Process for the preparation of apixaban and intermediates thereof

1. A process for the preparation of Apixaban compound of formula (1)

comprising steps of:

a. reacting aniline with compound of formula (22) in presence of inorganic base or aqueous solution of inorganic base or absence of any base optionally in presence of phase transfer catalyst to obtain compound of formula (24) wherein X is leaving group;

b. optionally isolating the compound of formula (24);

c. (i) cyclizing compound of formula (24) in presence of inorganic base or aqueous solution inorganic base optionally in presence of phase transfer catalyst to obtain compound of formula (21);

(ii) nitrating compound of formula (21) with nitric acid in sulphuric acid or acetic acid to obtain compound of formula (10);

or

(iii) nitrating compound of formula (24) with nitric acid in sulphuric acid or acetic acid to obtain compound of formula (25);

(iv) cyclizing compound of formula (25) in presence of inorganic base or aqueous solution of inorganic base optionally in presence of phase transfer catalyst to obtain compound of formula (10);

d. reacting compound of formula (10) with chlorinating agent in presence of non-halogenated solvent to obtain compound of formula (11);

e. reacting compound of formula (11) with morpholine optionally in presence of solvent to obtain nitro-morpholine compound of formula (16);

f. optionally isolating and purifying the nitro-morpholine compound of formula (16);

g. reducing nitro-morpholine compound of formula (16) in presence of hydrazine hydrate with catalytic amount of Raney Nickel to obtain amino-morpholine compound of formula (17);

h. reacting amino-morpholine compound of formula (17) with compound of formula (22) in presence of inorganic base or aqueous solution of inorganic base or absence of any base optionally in presence of phase transfer catalyst to obtain an amide-compound of formula (23) wherein X is leaving group;

i. optionally isolating the amide-compound of formula (23);

j. cyclizing amide-compound of formula (23) in presence of inorganic base or aqueous solution of inorganic base optionally in presence phase transfer catalyst to obtain a lactam compound of formula (18);

k. reacting hydrazono compound of formula (6) with lactam compound of formula (18) in presence of a solvent and base to obtain ester compound of formula (8);

l. converting ester compound of formula (8) into the Apixaban compound of formula (1) in presence of anhydrous methanolic ammonia

2. The process according to claim 1 , wherein inorganic base is selected from the group consisting of sodium carbonate, potassium carbonate, lithium carbonate, lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonium hydroxide, lithium hydrate, potassium hydrate, sodium hydrate, lithium hydrogen carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate or aqueous solution thereof and mixture(s) thereof.

3. The process according to claim 1 , wherein reaction of step (a), step (c)(i), step (c)(iv), step (h) and step (j) is carried out in presence of a solvent selected from group consisting of MDC, toluene, ethyl acetate, methyl acetate, CHCl 3 , chlorobenzene, DMF, dimethylacetamide, N-methylpyrrolidone, acetonitrile, dimethyl sulfoxide, THF, dioxane and mixture(s) thereof.

4. The process according to claim 1 , wherein a phase transfer catalyst selected from group consisting of methyltridecyl ammonium chloride, trimethyl ammonium chloride, tetrabutyl ammonium bromide, dimethylethylhexadecyl ammonium bromide, ethyltripentyl ammonium iodide, benzyltrimethylammonium chloride, hexadecyltributylphosphonium bromide.

5. The process according to claim 1 , wherein leaving group is selected from group consisting of Cl, Br, I, F, mesylate, triflate, tosylate and tert-butyldimethylsilyloxy group.

6. The process according to claim 1 , wherein non-halogenated solvent is selected from the group consisting of toluene, xylene, benzene, acetic acid, ethyl acetate, THF, methyl t-butyl ether, methyl ethyl ketone, dioxane and mixture(s) thereof.

7. The process according to claim 1 , wherein chlorinating agent is selected from group consisting of SOCl 2 , PCl 3 , PCl 5 .

8. The process according to claim 1 , wherein solvent in step (e) is N-methylpyrrolidone or DMF.

9. The process according to claim 1 , wherein the reaction in step (g) is carried out in presence of a solvent selected from water, IPA, EtOH, MeOH, n-propanol or aqueous solutions thereof or mixture(s) thereof at temperature range of 50° C. to 75° C.

10. The process according to claim 1 , wherein solvent in step (k) is selected from the group consisting of ethyl acetate, dichloromethane, tetrahydrofuran, acetonitrile and mixture(s) thereof.

11. The process according to claim 1 , wherein base in step (k) is selected from the group consisting of triethyl amine, diisopropylethylamine.

12. The process according to claim 1 , wherein reaction in step (l) is carried out at temperature range of 60° C. to 70° C. in an autoclave.