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Reaktionen von Steroiden mit Dialkylaminoschwefeltrifluoriden . I. 11β‐Hydroxysteroide. Über STeroide, 233. Mitteilung
Author(s) -
Biollaz Michel,
Kalvoda Jaroslav
Publication year - 1977
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19770600821
Subject(s) - chemistry , hydrolysis , alkoxy group , difluoride , medicinal chemistry , organic chemistry , alkyl
Reactions of Steroids with Dialkylaminosulfur Trifluorides. I. 11β‐Hydroxysteroids. Reactions of three types of 11β‐hydroxy steroids with dialkylaminosulfur trifluorides (DAST) have been studied. 9Δ‐unsubstituted 11‐alcohols are dehydrated with DAST to Δ 9(11) ‐unsaturated compounds under very mild conditions. 9α‐Chloro‐11β‐hydroxy steroids are quantitatively fluorinated in position 11 yielding the known 9α‐chloro‐11β‐fluoro derivatives. Finally, 9α, 11Δ‐fluorohydrins at 0–25° are selectively transformed with DAST into Δ 11 ‐9α‐fluorides. When the latter reaction is run at lower temperature, the corresponding 11‐piperidinesulfinates, products of partial hydrolysis of the alkoxy‐dialkylaminosulfur difluoride intermediates postulated by Middleton , can be isolated in high yields. A rational explanation of the results is presented.