- Preparation method of dexzopiclone photodegradation impurity
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The invention relates to a preparation method of a dexzopiclone photodegradable impurity, and belongs to the technical field of chemical synthesis. The invention relates to a preparation method of 6-(5-chloropyridin-2-yl)-6, 7-dihydro-5H-pyrrolo [3, 4-b] pyrazin-5-one (compound I), which is prepared by reacting a compound II or a compound III with diisobutylaluminum hydride under certain conditions. The invention provides a synthetic method of the 6-(5-chloropyridin-2-yl)-6, 7-dihydro-5H-pyrrolo [3, 4-b] pyrazin-5-one (compound I), which is reasonable in process, mild in condition and simple and convenient to operate, and the method is simple to operate and has a certain commercial value.
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Paragraph 0017; 0019; 0021; 0023
(2020/12/30)
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- Synthesis of RP 48497, an impurity of eszopiclone
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RP 48497 is a photodegradation product of eszopiclone, a non-benzodiazepine sedative-hypnotic used in the treatment of insomnia. We report herein the first synthesis of RP 48497 via reduction, chlorination, and recyclization of 6-(5-chloropyridin-2-yl)-7-hydroxy-6,7-dihydropyrrolo[3,4-b]pyrazin-5-one (3), a key intermediate in the synthesis of eszopiclone. The structure of RP 48497 was confirmed by its 1H-NMR and MS data. The mechanism of the reduction step in the synthesis of RP 48497 was also studied and the key parameters were determined. These findings should be important for quality control purposes in the manufacture of eszopiclone.
- Sha, Yu,Zhang, Lei,Du, Gui-Jie,Ren, Jian,Cheng, Mao-Sheng
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p. 1817 - 1821
(2008/12/22)
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