Yang RS, Wang X, Tang W, Celly C, Sheng H. Mechanistic insight into the oxazoline decomposition of DFC-M, a synthetic intermediate of florfenicol.
J Pharm Biomed Anal 2019;
174:235-241. [PMID:
31181485 DOI:
10.1016/j.jpba.2019.05.009]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 04/30/2019] [Accepted: 05/04/2019] [Indexed: 10/26/2022]
Abstract
2-(dichloromethyl)-5[4-(methylsulfonyl)-phenyl]-4-(fluoromethyl)-oxazoline (DFC-M, 1) is a key oxazoline-containing intermediate in commercial process for the synthesis of Florfenicol (3), a marketed broad spectrum veterinary antibiotic. DFC-M was not stable in solution due to the presence of oxazoline moiety, which provided further hindrance for analytical sample preparation and HPLC analysis. Hence, the mechanistic study on the in-solution degradation of DFC-M was carried out via online and offline UPLC-HR-ESI-MS as well as in-situ NMR, and the degradation pathways were proposed. This mechanistic information, together with the follow-up solution stability study, provided crucial information regarding the solution handling and mobile phase selection for DFC-M analysis during commercial processing.
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