Diisopropylcarbodiimide → N,N'-Bis(1-methylethyl)urea

Participants

Reaction Steps

N-Hydroxysuccinimide (1.70 g, 14.77 mmol) and DIC (1.87 g, 14.77 mmol) were added sequentially to a stirred solution of Fmoc-Gly-OH (4.0 g, 13.45 mmol) in dichloromethane (15 mL); the resulting mixture was stirred at room temperature for 4 h. The N,N′-diisopropylurea formed was removed by filtration and the solid was washed with ether (20 mL). The volatiles were removed and the solid Fmoc-Gly-succinimidyl ester formed was washed with ether (3×20 mL). Fmoc-Gly-succinimidyl ester was then redissolved in dry DMF (15 mL) and 3-aminodeoxycholic acid (5.21 g, 12.78 mmol) was added to the clear solution. The reaction mixture was stirred at room temperature for 4 h, water (200 mL) was added and the precipitated solid was filtered, washed with water, dried and purified by silica gel chromatography (TLC (silica): (Rf: 0.50, silica gel, CH2Cl2/CH3OH, 9:1) (eluant: CH2Cl2/CH3OH (9:1)) to give (3β,5β,7α,12α)-3-[[(9H-Fluoren-9-ylmethoxy)amino]acetyl]amino-7,12-dihydroxycholan-24-oic acid as a colorless solid. Yield: 7.46 g (85%).

Provenance & Evidence