Methyl Isobutyl Ketone → trans-3-hydroxy-N,N,gamma-trimethyl-alpha,alpha-diphenyl-4-[(phenylmethyl)amino]-1-piperidinebutanamide

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Reaction Steps

A mixture of 17.6 parts of trans-4-[(phenylmethyl)amino]-3-piperidinol, 27 parts of sodium carbonate and 680 parts of 4-methyl-2-pentanone was stirred and refluxed for 45 minutes using a water separator. After cooling, 33.8 parts of N-(dihydro-5-methyl-3,3-diphenyl-2(3H)-furanylidene)-N-methylmethanaminium bromide were added and stirring was continued for 24 hours at reflux. The mixture was cooled and washed with water. The organic layer was dried, filtered and evaporated. The residue was dissolved in 1,1'-oxybisethane and acidified with 2-propanol, saturated with hydrogen chloride. The liquid was decanted and the half solid precipitated product was dissolved in water and treated with ammonium hydroxide. The product was extracted with trichloromethane. The extract was dried, filtered and evaporated. The residue was purified by column chromatography over silica gel using a mixture of trichloromethane and methanol, saturated with ammonia, (90:10 by volume) as eluent. The desired fractions were collected and the eluent was evaporated. The residue was solidified on scratching in petroleum ether. The product was filtered off and crystallized twice from acetonitrile. The product was filtered off and dried, yielding 18.8 parts (45%) of trans-3-hydroxy-N,N,γ-trimethyl-α,α-diphenyl-4-[(phenylmethyl)amino]-1-piperidinebutanamide; mp. 134.5° C. (interm. 18).

Provenance & Evidence