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Synthesis of 25-Hydroxy-provitamin D3 by Direct Hydroxylation of Protected 7-Dehydrocholesterol
Agnieszka Wojtkielewicz1, Aneta Baj1, Adam D Majewski2
1Faculty of Chemistry, University of Bialystok, Ciołkowskiego 1K, 15-245 Białystok, Poland.
Abstract:
A new synthetic route to 25-hydroxy-provitamin D3 was elaborated. The synthesis consists of direct hydroxylation at C-25 of 7-dehydrocholesterol hetero Diels-Alder adducts. The adducts were prepared by [4 + 2] cycloaddition of azadienophiles to the steroidal diene. The hydroxylation reactions of adducts were carried out with different dioxiranes or with chromyl trifluoroacetate. The byproducts of these reactions were isolated and identified. The strengths and weaknesses of hydroxylation methods with different oxidizing agents were discussed.
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