INTRODUCTION

Aspect of the present application relate to process for the preparation of plerixafor.

The drug compound having the adopted name "Plerixafor" can be represented by structural formula (I) which is a bicyclam derivative, a selective reversible antagonist of the CXCR4 chemokine receptor which blocks binding of its cognate ligand, stromal cell-derived factor-1q (SDF-1a), also known as CXCL12.

Formula I

Plerixafor is a white to off-white crystalline solid. A chemical name for plerixafor is 1,1'-[1,4-phenylenebis(methylene)]bis-1,4,8,11-tetraazacyclotetradecane and it is the active ingredient in MOZOBIL® injection, which is approved for the use in combination with granulocyte-colony stimulating factor (G-CSF) to mobilize hematopoietic stem cells to peripheral blood for collection & subsequent autologous transplantation in patients with non-hodgkin's lymphoma & multiple myeloma.

Plerixafor is disclosed in Ciampolini et al. Inorganic Chemistry (1987), 26(21), 3527-33 titled "Dinickel and dicopper complexes with N, N-linked bis(cyclam) ligands". A number of syntheses of plerixafor have been reported in references such as US 5,047,527, US 5,612,478, US 5,606,053, and US 6,489,472. The prior art processes suffer from one or more drawbacks such as low purity, less yield and lengthy workup which does not result an industrially feasible process.

Therefore, there remains a need for an environmentally-friendly, cost-effective and industrially applicable process for the preparation of plerixafor which alleviates the problems associated with the prior art processes as discussed above.

SUMMARY

In an aspect, the application provides a process for the preparation of highly pure plerixafor, which comprises:

a) protecting cyclam with Boc anhydride to provide the compound of Formula II;

Formula II

b) reacting the compound of Formula II with dihalo-p-xylene to provide the compound of Formula III;

Formula III

c) deprotecting in-situ the obtained compound of Formula III to provide plerixafor of Formula I; and

Formula I

d) purifying to provide pure plerixafor.

BRIEF DESCRIPTION OF THE DRAWING

Fig. 1 depicts a PXRD pattern of plerixafor, obtained by the procedure of Example 2.

DETAILED DESCRIPTION In an aspect, the application provides a process for the preparation of highly pure plerixafor, which comprises: a) protecting cyclam with Boc anhydride to provide the compound of Formula II;

Formula II

b) reacting the compound of Formula II with dihalo-p-xylene to provide the compound of Formula III;

Formula III

c) deprotecting in-situ the obtained compound of Formula III to provide plerixafor of Formula I; and

Formula I

d) purifying to provide pure plerixafor. In embodiments of step a), cyclam which is used as a starting material can be prepared by any method known in the art. Optionally, cyclam can be purified by recrystallization, slurry washing, column chromatography or any suitable method known in art for purification before its use in the reaction. Cyclam can be used in the form of its salts like hydrochloride, hydrobromide, or any other suitable salt.

Step a) involves the protection of cyclam by using Boc anhydride (di-tert-butyl dicarbonate) to provide Boc protected compound of Formula II. In embodiments of step a), the cyclam can also be protected by using other suitable amine protecting groups. In embodiments, the other amine protecting groups which may be used for cyclam protection selected from the group of carbobenzyloxy, p-methoxybenzyl carbonyl, tert-butyloxycarbonyl, 9-fluorenylmethyloxycarbonyl, acetyl, benzoyl, benzyl, carbamate, p-methoxybenzyl, 3,4-dimethoxybenzyl, p-methoxyphenyl, or the like.

