Hydrochloric Acid → Nalpha-Boc-Ndelta-Cbz-ornithinol

Participants

Reaction Steps

A well, stirred cold solution (0° C.) of Nα-Boc-Nδ-Cbz-ornithine (5 g, 13.6 mmol), diisopropylethylamine (5.9 ml, 34 mmol), and tetrahydrofuran (60 ml) was treated with ethyl chloroformate (3.25 ml, 34 mmol) at 0° C. Sodium borohydride (2.58 g, 68 mmol) was added, followed by the slow addition of 1:1-tetrahydrofuran/water (10 ml) 30 minutes later. The reaction mixture was acidified with 6N hydrochloric acid and the solution was extracted with dichloromethane. The organic layer was dried over anhydrous sodium sulfate and purified by chromatography to give Nα-Boc-Nδ-Cbz-ornithinol (3.9 g): 1H NMR (400 MHz, CDCl3) δ1.2-1.4 (m, 13H), 3.0 (t, J=6.4 Hz, 2H), 3.4 (s, 2H), 3.8 (s, 1H), 4.95 (s, 2H), and 7.1-7.2 (m, 5H).

Provenance & Evidence