Showing papers on "Flavanone published in 1972"
TL;DR: The mass spectra of isomeric 2′-hydroxy-chalcones and flavanones (i.e. 2-phenyl-chroman-4-ones) are essentially identical as discussed by the authors.
Abstract: The mass spectra of isomeric 2′-hydroxy-chalcones and flavanones (i.e. 2-phenyl-chroman-4-ones) are essentially identical. Thermal isomerisation prior to ionisation was ruled out. A study of metastable transitions (first and second field free region of a double focusing instrument), as well as low energy spectra of both isomers, pointed towards completely identical fragmentation pathways for the two compounds. Five deuterated compounds were then investigated. The heats of formation of the most important ions were determined. It was concluded that an intramolecular equilibrium exists between a chalcone type and a flavanone type molecular ion.
41 citations
TL;DR: In this paper, a third chalcone, derricidin, has been found and its structure determined, and the almost, but not completely, identical fragmentation of such chalecone-flavanone pairs in the mass spectrometer is discussed and interpreted.
37 citations
TL;DR: Nigrescin, the first optically active 2-hydroxy-2-benzylcoumaranone, and a (+)-2,3- trans -flavan-3,4- cis -diol, represent new members of the natural 3′,4′,7,8-tetrahydroxyflavonoid group as mentioned in this paper.
33 citations
TL;DR: In this article, it was shown that dihydroflavonols containing orthodihydroxyl groups in the A-ring and 5-deoxy dihydronols (through the 3-hydroxy-4-oxo-system) can form acid-labile complexes with AlCl3 in MeOH.
17 citations
TL;DR: On u.v. irradiation, flavanone rearranges to 4-phenyldihydrocoumarin and 2′-hydroxychalcone, and undergoes fragmentation to yield a highly reactive keto-keten as discussed by the authors.
Abstract: On u.v. irradiation, flavanone rearranges to 4-phenyldihydrocoumarin and 2′-hydroxychalcone, and undergoes fragmentation to yield a highly reactive keto-keten.
8 citations
Journal Article•
4 citations
TL;DR: In this paper, the optically active 5.7.4′-trihydroxy-flavanone (Selinone) was confirmed by partial synthesis of the corresponding racemic compounds.
Abstract: Die optisch aktiven 5.7.4′-Trihydroxy-flavanon-4′-[γ.γ-dimethyl-allylather] (5) (Selinon) aus Selinum vaginatum Clarke und 5.4′-Dihydroxy-7.3′-dimethoxy-flavanon-4′[γ.γ-dimethylallyl-ather] (8) aus Melicope sarcococca Laut. wurden durch partielle Synthese der racemischen Verbindungen in ihrer Struktur bestatigt. Phloracetophenon-4-0-β-neohesperidosid wurde mit 4-[γ.γ-Dimethyl-allyloxy]-benzaldehyd (2) bzw. 3-Methoxy-4[γ.γ-dimethyl-allyloxy]-benzaldehyd (3) zum Chalkonglykosid kondensiert, zum Flavanonglykosid (4 bzw. 6) isomerisiert und enzymatisch zum Aglykon (±)-Selinon (5) bzw. (±)-5.7-Dihydroxy-3′-methoxy-4′-[γ.γ-dimethyl-allyloxy]-flavanon (7) hydrolysiert. 7 wurde mit Diazomethan zu (±)-5-Hydroxy-7.3′-dimethoxy-4′-[γ.γ-dimethyl-allyoxy]-flavanon (8) methyliert.
Synthesis of the Naturally Occurring 4′-(γ.γ-Dimethylallyl) Ethers of 5.7.4′-Trihydroxyflavanone (Selinone) and 5.4′-Dihydroxy-7.3′-dimethoxyflavanone
The structures of the optically active 5.7.4′-trihydroxyflavanone 4′-(γ.γ-dimethylallyl) ether (5) (Selinone) from Selinum vaginatum Clarke and 5.4′-dihydroxy-7.3′-dimethoxyflavanone 4′-(γ.γ-dimethylallyl) ether (8) from Melicope sarcococca Laut. were confirmed by partial synthesis of the corresponding racemic compounds. Phloracetophenone 4-0-β-neohesperidoside was condensed with 4-(γ.γ-dimethylallyloxy) benzaldehyde (2) and 3-methoxy-4-(γ.γ-dimethyl-allyloxy) benzaldehyde (3) to form the chalcone glycosides which were isomerised to the flavanone glycosides 4 and 6, respectively. Subsequent enzymic hydrolysis of the two compounds gave (±)-selinone (5) and (±)-5.7-dihydroxy-3′-methoxy-4′-(γ.γ-dimethylallyloxy)-flavanone (7). The latter on methylation with diazomethane yielded (±)-5-hydroxy-7.3′-dimethoxy-4′-(γ.γ-dimethylallyloxy)flavanone (8).
3 citations
TL;DR: In this paper, the ionization constants of the hydroxy groups in 5-hydroxy, 3,5 and 4′,5-dihydroxy- and 3-hydrox-5-methoxyflavones and in 5hydroxy-7-mETHoxyflavanone have been determined.
Abstract: The ionization constants of the hydroxy groups in 5-hydroxy-, 3,5- and 4′,5-dihydroxy- and 3-hydroxy-5-methoxyflavones and in 5-hydroxy-7-methoxyflavanone have been determined. It has been shown that because of intramolecular hydrogen bonding the 5-hydroxy group has a reduced acidity. However, the capacity for ionization of the 5-hydroxy group changes under the influence of hydroxy groups introduced into the 3, 4′, or 7 positions, and also on passing to the flavanone series.
1 citations