反应详情

温度

200 °C

36.2 g (164 mmol) of the compound from Example III are well stirred with 27.4 g of selenium dioxide in 130 g of naphthalene at 180° C. After 5 h, a further 3.65 g of SeO2 are added and the mixture is stirred for a further 3 h at 200° C. It is allowed to cool and is dissolved in CH2Cl2 and the solution is concentrated on a rotary evaporator after addition of 200 g of silica gel. The residue is applied to a large silica gel column and chromatographed (toluene→ethyl acetate). Yield: 18 g (47%) M.p.: 148° C.

1. temperatureto cool
2. concentrationthe solution is concentrated on a rotary evaporator
3. additionafter addition of 200 g of silica gel
4. customchromatographed (toluene→ethyl acetate)