Gx 400 spectrometer

Shimadzu 1700 spectrophotometer was used for UV absorption spectra. Melting points were determined on Electrothermal 9100 equipment. Mass spectra were measured on a Jeol Mass Spectrometer SSQ 7000, Digital DEC 300. NMR spectra were measured in DMSO or CD₃OD or CDCl₃; ¹H–NMR spectra were obtained at 400 MHz and ¹³ C-NMR spectra at 100 MHz on a JEOL GX-400 spectrometer with the chemical shifts (δ ppm) expressed relative to TMS as internal standard. Pre-coated silica gel 60 F₂₅₄ (Merck, Darmstadt, Germany) was used for the TLC analysis. Vacuum liquid chromatography (VLC) was performed on silica gel 60 GF (Merck, Darmstadt, Germany). Sephadex LH-20 (Sigma-Aldrich, St. Louis, Missouri, United States) and silica gel 100 C₁₈-Reversed Phase (Fluka, Switzerland) were also used. Analysis of phenolics was performed on Hewlett Packard HPLC (HP 1050HPLCDADw/Data System) equipped with a Hypersil-ODS (4.6 X 250 mm, 5 μm) column and a UV detector.

N-Hexane, chloroform, n-butanol and ethanol were purchased from Fisher Scientifics (UK). Silica Gel 60, xanthine oxidase, xanthine, allopurinol, and uric acid assay kit were purchased from Sigma (USA). All other chemicals were of analytical grade. Melting point was determined on Electrothermal 9100 equipment. Mass spectrum was measured on a Jeol Mass Spectrometer SSQ 7000, Digital DEC 300. NMR spectrum was measured in DMSO. ¹H–NMR spectrum was obtained at 400 MHz on a JEOL GX-400 spectrometer with the chemical shifts (δ ppm) expressed relative to TMS as internal standard. Precoated Silica Gel 60 F254 (Merck, Darmstadt, Germany) was used for the TLC analysis. Vacuum liquid chromatography (VLC) was performed on Silica Gel 60 GF (Merck, Darmstadt, Germany)

Measurements of melting points were performed with a micromelting point instrument (Yanagimono, Tokyo, Japan) and are uncorrected. Microanalysis, ¹H-NMR and mass spectral measurements were performed at the Central Microanalytical Department of Pharmaceutical Sciences, Fukuoka University. The ¹H-NMR spectra were determined at 500 MHz using a JEOL GX-400 spectrometer (JEOL, Ltd., Tokyo, Japan) in a solution of CD₃OD with tetramethylsilane as an internal standard. The following abbreviations are used: s = singlet, d = doublet and m = multiplet. Field desorption mass (FD-MS) spectra were determined using a JEOL D-300 spectrometer (JEOL).