13CNMR Spectra of β-diketones from waxes of the gramineae

摘要: Abstract The 13 CNMR spectra of six β-diketones and seven oxygenated have been measured. β-dicarbonyl grouping has the following effects on chemical shifts neighbouring carbons: α-, + 8.72; β-, − 3.98; γ-, −0.42; δ-, −0.33; ϵ-,−0.20; ζ-,−0.09; η-, −0.05; θ-, −0.03 ppm. indicate position up to 10,12-position. positions hydroxyl oxo groups, eighth carbon from end chain, are also shown by long-range effects. relative a β-diketone another oxygen-containing group can be established spectrum with little ambiguity when they separated or fewer methylene groups. For these structures NMR spectroscopy is more reliable than mass spectroscopy, which gives results difficult interpret groups close together.Components mixtures hydroxy β-diketones, grass waxes, identified proportions indicated spectra.