In embodiments of step a), the reaction may be carried out in the presence or absence of a base. The base, if present can be selected from an organic base or an inorganic base. Bases that are useful in the reaction include, but are not limited to: inorganic bases such as alkali metal or alkaline earth metal carbonates, hydrogen carbonates, hydroxides, oxides, carboxylates, and alkoxides, e.g., potassium carbonate, potassium hydrogen carbonate, potassium hydroxide, potassium acetate, potassium methoxide, sodium carbonate, sodium hydrogen carbonate, sodium hydroxide, sodium acetate, sodium methoxide, lithium carbonate, lithium hydrogen carbonate, lithium hydroxide, lithium acetate, lithium methoxide, barium hydroxide, calcium oxide, and alkali metal hydrides e.g. lithium hydride, sodium hydride, potassium hydride, or the like; and organic bases such as, for example tertiary amines, e.g., triethylamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, 4-ethylmorpholine, N-methylmorpholine, dimethylaminopyridine, diisopropylamine, diisopropylethylamine pyridine, or the like. In embodiment of step a) the protection of cyclam can be carried out without using any base.

In embodiments of step a), the reaction may be carried out in a suitable inert solvent. Examples of such solvents include but are not limited to aliphatic hydrocarbons such as n-pentane, hexane, cyclohexane, heptane, or petroleum ether; aromatic hydrocarbons such as toluene or xylene; halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, chlorobenzene or dichlorobenzene; ether solvents such as diethyl ether, diisopropyl ether, tetrahydrofuran, dioxane, or dimethoxyethane; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone or diethyl ketone; ester solvents such as ethyl acetate, propyl acetate or butyl acetate; alcohol solvents such as methanol, ethanol, 2-fluoroethanol, 2,2,2-trifluoroethanol, ethylene glycol, 1-propanol, 2-propanol, 2-methoxyethanol, 1-butanol, 2-butanol, i-butyl alcohol, t-butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, cyclohexanol, benzyl alcohol, phenol, glycerol, or C1-C6 alcohols; carboxylic acid solvents such as acetic acid or propionic acid; nitrite solvents such as acetonitrile or propionitrile; or their mixture thereof.

In embodiments of step a), the protection reaction is selective. In embodiments of step a), the molar ratio of the amount of protecting agent used to introduce the amine protecting group to the amount of cyclam is about 4:1, about 3.5:1, about 3:1, about 2.5:1, about 2.0:1, about 1.5:1, or any suitable ratio. In embodiments of step a), the molar ratio of the amount of Boc anhydride used to introduce the Boc protecting group to the amount of cyclam is about 4:1, about 3.5:1, about 3:1, about 2.5:1, about 2.0:1, about 1.5:1, or any suitable ratio. Preferably, the ratio of Boc anhydride and cyclam is about 3:1 to 2:1.

In embodiments of step a), Boc anhydride can be added to the solution containing cyclam or the solution containing cyclam can be added to Boc anhydride. In embodiments of step a), Boc anhydride can be added dropwise or in a single lot or in parts to the solution containing cyclam. In embodiments of step a), Boc anhydride can be added to the solution containing cyclam for a period of about 5 minutes to about 2 hours or longer.

In embodiments of step a), Boc anhydride can be added to the solution containing cyclam at a temperature ranging from about -50°C to about the boiling point of the solvent. In one embodiment, Boc anhydride can be added to the solution containing cyclam from about -50°C to about 25°C.

In embodiments of step a), the reaction may be carried out at a temperature ranging from about -50°C to about the boiling point of the solvent. In one embodiment, the reaction can be carried out from about -50°C to about 50°C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents and solvent employed. However, provided that the reaction is effected under the conditions outlined above, for a period of about 1 hour to about 24 hours or longer.

In embodiments of step a), the product of step a), may be isolated directly from the reaction mixture itself after the reaction is complete, or after conventional work up with techniques such as quenching with a suitable reagent, extraction, or the like. In embodiments of step a), the product of step a), i.e., compound of Formula II is optionally isolated by extracting in a solvent followed by removal of the solvent by evaporation. In embodiments of step a), the product of step a), i.e., compound of Formula II can be used in the next step without isolation i.e., in situ.

