Silica gel 60 f254 plates

Nuclear magnetic resonance (NMR) spectra were recorded using a JNM-ECS400 NMR spectrometer (JEOL Ltd., Tokyo, Japan) operated at 400 MHz (¹H) with tetramethylsilane as internal standard. Gas chromatograph–mass spectrometry (GC–MS) analyses were performed using a Shimadzu QP 2010 mass spectrometer (Shimadzu, Kyoto, Japan) equipped with a Shimadzu GC2010 gas chromatography system and an AOC-20i autosampler. High-performance liquid chromatography (HPLC) analyses were performed using an LC-20AD pump equipped with an SPD-20A UV/VIS detector (Shimadzu Corporation). Column chromatography was run on silica gel (Silica gel 60; Nacalai Tesque Inc., Kyoto, Japan). Precoated thin-layer chromatography (TLC) was performed on Silica gel 60 F₂₅₄ plates (FUJIFILM Wako Pure Chemical Corporation, Osaka, Japan). Electron ionization–mass spectrometry (EI–MS) spectra were obtained with a JMS-700 MStation mass spectrometer (JEOL Ltd.). The optical rotations were measured on a DIP-1000 polarimeter (JASCO Corporation, Hachioji, Tokyo, Japan).

Silica gel column chromatography was performed with Silica gel 60 (20–230 mesh; Nacalai Tesque Inc., Kyoto, Japan) or Wakogel C-300 HG (Fujifilm Wako Pure Chemical Corporation, Osaka, Japan). Precoated TLC was performed on Silica gel 60 F₂₅₄ plates (Fujifilm Wako Pure Chemical Corporation). NMR spectra were recorded using a JNM-ECS400 NMR spectrometer (JEOL Ltd., Akishima, Tokyo, Japan), which was operated at 400 MHz (¹H) and 100 MHz (¹³C). Tetramethylsilane (internal standard of NMR spectrometry), deuterated chloroform (CDCl₃), and deuterated methanol (CD₃OD) were obtained from Euriso-Top (Saint-Aubin, France). Optical rotations of compounds were measured on a DIP-1000 polarimeter (JASCO Corporation, Hachioji, Tokyo, Japan). EI–MS spectra were obtained with a JMS-700 MStation mass spectrometer (JEOL Ltd.). ChemDraw software (PerkinElmer Inc., Waltham, MA, USA) was used to draw chemical structures.