Process for the preparation of 7alpha-methylsteroids

1 . A process for the preparation of 7α-methyl steroids of the formula I

wherein

R1 is hydrogen, methyl or C≡CH;

R2 is (CH 2 ) n OH, wherein n is 0, 1 or 2;

by a copper mediated 1,6-conjugate addition of a Grignard reagent CH 3 MgX, X being a halogen, to the 4,6-unsaturated 3-ketosteroid of formula II,

wherein R1 and R2 are as previously defined,

comprising:

protecting the hydroxy group of the steroid of formula II with a trialkylsilyl group,

followed by treating the hydroxy protected steroid with the Grignard reagent CH 3 MgX.

2 . The process of claim 1 , wherein R1 is hydrogen, methyl or C═CH and R2 is OH; or R1 is hydrogen and R2 is (CH 2 ) 2 OH.

3 . The process of claim 1 , wherein the Grignard reagent is CH 3 MgCl.

4 . The process of claim 1 , wherein the trialkylsilyl group is a trimethylsilyl group.

5 . The process of claim 1 , wherein the solvent of the Grignard reaction is tetrahydrofuran, diethyl ether or a mixture thereof.

6 . The process of claim 1 , wherein the concentration of the steroid of formula (II) is 0.1 to 0.3 molar.

7 . The process of claim 1 , wherein the molar ratio of the steroid of formula (II) to the Grignard reagent is 1:1 to 1:7.

8 . The process of claim 1 , wherein as copper catalyst copper(II) acetate or copper(II) chloride is used.

9 . The process of claim 1 , wherein the reaction temperature of the Grignard reaction is −78° C. to 0° C.

10 . A compound 21-hydroxy-19-norpregn-4,6-dien-3-one.