J 500c spectropolarimeter

The UV–visible (UV–VIS) spectra were recorded with a Hitachi U-2001 (Hitachi High-Technologies Corporation, Tokyo, Japan) in diethyl ether (Et₂O). The positive ion fast atom bombardment mass spectrometry (FAB MS) spectra were recorded using a JEOL JMS-HX 110A mass spectrometer (JEOL, Tokyo, Japan) with m-nitrobenzyl alcohol as a matrix. The positive ion electro spray ionization time of flight mass (ESI-TOF MS) spectra were recorded using a Waters Xevo G2S Q TOF mass spectrometer (Waters Corporation, Milford, CT, USA). The ¹H-NMR (500 MHz) and ¹³C-NMR (500 MHz) spectra were measured with a Varian UNITY INOVA 500 spectrometer (Agilent Technologies, Santa Clara, CA, USA) in CDCl₃. The chemical sifts are expressed in ppm relative to tetramethyl silane (TMS) (δ = 0) as an internal standard for ¹H-NMR and CDCl₃ (δ = 77) as an internal standard for ¹³C-NMR. J values are given in Hz. The CD spectra were recorded in EPA [Et₂O–isopentane–ethanol (5:5:2)] at room temperature with a Jasco J-500C spectropolarimeter (Jasco corporation, Tokyo, Japan). Preparative high-performance liquid chromatography (HPLC) was performed on a Shimadzu LC-6AD with a Shimadzu SPD-6AV spectrophotometer (Shimadzu Corporation, Kyoto, Japan) set at 450 nm. The column used was a 250mmX10mm i.d. 10 μm Cosmosil 5SL-II and 5C18 II (Nacalai tesque, Kyoto, Japan).

UV-visible (UV-VIS) absorption spectra were recorded with a Hitachi U-2001 spectrophotometer (Hitachi Field Navigator, Tokyo, Japan) in diethyl ether (Et₂O). MS analysis of carotenoids was performed using a Waters Xevo G2S Q-TOF mass spectrometer (Waters Corporation, Milford, CT, USA). ESI-TOF-MS spectra were acquired by scanning from m/z 100 to 1,500 with a capillary voltage of 3.2 kV, cone voltage of 40 eV, and source temperature of 120°C. The ¹H-NMR (500 MHz) spectrum was measured with a Varian Unity Inova 500 spectrometer (Varian Corporation, Palo Alto, CA, USA) in CDCl₃ with TMS as an internal standard. Because of the small amount of carotenoid sample (about 30 μg), ¹H-NMR was measured using a SHIGEMI microtube (sample solution volume 200 μl) (Shigemi Co., Ltd., Tokyo, Japan). The CD spectrum was recorded in Et₂O at room temperature with a Jasco J-500C spectropolarimeter (JASCO Corporation, Tokyo, Japan). Preparative HPLC was performed with a Hitachi L-6000 HPLC intelligent pump and Hitachi L-4250 UV-VIS detector (Hitachi Field Navigator, Tokyo, Japan) set at 450 nm. The column used was a 250 × 4.6 mm i.d. Cosmosil 5C18-II (Nacalai Tesque, Kyoto, Japan).