Approaches to the synthesis of triterpenoids. VI. The synthesis of 3,3,10aβ-trimethyl-l,2,3,4,4aβ,5,8,9,10,10a-decahydrophenanthren-7(6H)-one, a potential intermediate for pentacyclic triterpene synthesis

1981 ◽  
Vol 59 (6) ◽  
pp. 1010-1017 ◽  
Author(s):  
John W. ApSimon ◽  
David Moir ◽  
Kazuyuki Yamasaki
Keyword(s):  
Nmr Spectra ◽  
Efficient Synthesis ◽  
Pentacyclic Triterpene ◽  
Naturally Occurring ◽  
Ring Junction ◽  
Triterpene Synthesis ◽  
Synthetic Intermediate ◽  
Related Compounds ◽  
C Nmr

Investigations of the CDE ring construction of naturally occurring triterpenoids are described. The efficient synthesis of 3,3,10aβ-trimethyl-1,2,3,4,4aβ,5,8,9,10,10a-decahydrophenanthren-7(6H)-one(25) has been achieved. The D/E ring junction of the molecule, as well as that of related compounds, has been established by the use of 13C nmr spectra. The synthetic intermediate 25 can be considered as a key substance for a synthetic entry to friedelin (1) in addition to β-amyrin (23).

Solution Structures of Pyrophthalones, I Structure and Conformation of 1,3-Indandionato-2(2-pyridinium)-betaïn — a 1H/13C NMR Approach

1987 ◽  
Vol 42 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Erhard T. K. Haupt ◽  
Heindirk tom Dieck ◽  
Panayot R. Bontchev
Keyword(s):  
Hydrogen Bond ◽  
Intramolecular Hydrogen Bond ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Complete Analysis ◽  
Solution Structures ◽  
The Stability ◽  
Intramolecular Hydrogen ◽  
Related Compounds ◽  
C Nmr

AbstractThe complete analysis of the 1H/13 C NMR spectra of α-Pyrophthalone and related compounds demonstrates that the earlier static planar description of the molecules is invalid for polar sol-vents, and here the stability of any intramolecular hydrogen bond is small.

Synthesis of Several Hydroxylated 23-(Benzimidazol-2-yl-, Benzoxazol-2-yl and Benzothiazol-2-yl)norcholanes and Some Related Compounds

1995 ◽  
Vol 60 (2) ◽  
pp. 257-275 ◽  
Author(s):  
Thi Thu Huong Nguyen ◽  
Jiří Urban ◽  
Eva Klinotová ◽  
Jan Sejbal ◽  
Jiří Protiva ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Succinic Anhydride ◽  
Benzimidazole Derivative ◽  
Acid Chlorides ◽  
H Nmr ◽  
Hydroxy Compounds ◽  
Related Compounds ◽  
Anti Hiv ◽  
C Nmr

The bile acids Ia - Id (lithocholic, chenodeoxycholic, deoxycholic, cholic) and their derivatives (O-acetylated acids and O-acetylated acid chlorides) reacted under various conditions with 1,2-diaminobenzene, 2-aminophenol and 2-aminothiophenol and afforded the title benzimidazoles II and VII, benzoxazoles V and benzothiazoles VI. Alkylation of the benzimidazole derivative IIa with 2-dimethylaminoethyl chloride resulted in 3α-hydroxy-23-[1-(2-dimethylaminoethyl)ben zimidazol-2-yl]- norcholane (IVa). The use of 1,2-diamino-4-methylbenzene enabled the preparation of 3α-acetoxy-23-[5(6)-methylbenzimidazol-2-y l]norcholane (VIII). Reactions of the 3α-hydroxy compounds IVa, Va and VIa with succinic anhydride resulted in the hemisuccinates IVi - VIi. The boric acid mediated condensation of O-acetyllithocholic acid (Ie) with 3,4-diaminopyridine gave compound X which was transformed to 3α-acetoxy-23-[1H-imidazo(4,5- c)pyridin-2-yl]norcholane (IX). The structure of the products was corroborated by the mass, IR, 1H NMR and 13C NMR spectra. Some of the compounds were tested for antileukemic and for the anti-HIV activity in vitro.

scholarly journals Bioactive Isocoumarins from a Terrestrial Streptomyces sp. ANK302

