Field of the Invention:
The present invention relates to an improved and novel process for the preparation of 7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl) methyl dodecanoate compound of formula-1, which is represented by the following structural formula:

Formula-1
Background of the Invention:
7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl dodecanoate is known as Aripiprazole Lauroxil. It is developed by Alkerms under the trade name Aristada® for the treatment of schizophernia.
7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl dodecanoate is an atypical antipsychotic agent.
7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl dodecanoate is first disclosed in US8431576. The said patent discloses the process for the preparation of the compound of formula-1 which provides low yields with less purity.
There is a need for the development of the alternative process for the preparation of the compound of formula-1 with respect to higher yields and purity.
US8431576 patent describes PXRD pattern of the crystalline form of compound of formula-1. Herein after the said crystalline form is designated as crystalline form-I.
Brief description of the Invention:
The first aspect of the present invention is to provide an improved process for the preparation of 7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl) methyl dodecanoate compound of formula-1.
The second aspect of the present invention is to provide an alternative process for the preparation of 7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl dodecanoate compound of formula-1.

The third aspect of the present invention is to provide an alternative process for the preparation of the compound of formula-1.
The fourth aspect of the present invention is to provide novel process for the preparation of the compound of formula-1.
The fifth aspect of the present invention is to provide a process for the preparation of the compound of general formula-10.
The sixth aspect of the present invention is to provide an alternative process for the preparation of the compound of general formula-10.
The seventh aspect of the present invention is to provide novel process for the preparation of the compound of formula-7.
The eighth aspect of the present invention is to provide the purification of lauric acid compound of formula-3.
Brief description of the Drawings:
Figure-1: Illustrates the powder X-ray diffraction of the compound of formula-7 obtained
according to the present invention.
Figure-2: Illustrates the powder X-ray diffraction of the compound of formula-1 obtained
according to the present invention.
Figure-3: Illustrates the DSC thermogram of the compound of formula-1 obtained according
to the present invention.
Detailed description of the Invention:
The present invention provides process for the preparation of 7-{4-[4-(2,3-dichloro
phenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl dodecanoate
compound of formula-1.
As used herein the term “suitable solvent” used in the present invention refers to “hydrocarbon solvents” such as n-hexane, n-heptane, cyclohexane, pet ether, toluene, pentane, cycloheptane, methyl cyclohexane, m-, o-, or p-xylene and the like; “ether solvents” such as dimethoxymethane, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, furan, diethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, anisole, t-butyl methyl ether, 1,2-dimethoxy ethane and the like; “ester solvents” such as methyl acetate,

ethyl acetate, isopropyl acetate, n-butyl acetate and the like; “polar-aprotic solvents” such as dimethylacetamide (DMA), dimethylformamide (DMF), dimethylsulfoxide (DMSO), N-methylpyrrolidone (NMP) and the like; “chloro solvents” such as dichloromethane, dichloroethane, chloroform, carbontetra chloride and the like; “ketone solvents” such as acetone, methyl ethyl ketone, methyl isobutyl ketone and the like; “nitrile solvents” such as acetonitrile, propionitrile, isobutyronitrile and the like; “alcohol solvents” such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, 2-nitroethanol, 2-fluoroethanol, 2,2,2-trifluoroethanol, ethylene glycol, 2-methoxyethanol, l,2-ethoxyethanol, diethylene glycol, 1, 2, or 3-pentanol, neo-pentyl alcohol, t-pentyl alcohol, diethylene glycol monoethyl ether, cyclohexanol, benzyl alcohol, phenol, or glycerol and the like; “polar solvents” such as water or mixtures thereof.
The term “suitable base” used in the present invention refers to inorganic bases
selected from “alkali metal carbonates” such as sodium carbonate, potassium carbonate,
lithium carbonate, cesium carbonate and the like; “alkali metal bicarbonates” such as sodium
bicarbonate, potassium bicarbonate, lithium bicarbonate, cesium bicarbonate and the like;
“alkali metal hydroxides” such as sodium hydroxide, potassium hydroxide, lithium hydroxide
and the like; “alkyl metals” such as n-butyl lithium and like; “metal hydrides” such as
lithium hydride, sodium hydride, potassium hydride and the like; “alkali metal phosphates”
such as disodium hydrogen phosphate, dipotassiumhydrogen phosphate; and “organic bases”
selected from but not limited to methyl amine, ethyl amine, diisopropyl amine,
diisopropylethyl amine (DIPEA), diisobutylamine, triethylamine, tert.butyl amine, pyridine,
4-dimethylaminopyridine (DMAP), N-methyl morpholine (NMM), n-methyl pyridine
(NMP), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo[4.3.0]non-5-ene
(DBN), 1,4-diazabicyclo[2.2.2]octane (DABCO), imidazole; “alkali metal alkoxides” such as
sodium methoxide, sodium ethoxide, potassium methoxide, potassium ethoxide, sodium
tert.butoxide, potassium tert.butoxide and the like; “alkali metal amides” such as sodium
amide, potassium amide, lithium amide, lithium diisopropyl amide (LDA), sodium
bis(trimethylsilyl)amide (NaHMDS), potassium bis(trimethylsilyl)amide, lithium
bis(trimethysilyl)amide (LiHMDS) and the like; or mixtures thereof.
The term “acid” used in the present invention refers to inorganic acids selected from

hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid etc; organic acids such as acetic acid, maleic acid, malic acid, tartaric acid, oxalic acid, trifluoroacetic acid, methane sulfonic acid, p-toluene sulfonic acid; chiral acids such as S-(+) mandelic acid, R-(-) mandelic acid, L-(+)tartaric acid, D-(-)tartaric acid, L-malic acid, D-malic acid, D-maleic acid, (-)-naproxen, (+)-naproxen, (lR)-(-)-camphor sulfonic acid, (IS)- (+)-camphor sulfonic acid, (lR)-(+)-bromocamphor-10-sulfonic acid, (lS)-(-)- bromocamphor-10-sulfonic acid, (-)-Dibenzoyl-L-tartaric acid, (-)-Dibenzoyl-L-tartaric acid monohydrate, (+)-Dibenzoyl-D-tartaric acid, (+)-Dibenzoyl-D-tartaric acid monohydrate, (+)-dipara-tolyl-D-tataric acid, (-)-dipara-tolyl-L-tataric acid, L(-)- pyroglutamic acid, L(+)-pyroglutamic acid, (-)-lactic acid, L-lysine, D-lysine etc., and like.
The term “condensing agent or coupling agent” used in the present invention is
selected form N,N'-dicyclohexylcarbodiimide (DCC), N,N’-diisopropylcarbodiimide (DIC),
carbonyldiimidazole (CDI), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride
(EDC.HCl), O-(7-aza-benzotriazole-1-yl)-N,N,N′,N′-tetramethyl uronium hexafluoro
phosphate (HATU), alkyl or aryl chloroformates such as ethyl chloroformate,
benzylchloroformate, diphenylphosphoroazidate (DPPA), thionyl chloride, pivalyl chloride,
oxalyl chloride, phosphorous oxychloride, phosphorous pentachloride, 4-methyl-2-
oxopentanoyl chloride (i-BuCOCOCl), benzotriazol-1-yl-oxytripyrrolidino phosphonium
hexafluorophosphate (PyBOP), methane sulfonyl chloride and the like; optionally in
combination with 1-hydroxy-7-azatriazole (HOAt), 1-hydroxybenzotriazole (HOBt), 1-
hydroxy-1H-1,2,3-triazole-4-carboxylate (HOCt), O-(benzotriazol-1-yl)-N,N,N',N'-
tetramethyluronium tetrafluoroborate (TBTU), N-hydroxysuccinamide (HOSu), N-
hydroxysulfosuccinimide (Sulfo-NHS), 4-dimethylaminopyridine (DMAP).
The term “phase transfer catalyst” used in the present invention is selected from but are not limited to quaternary ammonium salts, quaternary phosphonium salts, crown ethers, cryptands.
The suitable N-protecting agent is selected such that it is capable of protecting the nitrogen atom with any of N-protecting groups known to the person skilled in the art.
The suitable hydroxy protecting agent is selected such that it is capable of protecting the oxygen atom with any of hydroxy protecting groups known to the person skilled in the

art.
The term “deprotecting agent” used in the present invention is selected based on the protecting group employed. The deprotecting agent is selected from but not limited to acids; bases; hydrogenating agents such as Pd/C, Pd(OH)2/C (Pearlman’s catalyst), palladium acetate, platinum oxide, platinum black, sodium borohydride, Na-liquid ammonia, Raney-Ni, tri(C1-C6)alkylsilanes, tri(C1-C6)alkylsilyl halides and the like.
The first aspect of the present invention provides an improved process for the preparation of the compound of formula-1, comprising of;
a) Reacting Aripiprazole compound of formula-2 with dihalomethane compound of general formula-5 in presence of a suitable base in a suitable solvent optionally in presence of a suitable catalyst to provide the compound of general formula-6,
b) reacting the compound of general formula-6 with lauric acid compound of formula-3 in presence of a suitable base in a suitable solvent to provide the compound of formula-1,
c) optionally purifying the compound of formula-1 using the suitable solvent.
Wherein in step-a) to c) the suitable solvent is selected from alcohol solvents, hydrocarbon solvents, ether solvents, ester solvent, chloro solvents, polar aprotic solvents, ketone solvents, polar solvents or mixtures thereof; in step-a) and step-b) the suitable base is selected from inorganic or organic bases; in step-a) the suitable catalyst is selected from alkali metal iodides such as sodium iodide, potassium iodide, lithium iodide; phase transfer catalyst.
The second aspect of the present invention provides an alternative process for the preparation of the compound of formula-1, comprising of;
a) Reacting lauric acid compound of formula-3 with dihalomethane compound of general formula-5 in presence of a suitable base in a suitable solvent optionally in presence of a suitable catalyst to provide the compound of general formula-4,
b) optionally purifying the compound of general formula-4 using a suitable solvent,
c) reacting the compound of general formula-4 with Aripiprazole compound of formula-2 in presence of a suitable base in a suitable solvent to provide the compound of formula-1,

Wherein in step-a) to d) the suitable solvent is same as defined in the first aspect of the present invention; in step-a) and c) the suitable base is same as defined in the first aspect of the present invention; in step-a) the suitable catalyst is same as defined in the first aspect of the present invention.
The third aspect of the present invention provides an alternative process for the preparation of compound of formula-1 comprising of:
a) Reacting the compound of formula-2 with paraformaldehyde or formaldehyde in presence of a suitable base in a suitable solvent to provide the compound of formula-7,
b) reacting the compound of formula-7 with lauric acid compound of formula-3 in presence of a suitable coupling agent in a suitable solvent to provide the compound of formula-1,
c) optionally purifying the compound of formula-1 using the suitable solvent.
Wherein in step-a) to c) the suitable solvent is same as defined in the first aspect of the present invention; in step-a) the suitable base is same as defined in the first aspect of the present invention; in step-b) the suitable coupling agent is same as defined above.
Preferred embodiment of the present invention provides an alternative process for the preparation of compound of formula-1 comprising:
a) reacting the compound of formula-2 with formaldehyde in presence of triethyl amine in dimethylformamide to provide the compound of formula-7,
b) reacting the compound of formula-7 with lauric acid compound of formula-3 in presence of N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine in dichloromethane to provide the compound of formula-1,
c) purifying the compound of formula-1 using methanol.
An aspect of the present invention provides a process for the preparation of 7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl dodecanoate compound of formula-1 having specific surface area less than 0.5 m2/g comprising the following step:
a) treating the lauric acid compound of formula-3 with thionyl chloride in dichloromethane,
b) reacting the acid chloride obtained in step-a) in-situ with paraformaldehyde in presence of zinc chloride provide chloromethyl laurate compound of formula-4a,
c) purifying the obtained compound using cyclohexane,

e) f)
d) reacting the compound of formula-4a with aripiprazole compound of formula-2 in presence of potassium tertiary butoxide and 4-dimethylaminopyridine in tetrahydrofuran to provide the compound of formula-1, purifying the compound of formula-1 using methanol,
optionally further recrystallizing the compound of formula-1 in acetone to provide the compound of formula-1 having specific surface area less than 0.5 m2/g.
The first to third aspects of the present invention are schematically represented as follows:
Scheme-I
Cl f~N'
CH2X2 a rN-
a-rrV^
Formula-5^Ci ^^ N^
Formula-2 Paraformaldehyde
XVN
Formula-6 o
OH
Formula-3 Coupling agent
Base