In embodiments of step a), the product of step a), i.e., compound of Formula II can be purified before using in the next step. In embodiments of step a), the product of step a), i.e., compound of Formula II can be purified by using acids like acetic acid, para-toluenesulfonic acid or the like. In embodiments, the compound of Formula II can be purified by treating the solution containing compound of Formula II with aqueous acids like acetic acid or the like.

In embodiments of step a), the obtained product in the above step is basified with aqueous solution of suitable bases like sodium hydroxide, potassium hydroxide or the like. In embodiments, the obtained product is basified with aqueous solution of sodium hydroxide and extracting in a solvent to get pure product i.e., compound of Formula II.

In embodiments, the compound of Formula II can also be purified by slurring the solution containing compound of Formula II with silica gel. In an embodiment, the product of Formula II can be purified using acid base treatment or silicagel treatment or both in any order. In embodiments, the compound of Formula II can be used in the next step without isolation during purification.

Step b) involves the reaction of compound of Formula II with dihalo-p-xylene to provide compound of Formula III. In embodiments of step b), 1, 4-phenylenebis (methylene) compound containing any leaving group can be used in place of dihalo-p-xylene. In embodiments, preferably dibromo-p-xylene is used in the reaction of step-b. In embodiments of step b), the reaction can be carried out in the presence of a base and a solvent. Any of the bases listed in step a), can be used for the reaction. Any of the solvents listed in step a), can be used for the reaction of this step.

In embodiments of step b), the reaction may be carried out at a temperature ranging from about 0°C to about the boiling point of the solvent. In one embodiment, the reaction can be carried out from about 25°C to about 90°C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents and solvent employed. However, provided that the reaction is effected under the conditions outlined above, for a period of about 1 hour to about 24 hours or longer.

In embodiments of step b), the product may be isolated directly from the reaction mixture itself after the reaction is complete, or after conventional work up with techniques such as quenching with a suitable reagent, extraction, or the like. In embodiments of step b), the product of step b), i.e., compound of Formula III is optionally isolated by extracting in a solvent followed by removal of the solvent by evaporation. In embodiments of step b), the product of step b), i.e., compound of Formula III may be used in the next step without isolation.

Step c) involves the preparation of plerixafor by the deprotection of compound of Formula III. In embodiments of step c), the deprotection is carried out by using mineral acids such as hydrochloric acid or hydrobromic acid in the presence of a suitable solvent such as water, methanol, ethanol, isopropanol, tetrahydrofuran, acetonitrile, or their mixtures with water.

In embodiments of step c), the reaction may be carried out at a temperature ranging from about 0°C to about the boiling point of the solvent. In one embodiment, the reaction can be carried out from about 15°C to about 80°C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents and solvent employed. However, provided that the reaction is effected under the conditions outlined above, for a period of about 1 hour to about 24 hours or longer.

In embodiments of step c), the product may be isolated directly from the reaction mixture itself after the reaction is complete, or after conventional work up with techniques such as quenching with a suitable reagent, extraction, or the like. In embodiments of step c), the product of step c), i.e., plerixafor is optionally isolated by extracting in a solvent followed by removal of the solvent by evaporation. In embodiments of step c), the product of step c), i.e., plerixafor may be isolated by filtration.

In embodiments of step c), the mother liquor obtained after filtration of Plerixafor can be concentrated and purified according to the procedure as described in the present application to recover Pleraxafor from the mother liquor.

In embodiments of step c), plerixafor that is isolated can be dried at suitable temperatures, such as from about 40°C to about 100°C and suitable pressures from about 1 hour to about 24 hours or longer, using drying equipment known in the art, such as a tray dryer, vacuum oven, air oven, fluidized bed dryer, spin flash dryer, flash dryer, or the like. Drying temperatures and times will be sufficient to achieve desired product purity.

