Atr tensor 37 spectrophotometer

The purified compound 1 was subjected to spectroscopic analyses (UV, IR, ¹H-NMR, ¹³C-NMR, ESI, and MS/MS studies) for identification and characterization. The optical measurements were conducted by using a polarimeter (JASCO DIP360, Jasco Co., Tokyo, Japan). A Bruker ATR-Tensor 37 spectrophotometer (Bruker, Ettlingen, Germany) was used to record the IR spectra. To obtain the ESI mass spectra, a QSTAR mass spectrometer (Applied Biosystems, Foster, CA, USA) with capillary voltage of 5–5.5 kV was used. The NMR spectra (¹H and ¹³C) were obtained by using a Bruker NMR spectrometer (Burker, Fallanden, Switzerland) operated at 600 MHz and 150 MHz, respectively.

The ¹H- and ¹³C NMR spectra were measured on 600 MHz and 150 MHz NMR spectrometer (BRUKER, Zürich, Switzerland) using the solvent peaks (CDCl₃, δ_H: 7.26; δ_C: 77.0), (CD₃OD, δ_H: 4.87; δ_C: 48.5) as internal references. Data were determined in the following order: chemical shift (δ) in ppm; multiplicities are indicated s = singlet, d = doublet, t = triplet, dd = doublet of doublet, m = multiplet; coupling constants (J) are in hertz (Hz). High-resolution electrospray ionization mass spectrometry (HR-ESI-MS) spectra were recorded on Agilent 6530 LC Q-TOF (country of origin USA/EU, made in Singapore). Column chromatography was carried out by using silica gel of the selected particle size of 100–200 mesh. For TLC, pre-coated aluminum sheets (TLC silica gel 60 F254, Merck, Darmstadt, Germany) were used. Infrared (IR) spectra were recorded on a Bruker ATR-Tensor 37 spectrophotometer, Bruker (Ettlingen, Baden-Württemberg, Germany) with wave numbers (ν) in cm⁻¹. Visualization was accomplished with UV light (254 and 366 nm) or I₂ stain and by spraying with the ceric sulfate (Ce(SO₄)₂) reagent.