NOVELTY - Preparation of N-(1-(R)-(1-naphthyl)ethyl)-3-(3-(trifluoromethyl)phenyl)-1-propanamide involves reacting 3-(3-trifluoromethylphenyl)propionic acid, triethyl phosphite, 2,2'-dibenzothiazyl disulfide and organic solvent, adjusting pH, heating, cooling, obtaining 1-(1,3-benzothiazol-2-ylsulfanyl)-3-(3-(trifluoromethyl)phenyl)propan-1-one (I), reacting (R)-1-(1-naphthyl)ethylamine, 3-(3-trifluoromethylphenyl)propionic acid and organic solvent, adjusting pH, stirring, adding compound (I), reacting, leaving still, separating organic layer, washing, drying and recrystallizing.    USE - Preparation of N-(1-(R)-(1-naphthyl)ethyl)-3-(3-(trifluoromethyl)phenyl)-1-propanamide (claimed).    ADVANTAGE - The method enables preparation of N-(1-(R)-(1-naphthyl)ethyl)-3-(3-(trifluoromethyl)phenyl)-1-propanamide with high yield of 90% and suppressed generation of hydrochloric acid and sulfur dioxide gas, by simple and environmentally-friendly process.    DETAILED DESCRIPTION - Preparation of N-(1-(R)-(1-naphthyl)ethyl)-3-(3-(trifluoromethyl)phenyl)-1-propanamide involves adding 3-(3-trifluoromethylphenyl)propionic acid, triethyl phosphite, 2,2'-dibenzothiazyl disulfide and organic solvent in molar ratio of 1:1.1-1.4:1.1-1.4 to round-bottom flask, stirring at room temperature for 1-2 hours, dripping alkali solution (A), adjusting pH of reaction mixture to more than 7, heating at 20-40 degrees C for 3 hours, cooling to room temperature, obtaining 1-(1,3-benzothiazol-2-ylsulfanyl)-3-(3-(trifluoromethyl)phenyl)propan-1-one of formula (I), adding (R)-1-(1-naphthyl)ethylamine and 3-(3-trifluoromethylphenyl)propionic acid in molar ratio of 1.1-1.3:1 to round-bottom flask, adding organic solvent, adjusting pH of resultant mixture to more than 7 using alkali solution (B), stirring, adding compound (I), reacting at 20-30 degrees C for 11-13 hours, leaving still, separating organic layer, washing organic layer, drying and recrystallizing using mixture comprising ethyl acetate and n-hexane.