| 摘要 |
<p>PURPOSE:To economically, efficiently and readily obtain the subject compound, especially an optically active substance thereof by reacting an optically active 3,4-dihydroxybutyric acid derivative or a 3-hydroxybutyrolactone derivative with a brominating agent and an alcohol. CONSTITUTION:A compound expressed by formula I or II (R1, R2 and R6 are H or protecting group of alcohol; R3 is H or lower alkyl), especially an optically active (R)-or (S)-isomer thereof is allowed to react with a brominating reagent, preferably a hydrogen bromide reagent, especially a solution of hydrogen bromide in acetic acid, hydrobromic acid/concentrated sulfuric acid or sodium bromide/concentrated sulfuric acid and an alcohol, preferably methanol, ethanol, n-propanol, isopropanol, nbutanol, tert. butanol or isobutanol to efficiently afford the objective compound, expressed by formula III (R4 is H or protecting group of alcohol; R5 is lower alcohol) and useful as an intermediate for medicines, especially an optically active substance corresponding to the aforementioned raw material in high optical purity from the inexpensive raw material.</p> |
