Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

• Nicoleta G. Hădărugă,
• Gabriela Popescu,
• Dina Gligor (Pane),
• Cristina L. Mitroi,
• Sorin M. Stanciu and
• Daniel Ioan Hădărugă

Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30

• corresponding flavanones hesperetin and naringenin and the flavonol quercetin, respectively. These compounds have a disaccharide moiety connected to the aglycones through an ether linkage with the hydroxy groups in the 7 and 3 positions (Figure 1a). On the other hand, silibinins (the main components of

Solid-state studies and antioxidant properties of the γ-cyclodextrin·fisetin inclusion compound

• Joana M. Pais,
• Maria João Barroca,
• Maria Paula M. Marques,
• Filipe A. Almeida Paz and
• Susana S. Braga

Beilstein J. Org. Chem. 2017, 13, 2138–2145, doi:10.3762/bjoc.13.212

• include their content in cocoa powder [10], grains like rice, maize and wheat [11] and bread [12]. Fisetin, a flavonol, is among the most promising compounds of this class due to its broader range of activities. Besides those previously mentioned, fisetin also contributes to cancer prevention [13], helps

Glycoscience@Synchrotron: Synchrotron radiation applied to structural glycoscience

• Serge Pérez and
• Daniele de Sanctis

Beilstein J. Org. Chem. 2017, 13, 1145–1167, doi:10.3762/bjoc.13.114

• the biosynthesis of glycosidic linkage requires the transfer of a sugar residue from a donor to an acceptor [35]. Acceptor substrates are carbohydrates, proteins, lipids, DNA, flavonol, antibiotics and steroids. In contrast, glycosyl donor substrates are mostly sugar nucleotides, such as UDP-GlcNAc

Synthesis of icariin from kaempferol through regioselective methylation and para-Claisen–Cope rearrangement

• Qinggang Mei,
• Chun Wang,
• Zhigang Zhao,
• Weicheng Yuan and
• Guolin Zhang

Beilstein J. Org. Chem. 2015, 11, 1220–1225, doi:10.3762/bjoc.11.135

• -prenylation of 3-O-methoxymethyl-4′-O-methyl-5-O-prenyl-7-O-benzylkaempferol (8) via para-Claisen–Cope rearrangement catalyzed by Eu(fod)3 in the presence of NaHCO3, and the glycosylation of icaritin (3) are the key steps. Keywords: Claisen–Cope rearrangement; flavonol; icariin; prenylation; regioselectivity

• . Unlike reported results [24][25][26], we obtained the ortho-rearranged product, which was not the 6-(1,1-dimethylallyl) product 12a, but an inseparable epimeric mixture of the dihydrofuro-flavonol 12, presumably resulted from the cyclization of the 6-(1,1-dimethylallyl) chain with the 5-hydroxy group

• ), reflux, 95%; (h) Pd/C, 1,4-cyclohexadiene, MeOH, 84%. Decomposition of 8. Claisen rearrangement of flavonol 8. Reagents and conditions: (a) 15, DMF/CHCl3, Ag2CO3, molecular sieves (4 Å, powder); (b) 16, CH2Cl2, Ag2O, molecular sieves (4 Å powder), 31% for 2 steps; (c) NH3 (g), MeOH, 94%; (d) NH3 (g

Natural phenolic metabolites with anti-angiogenic properties – a review from the chemical point of view

• Qiu Sun,
• Jörg Heilmann and
• Burkhard König

Beilstein J. Org. Chem. 2015, 11, 249–264, doi:10.3762/bjoc.11.28

• flavonoids fisetin (67) and quercetin (68) belong to the flavonol subgroup that exhibit a double bond between C-2/C-3 and a hydroxy group at C-3. Flavonols are the most abundant flavonoid subtype in plants and commonly occur as glycosides. Nevertheless, pharmacological testing was historically concentrated

• that fisetin inhibits MMPs and reduces tumor-cell invasiveness and endothelial cell tube formation. Together with kaempferol, quercetin is the most abundant aglycone in flavonol glycosides. Quercetin glycosides occur in higher concentrations in onions, red wine, and green tea and in various medicinal

• ) reaction [99]. This allows the direct synthesis of flavone-3-ols, although the yields vary depending on the substrates used. Simpson et al. [100] improved the reaction conditions of AFO in order to synthesize the flavonol rhamnocitrin by using bismuth carbonate and acetic acid. This increased the yields to

Computational evidence for intramolecular hydrogen bonding and nonbonding X···O interactions in 2'-haloflavonols

• Tânia A. O. Fonseca,
• Matheus P. Freitas,
• Rodrigo A. Cormanich,
• Teodorico C. Ramalho,
• Cláudio F. Tormena and
• Roberto Rittner

Beilstein J. Org. Chem. 2012, 8, 112–117, doi:10.3762/bjoc.8.12

• isomerization around the α [H–O–C–C(=O)] and β [C(X)–C–C–C(OH)] torsional angles (Figure 1), giving the energy minima obtained at the B3LYP/aug-cc-pVDZ level depicted in Table 1. Flavonol itself (X = H) exhibits two stable conformers, with the most stable one having the hydroxy hydrogen directed toward the

• flavonol (see Supporting Information File 1). NBO analysis at the B3LYP/aug-cc-pVDZ level gives the hyperconjugation contribution for this interaction (n(C=)O → σ*OH) as 6.9 kcal mol−1, while the QTAIM data confirms the establishment of intramolecular HB as a stable, electrostatic interaction (see below

• preferences of the flavonols under study, except for the C…H(O) interaction of flavonol B (Table 3). The boldface values in the Table 3 are the reference atoms, i.e., hydrogen atoms that have smaller q(H), E(H), M1(H) and V(H) than the reference establish a stable HB. 2'-Fluoroflavonol exhibits four stable