Identification of the p-coumaric acid biosynthetic gene cluster in Kutzneria albida: insights into the diazotization-dependent deamination pathway

• Seiji Kawai,
• Akito Yamada,
• Yohei Katsuyama and
• Yasuo Ohnishi

Beilstein J. Org. Chem. 2024, 20, 1–11, doi:10.3762/bjoc.20.1

• intermediate in flavonoid biosynthesis and is much more ubiquitous than avenalumic acid. In general, p-coumaric acid is synthesized by phenylalanine ammonia-lyase and cinnamate 4-hydroxylase from phenylalanine or by a tyrosine ammonia-lyase from tyrosine [26]. However, the Cma system synthesizes p-coumaric

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• catalyst. The authors demonstrated that the introduction of the two indoles occurs in two distinct steps, a radical process and a Friedel–Crafts alkylation reaction. Coumarin and flavonoid derivatives are very valuable precursors in drug synthesis. In 2015, Ge et al. developed the regioselective and atom

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

• complexes was kneading the components at various molar ratios (1:1:1 and 3:1:1 for β-CD hydrate:hazelnut oil (average molar mass of 900 g/mol):flavonoid). The recovering yields of the ternary complexes were in the range of 51.5–85.3% and were generally higher for the 3:1:1 samples. The thermal stability was

• cheap method for the evaluation of quality and similarity/characteristics of these new types of cyclodextrin-based ternary complexes having enhanced properties and stability. Keywords: antioxidant; cyclodextrin; flavonoid; hazelnut vegetable oil; ternary supramolecular inclusion complex; Introduction

• of oils and fats is the addition of antioxidants. Among food grade antioxidants, natural polyphenols such as flavonoids and flavonoid-based extracts are widely used [35][36][37][38][39][40][41]. Generally, flavonoids have a high number of phenolic hydroxy groups that provide the antioxidant activity

Cytochrome P450 monooxygenase-mediated tailoring of triterpenoids and steroids in plants

• Karan Malhotra and
• Jakob Franke

Beilstein J. Org. Chem. 2022, 18, 1289–1310, doi:10.3762/bjoc.18.135

• . CYP93E1 also catalyses the conversion of sophoradiol to soyasapogenol B [37][40][46]. Members of other CYP93 subfamilies (CYP93A, B, C and G) are ubiquitous in flowering plants and are mostly involved in flavonoid biosynthesis [25][26]. Lastly, CYPs acting on either pentacyclic 6-6-6-6-5 scaffolds, such

A Streptomyces P450 enzyme dimerizes isoflavones from plants

• Run-Zhou Liu,
• Shanchong Chen and
• Lihan Zhang

Beilstein J. Org. Chem. 2022, 18, 1107–1115, doi:10.3762/bjoc.18.113

• biocatalytic dimerization reactions [20]. Contrary to flavone dimers and oligomers being abundant in nature, only limited dimeric compounds have been reported for isoflavones. Isoflavones bear a characteristic 3-phenylchroman skeleton, which is formed by the B-ring migration from the flavonoid scaffold

Glycosylated coumarins, flavonoids, lignans and phenylpropanoids from Wikstroemia nutans and their biological activities

• Meifang Wu,
• Xiangdong Su,
• Yichuang Wu,
• Yuanjing Luo,
• Ying Guo and
• Yongbo Xue

Beilstein J. Org. Chem. 2022, 18, 200–207, doi:10.3762/bjoc.18.23

• Lingnan region of China, was chemically investigated. A new biscoumarin glucoside, wikstronutin (1), along with three known bis- and tricoumarin glucosides (2–4), two flavonoid glycosides (5–6), and eleven lignan glucosides (7–17) were isolated from the stems and roots of W. nutans. The new structure

• identification of a new bis-coumarin glucoside 1, together with three known bis- and tricoumarin glucosides 2–4, two flavonoid glycosides 5 and 6, and eleven lignan glucosides 7–17 (Figure 1). Herein, we present the isolation and structural elucidation of these natural products and their in vitro biological

