The aromaticity of some of these rings was evident by the characteristic downfield shifts observed for five methine resonances in the 1H NMR spectrum (H 9.21, 8.07, 7.51, 7.50, and 6.94). Table 2 1H NMR Spectroscopic Data (500 MHz, in Hz)) for Compounds 6-8 in MeOH-(H 1.92) and H-20/4established the -orientation of these protons. Kupchan … Continue reading The aromaticity of some of these rings was evident by the characteristic downfield shifts observed for five methine resonances in the 1H NMR spectrum (H 9