Ethyl chloroformate → Butyramide, 4-piperidino-

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Reaction Steps

To a stirred and cooled (ice bath) solution of 4 parts of 2-(phenylmethoxy)benzoic acid in 90 parts of trichloromethane were added first 1.47 parts of N,N-diethylethanamine and then 1.6 parts of ethyl carbonochloridate at <5° C. After stirring for 1 hour in an ice bath, the thus obtained mixture was added dropwise to a cooled solution of 5.94 parts of trans-4-amino-3-hydroxy-N,N,γ-trimethyl-α,α-diphenyl-1-piperidinebutanamide in 90 parts of trichloromethane at a temperature below 5° C. Upon completion, stirring was continued overnight at room temperature. The organic layer was washed with water, a sodium carbonate solution in water and water, dried, filtered and evaporated. The residue was purified by column chromatography over silica gel using a mixture of trichloromethane and methanol (95:5 by volume) as eluent. The pure fractions were collected and the eluent was evaporated. The residue was C solidified in 2,2'-oxybispropane. The product was filtered off and dried in vacuo at 60° C. yielding 3.7 parts (40.7%) of trans-3-hydroxy-N,N,γ-trimethyl-α,α-diphenyl-4-[[2(piperidinebutanamide: mp 149.0° C. (compound 29).

Provenance & Evidence