Step d) involves the purification of plerixafor. In embodiments of step d), the plerixafor obtained in step d) can be purified by any method known in the art such as recrystallization involving single solvent, mixture of solvents, or solvent-anti-solvent technique; reprecipitation; slurring in a solvent; or chromatography to improve its chemical purity. Any of the solvents listed in step a), can be used for the purification of plerixafor. Plerixafor solution can also be obtained from the reaction mass of the previous stage for purification. Plerixafor can also be purified by converting it into acid-addition salt followed by neutralization with a base to produce the substantially pure plerixfor. Examples of such acids used for the purification of plerixafor include but are not limited to: inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, hydrobromic acid, or the like; and organic acids such as oxalic acid, maleic acid, fumaric acid, malic acid, tartaric acid, citric acid, benzoic acid, methanesulfonic acid, p-toluenesulfonic acid or the like. The nature of the solvent, solvent ratios, heating temperatures or heating rates, maintenance time, cooling temperature or cooling rate, and drying conditions also play a significant role in the purity of the plerixafor obtained during the purification.

In embodiments of step d), if the plerixafor obtained is an acid-addition salt after purification, then it may be converted to its freebase by neutralization with a base by the procedures known in the art.

In embodiments of step d), plerixafor can be purified by dissolving plerixafor in a solvent followed by the addition of anti-solvent. In specific embodiments, plerixafor is purified by dissolving plerixafor in dichloromethane followed by the addition of acetone as an anti solvent.

In embodiments of step d), plerixafor can also be purified by dissolving plerixafor in a single solvent or mixture of solvents to provide a solution and cooling the obtained solution to produce pure plerixafor. In specific embodiments, Plerixafor can be purified by dissolving plerixafor in the mixture of isopropanol and ethylacetate followed by cooling the solution. In embodiments, plerixafor can also be purified in the mixture of water, isopropanol and acetone. Any suitable ratio of these solvents may be used for the purification of plerixafor.

In embodiments of step d), the mother liquor obtained after filtration of Plerixafor can be concentrated and purified according to the procedure as described in the present application to recover Plerixafor from the mother liquor.

In embodiments of step d), plerixafor that is isolated can be dried at suitable temperatures, such as from about 40°C to about 100°C and suitable pressures from about 1 hour to about 24 hours or longer, using drying equipment known in the art, such as a tray dryer, vacuum oven, air oven, fluidized bed dryer, spin flash dryer, flash dryer, or the like. Drying temperatures and times will be sufficient to achieve desired product purity.

In one embodiment, the three steps of the above process i.e., step a) to step c) are performed without isolation of intermediates. In embodiments of step c) or d), isolated plerixafor can be in a crystalline form, amorphous form, mixture of crystalline and amorphous forms, hydrated, or solvated form.

In embodiments of step c) or d), plerixafor is isolated as crystalline material, characterized by a PXRD pattern having peaks at about 11.0, 11.7, 13.6, 18.8, 23.2, and 25.2 ± 0.2°26. In an aspect, plerixafor is isolated as crystalline material characterized bya PXRD pattern having peaks substantially in accordance with the pattern of Fig. 1.

In embodiments, highly pure Plerixafor means Plerixafor having purity more than 99.5% or more than 99.8% or more than 99.9% measured by HPLC. The possible impurities which may be present in plerixafor in addition to unreacted starting materials or intermediates described in the present application can have structural formulas as illustrated below.

(4-((1,4,8,11-tetraazacyclotetradecan-1-yl)methyl)phenyl)methanol 1 -(4-methylbenzyl)-1,4,8,11 –tetraazacyclotetradecane 1,8-bis(4-((1,4,8,11-tetraazacyclotetradecan-1-yl)methyl)benzyl)-1,4,8,11- tetraazacyclotetradecane 1,11-bis(4-((1,4,8,11-tetraazacyclotetradecan-1-yl)methyl)benzyl)-1,4,8,11- tetraazacyclotetradecane In embodiments, plerixafor obtained according to the procedure described in the present application and purified by a method of the present disclosure has less than about 0.1% by HPLC of any of the impurities mentioned above, and total impurities content less than about 0.5% by HPLC. In embodiments, plerixafor obtained has less than about 0.05% by HPLC of any of the impurities mentioned above, and total impurities content less than about 0.25% by HPLC. In embodiments, plerixafor obtained has less than about 0.02% by HPLC of any of the impurities mentioned above, and total impurities content less than about 0.15% by HPLC.

