The present invention relates to an improved process for preparing
simvastatin and more particularly, the improved process for preparing
simvastatin expressed by formula 1 with high yield and high purity by
performing the following sequential processes comprising: (i) hydrolysis
of lovastatin as starting material with potassium t-butoxide in an organic
solvent and small amount of water under a mild reaction condition,
followed by lactonization of the obtained solid intermediate with
preventing from formation of by-products; (ii) protection of an alcohol
group with t-butyldimethylsilyl group which can be easily removed with
concentrated hydrochloric acid without the formation of by-products; (iii)
acylation of the obtained protected intermediate with acyloxytriphenyl
phosphonium salt as an acylating agent under a mild reaction condition;
and (iv) removal of the silyl protective group with a concentrated
hydrochloric acid. The present invention is to provide the improved
process of preparing simvastatin expressed by formula 1 environmentally
sound, economically efficient, and industrially useful.
