U 3200 spectrophotometer

Melting points (m.p.) were recorded on a Buchi M−560 melting point apparatus equipped with a Buchi M−569 sample loader. UV spectra were recorded on a Hitachi U-3200 Spectrophotometer while IR spectra were recorded in KBr with a Shimadzu 8900 FT-IR spectrophotometer. ¹H NMR (500 MHz) and ¹³C NMR (125 MHz) spectra were recorded in deuterated solvents such as CDCl₃ and C₅D₅N on a Bruker Avance-500. Coupling constants, J values, are given in Hertz. DEPT 135°, DEPT 90°, HSQC and HMBC NMR experiments were carried out using the conventional pulse sequences. EIMS and HREIMS were obtained with a JEOL MSRoute-600H and Thermo Finnigan MAT 95XP mass spectrometers respectively. Optical rotations were measured on a JASCO Polarimeter P-2000. Thin-layer chromatography (TLC) was performed on TLC cards pre-coated with silica gel (Merck, PF254, 20x20 cm, 0.25 mm) revealed under UV lamp UVITEC 07-22243 at 254 nm and 365 nm and also with ceric(IV)sulphate solution spray or H₂SO₄ 10% spray reagent. Column chromatography was carried out on silica gel (70–230 mesh, Merck). Optical densities were measured on a Thermo Scientific Multiskan FC, Vantaa, Finland.