反应详情

The title compound of step 3 (500 mg, 2.8 mmol) in triethyl orthoformate (10 mL) was heated to reflux for 5 h. The mixture was concentrated in vacuo at 55° C. and purified by silica gel chromatography (PE: EA=1:1) to give the title compound (130 mg, yield: 30%) as a yellow solid.

1. temperatureto reflux for 5 h
2. concentrationThe mixture was concentrated in vacuo at 55° C.
3. custompurified by silica gel chromatography (PE: EA=1:1)