13C NMR spectra of a number of penta- and hexacyclic triterpenoids derived from glycyrrhetic acid
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The13C NMR spectra of 22 derivatives of 18α- and 18β-glycyrrhetic acids that have been investigated and an assignment of the signals has been made. It has been shown that a modification of the carboxy group of glycyrrhetic acid leads mainly to a change in the chemical shifts of the α-, β-, and γ-carbon atoms of ring E. The assignment of a number of signals has been confirmed by the use of the shift reagent Eu(fod)s. It has been established that the C28 and C16 signals are the most sensitive to a change in the C18 configuration in the spectra of glycyrrhetic acid derivatives.
KeywordsCarboxy Group Upfield Shift Singlet Signal Shift Reagent Boron Trifluoride Etherate
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- 1.E. Breitmaier and W. Voelter,13V NMR Spectroscopy, Verlag, Chemie, Weinheim (1974), p. 303.Google Scholar
- 4.F. W. Wehrli and T. Wirtlin, Interpretation of Carbon-13 NMR Spectroscopy, Heyden, London (1965).Google Scholar
- 5.G. Levy and G. Nelson, Carbon-13 in Nuclear Magnetic Resonance for Organic Chemists, Wiley-Interscience, New York (1972).Google Scholar
- 8.M. Mousseron-Canet and F. Crouzet, Bull. Soc. Chim. Fr.,5, No. 12, 4668 (1967).Google Scholar
- 9.G. A. Tolstikov and M. I. Goryaev, Glycyrrhetic Acid [in Russian], Alma-Ata (1966), p. 71.Google Scholar
- 10.V. M. Adanin and A. M. Khaletskii, Zh. Obshch. Khim.,37, No. 5, 1063 (1967).Google Scholar