Genicunolide A, B and C: three new triterpenoids from Euphorbia geniculata

• Alia Farozi,
• Javid A. Banday and
• Shakeel A. Shah

Beilstein J. Org. Chem. 2015, 11, 2707–2712, doi:10.3762/bjoc.11.291

• inflammations. Previous phytochemical investigations have demonstrated that this plant contains flavonoids: kaempferol, quercetin and 3-rhamnosyl quercetin [28] and triterpenes β-amyrin acetate [29] and geniculatin [30]. Reinvestigation of chemistry of the plant led to isolation of three new triterpenoids

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

• alternative access to icariin (1) and related compounds is demanded for large-scale production and practical application. Our interest in flavonoids with activities such as estrogen biosynthesis regulation and PDE inhibition, prompted us to seek for a practically synthetic approach to icariin. Previously our

• efficient method for the preparation of C-isopentenyl. In the case of flavonoids, control of the regioselectivity of ortho (C6)/para (C8)-rearranged products is still remained a challenging issue [20]. Once the prenyl ether 8 was obtained, attention was fastened on the para-Claisen–Cope rearrangement to

Selective methylation of kaempferol via benzylation and deacetylation of kaempferol acetates

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

Beilstein J. Org. Chem. 2015, 11, 288–293, doi:10.3762/bjoc.11.33

• . On the other hand, O-methylation is an effective approach to protect the reactive hydroxy groups of flavonoids and a strategy to improve the physicochemical properties such as solubility and intracellular compartmentation [18]. Some of the O-alkylated flavonoids possess biological activities, and

• biological activity evaluation of flavonoids [21][22], we report here a convenient and efficient method for mono-, di- and tri-O-methylation of kaempferol, by taking the advantage of the different reactive potential (hydrolysis, benzylation and methylation) of O-acetoxy groups in multi-acetylated kaempferol

Synthesis of the furo[2,3-b]chromene ring system of hyperaspindols A and B

• Danielle L. Paterson and
• David Barker

Beilstein J. Org. Chem. 2015, 11, 265–270, doi:10.3762/bjoc.11.29

• been isolated from H. chinense including prenylated acylphloroglucinols such as chinesins I (3) and II (4), xanthones, flavonoids, terpenoids, naphthodianthrones, and norlignans, such as hyperione A (5) and B (6) [1][6][7][8]. Chinesins I (3) and II (4) are acylphloroglucinol derivatives which possess

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

• such as flavonoids, caffeic acid derivatives and diarylheptanoids were found to have a pleiotropic influence on cellular signaling (e.g., by the inhibition of transcription factors such as NF-κB or Nrf2 [9][10], or antioxidative effects [10][11]). Furthermore, polyphenols are found in high

• cells (HMEC-1) have been given special attention. In contrast, compounds showing in vitro anti-angiogenic activity but also signs of strong unspecific cytotoxic effects in vitro have been excluded. The secondary metabolites discussed include six flavonoids from different subclasses: quercetin, fisetin

• 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

Trogopterins A–C: Three new neolignans from feces of Trogopterus xanthipes

• Soyoon Baek,
• Xuikui Xia,
• Byung Sun Min,
• Chanil Park and
• Sang Hee Shim

Beilstein J. Org. Chem. 2014, 10, 2955–2962, doi:10.3762/bjoc.10.313

• pain, and retained lochia due to stasis [4]. Recent studies have indicated that Trogopterus feces mainly consist of terpenoids [5][6][7][8][9], phenolic acids, sterols, aliphatics, fatty acids, and flavonoids [10][11]. They have been reported to possess various pharmacological properties such as

Thermal and oxidative stability of the Ocimum basilicum L. essential oil/β-cyclodextrin supramolecular system

• Daniel I. Hădărugă,
• Nicoleta G. Hădărugă,
• Corina I. Costescu,
• Ioan David and
• Alexandra T. Gruia

Beilstein J. Org. Chem. 2014, 10, 2809–2820, doi:10.3762/bjoc.10.298

• concentrations of volatile compounds (essential oils or volatile oils), among other compounds (e.g., flavonoids) [10], which furnish different flavoring and medicinal properties, such as antimicrobial, anti-inflammatory, analgesic, or antiseptic properties [11][12][13][14], in addition to antifungal and insect

Binding mode and free energy prediction of fisetin/β-cyclodextrin inclusion complexes

• Bodee Nutho,
• Wasinee Khuntawee,
• Chompoonut Rungnim,
• Piamsook Pongsawasdi,
• Peter Wolschann,
• Alfred Karpfen,
• Nawee Kungwan and
• Thanyada Rungrotmongkol

Beilstein J. Org. Chem. 2014, 10, 2789–2799, doi:10.3762/bjoc.10.296

• ; Introduction Flavonoids are polyphenolic compounds which are found in many plants as well as in several microorganisms [1][2]. They are herbal secondary metabolites with a wide range of biological and pharmacological activities and are used as therapeutic drugs having many benefits for protection and medical

• were used to describe the molecular mechanisms of inclusion complexation between the flavonoids quercetin/myricetin and cyclodextrin in comparison with the experimental results from 1H NMR spectroscopy [30]. Choi and coworkers [31] also reported a theoretical study based on MD simulations in order to

• understand the two flavonoids/β-CD complexes, hesperetin and naringenin complexes, in aqueous solution. The PM3 method was applied to calculate the energy regarding the antioxidant property of the flavonoid chysin in the complex with β-CD [32]. Interestingly, the molecular docking study on the fisetin/β-CD