• μg/mL). Conclusion In this paper, the new bis-coumarin glucoside wikstronutin (1) was isolated from the stems and roots of the medicinal plant species W. nutans, together with three known bis- and tricoumarin glucosides 2–4, two flavonoid glycosides 5 and 6, and eleven lignan glucosides 7–17. Their

The interaction between cucurbit[8]uril and baicalein and the effect on baicalein properties

• Xiaodong Zhang,
• Jun Xie,
• Zhiling Xu,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2020, 16, 71–77, doi:10.3762/bjoc.16.9

• ; inclusion complex; properties; Introduction Baicalein (5,6,7-trihydroxyflavonoid) has a molecular formula of C15H10O5 (BALE, Figure 1) and is a natural flavonoid found in the roots of Scutellaria baicalensis Georgi [1]. The compound displays pharmacological activity such as antimicrobial, anti-inflammatory

• ] easily. Because the hydroxy group on the carboxylic acid of the baicalin formed a hydrogen bond with the oxygen atoms of Q[8] at the portal, cycle C of baicalin was pushed into the cavity of Q[8]. Therefore, the inclusion model of cucurbit[8] with flavonoid compounds was determined by the structure of

• the specific flavonoid. Conclusion In this study, our results showed that BALE formed an inclusion complex (1:1) with cucurbit[8]uril. The inclusion constants of BALE with Q[8] obtained from the UV–vis absorption data was 2.15 × 107 L·mol−1 (10 mol·L−1 HCl), 3.59 × 107 L·mol−1 (10−2 mol·L−1 HCl) and

A golden opportunity: benzofuranone modifications of aurones and their influence on optical properties, toxicity, and potential as dyes

• Joza Schmitt and
• Scott T. Handy

Beilstein J. Org. Chem. 2019, 15, 1781–1785, doi:10.3762/bjoc.15.171

• Joza Schmitt Scott T. Handy Department of Chemistry, Middle Tennessee State University, Murfreesboro, TN 37132, USA 10.3762/bjoc.15.171 Abstract Aurones are a small subclass of the flavonoid family known primarily for their unusual structure and the golden yellow color they impart to the flowers

• –vis spectrum; Introduction Aurones are a fascinating minor sub-family of the flavonoid natural products [1][2]. While they feature the same C15 composition as other flavonoids, the skeleton is quite different, featuring a benzofuranone connected to an aromatic ring via an exocyclic alkene. This

Synthesis of the aglycon of scorzodihydrostilbenes B and D

• Katja Weimann and
• Manfred Braun

Beilstein J. Org. Chem. 2019, 15, 610–616, doi:10.3762/bjoc.15.56

• multiple phenolic functionality. These natural products that form as secondary metabolites on a branch of flavonoid biosynthesis found wide interest for their various biological effects like anti-oxidative and biofouling-preventing activity [1]. From crude extracts of the Mongolian medicinal plant

Assembly of fully substituted triazolochromenes via a novel multicomponent reaction or mechanochemical synthesis

• Robby Vroemans,
• Yenthel Verhaegen,
• My Tran Thi Dieu and
• Wim Dehaen

Beilstein J. Org. Chem. 2018, 14, 2689–2697, doi:10.3762/bjoc.14.246

• substituents on the chromene core and 1,2,3-triazole offer a lot of possibilities for further derivatization and optimization towards biologically relevant structures such as flavonoid structures. Our group developed a Knoevenagel-assisted three-component reaction of (protected) salicylaldehyde, ethyl

• and 5e furnishes piperazin-1-ylchromene 12 in 64% yield. Furthermore, as highly methylated flavonoid derivatives [47] and 6-(3,5-dimethoxyphenyl)chromenes [48][49] have been demonstrated to be potent anti-seizure drugs and anticancer agents, respectively, a Suzuki–Miyaura reaction was performed

Synthesis of naturally-derived macromolecules through simplified electrochemically mediated ATRP

• Paweł Chmielarz,
• Tomasz Pacześniak,
• Katarzyna Rydel-Ciszek,
• Izabela Zaborniak,
• Paulina Biedka and
• Andrzej Sobkowiak

