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.

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 spectra of some C19-diterpenoid alkaloids and their derivatives

1979 ◽  
Vol 57 (13) ◽  
pp. 1652-1655 ◽  
Author(s):  
S. William Pelletier ◽  
Naresh V. Mody ◽  
Rajinder S. Sawhney
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Conformational Changes ◽  
Nmr Spectra ◽  
Diterpenoid Alkaloids ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
C Nmr ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The natural abundance carbon-13 nuclear magnetic resonance spectra of some C19-diterpenoid alkaloids and their alkamines (lappaconitine, lappaconine, lapaconidine, ranaconine, 14-dehydrobrowniine, aconine, pseudoaconine, deoxyaconine, and hypaconine) have been determined at 15.03 MHz. With the aid of proton decoupling techniques, additivity relationships, and comparison with spectra of related alkaloids, self-consistent and unambiguous assignments of nearly all carbon resonances for these alkaloids have been made. Some important chemical shift trends have been observed, which are useful for identifying the basic C19-diterpenoid alkaloid skeleton and the hydroxy and methoxy group substitution patterns in these alkaloids. On the basis of 13C nmr spectra of lappaconitine and lappaconine, the anthranoyl ester moiety is assigned to the C-4 position in lappaconitine. The 13C nmr spectra of lapaconidine, aconine, and pseudoaconine taken in pyridine and chloroform have been compared to determine the conformational changes of the ring A hydroxy groups in these alkaloids.

13C Nuclear magnetic resonance spectroscopy in the elucidation of structures of diterpenoid alkaloids

1987 ◽  
Vol 65 (1) ◽  
pp. 99-103 ◽  
Author(s):  
Balawant S. Joshi ◽  
John K. Wunderlich ◽  
S. William Pelletier
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Diterpenoid Alkaloids ◽  
Chemical Examination ◽  
13C Nuclear Magnetic Resonance ◽  
C Nmr ◽  
Nuclear Magnetic

13C Nuclear magnetic resonance spectroscopy is an exceptionally useful tool for the structure determination of diterpenoid alkaloids. A detailed study of the 1H and 13C nmr spectra of aconitine and 3-deoxyaconitine has permitted definite assignments to all the carbon atoms of the molecule. Chemical shift revisions have been suggested for certain carbon atoms of the C19-diterpenoid alkaloids. Chemical examination of Aconitumcolumbianum Nutt. ssp. columbianum, A. forrestii Stapf, Delphiniumtatsienense Franch., and D. vestitum Wall, resulted in the isolation of several new C19-diterpenoid alkaloids. The structure derivation of those alkaloids was based mainly on 13C nmr spectroscopic evidence.

Identification of C-24 alkyl epimers of marine sterols by 13C nuclear magnetic resonance spectroscopy

1978 ◽  
Vol 56 (14) ◽  
pp. 1898-1903 ◽  
Author(s):  
J. L. C. Sright ◽  
A. G. McInnes ◽  
S. Shimizu ◽  
D. G. Smith ◽  
J. A. Walter ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Structural Changes ◽  
Chemical Shifts ◽  
Resonance Spectroscopy ◽  
H Nmr ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
Nuclear Magnetic

13C nuclear magnetic resonance spectra of diastereomeric C-24 alkyl sterols have been assigned. Differences in the chemical shifts of side-chain carbons permitted the determination of the absolute configuration at C-24 in several sterols since these chemical shifts are insensitive to structural changes remote from the asymmetric centre. An unknown sterol from Tetraselmissuecica has been identified as (24R)-24-methylcholest-5-en-3β-ol and the configuration assigned from 1H nmr data to the sterol from Phaeodoctylumtricornutum has been confirmed. The utility and potential of this method in characterising new sterols and their biological precursors is discussed.

13C Nuclear Magnetic Resonance Spectroscopy of Polydienes, Micro Structure of Poly(Butadiene)

1974 ◽  
Vol 47 (5) ◽  
pp. 1136-1150
Author(s):  
A. D. H. Clague ◽  
J. A. M. van Broekhoven ◽  
L. P. Blaauw
Keyword(s):  
Nmr Spectra ◽  
Resonance Spectroscopy ◽  
13C Nmr Spectra ◽  
Constant Ratio ◽  
Micro Structure ◽  
Sequence Distribution ◽  
13C Nuclear Magnetic Resonance ◽  
Random Manner ◽  
Cis And Trans ◽  
Detailed Picture

Abstract 13C nmr spectra have been recorded of several poly(butadiene)s and their hydrogenated analogs, with various amounts of 1,2 structure, but with a roughly constant ratio of cis-1,4 to trans-1,4 structures. From an assignment of these spectra a detailed picture has emerged of the sequence distribution of the cis- and trans-1,4 and the 1,2 units in the poly (butadiene) chain. It is shown that these units are distributed in an essentially random manner and that 1,2 units are head to tail incorporated.

Sign in / Sign up

Export Citation Format

Share Document