Formula-1

OH
Formula-3 Wherein X is halogen
V.JL Coupling agent ^ A „CH?X7 ^tffr,
Paraformaldehyde Formula-3 Lewis acid
>^OH Paraformaldehyde* >^O^X Base ^______
Formula-4 4a: X=C1

The fourth aspect of the present invention provides novel process for the preparation of the compound of formula-1, comprising of;
a) Reacting the compound of general formula-4 with the compound of general formula-8 in presence of a suitable base in a suitable solvent to provide the compound of general formula-10,
b) reacting the compound of general formula-10 with the compound of formula-11 in presence of a suitable base in a suitable base to provide the compound of formula-1,
c) optionally purifying the compound of formula-1 using the suitable solvent.

Wherein in step-a) to c) the suitable solvent is same as defined in the first aspect of the present invention; in step-a) and b) the suitable base is same as defined in the first aspect of the present invention.
The fifth aspect of the present invention provides a process for the preparation of the compound of formula-10, comprising of;
a) Reacting the compound of general formula-8 with paraformaldehyde or formaldehyde in presence of a suitable base in a suitable solvent to provide the compound of general formula-12,
b) reacting the compound of general formula-12 with the compound of formula-3 in presence of a suitable coupling agent in a suitable solvent to provide the compound of general formula-10,
c) optionally purifying the compound of general formula-10 using a suitable solvent.
Wherein in step-a) to c) the suitable solvent is same as defined in the first aspect of the
present invention; in step-a) the suitable base is same as defined in the first aspect of the
present invention; in step-b) the suitable coupling agent is same as defined above.
The sixth aspect of the present invention provides an alternative process for the preparation of the compound of general formula-10, comprising of;
a) Reacting the compound of general formula-8 with dihalomethane compound of general formula-5 in presence of a suitable base in a suitable solvent optionally in presence of a suitable catalyst to provide the compound of general formula-9,
b) reacting the compound of general formula-9 with lauric acid compound of formula-3 in presence of a suitable base in a suitable solvent to provide the compound of general formula-10,
c) optionally purifying the compound of general formula-10 using the suitable solvent.
Wherein in step-a) to c) the suitable solvent is same as defined in the first aspect of the
present invention; in step-a) and b) the suitable base is same as defined in the first aspect of
the present invention; in step-a) the suitable catalyst is same as defined in the first aspect of
the present invention.
The fourth to sixth aspects of the present invention are schematically represented as follows:

Base yT N
Paraformaldehyde^ f
^ ^ n ^ Formula-12 x ^ ^ -^ ^ -
X^^^^V^l If ^ CI r^NH
'tr'
^
II A IJ^ aT ^
ase
Formula-8 u Formula-4 X/X/ ° °
Formula-10
Formula-1
OH Formula-3
Formula-11
Formula-9 X O Wherein X is halogen
The seventh aspect of the present invention provides a novel process for the preparation of the compound of formula-7, comprising of;
a) Reacting the compound of general formula-8 with paraformaldehyde or formaldehyde in presence of a suitable base in a suitable solvent to provide the compound of general formula-12,
b) reacting the compound of general formula-12 with the compound of formula-11 in presence of a suitable base in a suitable solvent to provide the compound of formula-7,
c) optionally purifying the compound of formula-7 using a suitable solvent.
Wherein in step-a) to c) the suitable solvent is same as defined in the first aspect of the present invention; in step-a) & b) the suitable base is same as defined in the first aspect of the present invention.
The seventh aspect of the present invention is schematically represented as follows:
Scheme-III
Cl i^NH
-^^ O ^ Cl^^N^
x €L R X—^ Tgr a A—^PJ Base „ H^L Formula-11 ^ Cl^N^ «
^ Para- N J " ** 1QT N
C•formaldehyde QHO BaSe Formula? OHO
Formula-8 Formula-12 Formula-/ unu
The eighth aspect of the present invention provides the purification of lauric acid compound of formula-3, comprising of;

a) Dissolving lauric acid compound of formula-3 in a suitable solvent at a suitable temperature,
b) precipitating the compound by cooling the reaction mixture to a suitable temperature,
c) filtering the precipitated solid to provide pure lauric acid compound of formula-3.
Wherein in step-a) the solvent is same as defined in the first aspect of the present invention;
the suitable temperature is 30°C to reflux of the solvent used;
in step-b) precipitating the compound optionally by adding an anti-solvent to the reaction mixture; the suitable temperature is about -5°C to 30°C.
Preferred embodiment of the present invention provides the purification of lauric acid compound of formula-3, comprising;
a) dissolving lauric acid compound of formula-3 in aqueous acetone at 55 to 65°C,
b) precipitating the compound by cooling the reaction mixture to 0-10°C,
c) filtering the precipitated solid to provide pure lauric acid compound of formula-3.
Commercially available lauric acid is not having the required purity. By utilizing the commercially available material provides compound of formula-1 with low quality and yields. The present inventors developed the process for the purification of lauric acid. The use of highly pure lauric acid provided compound of formula-1 with excellent quality (ICH grade) and yields.
Lauric acid compound of formula-3 obtained according to the present invention is having purity by GC >99%, preferably >99.5% and having any of other single impurity is not more than 0.1%.
Lauric acid compound of formula-3 prepared according to the present invention is most useful in the preparation of highly pure 7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl dodecanoate compound of formula-1.
The novel intermediate compounds obtained according to the present invention are useful in the preparation of the compound of formula-1.
Further aspect of the present invention provides novel process for the preparation of the compound of formula-1 as represented by the following schemes:

