2135-16-2Relevant academic research and scientific papers
STEREOSELECTIVE METHOD OF PRODUCING 6ALPHA-FLUOROPREGNANES AND INTERMEDIARIES
-
Page 15, (2008/06/13)
6α-fluorpregnanes (I), where the dotted line between positions 1 and 2 represents a single or double bond; R1 is OH, OCOR2, X, SO3R3, or an (R7)(R8)(R9)SiO- group, where X is halogen, R2 and R3 are C1-6 alkyl or phenyl optionally substituted by C1-4 alkyl, and R7, R8 and R9, equal or different, are C1-6 alkyl or phenyl optionally substituted by C1-4 alkyl, can be obtained by means of a high stereoselectivity process comprising reacting a 3-(trisubstituted)silyloxy-pregna-3,5-diene (IV) with a fluorinating agent selected among N-fluorosulfonimides and N-fluorosulfonamides. The 6α-fluorpregnanes (I) are intermediates for the synthesis of steroids useful as anti-inflammatory and anti-asthmatic agents.
3-Acetoxy-9β-11β-epoxy-dienes and the preparation of the corresponding 6α-halogen-4-ene-3-ones
-
, (2008/06/13)
The invention relates to 3-acetoxy-9β,11β,-epoxy-pregna-1,3,5-trienes and the corresponding 3,5-dienes having the general formula 1, in which on the 1,2-position a double bond may be present and in which R3 is a hydrogen or halogen atom or a hyroxy-, acyloxy-, aroyloxy or sulphonyloxygroup; R1 and/or R2 are a hydrogen atom or a hydroxy-, aroyloxy-, acyloxy- or alkylgroup containing 1-6 carbon atoms, or in which R1 and R2 form together a 16,17-isopropylidene-dioxy group, a process for the preparation of this compounds by reacting the corresponding Δ1,4 -3-keto-pregnadienes or Δ4 -3-keto-pregnenes with isopropenylacetate and a process for their direct conversion into the corresponding 6α-halogen-substituted-pregna-1,4-diene-3-ones and pregn-4-ene-3-ones with the general formula 2 by reacting them with a positive-halogen producing agent.
