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

• . Keywords: benzylation; deacetylation; kaempferol; methylation; regioselectivity; Introduction Kaempferol [2-(4-hydroxyphenyl)-3,5,7-trihydroxychromen-4-one] (Figure 1) and its derivatives are widely distributed in plants such as beans, broccoli, strawberries, teas, and propolis [1][2]. They are well known

• -methylkaempferol exhibits modest cytotoxicity [17]. These methylated derivatives of flavonols are found as natural products in relative low quantity, whereas kaempferol is relatively rich in plants. Therefore, it is quite worthwhile to develop procedures for the preparation of methylated derivatives of 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

• Two novel racemic acylphoroglucinols, hyperaspidinols A (1) and B (2) (Figure 1) were recently isolated from the leaves of Hypericum chinense, a member of the St John’s Wort plants, which contains 490 flowering plants [1]. These plants have been used medicinally for treating illnesses such as

• hepatitis and depression, and as topical antimicrobials for wounds and snake bites [2][3][4][5]. There is great interest in secondary metabolites produced by plants from the Hypericum genus due to the bioactivity of many compounds that have been isolated from this source. A wide variety of compounds have

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

• natural metabolites available from plants, phenolic compounds play a particularly important role in human health as they occur in significant amounts in many fruits, vegetables and medicinal plants. In this review natural phenolic compounds of plant origin with significant anti-angiogenic properties are

• compound found in plants and has been isolated from, for example, the flowers of carrot (Daucus carrota L., Apiaceae). In 2007, Park and co-workers [15] found no change in the vascular density in the chick chorioallantoic membrane (CAM) assay in the presence of HBA, indicating that HBA had no influence on

• . Resveratrol Resveratrol (8) is a natural polyphenol that belongs to the stilbene-type compounds and exists in a large number of plants. It has been primarily extracted from grape (Vitis vinifera L., Vitaceae) and mulberry (Morus L., Moraceae) fruits (Figure 4) [34]. It has antioxidant effects, anti-estrogenic

Cathodic reductive coupling of methyl cinnamate on boron-doped diamond electrodes and synthesis of new neolignan-type products

• Taiki Kojima,
• Rika Obata,
• Tsuyoshi Saito,
• Yasuaki Einaga and
• Shigeru Nishiyama

Beilstein J. Org. Chem. 2015, 11, 200–203, doi:10.3762/bjoc.11.21

• interesting biological activities [1]. Due to their plausible roles as defense substances of plants, lignans, neolignans, and their congeners are promising candidates for agricultural chemicals, and some of their antioxidant and/or anti-inflammatory properties may be utilized for biological research and as

Effects of RAMEA-complexed polyunsaturated fatty acids on the response of human dendritic cells to inflammatory signals

• Éva Rajnavölgyi,
• Renáta Laczik,
• Viktor Kun,
• Lajos Szente and
• Éva Fenyvesi

Beilstein J. Org. Chem. 2014, 10, 3152–3160, doi:10.3762/bjoc.10.332

• , C22:6), which can be found in plants (flaxseed, walnut) and fish oil, respectively. ALA and linoleic acid (LA, C18:3 n−6 having the first double bond at the 6th carbon atom from the chain end, therefore classified as n−6 PUFA) are essential fatty acids, because they cannot be synthesized by the human

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

• with IC50 values of 34.77–45.68 μM. Keywords: cytotoxic activity; neolignans; Trogopterus xanthipes; Introduction Chemical studies of natural products including ones derived from plants and microorganisms have led to the isolation of numerous novel metabolites with biological activities [1][2]. As a

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

• oxidative stability; Introduction Aromatic and pharmaceutical plants have been used in both food and medicinal fields since ancient time. These valuable plants have been used directly as raw materials (such as teas/infusions, ground spices, dressings, sauces, etc.) [1][2][3], or indirectly by isolation of

• flavonolignan silybin from Silybum marianum L. or its disuccinate derivative, with hepatoprotective properties [4][5]. Ocimum genus (Lamiaceae family) is comprised of more than fifty species of herbs and shrubs growing in tropical and warm temperate regions [6][7][8][9]. All of these plants contain various

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

Encapsulation of biocides by cyclodextrins: toward synergistic effects against pathogens

• Véronique Nardello-Rataj and
• Loïc Leclercq

Beilstein J. Org. Chem. 2014, 10, 2603–2622, doi:10.3762/bjoc.10.273

• solubility. Carbendazim is a widely used systemic fungicide against different fungi affecting plants [38][39]. Its mechanism is linked to its antimitotic properties that inhibit the bacterial growth [40]. Due to its poor water-solubility, its application becomes a major constraining factor. In 1996, Schmidt

Synthesis and biological evaluation of novel N-α-haloacylated homoserine lactones as quorum sensing modulators

• Michail Syrpas,
• Ewout Ruysbergh,
• Christian V. Stevens,
• Norbert De Kimpe and
• Sven Mangelinckx

