Verfahren zur Herstellung von 7a, 16a-Dialkyl-steroiden der Pregnanreihe

The invention comprises steroids of the formula (wherein the D 1 and D 6 double bonds are optional and the alkyl groups each have 1 to 4 carbon atoms) and their preparation by (1) reacting a D 6-16a -alkyl-progesterone in which the 20-keto group is protected with an alkyl Grignard reagent to give, after release of the 20-keto group, a 7a ,16a -dialkyl-progesterone into which D 1- and/or D 6-double bonds may be introduced in known manner; or (2) oxidizing a D 5 - 3 - acyloxy - 16a - alkyl - pregnene to the corresponding 7-keto compound, treating this with an alkyl metal derivative to give the corresponding 7-hydroxy-7-alkyl-steroid and oxidizing and dehydrating this to give a D 4,6-7, 16a - dialkyl - pregnadiene - 3,20 - dione into which a D 1-double bond may be introduced. In (1) the 20-keto group may be protected as a ketal or by reduction to the 20-ol and the D 1-and D 6-double bonds may be introduced before or after its release. The D 1-double bond may be introduced chemically with a quinone or selenium dioxide or microbiologically, e.g. with Bacillus sphaericus or Corynebacterium simplex. The D 6-double bond may be introduced with a quinone of oxidation-reduction potential of less than - 0.5 v., it being necessary to use a 7b -alkyl compound (prepared along with the 7a -alkyl compounds in the reaction of the D 6-steroids with an alkyl Grignard reagent at room temperature and separated from them by known methods) in this process. Reference is also made to simultaneous introduction of D 1- and D 6-double bonds by bromination and dehydrobromination. Examples are given. D 4,6 - 3 - Keto - 16a - ethyl - 20 - ethylenedioxy-pregnadiene is prepared by ketalizing 16a -ethyl-pregnenolone acetate to give D 5-3b -acetoxy - 16a - ethyl - 20 - ethylenedioxy - pregnene, hydrolysing this to D 5-3b -hydroxy-16a -ethyl - 20 - ethylenedioxy - pregnane, converting this by the Oppenauer method to D 4-3-keto-16a -ethyl - 20 - ethylenedioxy - pregnane and refluxing this with chloranil in t-butanol. Other 20-protected D 4,6 - 3,20 - diketo - 16a - alkyl - pregnadienes are prepared similarly.