Beilstein J. Org. Chem. 2017, 13, 2466–2472, doi:10.3762/bjoc.13.243

• Pawel Chmielarz Tomasz Paczesniak Katarzyna Rydel-Ciszek Izabela Zaborniak Paulina Biedka Andrzej Sobkowiak Department of Physical Chemistry, Faculty of Chemistry, Rzeszów University of Technology, Al. Powstańców Warszawy 6, 35-959 Rzeszów, Poland 10.3762/bjoc.13.243 Abstract The flavonoid-based

• naturally-derived macromolecules showed narrow MWDs (Đ = 1.08–1.11). 1H NMR spectral results confirm the formation of quercetin-based polymers. These new flavonoid-based polymer materials may find applications as antifouling coatings and drug delivery systems. Keywords: flavonoids; on-demand seATRP

• solution to receive functionalised polymers. It is a naturally occurring flavonoid, which is abundantly found in citrus fruits, herbs, vegetables, seeds, tea, nuts, and red wine [24][25][26]. It is considered to be a strong antioxidant due to its ability to scavenge free radicals and bind transition metal

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

• cavity of γ-CD, which undergoes a slight geometric rearrangement in order to better accommodate fisetin. This host, the largest of the commercially available native cyclodextrins, is the most compatible with the size of flavonoid compounds. A smaller cyclodextrin, such as β-CD, is not able to fully

• include them. Having one glucose unit less, the cavity of β-CD is narrower and therefore the tilted structure of a flavonoid does not fit and one of the rings of the guest is positioned outside the cavity. This geometry was recently demonstrated for epigallocatechin, which has the same molecular backbone

Use of costic acid, a natural extract from Dittrichia viscosa, for the control of Varroa destructor, a parasite of the European honey bee

• Kalliopi Sofou,
• Demosthenis Isaakidis,
• Apostolos Spyros,
• Anita Büttner,
• Athanassios Giannis and
• Haralambos E. Katerinopoulos

Beilstein J. Org. Chem. 2017, 13, 952–959, doi:10.3762/bjoc.13.96

• gave mite mortality rates identical to those of the controls. In the second series of screening tests, the two flavonoid-type components (7-O-methylaromadendrin and 7-O-methylaromadendrin-3-acetate) from fraction B were isolated, tested, and found inactive. However, the major component, namely costic

Biomimetic synthesis and HPLC–ECD analysis of the isomers of dracocephins A and B

• Viktor Ilkei,
• András Spaits,
• Anita Prechl,
• Áron Szigetvári,
• Zoltán Béni,
• Miklós Dékány,
• Csaba Szántay Jr,
• Judit Müller,
• Árpád Könczöl,
• Ádám Szappanos,
• Attila Mándi,
• Sándor Antus,
• Ana Martins,
• Attila Hunyadi,
• György Tibor Balogh,
• György Kalaus (†),
• Hedvig Bölcskei,
• László Hazai and
• Tibor Kurtán

Beilstein J. Org. Chem. 2016, 12, 2523–2534, doi:10.3762/bjoc.12.247

• and TDDFT–ECD calculations. The synthesized flavonoid alkaloids were further characterized by physicochemical and in vitro pharmacological studies. Keywords: absolute configuration; Dracocephalum rupestre; dracocephins A–B; ECD calculation; flavonoid alkaloids; HPLC–ECD; Introduction Flavonoid

• alkaloids are a small subgroup of flavonoids possessing a five- or six-membered nitrogen heterocycle attached to C-6 or C-8 of ring A of the flavonoid moiety. They have been reported to exhibit a wide range of pharmacological activities [1]. Dracocephins A and B were isolated as a mixture of four

• racemates (2a, 2c/2b, 2d; 3a, 3c/3b, 3d) by HPLC–ECD analysis (Figure 1). The planar structure and absolute configuration of the first-eluted stereoisomer of dracocephins A (±)-2a–d was determined by single-crystal X-ray diffraction analysis as (2R,5”S)-2a [2]. The biosynthesis of these flavonoid

