Diisopropylethylamine → Tert-butyl 4-(tert-butoxycarbonylamino)-4-(1-(4-chlorophenyl)-4-hydroxybutylcarbamoyl)piperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (5.24 g, 13.77 mmol) was added in one portion to 1-(tert-butoxycarbonyl)-4-(tert-butoxycarbonylamino)piperidine-4-carboxylic acid (Intermediate 70) (4.31 g, 12.5 mmol), 4-amino-4-(4-chlorophenyl)butan-1-ol (Intermediate 16) (2.5 g, 12.5 mmol) and DIPEA (6.56 mL, 37.6 mmol) in DMA (62.6 mL) under nitrogen. The resulting solution was stirred at 60° C. for 3 hours and evaporated to dryness. The crude reaction mixture was dissolved in 100 mL EtOAc and then basified with saturated NaHCO3 (150 mL) and the organic fraction dried over MgSO4, filtered and evaporated to dryness. The organic fraction was purified by flash silica chromatography (eluent 0-10% 7N ammonia in MeOH/DCM). Pure fractions were then evaporated to afford tert-butyl 4-(tert-butoxycarbonylamino)-4-(1-(4-chlorophenyl)-4-hydroxybutylcarbamoyl)piperidine-1-carboxylate (5.06 g, 77%) as an off-white solid.

Provenance & Evidence