TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Salt: The salt (S1) is: a salt of (R)-1-naphthylethylamine with mandelic acid; and a salt of (S)-1-naphthylethylamine with mandelic acid, where the mandelic acid is D-mandelic acid. Preferred Process: In the process (P2), the cinacalcet and/or its salt is isolated and subsequently recrystallized. The reaction is carried out in the presence of a base selected from an organic base and an inorganic base. The cinacalcet is converted to its salt. The cinacalcet is converted to cinacalcet hydrochloride. The ester (II) is prepared by reducing 3-trifluorom ethyl cinnamic acid to obtain 3-(3-trifluoromethylphenyl) propanoic acid, reducing the 3-(3-trifluoromethylphenyl)propanoic acid to 3-(3-trifluoromethylphenyl)propan-1-ol and esterifying the 3-(3-trifluoromethylphenyl) propan-1-ol. The reaction of ester (II) with the salt of (R)-1-naphthylethylamine is carried out in the absence of an organic solvent. Preferred Components: The solvent for the reaction is ethanol, isopropyl alcohol or acetone. The solvent is ethanol and the product of the reaction is a salt of the (R)-isomer. The solvent is isopropyl alcohol or acetone and the product of the reaction is a salt of the (S)-isomer. The solvent for the reaction of ester (II) with the salt is water. The chiral acid is D-(-)-mandelic. The base is selected from triethylamine, tributylamine, diisopropylethylamine, pyridine, sodium carbonate and potassium carbonate. ACTIVITY - Endocrine-Gen.; Antithyroid.    MECHANISM OF ACTION - Calcium receptor activator. No biological data given.    EXAMPLE - Racemic 1-naphthylethylamine (450 gm) was suspended in ethanol (3.1 liters). D-mandelic acid (400 gm) was added under stirring. Pure (R)-naphthylethylamine mandalate (3-4 gm) was added as a seed and heated at 55-60 degrees C until a clear solution was obtained. The solution was cooled gradually to 25-30 degrees C and stirred for 12 hours to obtain a solid. The solid was suspended in ethanol (2.3 liters) and heated at a temperature of 55-60 degrees C for half an hour. The suspension was cooled gradually to 25-30 degrees C and stirred to obtain a solid. The solid was washed with ethanol and dried at 50-55 degrees C to obtain (R)-1-naphthylethylamine mandalate salt (250 gm, Yield 70%, chiral purity greater than or equal to 99%).