反应详情

Compound 14 (3.25 g, 14.9 mmol) was converted into oxadiazolone 15 as described earlier for the preparation of compound 3. The resulting crude light orange solid was stirred for 5 h in a mixture of DCM (15 mL) and TFA (8 mL). Concentration under reduced pressure and evaporation with toluene (2×10 mL) gave a brown solid which was purified by silica gel (40 g) column chromatography (eluent: EtOAc) to yield compound 16 (1.81 g, 69% over the three steps). Rf 0.5 (EtOAc).

1. concentrationConcentration
2. customunder reduced pressure and evaporation with toluene (2×10 mL)
3. customgave a brown solid which
4. customwas purified by silica gel (40 g) column chromatography (eluent: EtOAc)