反应详情

温度

0 °C

To 4-nitrophenyl chloroformate (1008 mg, 5.00 mmol) in THF (17 mL) at 0° C. was added ethyl carbazate (0.521 g, 5 mmol) and Et3N (2.08 mL, 15.00 mmol). The mixture was stirred at 0° C. for 30 min. Then a solution of 11-azido-3,6,9-trioxaundecan-1-amine (1.09 ml, 5.50 mmol) in 2 mL THF, and the mixture was stirred at room temperature for 16 h. Water was added, extracted twice with AcOEt, dried over MgSO4, filtered, and concentrated. The crude product was purified by silica gel chromatography (40-100% AcOEt/heptane, then 5% MeOH/AcOEt), giving ethyl 16-azido-4-oxo-8,11,14-trioxa-2,3,5-triazahexadecan-1-oate (I-18a: 1.23 g, 71%) as a colorless oil. LC-MS (M+1) 349.4, t=1.63 minute.

1. extractionextracted twice with AcOEt
2. dry with materialdried over MgSO4
3. filtrationfiltered
4. concentrationconcentrated
5. customThe crude product was purified by silica gel chromatography (40-100% AcOEt/heptane