Carbon-13 Magnetic Resonance: Diterpenoid Alkaloids From the Delphinium Species

1973 ◽  
Vol 51 (4) ◽  
pp. 486-499 ◽  
Author(s):  
Alan J. Jones ◽  
M. H. Benn
Keyword(s):  
Magnetic Resonance ◽  
Structural Changes ◽  
Substituent Effects ◽  
Structural Elucidation ◽  
Fourier Mode ◽  
Diterpenoid Alkaloids ◽  
Self Consistent ◽  
Proton Decoupling ◽  
Magnetic Resonance Spectra

The carbon-13 magnetic resonance spectra of the diterpenoid alkaloids lycoctonine (1), deoxylycoctonine (2), deoxymethylenelycoctonine (3), browniine (4), isolatizidine (5), delphonine (6), lycoctonal (7),and their corresponding hydrochloride or perchlorate salts have been determined at 22.63 MHz in the Fourier mode. With the aid of proton decoupling techniques, additivity relationships and the effects induced by specific structural changes, self-consistent assignments of nearly all the resonances have been made. Substituent effects are often of the same order but differ in magnitude from those for simpler systems reported in the literature. The effects of protonation do not unambiguously follow the additive trends indicated in simpler systems but do exhibit a reasonably constant pattern. The data have been applied in the structural elucidation of two previously unknown bases isolated from Delphinium bicolor Nutt.

13C nuclear magnetic resonance spectroscopy of methylenedioxy group-containing C19-diterpenoid alkaloids and their derivatives

1980 ◽  
Vol 58 (17) ◽  
pp. 1875-1879 ◽  
Author(s):  
S. William Pelletier ◽  
Naresh V. Mody ◽  
Oliver D. Dailey Jr.
Keyword(s):  
Structure Elucidation ◽  
Nmr Spectra ◽  
Structural Changes ◽  
Single Frequency ◽  
Resonance Spectroscopy ◽  
Diterpenoid Alkaloids ◽  
Methylenedioxy Group ◽  
13C Nuclear Magnetic Resonance ◽  
Self Consistent ◽  
Proton Decoupling

The natural abundance carbon-13 nmr spectra of some methylenedioxy group-containing C19-diterpenoid alkaloids and their derivatives (dictyocarpine, 14-acetyldictyocarpine, dictyocarpinine, 14-dehydrodictyocarpine, 14-dehydrodictyocarpinine, 6-dehydrodictyocarpinine, 6,14-didehydrodictyocarpinine, deltaline (eldeline), deltamine (eldelidine), 6-dehydrodeltamine, delcorine, 6-acetyldelcorine, and 6-dehydrodelcorine) have been determined. Self-consistent assignments of nearly all the resonances in these compounds have been made with the aid of single-frequency off-resonance proton decoupling techniques, additivity relationships, and the effects induced by certain structural changes. Particular attention is directed towards features of the spectra which are most useful for structure elucidation and identification of the C19-diterpenoid alkaloids.

Proton magnetic resonance spectra of some benzo[b]thiophens. An investigation of substituent effects in a heteroaromatic system

1968 ◽  
Vol 21 (7) ◽  
pp. 1853 ◽  
Author(s):  
B Caddy ◽  
M Martin-Smith ◽  
RK Norris ◽  
ST Reid ◽  
S Sternhell
Keyword(s):  
Magnetic Resonance ◽  
Long Range ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Spin Coupling ◽  
Heteroaromatic System ◽  
Spin Spin Coupling ◽  
Magnetic Resonance Spectra

N.m.r. data for 19 5-substituted and 13 polysubstituted benzo[b]thiophens are tabulated. The influence of the substituents at C5 on the chemical shifts of H4 and H6 is discussed. Long-range interproton spin-spin coupling between H3 and H7, and between H2 and H6, is general in benzo[b]thiophens. The vicinal coupling J6,7 in 5-substituted benzo[b]thiophens varies directly and linearly with the electronegativity of the substituents at C5.

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