Further aspect of the present invention provides a process for preparation of pure 7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl) methyl dodecanoate compound of formula-1, comprising:
a) dissolving the compound of formula-1 in a first solvent at a suitable temperature,
b) optionally filtering the reaction mixture,
c) cooling the reaction mixture,
d) stirring the reaction mixture,
e) filtering the solid obtained in step-d) and optionally washing with a first solvent,
f) optionally repeating the steps-a) to e) using a second solvent to get the pure compound of formula-1.
Wherein in steps-a) and e) the first solvent is selected from alcohol solvents, ether solvents, ester solvent, chloro solvents, polar aprotic solvents, ketone solvents or mixtures thereof; in step-a) the suitable temperature is 25°C to reflux temperature of the solvent used; in step-c) cooling the reaction mixture refers to the temperature range about -10°C to 30°C;
in step-f) the second solvent is the same or different from the first solvent, selected
from alcohol solvents, ether solvents, ester solvent, chloro solvents, polar aprotic
solvents, ketone solvents or mixtures thereof.
Preferred embodiment of the present invention provides a process for preparation of pure 7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl dodecanoate compound of formula-1, comprising:
a) dissolving the compound of formula-1 in methanol at 55-65°C,
b) filtering the reaction mixture,
c) cooling the reaction mixture to 20-30°C,
d) stirring the reaction mixture,
e) filtering the solid obtained in step-d) and washing with methanol,
f) repeating the steps-a) to e) using methanol solvent and further by acetone solvent to get the pure compound of formula-1.
Further aspect of the present invention provides the compound of formula-1 obtained according to the present invention having purity by HPLC >99%, preferably >99.5% which is having <0.1% of Aripiprazole & <0.1% of N-Hydroxymethyl impurities.

r
The following impurities are observed during the preparation of 7-{4-[4-(2,3-ichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl odecanoate compound of formula-1 as per the present invention and these all impurities are well controlling in less than 0.15%, preferably less than 0.1% by HPLC.


5

Further aspect of the present invention provides 7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl dodecanoate compound of formula-1 having specific surface area less than 0.5m2/g.
Further aspect of the present invention provides particle size of 7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl dodecanoate compound of formula-1 obtained according to the present invention having D(90) < 150 µm, D(50) < 50 µm and D(10) < 15 µm.
Further aspect of the present invention the compound of formula-1 obtained according to the present invention is designated as crystalline form-I and its PXRD pattern is illustrated in figure-2 and is further characterized by its powder X-Ray diffraction pattern


having peaks at 6.9, 8.5, 11.9, 13.3, 13.9, 14.8, 15.2, 18.2, 20.1, 20.8, 21.6, 22.1, 23.9 & 25.0 ± 0.2 degrees of 2-theta. Further it is having the endotherm at 84°C±3°C in its differential scanning calorimetric (DSC) thermogram as shown in figure-3.
The crystalline form-I of the compound of formula-1 obtained according to the present invention having purity by HPLC >99%, preferably >99.5%.
Method of Analysis:
a) Lauric acid and its related substances were analyzed by GC with the following
chromatographic conditions:
Apparatus: A gas chromatographic system is equipped with FID. Column: DB-1 Capillery column; Length: 30 mts; Injection temperature: 250°C; Detector temperature: 260°C; Carrier gas: Helium; Carrier gas pressure: 4psi; Hydrogen flow: 40 ml/min; Air flow: 400 ml/min; Make up (N2): 30ml/min; Injection volume: 1 [iL; Diluent: Acetonitrile.
b) Chloromethyl laurate and its related substances were analyzed by GC with the following
chromatographic conditions:
Apparatus: A gas chromatographic system is equipped with FID. Column: HP-5 Capillery column; Length: 30 mts; Injection temperature: 280°C; Detector temperature: 260°C; Carrier gas: Helium; Carrier gas pressure: 10psi; Hydrogen flow: 40 ml/min; Air flow: 400 ml/min; Make up (N2): 30ml/min; Injection volume: 1 [iL; Diluent: Acetonitrile.
c) The compound of formula-1 and its related substances were analyzed by HPLC with the
following chromatographic conditions:
Apparatus: A liquid chromatograph is equipped with variable wavelength UV Detector. Column: Zobrax Bonus RP, 250 x 4.6 mm, 5 µm (or) Equivalent; Wavelength: 215 nm; Column temperature: 30°C; Injection volume: 5 uL; Diluent: Acetonitrile:Methanol (50:50 v/v); Needle wash: Methanol; Elution: Gradient; Buffer: Weigh and transfer accurately 1.0 gm of 1-octane sulphonic acid sodium salt anhydrous in 1000mL of milli-Q-water, mix well and filter. Then add 2mL of perchloric acid, 1ml triethyl amine and adjust pH:3.5 with aqueous sodium hydroxide solution & mix well.
Mobile phase-A: Buffer (100%); Mobile phase-B: Acetonitrile:Buffer:Methanol [80:10:10 v/v/v]

