Phosgene → HCID 58997019, compound

Participants

Reaction Steps

To a 0° C. solution of COMPOUND 249 (106 mg, 0.341 mmol) in toluene (5 mL) and DIPEA (0.12 mL, 0.68 mmol) was added phosgene solution in toluene (20 wt %, 0.185 mL, 0.375 mmol). After one hour the TLC of the reaction mixture showed that starting material was still present, and additional phosgene solution (0.050 mL) and DIPEA (0.100 mL) were added. After 30 min, excess anhydrous hydrazine (0.2 mL) was added and the mixture was warmed to room temperature and was stirred for 30 minutes. Reaction mixture was concentrated under reduced pressure and the residue was purified by radial chromatography (19:1:0.1 CH2Cl2:MeOH:NH4OH) on silica gel twice, however complete purification was not achieved. The material (41 mg, 33%, 0.103 mmol) was dissolved in THF, and Et3N (0.200 mL) and Boc2O (100 mg, 0.50 mmol) were added. The mixture was stirred at room temperature for 2 days. The solvent was removed and the crude material was purified by radial chromatography (20:1:1 CH2Cl2:MeOH:NH4OH) to provide 21 mg (43%) of mono-Boc protected product.

Provenance & Evidence