| 摘要 |
Process for preparing flumethasone (6.alpha.,9.alpha.-difluoro- 11(3,17.alpha.,21-trihydroxy-16.alpha.-methyl- pregna-1,4-diene-3,20-dione), flumethasone 21-acetate or its 17-carboxyl androsten analogue of the formula: <IMG> which process comprises (a) reacting a compound of formula (II) <IMG> 18 with benzoyl chloride to form a 3-enolic ester of the formula (IIIa): <IMG> b) reacting the enol benzoate (IIIa) with an electrophilic fluorination agen t to introduce fluorine in the C6- position to form a compound of formula (IIIb): <IMG> 19 (c) deprotecting the compound (IIIb) at C3 to form a compound of formula (IV ): <IMG> (d) fluorinating the 9,11-epoxy group of compound IV by reacting it with hydrofluoric acid to yield flumethasone 21-acetate; and optionally (e) hydrolysing the flumethasone 21-acetate, in the presence or absence of a n oxidising agent, to yield compound (I) or flumethasone, respectively.</SDOAB >
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