^<13>C Nuclear Magnetic Resonance Studies on Phenols : Effects of a Lanthanide Shift Reagent and Triethylamine

抄録

^<13>C Nuclear magnetic resonance (¹³C-NMR) spectra of 16 phenolic compounds were recorded and the Eu (fod)₃ and triethylamine induced shifts of their carbon resonances were measured. Generally, these shift reagents are useful for analyzing ¹³C-NMR spectra of phenols. By means of Eu (fod)₃, aromatic carbons of phenols were shifted in the order ; ortho, meta and para carbons to a phenolic group. Some anomalous shifts were observed on using Eu (fod)₃, the upfield shift for the C-6 nucleus in 2-methoxyphenol and the relatively large downfield shifts for the C-6 nuclei in ortho-alkylphenols. Triethylamine induced a downfield shift for the C-1, C-2 and C-6 nuclei, and an upfield shift for the C-3, C-4 and C-5 nuclei of phenols with exception of 2-methoxyphenol.