Sodium Carbonate → 8-[3-(5-chloro-1,3-dihydro-2-oxo-2H-benzimidazol-1-yl)propyl]-1-phenyl-1,3,8-triazaspiro[4,5]decan-4-one

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Reaction Steps

A mixture of 4.9 parts of 5-chloro-1,3-dihydro-2-oxo-2H-benzimidazole-1-propanol methanesulfonate, 3.7 parts of 1-phenyl-1,3,8-triazaspiro[4,5]decan-4-one, 3.4 parts of sodium carbonate and 90 parts of N,N-dimethylformamide is stirred and heated for 1 hour at 50°-60° C. The N,N-dimethylformamide is distilled off and the residue is taken up in water. The product is extracted with 4-methyl-2-pentanone. The extract is dried, filtered and evaporated. The residue is purified by column-chromatography over silica gel using a mixture of trichloromethane and 10% of methanol as eluent. The pure fractions are collected and the eluent is evaporated. The residue solidifies on triturating in 4-methyl-2-pentanone. The product is filtered off and crystallized twice: first from 2-propanol and then from a mixture of N,N-dimethylformamide and water, yielding 1.8 parts (25%) of 8-[3-(5-chloro-1,3-dihydro-2-oxo-2H-benzimidazol-1-yl)propyl]-1-phenyl-1,3,8-triazaspiro[4,5]decan-4-one; mp. 233.7° C.

Provenance & Evidence