983g ft ir spectrophotometer

All chemicals, including caffeic acid, N,N-dimethylformamide, trimethylamine, BOP, CH₂Cl₂, EtOAc, HCl, thionyl chloride, SOCl₂, NaHCO₃ (aq.), and MgSO₄, were of analytical-grade purity. They were purchased from the branch of Merck in Taipei, Taiwan, and the branch of Sigma Aldrich in Taichung, Taiwan. UV spectra were recorded on a Shimadzu UV-1601PC spectrophotometer. Infrared (IR) spectra were measured on a Perkin-Elmer-983G FT-IR spectrophotometer. ¹H- and ¹³C-NMR and 2D NMR spectra were obtained on a Bruker DRX-500 FT-NMR spectrometer with tetramethylsilane (TMS) as the internal standard. EI-MS were measured with a Jeol-JMSHX300 mass spectrometer. Silica gel (230–400 mesh; Merck & Co., Inc.) was used for column chromatography (CC). Pre-coated Silica gel (60 F-254; Merck & Co., Inc.) plates were used for TLC. The spots on TLC were detected by spraying with 5% H₂SO₄ and then heating at 100 °C.

Silica gel 60 F₂₅₄ precoated plates (Merck). Column chromatography (CC): silica gel (Merk 70–230 mesh). High-performance liquid chromatography (HPLC): LDC Analytical-III system; column: Keystone spherisorb silica, 5 μm, 250 × 10 mm. M.p.: Yanaco-MP-S3 micro-melting-point apparatus; uncorrected. Optical rotation: Jasco-DIP-1000 polarimeter; in methanol. UV Spectra: Helios Beta UV-Visible spectrophotometer; λ_max (logε) in nm. IR Spectra: Perkin-Elmer-983G FT-IR spectrophotometer; ν in cm⁻¹. ¹H-, ¹³C-, and 2D-NMR Spectra: Varian-Unity-Plus-400 and Bruker-DMX-500 spectrometers; δ in ppm, J in Hz. EIMS and HREIMS: Jeol-JMS-HX300 mass spectrometer; m/z (rel. %).