Nitrogen → HCID 58787854, compound

Participants

Reaction Conditions

Reaction Steps

20 mL of dimethoxyethane was added to a dry 100 mL round bottom under N2. 4.54 g (10.0 mmol) of Fmoc-Orn(Boc)—OH, lxxx, was added with stirring. The suspension was cooled in an ice/water/salt bath at −15° C. To the well suspended solid was added 1.11 mL (10 mmol) of N-methylmorpholine followed by 1.36 mL (10 mmol) of isobutyl chloroformate. The reaction was stirred vigorously for 1 min then vacuum filtered. The filtrate was stirred, and a solution of 570 mg (15 mmol) of sodium borohydride in 20 mL of water was immediately added. After 20 min, 150 mL of water was added, and after an additional hour, the resulting white precipitate was filtered, washed with water and hexane, then dried in a vacuum oven at 40° C. for 36 hours to give 3.75 g (8.52 mmol, 85%); white solid; TLC Rf (60% ethyl acetate/hexane): 0.45; mp: 107–109° C.; HRMS calcd (M+ less C4H9O, C21H23N2O4) 367.1658, found 367.1664. 1H NMR (300 MHz, D2O) δ 7.74 (d, 2H, J=7.5), 7.58 (d, 2H, J=7.2), 7.38 (t, 2, J=7.3), 7.29 (t, 2H, J=7.2), 5.05 (m, 1H), 4.57 (m, 1H), 4.42 (d, 2H, J=6.6), 4.19 (t, 1H, J=6.5), 3.72–3.50 (m, 3H), 3.11 (m, 2H), 2.14 (m, 1H), 1.62–1.41 (m, 4H), 1.43 (s, 9H). 13C NMR (125 MHz, CDCl3) δ 156.7, 156.2, 143.8, 141.2, 127.6, 127.0, 125.0, 119.9, 79.2, 66.4, 64.8, 52.8, 47.2, 40.2, 28.4, 28.2, 26.7.

Provenance & Evidence