Formic Acid → 1-{1-[3-(6-chloro-1H-benzimidazol-1-yl)propyl]-4-piperidinyl}-1,3-dihydro-2H-benzimidazol-2-one

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Reaction Steps

A mixture of 4 parts of 1-[1-{3-[N-(2-amino-5-chlorophenyl)amino]propyl}-4-piperidinyl]-1,3-dihydro-2H-benzimidazol-2-one, 6 parts of a concentrated hydrochloric acid solution and 30 parts of formic acid is stirred and refluxed overnight. The reaction mixture is evaporated and water is added to the residue. The whole is alkalized with a diluted ammonium hydroxide solution and the product is extracted with trichloromethane. The extract is dried, filtered and evaporated. The residue is crystallized from 4-methyl-2-pentanone. The product is filtered off and recrystallized from 2-propanol, yielding 1.1 parts (27%) of 1-{1-[3-(6-chloro-1H-benzimidazol-1-yl)propyl]-4-piperidinyl}-1,3-dihydro-2H-benzimidazol-2-one; mp. 214.9° C.

Provenance & Evidence