2011 ◽  
Vol 6 (1) ◽  
pp. 1934578X1100600 ◽  
Author(s):  
Dhafer Saber Zinad ◽  
Khaled A. Shaaban ◽  
Muna Ali Abdalla ◽  
Md. Tofazzal Islam ◽  
Anja Schüffler ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Nmr Spectra ◽  
2D Nmr ◽  
Plasmopara Viticola ◽  
Bacterial Product ◽  
Streptomyces Sp ◽  
Naturally Occurring ◽  
2D Nmr Spectra ◽  
Related Compounds ◽  
Resolution Mass

Four isocoumarins have been isolated from the terrestrial Streptomyces sp. ANK302, namely 6,8-dimethoxy-3-methylisocoumarin (1), 6,8-dihydroxy-3-methylisocoumarin (2), 6,8-dihydroxy-7-methoxy-3-methylisocoumarin (3), and 6,7,8-trimethoxy-3-methylisocoumarin (4). Compound 1 is a new naturally-occurring isocoumarin, and 2 was isolated as a new bacterial product. The structures 1-4 were deduced from high resolution mass, 1D and 2D NMR spectra and by comparison with related compounds from the literature. Compound 2 showed a strong zoosporicidal activity at a concentration of 5 μg/mL against a phytopathogenic oomycete, Plasmopara viticola, and 1 was active against Candida albicans.

Action of Grignard reagents on hexuronic esters and attempted dehydration of tertiary alcohols to give hex-5-enopyranosides

1976 ◽  
Vol 54 (11) ◽  
pp. 1708-1713 ◽  
Author(s):  
Gerald O. Aspinall ◽  
Osamu Igarashi ◽  
Thinnayam N. Krishnamurthy ◽  
Walter Mitura ◽  
Masuo Funabashi
Keyword(s):  
Nmr Spectra ◽  
Grignard Reagents ◽  
Glycosidic Linkage ◽  
Tertiary Alcohols ◽  
Hydrolysis Of ◽  
Related Compounds ◽  
Controlled Hydrolysis ◽  
C Nmr

The attempted formation of hex-5-enopyranosides from glycosiduronates by the action of Grignard reagents followed by dehydration affords hex-6-enopyranosides or 1,6-anhydrohexopyranoses as major products. 13C nmr spectra of 6,6-di-C-substituted hexose derivatives are compared with those of a number of structurally related compounds. The formation of a hex-5-enopyranoside and the selective cleavage of its glycosidic linkage is illustrated by the synthesis and controlled hydrolysis of methyl 6-O-(6-deoxy-2,3,4-tri-O-methyl-β-L-arabino-hex-5-enopyranosyl)-2,3,4-tri-O-methyl-β-D-glucopyranoside(2).

Phenol sulfate esters: ultraviolet, infrared, 1H and 13C nuclear magnetic resonance spectroscopic investigation

1978 ◽  
Vol 56 (20) ◽  
pp. 2681-2685 ◽  
Author(s):  
Mark A. Ragan
Keyword(s):  
Spectroscopic Investigation ◽  
Spectroscopic Properties ◽  
Synthetic Methods ◽  
Sulfate Ester ◽  
H Nmr ◽  
Naturally Occurring ◽  
13C Nuclear Magnetic Resonance ◽  
Supplementary Material ◽  
Related Compounds ◽  
C Nmr

Renewed interest in naturally occurring phenol sulfate ester salts has necessitated modem spectroscopic investigation of these compounds. Synthetic methods, plus spectroscopic (uv, ir, 1H nmr, 13C nmr), chromatographic, and electrophoretic properties are given for the potassium salts of phenyl sulfate (1), pyrocatechol disulfate (2), resorcinol disulfate (3), hydroquinone disulfate (4), phloroglucinol mono- (5), di- (6), and tri- (7) sulfates, and for the 2-sulfate (8) and 2,5-disulfate (9) of 1,2,3,5-tetrahydroxybenzene (10). 13C nmr chemical shift effects resulting from the replacement of phenolic —OH with —OSO3K are reported. Spectroscopic properties of the related compounds 1,2,3-tribenzyloxybenzene (11), 2,6-dibenzyloxy-1,4-benzoquinone (12), 2,6-dimethoxy-1,4-benzoquinone (13), 1,3-dibenzyloxy-2,5-dihydroxybenzene (14), and of a tentatively identified 1,3-dibenzyloxy-2,5-dihydroxybenzene monoethyl ether (15) are available as supplementary material.

