2,3-Dihydroxybutanedioic Acid → (+)-5-chloro-1-{1-[3-(1,3-dihydro-2-oxo-2H-benzimidazol-1-yl)propyl]-4-piperidinyl}-1,3-dihydro-2H-benzimidazol-2-one 2,3-dihydroxybutanedioate

Participants

Reaction Steps

To a stirred solution of 1 part of 5-chloro-1-{1-[3-(1,3-dihydro-2-oxo-2H-benzimidazol-1-yl)propyl]-4-piperidinyl}-1,3-dihydro-2H-benzimidazol-2-one in 32 parts of ethanol is added a solution of 0.35 parts of (±)-2,3-dihydroxy-1,4-butanedioic acid in 8 parts of ethanol. Upon stirring, the product is allowed to crystallize. It is filtered off and dried, yielding 1 part of (±)-5-chloro-1-{1-[3-(1,3-dihydro-2-oxo-2H-benzimidazol-1-yl) propyl]-4-piperidinyl}-1,3-dihydro-2H-benzimidazol-2-one 2,3-dihydroxybutanedioate. ethanolate; mp. 153.5° C.

Provenance & Evidence