PXRD analysis of compound of formula-1 produced by the present invention was carried out using BRUKER D8 ADVANCED/AXS X-Ray diffractometer using Cu Kα radiation of wavelength 1.5406 A° and continuous scan speed of 0.03°/min.
Differential scanning calorimetric (DSC) analysis was performed on Q10 V9.9 Build 303 calorimeter (or) Q2000 V24.11 Build 124 calorimeter with aluminium pans, heating the samples from 40 to 120°C under closed conditions at a rate of 5.00°C/min.
Advantages of the present invention:
• Using of the pure of lauric acid in the preparation of the compound of formula-1 gives pure compound of formula-1.
• Purification of the compound of formula-1 as per the present invention provides ICH purity of compound of formula-1 which is having less than 0.5% of total impurities.
• The compound of formula-1 obtained according to the present invention is well suitable in the preparation of pharmaceutical composition.
• The process is environment friendly, economically viable, good in quality and yield and scalable to industrial level.
The process described in the present invention was demonstrated in examples illustrated below. These examples are provided as illustration only and therefore should not be construed as limitation of the scope of the invention.
Examples:
Example-1: Preparation of 7-(4-(4-(2,3-Dichlorophenyl)piperazin-1-yl)butoxy)-1-
(hydroxymethyl)-3,4-dihydroquinolin-2(1H)-one compound of formula-7:
500 ml of formaldehyde and triethyl amine (5 ml) were slowly added to the mixture of Aripiprazole (100 gm) and dimethylformamide (800 ml) at 25-30°C and stirred the reaction mixture for 10 minutes. Heated the reaction mixture to 85-90°C and stirred for 45 hours. Cooled the reaction mixture to 25-30°C. Water was slowly added to the reaction mixture at 25-30°C and stirred for 2 hours at the same temperature. Filtered the precipitated solid and washed with water. The obtained compound was slurried in 500 ml of tetrahydrofuran at 25-30°C for 3 hours. Filtered the compound, washed with tetrahydrofuran and dried to get the title compound. Yield: 76 gm. Purity by HPLC: 97.90%. PXRD of the obtained compound was depicted in figure-1.

Example-2: Purification of Lauric acid:
Dissolved 100 gms of lauric acid in 200 ml of 5% aqueous acetone at 55-60°C. Cooled the reaction mixture to 0-5°C and stirred for 3 hours at the same temperature. Filtered the precipitated solid, washed with 5% aqueous acetone and dried to get the title compound. Yield: 45 gms; Purity by GC: 99.81%. M.R.: 42-45°C.
Example-3: Preparation of the compound of formula-1:
83.6 gms of Lauric acid and 1 gm of DMAP were slowly added to the solution of 100 gms of the compound of formula-7 in 500 ml of dichloromethane at 25-30°C. The solution of DCC (86.1 gm) in 500 ml of dichloromethane was slowly added to the reaction mixture at 25-30°C and stirred for 8 hours at the same temperature. Filtered the reaction mixture and washed with dichloromethane. The filtrate was washed with water and distilled off the solvent completely under reduced pressure and co-distilled with methanol. The obtained compound was dissolved in 1000 ml of methanol at 55-60°C. Cooled the reaction mixture to 25-30°C and stirred for 2 hours at the same temperature. Filtered the precipitated solid, washed with methanol and dried to get the title compound. Yield: 85 gms. Purity by HPLC: 98.92%.
Example-4: Preparation of the compound of formula-1:
65 gms of thionyl chloride was slowly added to the mixture of lauric acid (83.6 gm), dichloromethane (500 ml) and dimethylformamide (1 ml) at 25-30°C and stirred the reaction mixture for 2 hours. Distilled off the solvent completely from the reaction mixture. The obtained lauroyl chloride was diluted with 1500 ml of dichloromethane at 25-30°C. This solution was slowly added to the mixture of the compound of formula-7 (100 gm), triethylamine (105.7 gm) and dichloromethane (100 ml) at 25-30°C and stirred the reaction mixture for 2 hours at the same temperature. Water was added to the reaction mixture at 25-30°C and stirred for 15 minutes. Separated both the organic and aqueous layers and washed the organic layer with water. Distilled off the solvent completely from the organic layer and co-distilled with methanol. The obtained compound was dissolved in 1000 ml of methanol at 55-60°C. Cooled the reaction mixture to 25-30°C and stirred for 2 hours at the same temperature. Filtered the precipitated solid, washed with methanol and dried to get the title compound. Yield: 83 gms, HPLC purity: 98.44%.
Example-5: Preparation of the compound of formula-1:

The mixture of the compound of formula-7 (100 gm), Lauric anhydride (121.56 gm) and tetrahydrofuran (500 ml) was heated to 60-65°C and stirred the reaction mixture for 1 hour at the same temperature. 2.74 gms of triethylmaine was added to the reaction mixture at 60-65°C and stirred the reaction mixture for 30 hours at the same temperature. Cooled the reaction mixture to 25-30°C and ethyl acetate, n-heptane and followed by 5% sodium bicarbonate solution were added to the reaction mixture at 25-30°C and stirred the reaction for 10 minutes. Separated both the organic and aqueous layers. Aqueous layer was extracted with ethyl acetate. Combined the organic layers and washed with aqueous sodium bicarbonate solution. Distilled off the solvent completely from the organic layer. The obtained compound was purified by the column chromatography using 40% ethyl acetate in cyclohexane as eluents. The obtained compound was dissolved in isopropyl acetate (120 ml) at 60-65°C, n-heptane (200 ml) was added to the reaction mixture at 60-65°C and stirred the reaction mixture for 30 minutes at the same temperature. Cooled the reaction mixture to 10-15°C and stirred for 3 hours at same temperature. Filtered the precipitated solid, washed with n-heptane and dried to get the title compound. Yield: 38 gms. Purity by HPLC: 98.44%.
Example-6: Purification of the compound of formula-1:
110 gms of the compound of formula-1 was dissolved in 330 ml of ethyl acetate at 55-60°C. To this solution 11 gms of carbon was added at 60-65°C and stirred the reaction mixture for 15 minutes at the same temperature. Filtered the reaction mixture through hyflow bed and washed with ethyl acetate. Distilled off the solvent from the filtrate under reduced pressure and co-distilled with methanol. Dissolved the obtained compound in 550 ml of methanol at 65-70°C. Cooled to the reaction mixture to 25-30°C and stirred for 2 hours at the same temperature. Filtered the precipitated solid, washed with methanol and dried to get the title compound.Yield: 98 gms. Purity by HPLC purity: 99.67%.
Example-7: Preparation of chloromethyl laurate:
71.3 gms of thionyl chloride was slowly added to the mixture of Lauric acid (100 gm), dichloromethane (1000 ml) and dimethylformamide (1 ml) at 25-30°C and stirred the reaction mixture for 2 hours. Distilled off the solvent completely from the reaction mixture. The mixture of paraformaldehyde (14.99 gm) and anhydrous zinc chloride (1.36 gm) was cooled to 0-5°C. The above obtained acid chloride was add to the reaction mixture at 0-5°C

