Potassium Nitrate → Previtamin D3

Beteiligte Stoffe

Reaktionsschritte

(24R)-5,7-Ergostadiene-1α,3β,25-triol (IIb) (100 mg, 0.23 mmol) prepared in Example 13 was dissolved in ether (1000 ml) and the solution was irradiated for 3 minutes with high pressure mercury lamp using 1.5% aqueous potassium nitrate solution as a filter under water-cooling in an argon gas stream. From the reaction solution was distilled off ether and the resultant residue was purified by preparative high performance liquid chromatography (HPLC) [column: LiChrosorb® Si60 (7 μm), φ25×250 mm, Merck Co., Ltd.; column effluent: 6% methanol-methylene chloride; flow rate: 6.0 ml/ml, detected at 265 nm] to give 25.0 mg of previtamin D (XIIb).

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