Antibacterial structure–activity relationship studies of several tricyclic sulfur-containing flavonoids

• Lucian G. Bahrin,
• Henning Hopf,
• Peter G. Jones,
• Laura G. Sarbu,
• Cornelia Babii,
• Alina C. Mihai,
• Marius Stefan and
• Lucian M. Birsa

Beilstein J. Org. Chem. 2016, 12, 1065–1071, doi:10.3762/bjoc.12.100

• new broad absorption band at around 1040 cm−1 is attributed to the tetrafluoroborate anion. ESIMS confirms the structure of the positive molecular fragment of each tricyclic flavonoid ([M − BF4]+). Single crystals suitable for X-ray analysis were obtained for 5a and 5b and the results are presented in

• -substituted flavonoids 5d–m. In order to investigate the influence of halogen substituents on the biological properties of tricyclic flavonoids, we first synthesized flavonoid 5m (R1 = R3 = H) having no halogen substituents in the structure as a reference compound. The MIC and MBC values obtained for this

• tricyclic flavonoids and showed the lowest MIC of all tested compounds against this bacterial strain. With respect to bactericidal properties, the lowest value against S. aureus was again recorded for flavonoid 1. The other seven newly synthesized tricyclic flavonoids also displayed good bactericidal

Unconventional application of the Mitsunobu reaction: Selective flavonolignan dehydration yielding hydnocarpins

• Guozheng Huang,
• Simon Schramm,
• Jörg Heilmann,
• David Biedermann,
• Vladimír Křen and
• Michael Decker

Beilstein J. Org. Chem. 2016, 12, 662–669, doi:10.3762/bjoc.12.66

• the biologically important enantiomers of hydnocarpin D, hydnocarpin and isohydnocarpin, respectively. This represents the only one-pot semi-synthetic method to access these flavonolignans in high yields. Keywords: dehydration; flavonoid; hydnocarpin; Mitsunobu; silybin; Introduction Flavonolignans

Thermal and oxidative stability of Atlantic salmon oil (Salmo salar L.) and complexation with β-cyclodextrin

• Daniel I. Hădărugă,
• Mustafa Ünlüsayin,
• Alexandra T. Gruia,
• Cristina Birău (Mitroi),
• Gerlinde Rusu and
• Nicoleta G. Hădărugă

Beilstein J. Org. Chem. 2016, 12, 179–191, doi:10.3762/bjoc.12.20

• water and solvent contents in host–guest supramolecular systems by thermal analyses have already been performed for CD/flavonoid and CD/essential oil complexes [37][39]. Differential scanning calorimetry (DSC) analysis DSC can provide further information on the physical and chemical processes occurring

Co-solvation effect on the binding mode of the α-mangostin/β-cyclodextrin inclusion complex

• Chompoonut Rungnim,
• Sarunya Phunpee,
• Manaschai Kunaseth,
• Supawadee Namuangruk,
• Kanin Rungsardthong,
• Thanyada Rungrotmongkol and
• Uracha Ruktanonchai

Beilstein J. Org. Chem. 2015, 11, 2306–2317, doi:10.3762/bjoc.11.251

• given in Table 1. Details of molecular dynamics simulations In the present study, all MD simulations were performed using the SANDER module of the Amber10 software package in accordance with the recently reported MD simulations of flavonoid/β-CD inclusion complexes in water [34][35]. The particle-mesh

Dicarboxylic esters: Useful tools for the biocatalyzed synthesis of hybrid compounds and polymers

• Ivan Bassanini,
• Karl Hult and
• Sergio Riva

Beilstein J. Org. Chem. 2015, 11, 1583–1595, doi:10.3762/bjoc.11.174

• the alkaline protease from Bacillus subtilis on 7 [25]. The carboxyacetyl (malonyl) derivative of some flavonoid glycosides (i.e., 8b) and of ginsenoside Rg1 (9b) could be obtained with two-step sequences. The preliminary CAL-B catalyzed acylations of 8 with dibenzyl malonate and of 9 with bis(2,2,2

