Adding anhydrous methyl 2-[(3S)-[3-[(2E)-(7-chloro quinolin-2-yl)ethenyl]phenyl]-3-hydroxypropyl]benzoate (1) solution in organic polar solvent such as acetonitrile, THF to a solution of sodium iodide at temperature of about 10° C. to about 25° C. followed by addition of trimethylchloro silane to the mass, raising the temperature to about 35° C. to about 55° C., maintaining the reaction mass at temperature of 35° C. to 55° C. for about 10 hrs to 24 hrs, isolation, slurring the wet cake with mixture of ethyl acetate, water gives the crude iodo derivative (IV, X═I). The crude on dissolution in mixture of methylene chloride, methanol followed by washing with sodium bicarbonate solution, water, drying over dehydrating agents such as anhydrous sodium sulphate, anhydrous magnesium sulphate, removal of solvent under reduced pressure at temperature below 50° C. followed by purification with column chromatography gives the pure methyl 2-[(3S)-[3-[(2E)-(7-chloro quinolin-2-yl)ethenyl]phenyl]-3-iodopropyl]benzoate (IV, X═I).
