Die Konstitution des Visnagins (aus Ammi visnaga). (II. Mitteil. über natürliche Chromone.)

Späth, Ernst; Gruber, Werner

doi:10.1002/cber.19410740820

Cited by 47 publications

(14 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…19,20 In the present work, both visnaginone 1a and khellinone 1b were treated with ethyl bromoacetate in the presence of potassium carbonate to give (4-methoxy-(2a) and 4,7-dimethoxy-5-acetylbenzofuran-6-yloxy)acetic acid ethyl ester (2b). 21 The 1 H NMR spectrum of compound 2a showed ethyl signals at δ = 1.28 (CH 3 ), 4.20 (CH 2 ), and a singlet at δ = 4.65, characteristic for (OCH 2 ).…”

Section: Resultsmentioning

confidence: 99%

SYNTHESIS OF BENZO[1,2-b: 5,4-b′]- DIFURANYL-TRIAZOLES, -OXADIAZOLES, -THIAZOLIDINONES, -THIADIAZOLES, AND THE USE OF DNA IN EVALUATION OF THEIR BIOLOGICAL ACTIVITY

Keshk

Abu‐Hashem

Girges

et al. 2004

Phosphorus, Sulfur, and Silicon and the Related Elements

View full text Add to dashboard Cite

Section: Resultsmentioning

confidence: 99%

SYNTHESIS OF BENZO[1,2-b: 5,4-b′]- DIFURANYL-TRIAZOLES, -OXADIAZOLES, -THIAZOLIDINONES, -THIADIAZOLES, AND THE USE OF DNA IN EVALUATION OF THEIR BIOLOGICAL ACTIVITY

Keshk

Abu‐Hashem

Girges

et al. 2004

Phosphorus, Sulfur, and Silicon and the Related Elements

View full text Add to dashboard Cite

“…We present here the synthesis of new allylfurochromone-3-carboxaldehyde as starting material in the synthesis of condensed or isolated heterocyclic furobenzopyranones derivatives. O-allylation of 5acetyl-6-hydroxy-4-methoxy-benzofuran "visnaginone" [32] which was previously prepared from hydrolysis of the naturally occurring compound "visnagin" gave the corresponding O-allyl visnaginone (1). Compound 1 was refluxed in N,N-diethylaniline and underwent Claisen rearrangement to provide 5-acetyl-7-allyl-6hydroxy-4-methoxybenzofuran (2) in quantitative yield [24] (Scheme 1).…”

Section: Resultsmentioning

confidence: 99%

Synthesis and reactions of some new benzopyranone derivatives with potential biological activities

El‐Desoky

Al‐Shihry

2008

Journal of Heterocyclic Chem

View full text Add to dashboard Cite

O O OCH 3 O CH=X X=O, NH, CN, cyclohex., Indandione O OH OCH 3 O N CN NH 2 10a O O OCH 3 O X N 16a-e R O O OCH 3 CH 3 O X Ar 18 -21 3 -9 X= O, SReaction of visnaginone which derived from the naturally occurring compound "visnagine", with allyl bromide gave O-allyl visnaginone 1, which underwent Claisen rearrangement to yield 7-allylbenzofuran 2 derivative. Vilsmeier Haack formylation of 2 afforded our versatile starting compound furochromene-6carboxaldehyde (3) which was condensed with cyclohexane-1,3-dione, indandione, malononitrile or ethyl cyanoacetate to yield the ylidene nicotinonitrile and pyridone derivatives 4,7,10a-b. Reaction of 3 with aniline or aniline acting on multiple function X-H (X = NH, O, S) at its ortho position afforded the corresponding anils, imidazolylfurochromene and azepines compounds 11-17. On the other hand, oxidation of visnagin afforded chromene-6-carboxaldehyde derivative 18 which was condensed with different aryl or (heteroaryl) acetonitrile followed by hydrolysis to give pyrano[3,2-g]chromen-4,8-dione derivatives 20a-d and 22.

show abstract

“…Khellinone 1 and visnaginone 2 were obtained by the method of Spaeth and Gruber [30,31], i.e., by the ring-opening reactions of khellin and visnagin in the alkaline solution. Single crystals of 1 and 2 suitable for an X-ray diffraction were prepared by a slow evaporation of the solvent from an ethanolic solution at room temperature.…”

Section: Synthesis Of Visnaginone and Khellinonementioning

confidence: 99%

Derivatives of benzo[b]furan. Part I. Conformational studies of khellinone and visnaginone

et al. 2012

View full text Add to dashboard Cite

The structural analysis of khellinone and visnaginone indicated the planarity of the benzo [b]furan ring system. The oxygen or carbon atoms of the substituents, -OH, -OCH 3 , and -C(=O)CH 3 , are nearly coplanar with the aromatic ring. The molecular conformation is stabilized by the intramolecular O-HÁÁÁO hydrogen bond formed between the ortho-substituted hydroxyl and acetyl groups. The intermolecular contacts present in the crystal structure are the C-HÁÁÁO and C-HÁÁÁp interactions and the pÁÁÁ p stacking. The energy surface for the internal rotation about the C sp2 -O/C bonds in the khellinone and visnaginone molecules has been explored by quantum-chemical calculations. The density functional theory (DFT) methods yielded three stable conformers of khellinone and two of visnaginone obtained by a rotation of the methoxy group about the C4 sp2 -OCH 3 bond. The most stable conformation in the gas phase is consistent with the stereochemistry of the molecules adopted in the solid. The secondary minima conformers have energies higher by 0.3-1.8 kcal/mol. The energy of the intramolecular O-HÁÁÁO interactions, present in the molecular structure of all stable conformers, is around 18 kcal/mol at the DFT level. A complete and reliable assignment of the bands in the IR and Raman spectra of both compounds has been performed.

show abstract

Die Konstitution des Visnagins (aus Ammi visnaga). (II. Mitteil. über natürliche Chromone.)

Cited by 47 publications

References 3 publications

SYNTHESIS OF BENZO[1,2-b: 5,4-b′]- DIFURANYL-TRIAZOLES, -OXADIAZOLES, -THIAZOLIDINONES, -THIADIAZOLES, AND THE USE OF DNA IN EVALUATION OF THEIR BIOLOGICAL ACTIVITY

SYNTHESIS OF BENZO[1,2-b: 5,4-b′]- DIFURANYL-TRIAZOLES, -OXADIAZOLES, -THIAZOLIDINONES, -THIADIAZOLES, AND THE USE OF DNA IN EVALUATION OF THEIR BIOLOGICAL ACTIVITY

Synthesis and reactions of some new benzopyranone derivatives with potential biological activities

Derivatives of benzo[b]furan. Part I. Conformational studies of khellinone and visnaginone

Contact Info

Product

Resources

About