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

• , Southwest University for Nationalities, Chengdu 610041, China 10.3762/bjoc.11.135 Abstract The hemisynthesis of the naturally occurring bioactive flavonoid glycoside icariin (1) has been accomplished in eleven steps with 7% overall yield from kaempferol. The 4′-OH methylation of kaempferol, the 8

• cyclization in route 1, and therefore enhances the proportion of the para-rearrangement product 8. Obviously, strong alkali could lead to heterocycle cleavage of the flavonoid skeleton. Gratifyingly, when prenyl ether 8 was treated with catalytic amounts of Eu(fod)3 and NaHCO3 in PhCl at 85 °C for 24 h (Table

• rearrangement product, thus selectively promoting the para-Claisen–Cope rearrangement of flavonoid 5-prenyl ether. This procedure could afford facile access to the derivatives of icariin (1) and other structurally related flavonoid analogues. Structures of icariin (1), icariside I (2) and icaritin (3). Reagents

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

• result in heterocycle cleavage of the flavonoid skeleton. To obtain 3,7-di-O-methylkaempferol (7), we envisioned the possibility of methylation from the 4′-O-acetylkaempferol (6), which can be derived from 2. We were delighted that the combination of reflux with aluminum chloride in polar solvent CH3CN

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

• on the investigation of the aglycones. Although this has been often criticized, it is most likely an important aspect with regard to flavonoid metabolism. It has been shown that the flavonoid glycosides are not absorbed after oral intake but are cleaved by lactase-phlorizin hydrolase and absorbed as

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

• to investigate the preferential binding mode and encapsulation of the flavonoid fisetin in the nano-pore of β-cyclodextrin (β-CD) at the molecular level using various theoretical approaches: molecular docking, molecular dynamics (MD) simulations and binding free energy calculations. The molecular

• complexes. In addition, the quantum mechanics calculations with M06-2X/6-31G(d,p) clearly showed that both solvation effect and BSSE correction cannot be neglected for the energy determination of the chosen system. Keywords: cyclodextrin; fisetin; flavonoid; MM-PBSA; molecular dynamics simulation; QM-PBSA

• treatment because of their high potency [3][4]. Fisetin (3,3',4',7-tetrahydroxyflavone, 2-(3,4-dihydroxyphenyl)-3,7-dihydroxy-chromen-4-one, Figure 1), one flavonoid in the subclass of flavonols, is found in smoke tree (Cotinus coggyria) [5]. It is also present in many fruits and vegetables such as

cis–trans Isomerization of silybins A and B

• Michaela Novotná,
• Radek Gažák,
• David Biedermann,
• Florent Di Meo,
• Petr Marhol,
• Marek Kuzma,
• Lucie Bednárová,
• Kateřina Fuksová,
• Patrick Trouillas and
• Vladimír Křen

Beilstein J. Org. Chem. 2014, 10, 1047–1063, doi:10.3762/bjoc.10.105

• configuration is known [1][2] and their separation was accomplished recently [3][4][5]. Both silybin isomers as well as other flavonolignans from silymarin (crude defatted extract from the fruits of S. marianum) are products of a phenolic oxidative coupling of the flavonoid taxifolin and the lignan coniferyl

Physalin H from Solanum nigrum as an Hh signaling inhibitor blocks GLI1–DNA-complex formation

• Midori A. Arai,
• Kyoko Uchida,
• Samir K. Sadhu,
• Firoj Ahmed and
• Masami Ishibashi

Beilstein J. Org. Chem. 2014, 10, 134–140, doi:10.3762/bjoc.10.10

• physalin F (5; IC50, 0.66 μM) [17], physalin B (6; IC50, 0.62 μM) [17], colubrinic acid (IC50, 38 μM) [18], caldenolides (IC50, 0.1–0.45 μM) [19], taepeenin D (IC50, 1.6 μM) [20] and a flavonoid glycoside (IC50, 0.5 μM) [21] were isolated by using this screening assay. Recently, we found that vitetrifolin