Sodium triacetoxyborohydride → alpha-(r)-(3-(s)-((4-(4-Benzyltriazol-2-yl)piperidin-1-yl)methyl)-4-(s)-phenylpyrrolidin-1-yl)-cyclohexaneacetic acid

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Reaction Steps

A Solution of α-(R)-(3-(R)-Formyl-4-(S)-phenylpyrrolidin-1-yl)-cyclohexaneacetic acid, para-methoxybenzyl ester (52 mg, 0.12 mmol, (prepared above as Aldehyde 5)), 4-(4-benzyltriazol-2-yl)piperidine (41 mg, 0.17 mmol from Step C) and sodium triacetoxyborohydride, (51 mg 0.24 mmol) in 1 mL of 1,2-dichloroethane was stirred for 12 h. The solvent was removed and the product was purified by preprative HPLC (column: YMC Combiprep ODS-A 20×50 mm, gradient: 5% acetonitrile/water w/0.1% TFA for 1 min then ramp to 100% acetonitrile w/0.1% TFA over 6 min, flow: 20 mL/min). The so isolated material was stirred in 3 mL formic acid for 16 h. After removal of solvent the residue was purified by ion exchange chromatography (3 grams SCX resin, 100% MeOH→2.0M NH3/MeOH) to give 17 mg (42%) of the title compound. 1H NMR (500 MHz, CD3OD). δ1.0-3.6 (m, 29H), 4.05 (s, 2H), 7.15-7.35 (m, 10H), ESI-MS. M/z; (M+H)=542.4 (obs), 542.34 (calc.).

Provenance & Evidence