title: Epimerization kinetics of moxalactam in frozen solution.
abstract: The epimerization rate constants of R- and S-epimers of moxalactam (LMOX) in a frozen aqueous solution decreased as the temperature decreased. The reaction proceeded in the unfrozen region remaining in the frozen solution, without being affected by the ice. The reaction stopped completely below the collapse temperature of the LMOX aqueous solution. The ratio of R- and S-epimers at equilibrium, which was equal to the ratio of the epimerization rate constant, increased as the temperature decreased. This change in the ratio at equilibrium could be ascribed to the difference in the activation energy between the two epimers.
authors.affiliation: Shionogi Research Laboratories, Shionogi & Co., Ltd., Osaka, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Hashimoto
authors.forename: T
authors.initials: T
authors.lastname: Ichihashi
authors.forename: E
authors.initials: E
authors.lastname: Yamamoto
authors.forename: K
authors.initials: K
authors.lastname: Hirano
authors.forename: M
authors.initials: M
authors.lastname: Inoue
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.forename: H
authors.initials: H
authors.lastname: Yamada
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005615:Freezing; D009070:Moxalactam / Q000032:analysis*; D012996:Solutions; D013237:Stereoisomerism; D013696:Temperature; D013997:Time Factors
chemical_list: D012996:Solutions; D009070:Moxalactam