Sodium hydride → 1-[(2-methyl-5-oxazolyl)methyl]-2-[[1-(phenylmethyl)-4-piperidinyl]methyl]-1H-benzimidazole

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To a solution of 26 parts of 2-[[1-(phenylmethyl)-4-piperidinyl]methyl]-1H-benzimidazole in 282 parts of N,N-dimethylformamide there were added 4.8 parts of a dispersion of sodium hydride in mineral oil (50%) under a nitrogen atmosphere. After stirring for 1 hour, there was added portionwise a solution of 15 parts of 5-(bromomethyl)-2-methyloxazole in 47 parts of N,N-dimethylformamide, while cooling in an ice-bath (<20° C.). The whole was stirred for 18 hours and allowed to warm to room temperature. The oily layer was separated and discarded. The N,N-dimethylformamide layer was poured into water and the whole was extracted with 4-methyl-2-pentanone (3×). The combined extracts were washed with water, dried, filtered and evaporated. The residue was purified by column chromatography (silica gel; CH2Cl2 /CH3OH 90:10). The eluent of the desired fraction was evaporated and the residue was successively crystallized from 2,2'-oxybispropane and acetonitrile, yielding 14.31 parts (42.0%) of 1-[(2-methyl-5-oxazolyl)methyl]-2-[[1-(phenylmethyl)-4-piperidinyl]methyl]-1H-benzimidazole; mp. 108.6° C. (comp. 1).

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