In embodiments, Plerixafor obtained according to the procedure described in the present application can used in pharmaceutical composition. Plerixafor obtained according to the processes of the present application can be milled or micronized by any process known in the art, such as ball milling, jet milling, wet milling etc., to produce desired particle sizes and particle size distributions.

In an embodiment, any of the intermediates described herein may be purified by the general procedures known in the art. In an embodiment, any of the intermediates described herein may be in the state of residue, crystalline, amorphous, hydrate, solvate, or anhydrous form.

Certain specific aspects and embodiments of the present application will be explained in greater detail with reference to the following examples, which are provided only for purposes of illustration and should not be construed as limiting the scope of the application in any manner. Variations of the described procedures, as will be apparent to those skilled in the art, are intended to be within the scope of the present application.

Throughout this application, various publications are referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art as known to those skilled therein as of the date of the application described and claimed herein.

While particular embodiments of the present application have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the application. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this application.

DEFINITIONS The following definitions are used in connection with the disclosure of the present application, unless the context indicates otherwise. In general, the number of carbon atoms present in a given group or compound is designated "Cx-Cy", where x and y are the lower and upper limits, respectively. For example, a group designated as "C1-C6" contains from 1 to 6 carbon atoms. The carbon number as used in the definitions herein refers to carbon backbone and carbon branching, but does not include carbon atoms of the substituents, such as alkoxy substitutions or the like. The term "reacting" is intended to represent bringing the chemical reactants together under conditions that cause the chemical reaction indicated to take place.

The following abbreviations and acronyms are used herein and have the indicated definitions: "Boc anhydride" is intended to represent di-tert-butyl dicarbonate in the present application and Boc is the t-butoxycarbonyl radical. PXRD means powder X-ray diffraction.

"Amine-protecting group" refers to a radical when attached to a nitrogen atom in a target molecule is capable of surviving subsequent chemical reactions applied to the target molecule i.e. hydrogenation, reaction with acylating agents, alkylation etc. The amine-protecting group can later be removed. Amine protecting groups include, but are not limited to, fluorenylmethoxycarbonyl (FMOC), tert-butoxycarbonyl (t- BOC), benzyloxycarbonyl (Z), those of the acyl type (e.g., formyl, benzoyl, trifluoroacetyl, aryl- and alkylphosphoryl, o-nitrophenylsulfenyl, o- nitrophenoxyacetyl), and of the urethane type {e.g. tosyloxyalkyloxy-, cyclopentyloxy-, cyclohexyloxy-, 1,1-dimethylpropyloxy, 2-(p-biphenyl)-2-propyloxy- and benzylthiocarbonyl). Amine-protecting groups are made using a reactive agent capable of transferring an amine-protecting group to a nitrogen atom in the target molecule. Examples of an amine-protecting agent include, but are not limited to, C1- C6 aliphatic acid chlorides or anhydrides, C6-C14arylcarboxylic acid chlorides or anhydrides, t-butyl chloroformate, di-tert-butyl dicarbonate, butoxycarbonyloxyimino- 2-phenylacetonitrile, t-butoxycarbonyl azide, t-butyl fluoroformate, fluorenylmethoxycarbonyl chloride, fluorenylmethoxycarbonyl azide, fluorenylmethoxycarbonyl benzotriazol-1 -yl, (9-fluorenylmethoxycarbonyl) succinimidyl carbonate, fluorenylmethoxycarbonyl pentafluorophexoxide, trichloroacetyl chloride, methyl-, ethyl-, trichloromethyl- chloroformate, or other amine protecting agents known in the art. Examples of such known amine-protecting agents are found in pages 385-397 of T. W. Green, P. G. M. Wuts, "Protective Groups in Organic Synthesis, Second Edition", Wiley-lnterscience, New York, 1991.