Effect of cyclodextrin complexation on phenylpropanoids’ solubility and antioxidant activity

• Miriana Kfoury,
• David Landy,
• Lizette Auezova,
• Hélène Greige-Gerges and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2014, 10, 2322–2331, doi:10.3762/bjoc.10.241

• , cinnamon, etc). PPs play a vital role in plants integrity and defense against biotic or abiotic stresses and are considered as “secondary metabolites” [1]. They are divided in several major classes such as coumarins, flavonoids, phenylpropenes and hydroxycinnamic acids [2]. PPs have an important

Lanostane- and cycloartane-type triterpenoids from Abies balsamea oleoresin

• Serge Lavoie,
• Charles Gauthier,
• Jean Legault,
• Sylvain Mercier,
• Vakhtang Mshvildadze and
• André Pichette

Beilstein J. Org. Chem. 2013, 9, 1333–1339, doi:10.3762/bjoc.9.150

• ]. Since then, more than 277 secondary metabolites have been isolated, and mainly identified as terpenoids, flavonoids and lignans [3]. Balsam fir Abies balsamea (L.) Mill., a popular Christmas tree in Canada, has been used traditionally by North American aboriginal people as an antiseptic, tuberculosis

Amyloid-β probes: Review of structure–activity and brain-kinetics relationships

• Todd J. Eckroat,
• Abdelrahman S. Mayhoub and
• Sylvie Garneau-Tsodikova

Beilstein J. Org. Chem. 2013, 9, 1012–1044, doi:10.3762/bjoc.9.116

• conformationally restricted chalcone derivatives as their basic structures result from insertion of an oxygen atom between the double bond and the phenyl ring attached to the carbonyl group of the chalcone scaffold (Figure 1B, with oxygen atoms depicted in red). The affinity of flavonoids towards Aβ aggregates was

• first established by using fluorescence staining in brain sections of Tg2576 transgenic mice [10]. The absence of spots in wild-type mouse brain sections indicated the specificity of flavonoids towards Aβ aggregates in AD mouse models. The [18F]-labeled pegylated flavones 29a–c showed high affinity

Tricyclic flavonoids with 1,3-dithiolium substructure

• Lucian G. Bahrin,
• Peter G. Jones and
• Henning Hopf

Beilstein J. Org. Chem. 2012, 8, 1999–2003, doi:10.3762/bjoc.8.226

• Chemistry, Technical University of Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany 10.3762/bjoc.8.226 Abstract The synthesis of new 3-dithiocarbamic flavonoids has been accomplished by the reaction of the corresponding 2-hydroxyaryl dithiocarbamates with aminals. These flavonoids were obtained as

• a mixture of diastereoisomers, the anti isomer being the major one. The heterocyclization of these compounds provided novel tricyclic flavonoids bearing a 1,3-dithiolium-2-yl ring fused at the 3,4-carbon positions of the benzopyran moiety. Keywords: aminals; benzopyrans; dithiocarbamates

• ; dithiolium salts; flavonoids; Introduction The great diversity in physical, chemical and biochemical properties of flavonoids gives them the ability to influence the biological activity of plants, microbes and animals [1][2][3]. Flavonoids are known to be good antioxidants and this is believed to be the

Bioactive selaginellins from Selaginella tamariscina (Beauv.) Spring

• Chao Yang,
• Yutian Shao,
• Kang Li and
• Wujiong Xia

Beilstein J. Org. Chem. 2012, 8, 1884–1889, doi:10.3762/bjoc.8.217

• diseases. The role of free radicals in ageing, in cancer, and in cardiovascular, neurodegenerative and other diseases is more and more widely accepted [21][22]. Antioxidants are attracting increasing scientific and clinical attention. Natural phenolic compounds (flavonoids, lignans, phenolic acids

Continuous-flow hydration–condensation reaction: Synthesis of α,β-unsaturated ketones from alkynes and aldehydes by using a heterogeneous solid acid catalyst

• Magnus Rueping,
• Teerawut Bootwicha,
• Hannah Baars and
• Erli Sugiono

Beilstein J. Org. Chem. 2011, 7, 1680–1687, doi:10.3762/bjoc.7.198

• large number of important biologically active compounds. They show pharmacological properties such as antimalarial, antitumor, antiviral, and anti-inflammatory activities [55][56][57][58][59][60]. They are also well known to be key intermediates in the synthesis of flavones, flavonoids, isoflavonoids

An efficient partial synthesis of 4′-O-methylquercetin via regioselective protection and alkylation of quercetin

• Nian-Guang Li,
• Zhi-Hao Shi,
• Yu-Ping Tang,
• Jian-Ping Yang and
• Jin-Ao Duan

Beilstein J. Org. Chem. 2009, 5, No. 60, doi:10.3762/bjoc.5.60

• ; Introduction Flavonoids, such as flavones and flavonols, are secondary plant metabolites found in many foods, especially in fruits and vegetables [1][2]. Quercetin (1) (Figure 1), the major individual non-polymeric molecule among the polyphenols represents 60–75% of the flavonoid intake [3]. Quercetin is a

• functions such as sulfate or glucuronide groups. These compounds will allow structure–activity relationship studies of flavonoids to be carried out. Their easily obtained labeled forms will give access to isotopic dilution dosage by LC-MS or LC-MS/MS and will help in the identification of unknown flavonoid