-imidazol-1yl)-2-methylpropyl]-2-methyl-1H-benzimidazole dihydrochloride.monohydrate; mp. 214.8° C. (comp. 22).

Source