Process for preparation of androgen receptor antagonist
The present invention provides an isopropanol solvate of enzalutamide. The present invention also provides a process for the preparation of androgen receptor antagonist. In particular, the present invention provides a process for the preparation of enzalutamide or its pharmaceutically acceptable salts, hydrates, solvates, polymorphs or intermediates thereof.
1. A process for the preparation of enzalutamide of Formula (I)
the process comprising:
reacting a compound of Formula (VI)
with a compound of Formula (V)
wherein L is Cl, Br, I or a leaving group,
to obtain a compound of Formula (IV)
optionally, purifying the compound of Formula (IV);
reacting the compound of Formula (IV) with a compound of Formula (II)
to obtain the enzalutamide of Formula (I); and
optionally, purifying the enzalutamide of Formula (I) in one or more of solvents.
2. The process according to claim 1 , wherein the compound of Formula (IV) is reacted with the compound of Formula (II) in presence of a base in one or more solvents.
3. The process according to claim 2 , wherein the base comprises of inorganic base or organic base wherein the inorganic base comprises one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide; sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate; and ammonia or its aqueous solution; or the organic base comprises one or more of methyl amine, ethyl amine, TEA, TBA, DIPA, DIPEA, pyridine, piperidine, morpholine, DBU, DABCO and DBN.
4. The process according to claim 2 , wherein the solvent comprises one or more of esters selected from ethyl acetate, isopropyl acetate, t-butyl acetate, and isobutyl acetate; hydrocarbons selected from toluene, xylene, ethyl benzene, heptane, hexane, and cyclohexane; and chlorinated solvents selected from methylene dichloride, ethylene dichloride, chlorobenzene, chloroform, and carbon tetrachloride.
5. The process according to claim 1 , wherein the purification of compound (IV) is performed in one or more solvents comprises of alcohols selected from methanol, ethanol, isopropanol, butanol, t-butanol, and isoamylalcohol; ketones selected from acetone, methyl isobutyl ketone, and methyl ethyl ketone; esters selected from ethyl acetate, isopropyl acetate; t-butyl acetate, and isobutyl acetate; and chlorinated solvents selected from methylene dichloride, ethylene dichloride, and chlorobenzene.
6. The process according to claim 1 , wherein enzalutamide of Formula (I) is obtained in crystalline Form-A characterized by x-ray powder diffraction (XRD) having characteristic peaks expressed in degrees 2θ (±0.2° 2θ) at about 13.1°, 13.4°, 14.3°, 16.6°, 21.1°, 22.7° and 24.4°±0.2° 2θ and/or by differential scanning calorimetry (DSC) having onset at about 197±5° C. and an endothermic peak at about 198±5° C.