Diisopropylethylamine → tert-Butyl ((1R,3S)-3-Isopropyl-3-{[3-(trifluoromethyl)-7,8-dihydro-1,6-naphthyridin-6(5H)-yl]carbonyl}cyclopentyl)carbamate

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Reaction Steps

To a solution of 3-(trifluoromethyl)-5,6,7,8-tetrahydro-1,6-naphthyridine dihydrochloride (159 mg, 0.574 mmol) of Step A-1, (1S,3R)-3-[(tert-butoxycarbonyl)amino]-1-isopropylcyclopentanecarboxylic acid (0.21 g, 0.79 mmol) of Step A-4 in Example 1 in dichloromethane (10 mL) were added 4-dimethylaminopyridine (38 mg, 0.32 mmol) and diisopropylethylamine (180 mg, 1.4 mmol) followed by bromotris(pyrrolydino)phophonium hexafluorophosphate (270 mg, 0.57 mmol). After being stirred overnight at room temperature, the solution was diluted with dichloromethane, washed with saturated NaHCO3, water and brine, dried over Na2SO4, filtered, and evaporated in vacuo. The residue was purified by flash chromatography on silica eluting with 30% ethyl acetate in hexanes to give 300 mg of desired product. MS calculated for C23H32F3N3O3: (M+H)+456; found 356.2 (M−Boc+H)+.

Provenance & Evidence