反应详情

(22E)-5,7,22-Ergostatriene-1α,3β,25-triol (Ia) (100 mg, 0.23 mmol) was dissolved in a mixed solution of ether (950 ml) and tetrahydrofuran (50 ml), and the solution was irradiated with high pressure mercury lamp using an 1.5% aqueous potassium nitrate solution as a filter with water cooling in a nitrogen stream for 3 minutes. From the reaction solution was distilled off the solvent and the residue containing previtamin D was dissolved in ethanol (30 ml) and the solution was refluxed for one hour. After distilling off ethanol, the residue was purified by high pressure liquid chromatography (HPLC) (column: LiChrosorb® Si60 (7 μm), φ25×250 mm, Merck Co., Ltd.; column effluent: 4% methanol-methylene chloride; flow rate: 8.0 ml/min; detected at 264 nm) to give 22 mg of the title compound (IIa) which was recrystallized from hexane-ether. m.p. 168°-170° C.

1. customthe solution was irradiated with high pressure mercury lamp
2. filtrationa filter with water cooling in a nitrogen stream for 3 minutes
3. distillationFrom the reaction solution was distilled off the solvent
4. additionthe residue containing previtamin D
5. dissolutionwas dissolved in ethanol (30 ml)
6. temperaturethe solution was refluxed for one hour
7. distillationAfter distilling off ethanol
8. customthe residue was purified by high pressure liquid chromatography (HPLC) (column