and stirred for 60 minutes at the same temperature. Raised the temperature of the reaction mixture to 25-30°C, followed by heating to 90-95°C and stirred for 16 hours at the same temperature. Cooled the reaction mixture to 25-30°C and stirred for 2 hours. Filtered the reaction mixture and distilled off the solvent completely from the filtrate under reduced pressure. Purified the obtained compound by column chromatography using cyclohexane as eluent. Yield: 73 gms.
Example-8: Preparation of the compound of formula-1:
Aripiprazole (100 gm) was added to the solution of chloromethyl laureate (416.11 gm) in 2500 ml of dichloromethane at 25-30°C and stirred the reaction mixture for 10 minutes. Dimethylamino pyridine (13.4 gm) and triethyl amine (93.2 ml) was slowly added to the reaction mixture at 25-30°C and stirred for 22 hours at the same temperature. Water was added to the reaction mixture at 25-30°C and stirred for 10 minutes. Separated the both aqueous and organic layers and the organic layer was washed with aqueous sodium chloride solution. Distilled off the solvent from the organic layer under reduced pressure and co-distilled with methanol. Recrystallized the obtained compound from methanol to get the title compound. Yield: 73 gm.
Example-9: Purification of Lauric acid compound of formula-3:
Lauric acid (30 kgs) was dissolved in 5% aqueous acetone (57 lts of acetone and 3 lts of water) at 55-60°C. Cooled the reaction mixture to 5-10°C and stirred for 3 hours. Filtered the precipitated solid, washed with chilled aqueous acetone and dried to get the pure Lauric acid. Yield: 15.20 kg. Purity by GC: 99.94%.
Example-10: Preparation of chloromethyl laurate [Formula-4a]:
Thionyl chloride (10.7 kgs) was slowly added to a mixture of Lauric acid (15 kgs), dichloromethane (75 Lts) and dimethylformamide (0.14 kgs) at 25-30°C and stirred for 2 hours at the same temperature. Distilled off the solvent completely from the reaction mixture under reduced pressure. The above obtained acid chloride was cooled to 25-30°C and added to the mixture of paraformaldehyde (2.3 kgs) and anhydrous zinc chloride (0.2 kgs) at the same temperature. Heated the reaction mixture to 90-95°C and stirred for 12 hours at the same temperature. Cooled the reaction mixture to 25-30°C, ethyl acetate followed by aqueous sodium carbonate solution was added to the reaction mixture and stirred for 45

minutes at the same temperature. Filtered the reaction mixture. Both the aqueous and organic layers were separated from the obtained filtrate. Organic layer was washed with aqueous sodium chloride solution. Distilled off the solvent completely from the organic layer under reduced pressure and co-distilled with cyclohexane. The obtained residue was purified by column chromatography using cyclohexane as eluent. Yield: 7.1 kg. Purity by GC: 97.72%.
Example-11: Preparation of 7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl dodecanoate compound of formula-1:
4-Dimethylamino pyridine (0.68 kgs) and potassium tertiary butoxide (1.88 kgs) were added to the mixture of Aripiprazole (5 kgs) and tetrahydrofuran (50 liters) at -5 to 0°C. Chloromethyl laurate (6.94 kg) was slowly added to the reaction mixture at -5 to 0°C and stirred for 3 hours at the same temperature. Water and ethyl acetate were added to the reaction mixture. Raised the temperature of reaction mixture to 25-30°C and stirred for 30 minutes at the same temperature. Filtered the reaction mixture through hyflo bed and the obtained filtrate was stirred for 10 minutes at 25-30° C. Both the aqueous and organic layers were separated and aqueous layer was extracted with ethyl acetate. Combined the organic layers and dried over anhydrous sodium sulphate. Distilled off the solvent completely from the organic layer under reduced pressure and co-distilled with methanol. Slurried the obtained compound in methanol at 25-30°C. Dissolved the obtained compound in methanol (75 lits) at 60-65°C. Cooled the reaction mixture to 25-30°C and stirred for 3 hours at the same temperature. Filtered the precipitated solid and washed methanol. Again recrystallization the obtained compound in methanol. The obtained compound was dissolved in acetone (15 lits) at 55-60°C. Cooled the reaction mixture to 25-30°C and stirred for 3 hours at the same temperature. Filtered the precipitated solid, washed with acetone and dried to get the title compound.
Yield: 2.9 kg. Purity by HPLC: 99.65%, Aripiprazole impurity: 0.03%, N-Hydroxy methyl impurity: 0.05%, total impurities: 0.35%. SSA of the obtained compound: 0.344 m2/g
Example-12: Preparation of 7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl dodecanoate compound of formula-1:
Potassium tertiary butoxide (37.5 gm) was added to the mixture of Aripiprazole (100 gm) and tetrahydrofuran (1000 ml) at -5 to 0°C. Chloromethyl laurate (138.7 gm) was slowly added to

the reaction mixture at -5 to 0°C and stirred for 3 hours at the same temperature. Water and ethyl acetate were added to the reaction mixture. Raised the temperature of reaction mixture to 25-30°C and stirred for 30 minutes at the same temperature. Filtered the reaction mixture through hyflow bed and the obtained filtrate was stirred for 10 minutes at 25-30° C. Both the aqueous and organic layers were separated and aqueous layer was extracted with ethyl acetate. Combined the organic layers and dried over anhydrous sodium sulphate. Distilled off the solvent completely from the organic layer under reduced pressure and co-distilled with methanol. Slurried the obtained compound in methanol at 25-30°C.
Purification: The purification process was carried out by recrystallization of the obtained compound twice using methanol and once using acetone to provide pure compound of formula-1. Analysis of the impurities was carried out after each purifications and the data is given below:

