Diisopropylethylamine → (4-{4-[(1H-Imidazol-2-yl-carbamoyl)methoxy]phenyl}butyl)carbamic acid tert-butyl ester

Participants

Reaction Steps

[4-(4-tert-Butoxycarbonylaminobutyl)phenoxy]acetic acid 33 (1.19 g, 3.68 mmol) was dissolved in anhydrous THF (10 mL), CH2Cl2 (10 mL) and CH3CN (5 mL). To the solution were sequentially added HOAt (200 mg, 1.47 mmol), DMAP (135 mg, 1.10 mmol), and diisopropylethylamine (3.2 mL, 18.40 mmol), followed by the addition of EDC.HCl (1.03 g, 5.35 mmol). The reaction mixture was stirred at room temperature for 15 min. Amino imidazole sulfate (583 mg, 4.41 mmol) was then added and stirring was continued for 48 h. Solvents were removed by rotary evaporation. The residue was taken up in CH2Cl2 (250 mL), washed with water and brine, and concentrated under reduced pressure. Flash silica gel column chromatography eluting with methanol/dichloromethane (1:30, 1:20, v/v) gave the desired amide as a white solid (0.95 g, 66% yield). 1H NMR (300 MHz, CD3OD) δ 1.40 (s, 9H), 1.42-1.70 (m, 4H), 2.48-2.60 (m, 2H), 3.00-3.20 (m, 2H), 4.65 (s, 2H), 6.79-6.89 (m, 4H), 7.10 (d, 2H). m/z (ESI): 389 [C20H28N4O4+H]+.

Provenance & Evidence