Ultrashield 500 mhz nmr spectrometer

Optical rotation was obtained on a JASCO P-2000 polarimeter in MeOH. The UV spectra were recorded with a PerkinElmer UV-vis spectrophotometer, whereas the IR spectra were obtained using a PerkinElmer FTS FT-IR spectrophotometer. The Bruker Ultrashield 500 MHz NMR spectrometer was used to measure the 1D and 2D NMR spectra of the isolated compounds. Chemical shifts (δ) are expressed in ppm with CDCl₃ (δ_H 7.24 and δ_C 77.0) using TMS as an internal reference, reference to the solvent signals. A MicroTOF, Bruker Daltonics mass spectrometer was employed to acquire HRESIMS spectra. Column chromatography (CC) was performed on silica gel 60H (5–40 μm), silica gel 100 (63–200 μm) and Sephadex LH-20 (Pharmacia Fine Chemical Co., Ltd., Sweden). Semipreparative HPLC separations were performed on a Waters 626 liquid chromatography system equipped with a Grace C18 column (Econosil C₁₈, 10 μm, 10.0 i.d. × 250 mm) and a Waters 486 Tunable Absorbance detector (Waters, USA). Fractions obtained from CC were monitored by TLC using precoated plates of silica gel 60 F₂₅₄ (Merck).