Diisopropylethylamine → (s)-Azepane-1-carboxylic acid {1-[4-(9h-fluoren-9-yl)-piperazine-1-carbonyl]-3-methyl-butyl}-amide

Participants

Reaction Conditions

Reaction Steps

(S)-2-[(Azepane-1-carbonyl)-amino]4-methyl-pentanoic acid (0.300 g, 1.17 mmol, Example 1, Step B) was dissolved in dry DMF (4 mL) under nitrogen atmosphere and cooled to 0° C. in an ice-water bath. To this solution were added, in succession, N,N-diisopropylethylamine (0.816 mL, 4.68 mmol) and solid O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium hexafluorophosphate (0.444 g, 1.17 mmol). The resulting reaction mixture was stirred at that temperature for 30 minutes; solid 9-piperazinofluorene dihydrochloride (0.293 g, 1.17 mmol, Maybridge Chemical Co. Ltd., Tintagel Cornwall, U.K.) was then added. After stirring for, sequentially, 20 minutes at 0° C. and 20 minutes at ambient temperature, reaction mixture was mixed with 60 mL of diethyl ether; the resulting mixture was successively washed with saturated aqueous NaHCO3 solution (2×60 mL), brine (2×60 mL), and was dried over Na2SO4. The solution was concentrated in vacuo affording a viscous oil. The crude product was further purified by flash chromatography (50% EtOAc in hexane containing 1% MeOH to provide 0.21 g (37%) of the pure titled compound as a white foam: mp 63-73° C. APCI-MS m/z 489.3 (MH+).

Provenance & Evidence