Hydrochloric Acid → N-{(1S,2R)-1-(3,5-difluorobenzyl)-3-[(3-ethylbenzyl)amino]-2-hydroxypropyl}-4-[(methylsulfonyl)methyl]piperidine-1-carboxamide

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Reaction Steps

To an ice-cold, stirred solution of triphosgene (108 mg, 0.36 mmol) and diisopropylethylamine (0.6 mL, 3.3 mmol) in methylene chloride (2.0 mL) was added amino sulfone from step 4 (210 mg, 0.98 mmol) in methylene chloride (3.5 mL) dropwise. After 5 min a solution of dihydrochloride of (2R,3S)-3-amino-4-(3,5-difluorophenyl)-1-[(3-ethylbenzyl)amino]butan-2-ol (401 mg, 0.98 mmol) was added and the reaction mixture was warmed until the solution became homogeneous. The reaction mixture was diluted with methylene chloride, washed with 1 N hydrochloric acid (25 mL), saturated sodium bicarbonate (25 mL), and saturated sodium chloride, dried (magnesium sulfate), filtered, and concentrated under reduced pressure. Purification by flash column chromatography (silica, 15:85 methanol/chloroform) provided a clear solid. The solid was dissolved in methanol (1 mL), and treated with hydrochloric acid (0.3 mL of a 1.0 M solution in diethyl ether, 0.3 mmol). The resulting precipitate was collected by filtration to provide the title compound (38 mg): mp 130–134° C.; APCI MS m/z 538 [M+H]+.

Provenance & Evidence