Patent ID: 8314145

Claim:
A process for the synthesis of 17α-cyanomethyl-17β-hydroxy-estra-4,9-diene-3-one of the Formula (I) which comprises the steps of: (i) oxidizing 3-methoxy-17-hydroxy-estra-2,5(10)-diene of Formula (V) with aluminum isopropylate in the presence of cyclohexanone in an inert organic solvent under heating to obtain a compound of the Formula (IV) (ii) cyanomethylating the compound of the Formula (IV) with cyanomethyl lithium, wherein the cyanomethyl lithium reagent is prepared in situ from hexyllithium and acetonitrile, at a temperature between 0 and −30° C., to obtain 3-methoxy-17α-cyanomethyl-17β-hydroxy-estra-2,5(10)-diene of Formula (III) (iii) acidifying the compound of the Formula (III) with a strong organic acid in tetrahydrofuran solution to obtain 17α-cyanomethyl-17β-hydroxy-estr-5(10)-ene-3-one of Formula (II) and (iv) reacting the compound of the Formula (II) with 1-1.5 equivalent of pyridinium tribromide in pyridine solution at a temperature between 0 and 60° C., to obtain the compound of the Formula (I); and optionally purifying the obtained crude compound of the Formula (I).