title: Solid-state NMR study of fluorinated steroids.
abstract: Solid-state {(1)H}(13)C cross-polarization/magic angle spinning (CP/MAS) NMR spectroscopy was performed to analyze two fluorinated steroids, i.e., betamethasone (BMS) and fludrocortisone acetate (FCA), that have fluorine attached to C9, as well as two non-fluorinated analogs, i.e., prednisolone (PRD) and hydrocortisone 21-acetate (HCA). The (13)C signals of BMS revealed multiplet patterns with splittings of 16-215Hz, indicating multiple ring conformations, whereas the (13)C signals of FCA, HCA, and PRD exhibited only singlet patterns, implying a unique conformation. In addition, BMS and FCA exhibited substantial deviation (>3.5ppm) in approximately half of the (13)C signals and significant deviation (>45ppm) in the (13)C9 signal compared to PRD and HCA, respectively. In this study, we demonstrate that fluorinated steroids, such as BMS and FCA, have steroidal ring conformation(s) that are distinct from non-fluorinated analogs, such as PRD and HCA.
authors: Institute of Chemistry, Academia Sinica, Nankang, Taipei 11529, Taiwan, ROC.
authors: Kai-Jay
authors: KJ
authors: Yang
authors: Institute of Chemistry, Academia Sinica, Nankang, Taipei 11529, Taiwan, ROC.
authors: Su-Ching
authors: SC
authors: Lin
authors: Instrumentation Center, National Taiwan University, Taipei 11617, Taiwan, ROC.
authors: Shing-Jong
authors: SJ
authors: Huang
authors: Institute of Chemistry, Academia Sinica, Nankang, Taipei 11529, Taiwan, ROC.
authors: Wei-Min
authors: WM
authors: Ching
authors: Institute of Chemistry, Academia Sinica, Nankang, Taipei 11529, Taiwan, ROC.
authors: Chen-Hsiung
authors: CH
authors: Hung
authors: Institute of Chemistry, Academia Sinica, Nankang, Taipei 11529, Taiwan, ROC. Electronic address: tzougate@gate.sinica.edu.tw.
authors: Der-Lii M
authors: DL
authors: Tzou
mesh_terms: D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D012015:Reference Standards; D013259:Steroids, Fluorinated / Q000737:chemistry*
chemical_list: D013259:Steroids, Fluorinated
keywords: Anisotropic chemical shift; Betamethasone; Fludrocortisone acetate; Solid-state NMR; Steroidal ring conformation