1-Ethyl-3-(3'-dimethylaminopropyl)carbodiimide → Rac-((1r,2s)-2-{4-[cyclopropyl-(3-trifluoromethyl-benzenesulfonyl)-amino]-piperidine-1-carbonyl}-cyclohexyl)-carbamic acid tert-butyl ester

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Reaction Steps

N-Cyclopropyl-N-piperidin-4-yl-3-trifluoromethyl-benzenesulfonamide (0.348 g, 1.00 mmol), HOBt (0.135 g, 1.0 mmol), EDCI (0.230 g, 1.2 mmol) and rac-cis-2-(tert-butoxycarbonylamino)-cyclohexanecarboxylic acid (0.276 g, 1.1 mmol) were dissolved in 5 ml of dry CH2Cl2. The mixture was allowed to stir at room temperature for 12 hours. The reaction mixture was diluted with 30 ml of CHCl3 and washed with 10 ml of H2O. The organic layer was dried over MgSO4 and concentrated to dryness. The crude product was purified through a column of silica gel with a gradient of 30% to 70% EtOAc in hexane to afford the rac-((1R,2S)-2-{4-[cyclopropyl-(3-trifluoromethyl-benzenesulfonyl)-amino]-piperidine-1-carbonyl}-cyclohexyl)-carbamic acid tert-butyl ester (573 mg, 100%). The product (0.120 g, 0.21 mmol) was taken up in 1 ml of EtOAc, and cooled in ice bath. 4N HCl-EtOAc (1.0 ml) was added slowly, and the mixture was stirred at room temperature for 5 hours. The solvent was removed and remaining material was triturated with ethyl ether to give the desired product 4 (colorless amorphous, 90 mg, 84%) as hydrochloride salt. LC: 100%. MS: m/z=473.

Provenance & Evidence