Method for producing pitavastatin calcium
Production of pitavastatin calcium safely on an industrial scale with a high yield and high selectivity at low cost. A method of producing pitavastatin calcium including step (i) for acetalizing a compound represented by the formula (1) to give a compound represented by the formula (3), step (ii) for reacting a compound represented by the formula (3) with an acid to give a compound represented by the formula (4), and step (iii) for hydrolyzing a compound represented by the formula (4) and reacting same with a calcium compound.
1. A compound represented by the following formula (1′):
wherein R is a straight chain alkyl group having a carbon number of 1-8 or a branched alkyl group having a carbon number of 3-8 and X 1 is methanesulfonic acid.
2. A method for producing a compound represented by the following formula (1):
wherein X is sulfuric acid, hydrochloric acid, methanesulfonic acid, or p-toluenesulfonic acid and R is a straight chain alkyl group having a carbon number of 1-8 or a branched alkyl group having a carbon number of 3-8, comprising
(iv) reacting a compound represented by the following formula (6):
wherein R is as defined above, with sulfuric acid, hydrochloric acid, methanesulfonic acid, or p-toluenesulfonic acid at a reaction temperature of 10-50° C.
3. The production method according to claim 2 , wherein the compound represented by the formula (6) used in (iv) is obtained by bioreaction.