Melting and boiling points are uncorrected. The purity of products was established on a Fuli GC-9790 gas chromatograph with FTD, SE-30 capillary column (3.2 mm x 30 m). IR spectra were recorded on a Bruker EQUINOX 55 spectrometer.'H-NMR spectra were determined on a Bruker AC-400 instrument. Chemical shifts are reported in 6 from internal TMS. MS spectra were recorded on a Varian Saturn 2000. Elemental analyses were performed using a ...