反应详情

温度

0 °C

HCl. Boc-L-Arg(NO2)OH (5.00 g, 15.6 mmol) was dissolved in tetrahydrofuran (THF) (200 ml) and treated with isobutyl chloroformate (2.06 g, 15.6 mmol) in the presence of N-methylmorpholine (1.72 ml, 15.6 mmol) for 10 min at 0° C. The mixed anhydride preparation was filtered, and the filtrate was added to ethereal diazomethane [120 ml prepared from Diazald (5.4 g, 25 mmol)] over a period of 5 min. After the reaction was stirred at 0° C. for 45 min, acetic acid (0.5 ml) was added to quench the excess diazomethane. The product crystallized from the reaction mixture. The solvent was removed, and the residue was diluted with chloroform (25 ml). The crystalline product, Boc-L-Arg(NO2)CHN2, was filtered and dried in vacuo. Boc-L-Arg(NO2)CHN2 (3.97 g, 11.5 mmol) was dissolved in ethanol (23 ml) and cooled to 0° C. HCl (12.5 ml of a 10% solution in ethanol) was added dropwise over a period of 20 min. After the reaction mixture was stirred at room temperature (RT) for 1 hr, it was poured into diethyl ether (400 ml). The solution was allowed to stand for 2 hr at 5° C., filtered under N2, and dried in a vacuum desiccator to afford 1.72 g H-L-Arg(NO2)CH2Cl.HCl as a white powder. The product was characterized by 360 MHz 1H NMR.

1. filtrationwas filtered
2. customto quench the excess diazomethane
3. customThe product crystallized from the reaction mixture
4. customThe solvent was removed
5. additionthe residue was diluted with chloroform (25 ml)
6. filtrationThe crystalline product, Boc-L-Arg(NO2)CHN2, was filtered
7. customdried in vacuo
8. temperaturecooled to 0° C
9. stirringAfter the reaction mixture was stirred at room temperature (RT) for 1 hr
10. waitto stand for 2 hr at 5° C.
11. filtrationfiltered under N2
12. customdried in a vacuum desiccator