4-Phenyl-1,2,4-triazoline-3,5-dione → Cholesta-5,7-diene-1,3,25-triol, (1alpha,3beta)-

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Reaction Steps

140.3 g of the 1α,2α-epoxide of the 1,4-cyclic adduct of cholesta-1,5,7-triene-3β,25-diol and 4-phenyl-1,2,4-triazoline-3,5-dione obtained in Example 2 was dissolved in 15 ml of tetrahydrofuran, and 142 mg of lithium aluminum hydride was added little by little to the solution under agitation. Then, the mixture was mildly refluxed and boiled for 1 hour and cooled, and 20 ml of tetrahydrofuran was added to the reaction mixture. A saturated aqueous solution of Glauber salt was added to the reaction mixture until generation of bubbles was stopped, whereby excessive lithium aluminum hydride was decomposed. The reaction mixture was then filtered, and the residue was washed 3 times with 10 ml of tetrahydrofuran. The organic solvent layer was dried and the solvent was distilled off. The residue was purified by using a column packed with 20 g of Sephadex LH 20, and a fraction eluted by chloroform-hexane (65 : 35 V/V ratio) was collected and recrystallized from ether-hexane to obtain 49.9 mg of cholesta-5,7-diene-1α,3β,25-triol in the form of needles melting at 149° to 152° C.

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