Avance dpx 600 spectrometer

Optical rotations were measured on an Autopol III polarimeter #A7214 (Rudolph Research Analytical, Hackettstown, NJ, USA) equipped with a 5 cm cell. Infrared spectra were recorded on a NICOLET 5700 spectrometer (Thermo Electron Corp, Waltham, MA, USA) and ultraviolet spectra were also recorded on a Scinco UVS-2100 instrument (Scinco, Seoul, Korea). ¹H- and ¹³C-NMR spectra were recorded on an Avance DPX-600 spectrometer (Bruker, Billerica, MA, USA). FAB-MS were measured on a JMS-AX505WA mass spectrometer (JEOL, Tokyo, Japan). Solvents used in partitioning were first grade products of Dae Jung & Metals Co. (Siheung, Korea). HPLC grade solvents from Brudick & Jackson (Muskegon, MI, USA) were used in adsorption chromatography, TLC and HPLC. Younglin SDV 30 plus HPLC’s with Younglin M 720 UV detectors were used for isolation of compounds (YL Instruments, Anyang, Korea). NMR solvents were obtained from Cambridge Isotope Laboratories (CIL), Inc. (Tewksbury, MA, USA).

¹H and ¹³C NMR spectra and correlation NMR spectra such as correlation spectroscopy (COSY), heteronuclear multiple bond correlation (HMBC) and heteronuclear multiple quantum coherence (HSQC) were obtained from an Avance DPX 600 spectrometer (Bruker, Madison, WI, USA). These were obtained at operating frequencies 400 (¹H) and 100 MHz (¹³C) with CD₃OD and TMS were used as internal standards; chemical shifts were reported in δ values. The molecular mass was measured using the low-resolution electronic impact (EI) mass spectrometer equipped JMS-700 (Tokyo, Japan). The low-resolution mass spectrometer was operated in the negative ion mode with ion source at 250 °C and EI at 70 eV with direct insertion probe and the mass range in 50–600 m/z. Fast atom bombardment (FAB) mass spectrometer was recorded in the negative form using m-nitrobenzyl alcohol as a matrix in a JEOL JMSAX 505-WA spectrometer (Tokyo, Japan).