Rosuvastatin calcium and process for producing intermediate thereof
An object of the present invention is to provide a novel method capable of producing rosuvastatin calcium and intermediates therefor efficiently, inexpensively and with high purity. The present invention provides a method of efficiently producing rosuvastatin calcium and intermediates therefor having a high purity at an industrial scale, without using an extremely low temperature reaction or a special asymmetric catalyst.
1. A production method of a compound represented by the following formula (1a):
wherein R is a n-propyl group or an isopropyl group, comprising
(iia) condensing a compound represented by the following formula (3):
and a compound represented by the following formula (4a):
wherein R 2 is a tert-butyl group, in the presence of a base to obtain a compound represented by the following formula (5):
wherein R 2 is as defined for R 2 in said formula (4a); and
(iib) reacting the compound represented by formula (5) with an alcohol represented by R—OH wherein R is a n-propyl group or an isopropyl group.
2. The production method of claim 1 , wherein R is the isopropyl group.
3. The production method of claim 1 , wherein R is the n-propyl group.