Beilstein J. Org. Chem. 2014, 10, 2539–2549, doi:10.3762/bjoc.10.265

• components of microorganisms, algae, marine invertebrates, and some plants and animals [20][21]. Interest in these naturally occurring products is high as they often exhibit fascinating biological activities [22][23][24]. Furthermore, due to the reactivity of halogen substituents, this novel class of

Formal total syntheses of classic natural product target molecules via palladium-catalyzed enantioselective alkylation

• Yiyang Liu,
• Marc Liniger,
• Ryan M. McFadden,
• Jenny L. Roizen,
• Jacquie Malette,
• Corey M. Reeves,
• Douglas C. Behenna,
• Masaki Seto,
• Jimin Kim,
• Justin T. Mohr,
• Scott C. Virgil and
• Brian M. Stoltz

Beilstein J. Org. Chem. 2014, 10, 2501–2512, doi:10.3762/bjoc.10.261

• –Danheiser chemistry [66][67]. E) Rhazinilam (−)-Rhazinilam (44) has been isolated from various plants including Rhazya strica decaisne [68], Melodinus australis [69], and Kopsia singapurensis [70]. Shortly after the first isolation, its structure was elucidated by single crystal X-ray diffraction analysis

Oligomerization of optically active N-(4-hydroxyphenyl)mandelamide in the presence of β-cyclodextrin and the minor role of chirality

• Helmut Ritter,
• Antonia Stöhr and
• Philippe Favresse

Beilstein J. Org. Chem. 2014, 10, 2361–2366, doi:10.3762/bjoc.10.246

• ; enzyme; oxidative coupling; phenol oligomer; Introduction Lignin consists of mechanical stabilizing polyphenols and thus plays an important role in many plants [1][2]. For the in vitro synthesis of polyphenols via oxidative coupling reactions, laccases and peroxidases are suitable enzymes to catalyze

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

• efficiency; cyclodextrins; formation constant; phenylpropanoids; solubility; Introduction Phenylpropanoids (PPs), produced through the shikimic acid pathway, are one of the major groups of natural compounds. They could be found in a wide variety of plants (clove, anise, basil, tarragon, fennel, parsley

• , 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

Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

• Thilo Focken and
• Stephen Hanessian

Beilstein J. Org. Chem. 2014, 10, 1848–1877, doi:10.3762/bjoc.10.195

• ]. Methyl jasmonates and dihydrojasmonates (2001) The jasmonates, which comprise of methyl jasmonate (11) and the corresponding jasmonic acid, are important cellular regulators in plants. They participate in various developmental processes and defence mechanisms against biotic and abiotic stresses [114

Sacrolide A, a new antimicrobial and cytotoxic oxylipin macrolide from the edible cyanobacterium Aphanothece sacrum

• Naoya Oku,
• Miyako Matsumoto,
• Kohsuke Yonejima,
• Keijiroh Tansei and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2014, 10, 1808–1816, doi:10.3762/bjoc.10.190

• of the cells, 1 is is not expected to target cell cycle-associated events, such as the synthesis of proteins, DNA, or RNA. Despite their structural diversity, many oxylipins induce a common stress response in plants and animal cells, and this activity is attributed to their ability to modify the

Efficient routes toward the synthesis of the D-rhamno-trisaccharide related to the A-band polysaccharide of Pseudomonas aeruginosa

• Aritra Chaudhury,
• Sajal K. Maity and
• Rina Ghosh

Beilstein J. Org. Chem. 2014, 10, 1488–1494, doi:10.3762/bjoc.10.153

• synthesis has seen a rapid development over the last two decades [5][6][7]. The D-rhamnoside motif is of particular interest with its presence established in the LPS/EPS systems of various bacterial strains which are pathogenic towards both plants and animals. These species include the Burkholderia cepacia

Streptopyridines, volatile pyridine alkaloids produced by Streptomyces sp. FORM5

• Ulrike Groenhagen,
• Michael Maczka,
• Jeroen S. Dickschat and
• Stefan Schulz

Beilstein J. Org. Chem. 2014, 10, 1421–1432, doi:10.3762/bjoc.10.146

• compounds form a chemical structure space of volatiles released by bacteria and their number is limited, although this space is certainly only partially explored. Another group of volatile compounds forming a structure space is already known from the green part of plants (excluding flowery parts). The plant

Selective allylic hydroxylation of acyclic terpenoids by CYP154E1 from Thermobifida fusca YX

• Anna M. Bogazkaya,
• Clemens J. von Bühler,
• Sebastian Kriening,
• Alexandrine Busch,
• Alexander Seifert,
• Jürgen Pleiss,
• Sabine Laschat and
• Vlada B. Urlacher

Beilstein J. Org. Chem. 2014, 10, 1347–1353, doi:10.3762/bjoc.10.137

• terpenoids in plants represents the most prominent example [14]. Heme-containing cytochrome P450 monooxygenases (P450 or CYP) are predominantly responsible for structural and functional diversity of terpenoids: allylic hydroxylation of parental monoterpenes leads to further diversification via sequential

