benzyl N-(4-aminobutyl)carbamate;hydrochloride

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To 4-nitrophenyl chloroformate (1.008 g, 5.00 mmol) in THF (25.000 mL) at 0° C. was added ethyl carbazate (0.521 g, 5 mmol) and triethylamine (2.218 mL, 16.00 mmol). The mixture was stirred at 0° C. for 1 hour. Benzyl 4-aminobutylcarbamate hydrochloride (1.552 g, 6.00 mmol) was then added. The mixture was stirred at room temperature for 1 hour, water was then added, extracted twice with ethyl acetate, dried over MgSO4, filtered, and concentrated in vacuo. The crude product was purified by silica gel chromatography (40-100% ethyl acetate/heptane) giving ethyl 4,11-dioxo-13-phenyl-12-oxa-2,3,5,10-tetraazatridecan-1-oate (I-9a: 965 mg, 55%) as a white solid. LC-MS (M+1) 353.2, t=0.94 minute. The mixture was stirred at room temperature for 1 hour extracted twice with ethyl acetate dried over MgSO4 filtered concentrated in vacuo The crude product was purified by silica gel chromatography (40-100% ethyl acetate/heptane)