Patent ID: 7528265

Claim:
A method of preparing simvastatin of formula (I) comprising the steps of: (a) treating lovastatin of formula (II) with potassium hydroxide dissolved in a mixture of water and methanol to obtain the compound of formula (III); (b) relactonizing the compound of formula (III), and protecting the hydroxy group on the lactone ring to obtain the compound of formula (V); and (c) acylating the compound of formula (V) with 2,2-dimethylbutyryl chloride or 2,2-dimethylbutyryl bromide in the presence of an acylation catalyst which is a compound of formula (VII) or a compound of formula (VIII) in an organic solvent, followed by removing the silyl protecting group on the lactone ring to obtain simvastatin of formula (I): Wherein R 1 is C 1-20 alkyl or phenyl; R 2 is C 1-20 alkyl, phenyl, or benzyl; and X is Br or I.