Satheesh, Balasubramanian published the artcileIdentification, isolation and characterization of an unknown impurity of varenicline, Application In Synthesis of 375815-87-5, the publication is Scientia Pharmaceutica (2012), 80(2), 329-336, database is CAplus and MEDLINE.
An unknown impurity formed during stability sample anal. by a gradient reversed phase ultra-high pressure liquid chromatog. (UHPLC) of varenicline tablets at 0.2% level. A simple isocratic preparative method was developed to isolate the unknown impurity with 20 min run time. This unknown impurity was identified and characterized by spectroscopic techniques. Based on the spectral data, the unknown impurity was characterized as 4,6,7,8,9,10-hexahydro-1H-6,10-methanopyrazino[2,3-h][3]benzazepine-2,3-dione. The structure of this impurity was also established unambiguously, prepared by isolation and co-injected into UHPLC to confirm the retention time. To the best of the authors’ knowledge, this impurity was not reported elsewhere.
Scientia Pharmaceutica published new progress about 375815-87-5. 375815-87-5 belongs to quinoxaline, auxiliary class Neuronal Signaling,AChR,Natural product, name is 7,8,9,10-Tetrahydro-6H-6,10-methanoazepino[4,5-g]quinoxaline (2R,3R)-2,3-dihydroxysuccinate, and the molecular formula is C17H19N3O6, Application In Synthesis of 375815-87-5.
Referemce:
https://en.wikipedia.org/wiki/Quinoxaline,
Quinoxaline | C8H6N2 | ChemSpider