- Application of chiral 2-isoxazoline for the synthesis of syn-1,3-diol analogs
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The asymmetric cycloaddition of TIPS nitronate catalyzed by “Cu(II)-bisoxazoline” gave the 2-isoxazoline product in 95% yield, which was converted into tert-butyl (3S,5R)-6-hydroxy-3,5-O-isopropylidene-3,5-dihydroxyhexanoate in 14 steps through a β-hydroxy ketone.
- Feng, Juanjuan,Li, Tianyu,Zhang, Jiaxin,Jiao, Peng
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- New Statin intermediate, the preparation of the same and the preparation of Rosuvastatin using the same
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The present invention provides a novel producing method for producing a core intermediate (chemical formula IV) of rosuvastatin, a novel intermediate used therefor and a producing method of rosuvastatin hemi-calcium salts using the same. The novel intermediate of the present invention can be prepared with high purity and in high yields in mild conditions, and thus the rosuvastatin intermediate and rosuvastatin hemi-calcium salts can be conveniently and efficiently mass-produced without complicated processes.
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Paragraph 0183; 0184-0187
(2017/04/20)
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- PROCESS FOR PREPARING OPTICALLY ACTIVE 2- 6-(HYDROXY-METHYL)-1,3-DIOXAN-4-YL]ACETIC ACID DERIVATIVES
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The present invention is to provide a production technology by which an optically active 2-[6-(hydroxymethyl)-1,3-dioxan-4-yl]acetic acid derivative, which are of value as pharmaceutical intermediates, can be produced from inexpensive and readily available starting materials without using any extraordinary equipment such as an ultra-low-temperature reactor. The present invention is a production process of an optically active 2-[6-(hydroxymethyl)-1,3-dioxan-4-yl]acetic acid derivative ???which comprises reacting an enolate, prepared by permitting a base or a 0-valent metal to act on an acetic acid ester derivative with (S)-β-hydroxy-γ-butyrolactone at a temperature not lower than -30°C to give a dihydroxyoxohexanoic acid derivative, ???treating the same with an acylating agent in the presence of a base to produce a dihydroxyoxohexanoic acid monoacyl derivative, ???reducing this compound with a microorganism to produce a trihydroxyhexanoic acid monoacyl derivative, ???treating this compound with an acetal-forming reagent in the presence of an acid catalyst to produce an acyloxymethyldioxanylacetic acid derivative, and ???finally, subjecting this compound to solvolysis in the presence of a base.
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