TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: In the step (a), the resolution takes place at a temperature of 40-100 degrees C for 1-4 hours. In the step (b), the racemization of (R)-N,N-dimethyl-3-(2-thienyl)-3-hydroxypropanamine or its salt is performed in presence of an acid in a suitable solvent; and the racemization is carried out at temperature of 20-100 degrees C for 4-10 hours. In the step (b1), the coupling is carried out at a temperature of 0-200 (preferably 20-100) degrees C. In the step (b2), the oxalate salt (VIII) is prepared in an organic solvent selected from ester and/or chlorinated solvents, preferably ethyl acetate, propyl acetate, butyl acetate, isopropyl acetate, chloroform, and/or dichloromethane. In the step (c2), the demethylation of (5)-N,N-dimethyl-3-(1-naphthalenyloxy)-3-(2-thienyl)propanamine oxalate (VIII) takes place in presence of base selected from diisopropylamine; and the hydrolysis of the carbamate compound is carried out in the presence of alkali metal hydroxide selected from sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, barium hydroxide and cesium hydroxide; the hydrolysis of the resultant carbamate compound is carried out in aromatic hydrocarbon selected from toluene or xylene. In the step (d1), the duloxetine hydrochloride is obtained by treating duloxetine free base with concentrated hydrochloric acid. In the step (c2), the resulting crude duloxetine hydrochloride is optionally purified using ethyl acetate and water as solvent to obtain pure duloxetine hydrochloride. Preferred Components: The optically active acid is selected from mandelic acid, tartaric acid, camphor sulfonic acid, dibenzoyl tartaric acid, di-toluoyl tartaric acid. The organic solvent (S1) is selected from alcohols, ketones, ethers, and/or esters, preferably methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, methyl ethyl ketones, methyl isobutyl ketones, methyl tertiary butyl ether, tetrahydrofuran, dioxane, ethyl acetate, isopropyl acetate, and/or butyl acetate. The acid is selected from organic and/or inorganic acid. The organic acid is selected from formic acid, acetic acid, toluene sulfonic acid, trifluoroacetic acid, and camphor sulfonic acid. The inorganic acid is selected from hydrobromic acid, hydrochloric acid, perchloric acid, phosphoric acid, sulfamic acid, nitric acid, boron trifluoride, and potassium hydrogen sulfate. The mixture of organic and inorganic is hydrobromic acid along with acetic acid. The solvent (S2) is selected from chlorinated hydrocarbon, alicyclic hydrocarbon, amide, sulfoxide, nitrile, and/or water, preferably chloroform, dichloromethane, cyclohexane, dimethylacetamide, dimethylformamide, dimethylsulfoxide, acetonitrile, and/or propionitrile. The coupling agent is selected from N,N'-dicyclohexylcarbodimide, N,N'-diisopropylcarbodiimide, N,N-di-tert-butylcarbodiimide, 1,3-di-p-tolylcarbodiimide, bis(3-chloro-2-methyl phenyl)carbodiimide, bis(o-tolylcarbodiimide), tert-butyl-3-ethylcarbodiimide, N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide, bis(2,6-diisopropylphenyl)carbodiimide, bis(2,6-diethylphenyl)carbodiimide, N-cyclohexyl-N'-isopropylcarbodiimide, N-methyl-N'-phenylcarbodiimide, 1-cyclohexyl-3-(2-(4-N,N'-dicyclohexyl-N-methylcarbodiimidium iodide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC). The solvent (S3) used for coupling is selected from aromatic hydrocarbons, chlorinated hydrocarbons, esters, ethers, amides, sulfoxide, and/or nitriles, preferably toluene, xylene, chloroform, dichloromethane, ethyl aceate, propyl acetate, tetrahydrofuran, 1,4-dioxane, dimethyl formamide, dimethylacetamide, dimethylsulfoxide, acetonitrile, and/or propionitrile. The carboxylic acid is selected from formic acid, acetic acid, benzoic acid, methane sulfonic acid and toluene sulfonic acid. The aprotic solvent (S4) is selected from aliphatic hydrocarbons, aromatic hydrocarbons, chlorinated hydrocarbons, esters, ethers, amides, sulfoxide, and/or nitriles, preferably hexane, cyclohexane, toluene, xylene, chloroform, dichloromethane, ethyl acetate, propyl acetate, tetrahydrofuran, dioxane, dimethylformamide, dimethylacetamide, dimethylsulfoxide, acetonitrile, and/or propionitrile. The protic solvent (S5) is selected from methanol, ethanol, propanol, and/or butanol. The base is selected from organic or inorganic. The organic base is selected from diethylamine, triethylamine, diisopropylethylamine and pyridine. The inorganic base is selected from alkali metal or alkaline earth metal hydroxide, carbonate and bicarbonate. The alkali metal or alkaline earth metal is selected from lithium, sodium, potassium, magnesium, calcium and barium. The solvent (S6) is selected from amide, sulfoxide, and/or ester, preferably dimethylformamide, dimethylacetamide, dimethylsulfoxide, ethyl acetate, propyl acetate, and/or butyl acetate. EXAMPLE - (S)-N,N-Dimethyl-3-(1-naphthalenyloxy)-3-(2-thienyl) propanamine oxalate (50 g) was taken in toluene (200 ml) and water (100 ml) at room temperature. The pH of the resulting mixture was adjusted between 11-12 using 30% sodium hydroxide solutions. The resulting mass was heated at 40-45 degrees C for 1 hour. The reaction mass was cooled to room temperature, filtered and washed with toluene. The layers were separated and the aqueous layer was extracted with toluene. The organic layer was combined, washed with water and distilled under vacuum at 50-55 degrees C. To the resulting oily residue, toluene (200 ml) and diisopropyl ethylamine (8 g) was added at room temperature. The resulting mixture was cooled at 15-20 degrees C and phenyl chloroformate (23.2 g) was added. The reaction mass was stirred for 2 hours, sodium bicarbonate solution (1%) was added and the resulting mixture was heated at 40-45 degrees C for 1 hour. The resulting mixture was cooled to room temperature and the layers were separated. After work up, (S)-N-methyl-3-(1-naphthalenyloxy)-3-(2-thienyl)propanamine hydrochloride (crude Duloxetine hydrochloride) (yield: 62-66%; chiral purity: 99.5%) was obtained.