Hydrochloric Acid → HCID 11284867, compound

Participants

Reaction Steps

A mixture of 4-(di-tert-butoxycarbonyl-methyl)-L-phenylalanine (818 mg, 2.16 mmol), Fmoc-OSu (727 mg, 2.16 mmol) and NaHCO3 (906 mg, 10.8 mmol, 5 equivalents) in 48 ml of dioxane-water (1:1) was stirred at room temperature overnight. The reaction mixture was then cooled to 0° C. and acidified with 180 ml of 0.2 M HCl. The reaction product was extracted with ethyl acetate (30 ml×3), and the combined organic extracts were washed with brine, dried (Na2SO4) and concentrated. The crude product was purified by silica gel chromatography (CDCl3-EtOAc-MeOH) to provide N-Fmoc-4-(di-tert-butoxycarbonyl-methyl)-L-phenylalanine as a white solid (650 mg, 50.7%). 1H NMR (DCMSO) δ: 12.704 (1H, s, br), 7.786 (2H, d, J=7.32 Hz), 7.760 (1H, d, J=8.54 Hz), 7.658 (2H, t, J=7.81 Hz), 7.435˜7.200 (4H, m) 7.254 (4H, s), 4.586 (1H, s), 4.274˜4.081 (4H, m), 3.111˜3.040 (1H, dd, J=4.40, 13.67 Hz), 2.913˜2.815 (1H, dd, J=10.75, 13.92 Hz), 1.390 (1H, s), 1.380 (1H, s). FABMS (+Ve), m/z 602 [MH+], 546 [MH+—C4H8], 490 [MH+—2 C4H8]. Anal. calcd. for C20H29NO6: C, 66.90; H, 6.5; N, 2.3. Found: C, 90.40; H, 6.67; N, 2.24.

Provenance & Evidence