TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The solvent is selected from toluene, methanol, ethanol, isopropanol, n-propanol, ethyl acetate, methyl acetate and/or acetonitrile.    TECHNOLOGY FOCUS - PHARMACEUTICALS - Preferred Method: The step of providing solution of montelukast free acid involves dissolving montelukast free acid in the solvent. ACTIVITY - Antiasthmatic; Antiinflammatory; Antiallergic; Antianginal; Nephrotropic; Hepatotropic; Virucide; Ophthalmological; Immunosuppressive. No biological data is given.    MECHANISM OF ACTION - Leukotriene antagonist.    EXAMPLE - Dicyclohexyl amine salt of 2-(1-(1-(R)-3-(2-(E)-(7-chloro quinolin-2-yl)vinyl (phenyl)-3-(2-methoxy carbonyl phenyl)propyl sulfonyl methyl)cyclopropyl)acetic acid (100 g) and toluene (1000 ml) were charged to a flask, and stirred for 5 minutes. A mixture of acetic acid (15 ml) and water (500 ml) was added, and the mass was further stirred for another 30 minutes. The organic and aqueous layers were separated; the organic layer was washed with water (3x 500 ml) and dried over sodium sulfate. The solvent was removed under reduced pressure at below 50 degrees C. The resulting crude residue was dissolved in a mixture of toluene (760 ml) and tetrahydrofuran (760 ml); the solution was transferred into a round bottomed flask and cooled to 0 degrees C under nitrogen atmosphere. 3M Solution of methyl magnesium chloride in tetrahydrofuran (261 ml) were added dropwise during 2-3 hours at 0-5 degrees C. The reaction mass was maintained at 0-5 degrees C for 6-7 hours, and cooled to 0 degrees C. A mixture of acetic acid (90 ml) and water (750 ml) was slowly added at below 15 degrees C for one hour. The reaction mass was stirred at 25-35 degrees C for another one hour until clear dissolution. The organic and aqueous layers were separated, and the organic layer was washed with 5% sodium bicarbonate solution (2x 750 ml), followed by a water wash (2x 750 ml). The organic layer was dried over sodium sulfate. The dried organic layer was heated under reduced pressure to remove the solvent. The residue was treated with additional amount of methyl magnesium chloride. The crude product was dissolved in toluene (100 ml) and stirred at 25-35 degrees C to separate a solid. The separated solid was filtered and washed with toluene (30 ml). The wet solid and toluene (90 ml) were charged into a round-bottomed flask, heated to 90 degrees C, and stirred for 30 minutes until complete dissolution, cooled to 25-35 degrees C, and maintained for 6-10 hours. The solid was filtered and washed with toluene (22 ml). The re-precipitation process was repeated four to five times. The solid was dried to afford (R)-1-(((1-(3-(2-(7-chloro-2-quinolinyl)ethenyl)phenyl)-3-(2-(1-hydroxy-1-methylethyl)-phenyl)propyl)thio)methyl)cyclopropane acetic acid (montelukast free acid) (17.4 g).