Diisopropylethylamine → tert-Butyl [1-(3-nitro-6,7-dihydro-5H-cyclopenta[b]pyridin-4-yl)-5-(trifluoromethyl)piperidin-3-yl]carbamate

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Reaction Conditions

Reaction Steps

A mixture of 4-chloro-3-nitro-6,7-dihydro-5H-cyclopenta[b]pyridine (0.34 g, 1.7 mmol), cis-tert-butyl [5-(trifluoromethyl)piperidin-3-yl]carbamate (0.50 g, 1.9 mmol) in isopropyl alcohol (1.0 g) and DIPEA (1.0 mL, 5.7 mmol) was stirred at 110° C. for 2 h. The solution was allowed to cool to room temperature, then the mixture was concentrated under reduced pressure. The residue was purified by purified by column chromatography on silica gel using CombiFlash® apparatus (40 g column, eluting with 0 to 70% EtOAc in hexanes) to give the sub-title compound as a pale yellow powder (0.37 g, 50%). LCMS calc. for C19H26F3N4O4 (M+H)+ m/z=431.2. found: 431.0. The material was subjected to chiral HPLC (Phenomenex Lux® Cellulose 4 column, 21, 2×250 mm, 5 micron particle size; Mobile phase: 7% EtOH in hexanes; Flow rate: 18 mL/min. isocratic; Column loading: 10 mg/injection; Run time: 24 minutes) to give two separated enantiomers of the sub-title compound.

Provenance & Evidence