Flash chromatography was performed on Brinkmann silica gel (0.040—t). 063 mm) using mixtures oi 'EtOAc and hexane. TLC was performed on EM reagents precoatcd silica gel 60 F-254 analytical plates (0.25 mm). Electron-impact mass spectra were recorded on a Varian MAT-311 spectrometer. IR spectra were recorded on a Nicolet SMX FT spectrometer or on a Beckman IR 10. 1H-NMR spectra were recorded at 300 MHZ on a Nicolet spectrometer ...