Impurity, Decano Impurity & Undecano Impurity are well below 0.05%.
Particle Size of the obtained compound: D(10): 5.59 µm, D(50): 19.7 µm & D(90): 50.6 µm.
SSA of the obtained compound: 0.4 m2/g.
Example-13: Purification of the compound of formula-1 using acetone:
Dissolved the compound of formula-1 (2.5 kgs) in acetone (22.5 liters) at 35-40°C. Filtered the reaction mixture on hyflow bed and washed with acetone. The obtained filtrate was stirred for 30 minutes at 25-30°C. Cooled the reaction mixture to 0-5°C and stirred for 3 hours at the same temperature. Filtered the precipitated solid, washed with acetone and dried to get pure the title compound.

Yield: 2.1 kg. Purity by HPLC: 99.64%, Aripiprazole impurity: 0.04%, N-Hydroxy methyl impurity: 0.03%, total impurities: 0.36%. SSA of the obtained compound: 0.34 m2/g.
Example-14: Purification of the compound of formula-1 using methanol:
Dissolved the compound of formula-1 (100 gms) in methanol (1500 ml) at 60-65°C. Filtered the reaction mixture. The obtained filtrate was cooled to 25-30°C and stirred for 3 hours at the same temperature. Filtered the precipitated solid, washed with methanol and dried to get the title compound.
Yield: 85 gm. Purity by HPLC: 99.73%, Aripiprazole impurity: 0.04%, N-Hydroxy methyl impurity: 0.06%, HIUI: 0.03%. Particle Size of the obtained compound: D(10): 3.04 µm, D(50): 21.16 µm & D(90): 75.53 µm. SSA of the obtained compound: 0.36 m2/g. PXRD of the obtained compound is shown in figure-2 & DSC histogram is shown in figure-3.
Example-15: Purification of the compound of formula-1 using ethyl acetate:
Dissolved the compound of formula-1 (5 gms) in ethyl acetate (150 ml) at 60-65°C. Filtered the reaction mixture through hyflow bed. The obtained filtrate was cooled to 25-30°C and stirred for 3 hours at the same temperature. Filtered the precipitated solid, washed with ethyl acetate and dried to get the title compound. Yield: 4.1 gm. Purity by HPLC: 99.67%, Aripiprazole impurity: 0.07%, N-Hydroxy methyl impurity: 0.05%, HIUI: 0.04%.
Example-16: Purification of the compound of formula-1 using isopropanol:
Dissolved the compound of formula-1 (5 gms) in isopropanol (750 ml) at 65-70°C. Filtered the reaction mixture through hyflow bed. The obtained filtrate was cooled to 25-30°C and stirred for 3 hours at the same temperature. Filtered the precipitated solid, washed with ethyl acetate and dried to get the title compound. Yield: 4.2 gm. Purity by HPLC: 99.57%, Aripiprazole impurity: 0.05%, N-Hydroxy methyl impurity: 0.07%, HIUI: 0.05%.
Example-17: Purification of the compound of formula-1 using acetonitrile:
Dissolved the compound of formula-1 (10 gms) in acetonitrile (150 ml) at 60-65°C. Filtered the reaction mixture through hyflow bed. The obtained filtrate was cooled to 25-30°C and stirred for 3 hours at the same temperature. Filtered the precipitated solid, washed with acetonitrile and dried to get the title compound.
Yield: 5.8 gm. Purity by HPLC: 99.71%, Aripiprazole impurity: 0.02%, N-Hydroxy methyl impurity: 0.03%, HIUI: 0.12%.

comprising the following steps:
a) dissolving the compound of formula-1 in a first solvent at a suitable temperature,
b) optionally filtering the reaction mixture,
c) cooling the reaction mixture,
d) stirring the reaction mixture,
e) filtering the solid obtained in step-d) and optionally washing with solvent,
f) optionally repeating the steps-a) to e) using a second solvent to provide the pure compound of formula-1;
wherein in step-a) the first solvent is selected from alcohol solvents, ether solvents, ester solvent, chloro solvents, polar aprotic solvents, ketone solvents or mixtures thereof; the suitable temperature is 25°C to reflux temperature of the solvent used; in step-c) cooling the reaction mixture refers to the temperature range about -10°C to 30°C;
in step-f) the second solvent is the same or different from the first solvent, selected from alcohol solvents, ether solvents, ester solvent, chloro solvents, polar aprotic solvents, ketone solvents or mixtures thereof.
A process for the preparation of pure 7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl dodecanoate compound of formula-1 comprising the following steps:
a) dissolving the compound of formula-1 in a suitable solvent at 50-70°C,
b) filtering the reaction mixture,
c) cooling the reaction mixture to 10°C to 30°C,

d) stirring the reaction mixture,
e) filtering the solid obtained in step-d) to provide the pure compound of formula-1; wherein in step-a) the suitable solvent is methanol or acetone or ethyl acetate or acetonitrile or isopropanol.
. A process for preparation of pure 7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl dodecanoate compound of formula-1, comprising:
a) dissolving the compound of formula-1 in methanol at 55-65°C,
b) filtering the reaction mixture,
c) cooling the reaction mixture to 25-30°C,
d) stirring the reaction mixture,
e) filtering the solid obtained in step-d) and washing with methanol,
f) repeating the steps-a) to e) using methanol solvent and further by acetone solvent to get the pure compound of formula-1.
. A process for the preparation of 7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl dodecanoate compound of formula-1 having specific surface area less than 0.5 m2/g comprising the following step:
a) treating the lauric acid compound of formula-3 with chlorinating agent in a suitable solvent,
b) reacting the acid chloride obtained in step-a) in-situ with paraformaldehyde in presence of a catalyst or base provide the chloromethyl laurate compound of formula-4a,
c) optionally purifying the obtained compound using a suitable solvent,
d) reacting the compound of formula-4a with aripiprazole compound of formula-2 in presence of a suitable base in a suitable solvent to provide the compound of formula-1,
e) optionally purifying the compound of formula-1 using a suitable solvent;

