A RPOCESS FOR LACTONIZATION TO PRODUCE HIGHLY PURE SIMVASTATIN

摘要

There is disclosed a process for lactonization to produce highly pure simvastatin of formula which comprises lactonization of a compound of formula where Z is H or NH4 in a mixture of acetonitrile and glacial acetic acid to provide anhydrous conditions at a temperature of 65-70 degrees C and wherein the dimer impurity of formula formed is less than 0.1, thereafter adding water to the reaction mixture thereby causing simvastatin of formula I to precipitate from the reaction mixture. 3 claims