- PROCESS FOR THE PREPARATION OF 6-ALPHA-FLUORO PREGNANES
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Disclosed is a process for the preparation of 6-α-fluoro pregnanes of formula I wherein R1 is an acyl group, R2 can be H, alpha methyl or beta methyl, and the dotted line can represent a double bond, comprising fluorination with electrophilic fluorinating agents in the 6 position of compounds of formula III, wherein R1, R2 and the dotted line have the meanings stated above, in an inert solvent, in the presence of a basic catalyst at temperatures ranging between 0 and 30° C.
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Paragraph 0039; 0040; 0041
(2014/07/08)
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- PROCESS FOR THE PREPARATION OF 17-DESOXY-CORTICOSTEROIDS
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The present invention provides an improved process for the preparation of 17-desoxy corticosteroid derivatives in a single chemical step by reacting the 17-hydroxy starting material with an excess of Trimethylsilyl Iodide. The present invention is specifically advantageous in preparing 17-desoxy corticosteroid derivatives having one or more halogen groups at positions 2, 6, 7 or 9 of the corticosteroid such as Clocortolone or Desoximetasone.
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Page/Page column 19
(2012/02/05)
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- STEREOSELECTIVE METHOD OF PRODUCING 6ALPHA-FLUOROPREGNANES AND INTERMEDIARIES
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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.
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- Selective epoxidation of steroidal bromohydrins
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Vicinal steroidal epoxides are prepared by reacting the corresponding vicinal steroidal bromohydrin with a heterocyclic base such as 1,5-diazabicyclo[4.3.0]non-5-ene or 1,5-diazabicyclo[5.4.0]-undec-5-ene.
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