• exclusively to two allylic alcohols with a notable preference for 12-hydroxynerylacetone (16, 72% and 75%, respectively) (Table 2). Discussion As mentioned in the introduction a large number of regioselective hydroxylation reactions occur in plants. Recently a geraniol 10-hydroxylase from the plant

Synthesis of zearalenone-16-β,D-glucoside and zearalenone-16-sulfate: A tale of protecting resorcylic acid lactones for regiocontrolled conjugation

• Hannes Mikula,
• Julia Weber,
• Dennis Svatunek,
• Philipp Skrinjar,
• Gerhard Adam,
• Rudolf Krska,
• Christian Hametner and
• Johannes Fröhlich

Beilstein J. Org. Chem. 2014, 10, 1129–1134, doi:10.3762/bjoc.10.112

• mycotoxins, especially altered derivatives formed through conjugation to sugar moieties or sulfate, emerge after metabolization by living plants. Due to changed chemical structures and properties compared to the parent mycotoxins, these conjugates can usually not be detected applying standard analytical

New sesquiterpene hydroquinones from the Caribbean sponge Aka coralliphagum

• Qun Göthel and
• Matthias Köck

Beilstein J. Org. Chem. 2014, 10, 613–621, doi:10.3762/bjoc.10.52

• , siphonodictyals B1–B3 (6–8) could be derived from siphonodictyals E1–E3 (1–3), respectively. Aromatic sulfates occur in a wide range of higher plants and animals, particularly those growing in marine, estuarine, or freshwater environments. This is probably due to the high content of inorganic sulfate in aquatic

An oxidative amidation and heterocyclization approach for the synthesis of β-carbolines and dihydroeudistomin Y

• Suresh Babu Meruva,
• Akula Raghunadh,
• Raghavendra Rao Kamaraju,
• U. K. Syam Kumar and
• P. K. Dubey

Beilstein J. Org. Chem. 2014, 10, 471–480, doi:10.3762/bjoc.10.45

• -eudistomin; eudistomin; keto amide; oxidative amidation; Introduction β-Carboline alkaloids [1] are widespread in plants, animals and some are formed naturally in the biological system. Rinehart et al. [2] reported the isolation of β-carboline alkaloids such as eudistomins [3] and several of its analogues

Continuous flow nitration in miniaturized devices

• Amol A. Kulkarni

Beilstein J. Org. Chem. 2014, 10, 405–424, doi:10.3762/bjoc.10.38

• more of these limitations are experienced in every batch operation it is necessary to check their feasibility for continuous flow processing. Such transformations from batch to flow have been carried out for a lot of reactions and many continuous nitration plants of commercial scale exist. However, the

Convergent synthesis of a tetrasaccharide repeating unit of the O-specific polysaccharide from the cell wall lipopolysaccharide of Azospirillum brasilense strain Sp7

• Pintu Kumar Mandal,
• Debashis Dhara and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2014, 10, 293–299, doi:10.3762/bjoc.10.26

• be among the most promising ones [1]. Azospirillum brasilense (A. brasilense) is a plant growth-promoting bacterium, found abundant in the rizosphere of several leguminous plants and regular crops such as wheat, rice, corn etc. Azospirillum is a Gram-negative rizobacterium, which exerts a variety of

• Azospirillum against crown gall disease in plants [8][9], leaf and/or vascular diseases of tomato [10][11] as well as inhibitory properties against the development of bacterial diseases or promoting disease resistance on rice crops [12]. It has been demonstrated that Azospirilla produce a diverse range of

• macromolecules such as exopolysaccharides (EPS), lipopolysaccharides (LPS) and capsular polysaccharides (CPS), which influence their interactions with plants [13][14][15]. There are only a limited number of reports on structural studies of the LPS present in the cell wall of Azospirilla species despite their

Decandrinin, an unprecedented C₉-spiro-fused 7,8-seco-ent-abietane from the Godavari mangrove Ceriops decandra

• Hui Wang,
• Min-Yi Li,
• Félix Zongwe Katele,
• Tirumani Satyanandamurty,
• Jun Wu and
• Gerhard Bringmann

Beilstein J. Org. Chem. 2014, 10, 276–281, doi:10.3762/bjoc.10.23

• have been reported from plants of the genera Abies, Cephalotaxus, Colus, Cordia, Hyptis, Isodon, Pinus, Premna, Salvia, Taiwania, Thuja, and Vitex, including a 1,2-seco-abietane [8], a 1,10-seco-abietane [9][10], three 2,3-seco-abietanes [8][11][12][13], three 3,4-seco-abietanes [8][14], 31 4,5-seco

Synthesis of new enantiopure poly(hydroxy)aminooxepanes as building blocks for multivalent carbohydrate mimetics

• Léa Bouché,
• Maja Kandziora and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 213–223, doi:10.3762/bjoc.10.17

• in natural products, in particular as toxins in marine organisms or plants [6][7]. A few reports in the literature deal with seven-membered polyhydroxylated ethers like septanosides (containing an anomeric center) [8] as well as compounds without an acetal moiety. Known methods for the construction