C-13NMR化学シフトの図表化芳香族,複素芳香族化合物のサブチャート

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The authors had been reporting the tables and figures for the elucidation of C-13 nuclear magnetic resonance spectra, and the sub-charts were presented here, as a link of the series, for aromatic and heterocyclic carbons of mono and polynuclear molecules, with restrictions that the substitution of benzene was limited up to two, and in the case of complicated skeleton structure only the chemical shifts of basic molecule were listed. The figure was produced in case of monosubstituted benzene so as to cover the chemical shifts of all aromatic constituent carbons, and about disubstitution system, the chemical shifts of ring carbons (s-carbon) hydrogen of which was replaced by a substituent were arranged in conjunction with the other substituent. Fig. 1 was the sub-chart for monosubstituted ben zenes. It was observed that the chemical shifts of s-carbons were lowered in comparison with the unsubstituted except iodine compounds, and it caused higher shifts of adjacent ortho carbons. The degree of shifts of meta and para carbons were found less, and especially in the former case it had nearly the same transition level regardless of the species of the substituents. Fig.2 was for disubstituted benzenes. There was a common feature between mono and disubstituted benzene derivatives that the chemical shifts of s-carbons were lowered according to the orders of -CO, -CH3, -N and -O. The ranges of chemical shifts in the former case were 5563; 4356; 3854; 3443ppm respectively, and in the latter series the chemical shifts were distributed rather widely presumably influenced by the other substituents. Although it was found very difficult to assign exactly all the lines of aromatic carbons from the figure directly, Savitsky's "Additivity relations" was useful for the assignment of spectra of disubstituted benzene derivatives and it was found that it might be applied to tri and polysubstituted systems if more deviations were allowed. Chemical shifts of 33 kinds of monosubstituted benzenes were listed in Table I for the aid of characterization of polysubstituted benzene derivatives, and an example of its application was also given. Fig. 3 was for unsubstituted heterocyclic and polynuclear aromatic molecules. Every skeleton structure was found its own characteristic spectra pattern, and the assignment of the derivatives might be accomplished with the use of this figure and the information about the lines of substituent carbons and their effects on chemical shifts of the skeleton carbons.
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C-13NMR化学シフトの図表化芳香族,複素芳香族化合物のサブチャート

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C-13NMR化学シフトの図表化 芳香族,複素芳香族化合物のサブチャート

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C-13NMR化学シフトの図表化芳香族,複素芳香族化合物のサブチャート