发明授权
US4065452A 21,21-Dihalo steroids 失效
21,21-二卤类固醇

21,21-Dihalo steroids
摘要:
Novel, topically-active anti-inflammatory steroids are represented by the formula ##STR1## wherein X is fluoro, chloro or hydrogen; X.sup.1 is fluoro, chloro, bromo, or hydrogen; X.sup.2 is hydroxy or may be chloro when X.sup.1 is chloro; and X.sup.3 and X.sup.4 are independently fluoro, chloro or bromo. These steroids are prepared by formylating at the 21-position a 16.alpha.,17.beta.-isopropylidenedioxypregna-1,4,9(11)-triene-3,20-dione or the corresponding 21-fluoro compound, halogenating at the 21 position, deformylating, then reacting to add the desired components at the 9.alpha. and 11.beta. positions.
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