- Δ16-20-Ketosteroids by C2-Elongation from Δ16-17-Substituted Steroids
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Reactions of corticoid precursor steroids with a Δ16-double bond and iodine, trimethylsilyl, tributylstannyl or trifluoromethanesulfonyloxy groups in 17-position were studied with the aim of introducing an acyl substituent in 17-position.Starting with the 17-trimethylsilyl compounds, using acyl chlorides and AlCl3 as a catalyst, a mixture of chlorinated compounds were obtained, among others.Better results gave palladium-catalyzed reactions, such as the cross-coupling of 17-tributylstannyl compounds with acyl chlorides or the substitution of the 17-iodides or the 17-triflates by vinyl ethers.In the reaction of the 17-iodides, different protecting groups are tolerated; thus this method is of general use.No Δ16-17-triflates were obtained by the reaction of androsta-4-ene-3,17-dione or androsta-1,4-diene-3,17-dione with trifluoromethanesulfonyl anhydride.This is a limitation of the triflate method, which in the other cases gives the best yields (>80percent).
- Schweder, Bernd,Uhlig, Egon,Doering, Manfred,Kosemund, Dirk
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p. 439 - 444
(2007/10/02)
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- PREPARATION OF UNLABELLED AND 3H>-LABELLED EPITESTOSTERONE AND ITS METABOLITES
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Cold as well as 3H>-labelled substrates and metabolites IX-XI, XV, XVI, XX-XXII, XXIV, XXV and XXVIII were prepared by catalytic hydrogenation of epitestosterone (VIII) and Λ1-dehydroepitestosterone (XIII).The key step in the preparation of compound XXVIII was reaction of 3β-tosylates XXVI and XXX with potassium nitrite in dimethyl sulfoxide.
- Kasal, Alexander,Fuksova, Kveta,Pouzar, Vladimir
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p. 600 - 611
(2007/10/02)
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