Microtof mass spectrometer

Optical rotations were measured at room temperature on a JASCO-P-1020 polarimeter and IR spectra were recorded using a Perkin-Elmer (2000 FTIR) spectrophotometer using KBr windows. ECD spectra were measured on an Applied Photophysics Chirascan CD spectrometer using a 1 mm cell and CH₃CN as the solvent. ¹H, ¹³C and 2D NMR spectra were recorded on a Bruker AVANCE III NMR spectrometer, operating at 500 MHz for ¹H and 125 MHz for ¹³C, using standard experiments from the Bruker pulse programs library. Chemical shifts are reported in ppm (δ) referencing the solvent signal (CDCl₃) as internal standard respect to TMS (0 ppm), and coupling constants (J) are measured in Hz. HR-ESIMS was performed on a Bruker MicroToF Mass Spectrometer, using an Agilent 1100 HPLC to introduce samples. Gravity column chromatography was performed using silica gel (Merck Art. 9385) packed 1 or 4 cm diameter columns. TLC was performed on aluminium precoated silica gel plates (Merck 9385) visualised using anisaldehyde spray reagent. Mass spectra of compounds 9 and 10 were recorded on a Thermo Q-Exactive Orbitrap mass spectrometer using direct HESI injection.