New Statin intermediate, the preparation of the same and the preparation of Rosuvastatin using the same

PURPOSE: A method for preparing rosuvastatin hemicalcium salt using methyl 2-((4R,6S)-6-(triphenylphosphoranylidenemehtyl)-2,2-dimethyl-1,3-dioxan-4-yl)acetate is provided to obtain statin of high purity and high yield. CONSTITUTION: A method for preparing a compound of chemical formula 4 comprises: a step of reacting a compound of chemical formula 3 with 2,2-dimethoxypropane under the presence of acid; and a step of adding alkaline to the reacted solution to prepare the compound of chemical formula 4. The acid includes methane sulfonic acid, paratoluene sulfonic acid, perchloric acid, hydrochloric acid, nitric acid, acetic acid, sulfuric acid, or trifluoreacetic acid. The alkaline includes sodium hydrogen carbonate, potassium hydrogen carbonate, potassium carbonate, triethylamine, and ammonium hydroxide.