methyl 4-{(3S)-3-[(4-{[(3,4-dichlorophenyl)amino]carbonyl}piperazin-1-yl)methyl]piperidin-1-yl}-4-oxobutanoate → methyl 4-{(3R)-3-[(4-{[(3,4-dichlorophenyl)amino]carbonyl}piperazin-1-yl)methyl]piperidin-1-yl}butanoate

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Reaction Steps

To a solution of methyl 4-{(3S)-3-[(4-{[(3,4-dichlorophenyl)amino]carbonyl}piperazin-1-yl)methyl]piperidin-1-yl}-4-oxobutanoate (240 mg) in tetrahydrofuran (5 mL) at room temperature under argon was added a 1M solution of BH3 in THF (1 mL). The solution was heated to reflux temperature for 1 hour and then cooled to ambient temperature. The reaction was quenched with methanol and then concentrated at reduced pressure. To the residue was added saturated HCl in methanol (10 mL) and the mixture was heated to reflux temperature for 1 hour and then cooled to ambient temperature. The mixture was stirred at ambient temperature overnight and then concentrated at reduced pressure. The residue was purified using reverse phase HPLC eluting with a mixture of 5-95% acetonitrile in water and then SCX-2 column eluting with methanol then 7M NH3 in methanol to give methyl 4-{(3R)-3-[(4-{[(3,4-dichlorophenyl)amino]carbonyl}piperazin-1-yl)methyl]piperidin-1-yl}butanoate (80 mg, 34%).

Provenance & Evidence