An "ester" is an organic compound containing a carboxyl group -(C=0)-0-bonded to two other carbon atoms. "C3-C6 esters" include, but are not limited to, ethyl acetate, n-propyl acetate, n-butyl acetate, isobutyl acetate, t-butyl acetate, ethyl formate, methyl acetate, methyl propanoate, ethyl propanoate, methyl butanoate, ethyl butanoate, or the like.

An "ether" is an organic compound containing an oxygen atom -O- bonded to two other carbon atoms. "C2-C6 ethers" include, but are not limited to, diethyl ether, diisopropyl ether, methyl t-butyl ether, glyme, diglyme, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, dibutyl ether, dimethylfuran, 2-methoxyethanol, 2-ethoxyethanol, anisole, or the like.

A "halogenated hydrocarbon" is an organic compound containing a carbon bound to a halogen. Halogenated hydrocarbons include, but are not limited to, dichloromethane, 1, 2-dichloroethane, trichloroethylene, perchloroethylene, 1,1,1-trichloroethane, 1,1, 2-trichloroethane, chloroform, carbon tetrachloride, or the like.

A "ketone" is an organic compound containing a carbonyl group -(C=0)-bonded to two other carbon atoms. C3-C6 ketones" include, but are not limited to, acetone, ethyl methyl ketone, diethyl ketone, methyl isobutyl ketone, ketones, or the like.

A "nitrile" is an organic compound containing a cyano -(C=N) bonded to another carbon atom. "C2-C6 Nitriles" include, but are not limited to, acetonitrile, propionitrile, butanenitrile, or the like.

"Petroleum ether" is a group of various volatile, liquid hydrocarbon mixtures used chiefly as nonpolar solvents. Chemically, it is not ether like diethyl ether, but a light hydrocarbon. Petroleum ether is commonly available as 30 to 40°C, 40 to 60°C, 60 to 80°C, 80 to 100°C, 80 to 120°C and sometimes 100 to 120 °C boiling fractions. The 60 to 80°C fraction is often used as a replacement for hexane. Petroleum ether is mostly used by pharmaceutical companies in the manufacturing process. The 30-40CC fraction of petroleum ether consists mainly of pentane, and is sometimes used instead of pentane due to its lower cost. Petroleum ether should not be confused with the class of organic compounds called ethers, which contain the R-O-R functional group.

EXAMPLES

Example 1:

Preparation of Plerixafor: Cyclam (5 g) and dichloromethane (300 mL) were charged into a round bottom flask and stirred for 10 minutes at 30°C. The reaction mass was cooled to -10°C. The solution of Boc anhydride (12.9 mL dissolved in dichloromethane 25 mL) was added to the reaction mass at -10°C in 45 minutes. The reaction mass was maintained for 45 minutes at -8°C. Water (100 mL) was added to the reaction mass and stirred for 20 minutes at the same temperature. The layers were separated and organic layer was washed with saturated aqueous solution of sodium chloride (100 mL). The organic layer was concentrated up to 2-3 volume under vacuum at 45°C. Petroleum ether (50 mL) was added to the organic layer and concentrated until approximately 50 mL of solvent was collected. Petroleum ether (100 mL) was again added to the organic layer. Aqueous acetic acid solution (15 %) (50 mL) was added to the organic layer and stirred for 20 minutes. The layers were separated and the aqueous layer was taken in another flask. Petroleum ether (50 mL) was added to the aqueous layer. The aqueous solution of sodium hydroxide (10%) was added to the reaction mass to adjust pH 9-10 and stirred for 10 minutes at 30°C. The layers were separated and aqueous layer was extracted with pet ether (50 mL). The combined organic layers were concentrated up to 2-3 volume under vacuum at 45°C. Acetonitrile (50 mL) was added to the organic layer and concentrated until approximately 50 mL of solvent was collected. Again acetonitrile (40 mL) was added to the organic layer. Sodium carbonate (1.9 g) and 1, 4-bis (dibromo) methylbenzene (1 g) were charged to the above organic layer at 30°C. The reaction mass was heated to 75°C and maintained for 3 hours 30 minutes at the same temperature. After completion of the reaction, reaction mass was cooled to 30°C filtered and filtrate was taken into another flask. 1N Hydrochloric acid (36 mL) was added to the round bottom flask containing the filtrate and heated to 60°C and maintained for 1 hour. The acetonitrile was evaporated from the reaction mass, and washed with dichloromethane (25 mL X 2). The pH was adjusted from 12 to 14 with aqueous solution of sodium hydroxide (10%) and extracted with dichloromethane (25 mL X 2). The combined organic layers were concentrated under vacuum at 45°C to obtain a residue. Acetone (45 mL) was added to the residue under stirring to obtain a solution and maintained for 1 hour at 28°C. The solid material was obtained by the filtration and washed with acetone. The material was dried under suction. Yield: 550 mg.

