Sept. 7, 2008, ACD/Labs NMR Software Symposium (SMASH) 2008, Santa Fe, NM, USA

Identification of a Temazepam Related Substance Using MS, NMR, and Structure Elucidator

John Johnson, Covidien

Abstract

An unknown HPLC peak, at a level of 0.09% by normalized area percent, was observed in stability samples of a drug product containing the active Temazepam. After pre-concentration by preparative HPLC, the unknown's structure was elucidated using a combination of LC/MS and NMR techniques in addition to the ACD/Structure Elucidator software package. The LC/MS analysis, including accurate mass positive ion electrospray MS, indicated a molecular weight of 284.07152, which implied the molecular formula C16H13N2OCl. NMR analysis, including proton, APT, g-HMQC, and g-HMBC led to the identification of the unknown. The use of the Structure Elucidator software package was critical to arriving at the unexpected structure for this minor component.

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Relevant Solution: NMR Laboratory