The present invention relates to process for the preparation of 7-[4-(4-fluorophenyl)-6-isopropyl-2-(N-methyl-N-methylsulfonylamino)pyrimidin-5-yl]-(3R,5S)-dihydroxy-(E)-6-heptenoic acid calcium having formula (I). The compound of formula (I) has adopted name "Rosuvastatin Calcium". The present invention is also related to novel intermediates of formula (4) and formula (5) used in preparation of formula (I), and process of their preparation.