Triethylamine → tert-butyl 4-{[(3R,4R)-4-{[(4-chlorophenyl)carbonyl](methyl)amino}-3-(3,4-dichlorophenyl)piperidin-1-yl]methyl}piperidine-1-carboxylate

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Reaction Steps

To a mixture of 4-chloro-N-[(3R,4R)-3-(3,4-dichlorophenyl)piperidin-4-yl]-N-methylbenzamide monohydrochloride (300 mg) obtained in Example 137a, tert-butyl 4-formylpiperidine-1-carboxylate (735 mg) and triethylamine (105 μL) in acetic acid (0.69 mL)-ethyl acetate (10 mL) was added sodium triacetoxyborohydride (731 mg), and the mixture was stirred at room temperature for 14 hr. The reaction mixture was poured into water, and the resultant product was extracted with ethyl acetate. The organic layer was washed with water and dried, and the solvent was evaporated under reduced pressure. The obtained residue was purified by silica gel column chromatography (solvent gradient; 60→90% ethyl acetate/hexane, and then 0→30% methanol/ethyl acetate) to give the title compound (242 mg, 58%) as a white powder.

Provenance & Evidence