Abstract: 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.
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Sharov, Y.; Zhang, L.; Du, G.-J.; Ren, J.; Cheng, M.-S. Synthesis of RP 48497, an Impurity of Eszopiclone. Molecules 2008, 13, 1817-1821.
Sharov Y, Zhang L, Du G-J, Ren J, Cheng M-S. Synthesis of RP 48497, an Impurity of Eszopiclone. Molecules. 2008; 13(8):1817-1821.
Sharov, Yu; Zhang, Lei; Du, Gui-Jie; Ren, Jian; Cheng, Mao-Sheng. 2008. "Synthesis of RP 48497, an Impurity of Eszopiclone." Molecules 13, no. 8: 1817-1821.