Example 2: Purification of Plerixafor: Plerixafor (1 g) and dichloromethane (4 mL) were charged into a round bottom flask and stirred to get clear solution at 28°C. Acetone (20 mL) was added to the solution and stirred for 1 hour at 28°C. The solid was collected by filtration and washed with acetone (5 mL). The material was dried under suction. Yield: 720 mg. The obtained material was again purified by following the same procedure as above. HPLC purity: 99.02%.

Example 3:

Preparation of protected cyclam (compound of Formula II): Cyclam (200 g) and acetone (4000 mL) were charged into a round bottom flask at 25°C. The obtained slurry was stirred for 3 hours at 25°C and filtered and washed with acetone (200 mL). The solid product was dried under vacuum at 45°C for 4 hours. The dry solid product (100 g) obtained as above and dichloromethane (6000 mL) were charged charged into a round bottom flask at 25°C and stirred for 10 minutes. The obtained solution was cooled to -15°C and solution of di-tert-butyl dicarbonate (Boc anhydride) (258.6 mL dissolved in dichloromethane 500 mL) was added to the above solution in 45 minutes at -15°C. The reaction mass was maintained for 1 hour at -15°C and water (2000 mL) was added and stirred for 10 minutes. The layers were separated and the organic layer was washed with water and followed by washing with saturated aqueous solution of sodium chloride. The layers were separated. The organic layer was transferred in a flask and silica gel (200 g) was added to the organic layer at 25°C and stirred for 1 hour. The suspension was filtered and washed with dichloromethane (1000 mL). Silica gel (150 g) was again added to the organic layer containing dichloromethane and stirred for 1 hour at 25°C. The suspension was filtered and washed with dichloromethane (1000 mL). The combined organic layer was with water (2000 mL). The dichloromethane layer was concentrated up to 20 volumes and wash with water (2000 mL). The dichloromethane layer was concentrated up to 2 volumes and Petroleum ether (1000 mL) was added and concentrated up to 2 volumes. Petroleum ether (1000 mL) and aqueous acetic acid solution (15 %) (1000 mL) was added to the organic layer and stirred for 10 minutes at 25°C. Separate the layers and the aqueous layer was taken in another flask. Petroleum ether (1000 mL) was added to the aqueous layer. The aqueous solution of sodium hydroxide (10%) (800 mL) was added to the aqueous layer and stirred for 10 minutes at 25°C. The layers were separated and aqueous layer was extracted with Petroleum ether (500 mL). The combined organic layers were concentrated up to 2 volumes under vacuum at 45°C. Acetonitrile (1000 mL) was added to the organic layer and concentrated until approximately 1000 mL of solvent was collected. Acetonitrile (800 mL) was again added to make a solution which contains~105 g of compound of Formula II.