Diisophorone and Related Compounds, Part 29. 3-Aminodiisophorane Derivatives

1991 ◽  
Vol 46 (4) ◽  
pp. 530-540 ◽  
Author(s):  
Frederick Kurzer ◽  
Jayantilal N. Patel
Keyword(s):  
Nmr Spectra ◽  
The Individual ◽  
Related Compounds ◽  
C Nmr

3-Aminodiisophor-2(7)-en-1-ol and homologues are obtained from the readily accessible 3-ketones by reduction of their respective ketoximes, and are characterized as suitable derivatives. The 3-(ω-phenylthioureido) compound undergoes cyclodehydration to a substituted 8,11a-methanocycloocta[d,e][3.1]benzthiazine. The structures of the individual compounds are correlated with their assigned 13C NMR spectra.

13C NMR spectra of some naturally occurring binaphthoquinones and related compounds

1986 ◽  
Vol 25 (12) ◽  
pp. 2867-2871 ◽  
Author(s):  
Akella B. Sankaram ◽  
Vaddu V. Narayana Reddy ◽  
Madugula Marthandamurthi
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
13C Nmr Spectra ◽  
Naturally Occurring ◽  
Related Compounds

13C nuclear magnetic resonance spectral and conformational analysis of naturally occurring tetrahydrofuran lignans

1979 ◽  
Vol 57 (4) ◽  
pp. 441-443 ◽  
Author(s):  
Sebastião F. Fonseca ◽  
Lauro E. S. Barata ◽  
Edmundo A. Rúveda ◽  
Paul M. Baker
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Conformational Analysis ◽  
Nmr Spectra ◽  
H Nmr ◽  
Naturally Occurring ◽  
Nmr Data ◽  
Benzylic Carbon ◽  
13C Nuclear Magnetic Resonance ◽  
C Nmr

The 13C nmr spectra of the naturally occurring stereoisomers of the tetrahydrofuran lignans were recorded and the signals assigned. Based on these assignments, on the observed sensitivity of the benzylic carbon shifts to the orientation of the aryl groups, and on the comparison with previously reported 1H nmr data, the most probable conformations for the mentioned stereoisomers are suggested.

Conformational structure of ethylene glycol dibenzoate. Vibrational and NMR spectra

1981 ◽  
Vol 46 (8) ◽  
pp. 1913-1929 ◽  
Author(s):  
Bohdan Schneider ◽  
Pavel Sedláček ◽  
Jan Štokr ◽  
Danica Doskočilová ◽  
Jan Lövy
Keyword(s):  
Ethylene Glycol ◽  
Vibrational Spectra ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Conformational Structure ◽  
Infrared And Raman Spectra ◽  
H Nmr ◽  
Liquid States ◽  
Crystalline Forms ◽  
C Nmr

It was found that three crystalline forms of ethylene glycol dibenzoate can be prepared. Infrared and Raman spectra of these three forms, as well as of the glassy and liquid states, were measured. From 3JHH coupling constants obtained by analysis of the 13C satellite band of the -CH2- group in 1H NMR spectra, and from the 3JCH coupling constants of the -CO.O.CH2- fragment obtained by analysis of the carbonyl band in 13C NMR spectra it was found that in the liquid state the -CH2-CH2- group exists predominantly in the gauche conformational structure, and the bonds C-O-C-C assume predominantly a trans orientation. The results of the analysis of NMR and vibrational spectra were used for the structural interpretation of conformationally sensitive bands in vibrational spectra of ethylene glycol dibenzoate.

13C NMR spectra of 1-aryl-ferrocenylethylenes

1986 ◽  
Vol 51 (3) ◽  
pp. 670-676 ◽  
Author(s):  
Eva Solčániová ◽  
Štefan Toma ◽  
Tibor Liptaj
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Substituent Effects ◽  
13C Nmr Spectra ◽  
Bridge Group ◽  
C Nmr ◽  
Electron Effects

13C NMR spectra of 18 ferrocene analogues of trans stilbenes (1-aryl-2-ferrocenylethylenes) were measured. It was found that bridge group weakens the transfer of the substituent electron effects into ferrocene nucleus, especially distinctly into 3',4'positions of cyclopentadienyl ring. The transfer of substituent effects into β-position of the bridge -CH=CH- is greater in derivatives studied by us than in stilbenes. Synthesis of 1-(4-dimethylaminophenyl)-2-ferrocenylethylene is described.

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