The present invention provides a process for the preparation of rosuvastatin, its salts, esters, or the corresponding cyclized lactone form. The process provides obvious benefits with respect to economics and convenience to operate on a commercial scale. Detailed Description of the Invention CRESTOR patent expiration dates, news, global patents, generic entry, and litigation and lawsuits AstraZeneca won some important breathing space after defending its cholesterol-lowering blockbuster Crestor from a patent challenge in the US. The company said it has entered into a settlement agreement with Actavis and Egis Pharmaceuticals over their plan to launch generic Crestor (rosuvastatin (XVII) Scheme 2: Preparation of rosuvastatin calcium (XVII) as disclosed in U.S. Patent No. 6,844,437 B1 Marine et al. PCT Publication No. WO07/125547A2 discloses a process for the preparation of rosuvastatin as shown in Scheme 3. Rosuvastatin, sold under the trade name Crestor among others, is a statin medication, used to prevent cardiovascular disease in those at high risk and treat abnormal lipids. It is recommended to be used together with dietary changes, exercise, and weight loss. It is taken by mouth. Made by Watson Pharmaceuticals, generic rosuvastatin will likely hurt sales of Crestor, one of several older AstraZeneca drugs facing patent expiry. CEO Pascal Soriot recently warned of the effect generic competition may have on the company’s earnings this year. AstraZeneca today announced that it has entered into a settlement agreement in its US patent infringement litigation against Watson Laboratories, Inc., Actavis, Inc. (formerly known as Watson Pharmaceuticals, Inc.), and EGIS Pharmaceuticals regarding Watson’s proposed rosuvastatin zinc product. The drug, also known as rosuvastatin calcium, is scheduled to lose patent protection on July 8, potentially exposing it to an onslaught of generic competition. The introduction of generics would. Monday, 25 March 2013. AstraZeneca today announced that it has entered into a settlement agreement in its US patent infringement litigation against Watson Laboratories, Inc., Actavis, Inc. (formerly known as Watson Pharmaceuticals, Inc.), and EGIS Pharmaceuticals regarding Watson’s proposed rosuvastatin zinc product. AstraZeneca is a global, science-led biopharmaceutical business and our innovative medicines are used by millions of patients worldwide.