Example 4: Preparation of Plerixafor: Compound of formula (II) (45 g) in acetonitrile as obtained in example 3, Sodium carbonate (28.62 g) and 1, 4-bis (dibromo)methylbenzene (11.2 g) were charged to the above organic layer at 30°C. The reaction mass was heated to 79°C and maintained for 5 hours. After completion of the reaction, reaction mass was cooled to 32°C filtered. The filtrate was concentrated upto 2 volumes and taken in another flask. 1N Hydrochloric acid (300 mL) was added to the flask containing the filtrate and heated to 63°C and maintained for 1 hour. The aqueous solution of sodium hydroxide (20%) (180 mL) was added to the reaction mass at 26°C. The solid compound was obtained by filtration and washed with water (225 mL) and dried under suction for 25 minutes. The wet material as obtained was taken in another flask and 10 % Isopropanol: acetone mixture was (66 ml) added to the flask and stirred to obtain a slurry. The slurry was heated to 62 °C to obtain clear solution. The clear solution was slowly cooled to 25°C and stirred for 1 hour. The solid was collected by filtration and washed with acetone (45 mL) and dried under sucton. The material was further dried under vacuum at 45-50°C for 6 hours. Yield: 12.2 g; HPLC purity: 99.78%

Example 5: Purification of Plerixafor: Plerixafor (10 g) and mixture of 12% isopropanol: ethyl acetate (70 mL) was charged into a round bottom flask. The obtained suspension was heated to 65°C to get a solution. The solution was filtered and washed with mixture of 12% isopropanol: ethyl acetate (14 mL). The filtrate was taken in another flask and cooled to 15°C and maintained for 2 hours 30 minutes. The solid was collected by filtration and washed with ethyl acetate and dried under suction. The material was further dried under vacuum at 48°C for 4 hours. The obtained material was again purified by repeating the same procedure as above. Yield: 5.9 g; HPLC purity: 99.88%.

CLAIMS:

1. A process for preparing highly pure Plerixafor comprising:

a) protecting cyclam with Boc anhydride to provide the compound of Formula II;

Formula II

b) reacting the compound of Formula II with dihalo-p-xylene to provide the compound of Formula III;

Formula ill

c) deprotecting in-situ the obtained compound of Formula III to provide plerixafor of Formula I; and

Formula I

d) purifying to provide pure plerixafor.

2. A process according to claim 1, wherein the Boc-anhydride in step a) is added at temperature below 0°C.

3. A process according to claim 1, wherein compound of Formula II is used in the next step without isolation.

4. A process according to claim 1, wherein compound of Formula II is purified before using in the next step.

5. A process according to claim 1, wherein dihalo-p-xylene used in step b) is dibromo-p-xylene.

6. A process for preparing highly pure Plerixafor comprising:

a) protecting cyclam with Boc anhydride in dichlorometnane to provide the compound of Formula II;

b) purifying the compound of Formula II obtained in step b) by treating with aqueous acetic acid or silica gel or both in any order;

c) reacting the compound of Formula II with dibromo-p-xylene in acetonitrile in the presence of base to provide the compound of Formula III;

d) deprotecting in-situ the obtained compound of Formula III with hydrochloric acid to provide plerixafor of Formula I; and

e) purifying the Plerixafor obtained in step d) in a solvent.

7. A process according to claim 8, wherein the solvent used in step e) is selected from dichloromethane, acetone, isopropanol, ethyl acetate or mixture thereof.

8. A process for purification of Plerixafor comprising;

a) dissolving Plerixafor in the mixture of Isopropanol and ethyl acetate to provide a solution;

b) cooling the solution obtained in step a); and

c) isolating the pure plerixafor.

9. A process according to any of the preceding claims wherein Plerixafor obtained is having HPLC purity greater than 99.5%.

10. A pharmaceutical composition comprising Plerixafor obtained according to any of the preceding claims.