An improved process for lactonization in the preparation of statins

摘要

Provided is a lactonization process for HMG-CoA inhibitors of the statin class, the process comprising treating a statin compound with an alkali metal hydrogen sulphate used as a lactonizing agent. Further provided are processes with specified metals in the sulphate, and processes wherein the reaction is carried out in the presence of water miscible aprotic solvent or water immiscible solvent or a mixture thereof.