wherein in step a) the chlorinating agent is selected from thionyl chloride, oxalyl
chloride, sulfuryl chloride, phosphorous oxychloride, carbon tetra chloride,
phosphorous trichloride, phosphorous pentachloride, N-chlorosuccinamide (NCS);
in step b) the suitable catalyst is lewis acid, preferably Zinc chloride and base is
selected from organic or inorganic bases;
in step d) the suitable base is selected from organic or inorganic bases;
in steps a) to e) the suitable solvent is selected from alcohol solvents, hydrocarbon
solvents, ether solvents, ester solvent, chloro solvents, polar aprotic solvents, ketone
solvents, polar solvents or mixtures thereof.
A process for the preparation of the compound of formula-1 having specific surface area less than 0.5 m2/g comprising the following step:
a) treating the lauric acid compound of formula-3 with thionyl chloride in dichloromethane,
b) reacting the acid chloride obtained in step-a) in-situ with paraformaldehyde in presence of zinc chloride provide chloromethyl laurate compound of formula-4a,
c) purifying the obtained compound using cyclohexane,
d) reacting the compound of formula-4a with aripiprazole compound of formula-2 in presence of potassium tertiary butoxide and dimethylaminopyridine in tetrahydrofuran to provide the compound of formula-1,
e) purifying the compound of formula-1 using methanol,
f) optionally further recrystallizing the compound in acetone to provide the compound of formula-1 having specific surface area less than 0.5 m2/g.
A process for the preparation of 7-{4-[4-(2,3-dichlorophenyl)-piperazin-1-yl]butoxy}-2-oxo-3,4-dihydro-2H-quinolin-1-yl)methyl dodecanoate compound of formula-1 comprising the following step:
a) reacting aripiprazole compound of formula-2 with formaldehyde or paraformaldehyde in presence of base in a suitable solvent to provide the 7-(4-(4-(2,3-Dichlorophenyl)piperazin-1-yl)butoxy)-1-(hydroxymethyl)-3,4-dihydroquinolin-2(1H)-one compound of formula-7,

b) reacting the compound of formula-7 with lauric acid compound of formula-3 in presence of a suitable coupling agent in a suitable solvent to provide the compound of formula-1,
c) optionally purifying the compound of formula-1 using a suitable solvent; wherein in step a) the suitable base is selected from organic or inorganic bases; in step b) the suitable coupling agent is selected form N,N'-dicyclohexylcarbodiimide, N,N’-diisopropylcarbodiimide, carbonyldiimidazole, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, O-(7-aza-benzotriazole-1-yl)-N,N,N′,N′-tetramethyl uronium hexafluoro phosphate, alkyl or aryl chloroformates such as ethyl chloroformate, benzylchloroformate, diphenylphosphoroazidate, thionyl chloride, pivalyl chloride, oxalyl chloride, phosphorous oxychloride, phosphorous pentachloride, 4-methyl-2-oxopentanoyl chloride, benzotriazol-1-yl-oxytripyrrolidino phosphonium hexafluorophosphate, methane sulfonyl chloride and the like; optionally in combination with 1-hydroxy-7-azatriazole, 1-hydroxybenzotriazole, 1-hydroxy-1H-1,2,3-triazole-4-carboxylate, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate, N-hydroxysuccinamide, N-hydroxysulfosuccinimide, 4-dimethylaminopyridine;
In steps a) to c) the suitable solvent is selected from alcohol solvents, hydrocarbon solvents, ether solvents, ester solvent, chloro solvents, polar aprotic solvents, ketone solvents, polar solvents or mixtures thereof.
. The process according to any of preceding claims, the compound of formula-1 having purity by HPLC greater than 99%, preferably 99.5%; having Aripiprazole impurity less than 0.1%, preferably less than 0.05% by HPLC and having N-Hydroxymethyl impurity less than 0.15%, preferably less than 0.1% by HPLC.
. The compound of formula-1 obtained according to any of preceding claims is having the following characteristic features:
a) its powder X-Ray diffraction pattern having substantially in accordance with that shown in figure-2 (or)

b) its powder X-Ray diffraction pattern having peaks at 6.9, 13.9, 14.8, 15.2, 18.2, 20.1, 21.6, 22.1, 23.9 & 25.0 ± 0.2 degrees of 2-theta (or)
c) its differential scanning calorimetric (DSC) thermogram having the endotherm at 84°C±3°C (or)
d) its particle size of D(90) < 150 µm (or)
e) its specific surface area is less than 0.5 m2/g.
A process for the purification of lauric acid compound of formula-3 comprising the following steps:
a) dissolving lauric acid compound of formula-3 in a suitable solvent at a suitable temperature,
b) cooling the reaction mixture to a suitable temperature,
c) filtering the precipitated solid to provide pure lauric acid compound of formula-3,
Wherein in step-a) the suitable solvent is selected from alcohol solvents, hydrocarbon
solvents, ether solvents, ester solvent, chloro solvents, polar aprotic solvents, ketone
solvents, polar solvents or mixtures thereof; the suitable temperature is 30°C to reflux
temperature of the solvent used;
in step-b) the suitable temperature is about -5°C to 30°C.
A process for the purification of lauric acid compound of formula-3 comprising the following steps:
a) dissolving lauric acid compound of formula-3 in aqueous acetone at 55-65°C,
b) cooling the reaction mixture to -5°C to 30°C,
c) filtering the obtained solid to provide pure lauric acid compound of formula-3.