First thia-Diels–Alder reactions of thiochalcones with 1,4-quinones

• Grzegorz Mlostoń,
• Katarzyna Urbaniak,
• Paweł Urbaniak,
• Anna Marko,
• Anthony Linden and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2018, 14, 1834–1839, doi:10.3762/bjoc.14.156

• initially formed [4 + 2] cycloadducts. In general, the yields of the isolated products were high. With 5-chloro-10-hydroxy-1,4-anthraquinone, the thia-Diels–Alder reaction occurred with complete regioselectivity. In the case of the reaction of vitamin K3 (menadione) with diphenylthiochalcone, the initial

• 1,4-benzoquinone, 1,4-naphthoquinone, and 1,4-anthraquinone were investigated as a route to novel 4H-thiochromene-5,8-dione derivatives. Results and Discussion Aryl and hetary lthiochalcones 1a–d are easily obtained by treatment of the corresponding chalcones with Lawesson′s reagent in THF solution

• [15]. Along with the commercially available 1,4-benzoquinone (2a) and 1,4-naphthoquinone (2b), 1,4-anthraquinone (2c) and 5-chloro-10-hydroxy-1,4-anthraquinone (2d) were prepared from quinizarine according to known procedures [27][28]. First experiments were performed with 2b and thiochalcones 1a–d in

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

• anthraquinone–chalcone hybrids were synthesized using Claisen–Schmidt reaction in order to test their anticancer potential against human cancer cell lines and DNA binding affinity and specificity. It has been observed that three conjugates 32–34 exhibited significant cytotoxicity against LS174 and HeLa cancer

An air-stable bisboron complex: a practical bidentate Lewis acid catalyst

• Longcheng Hong,
• Sebastian Ahles,
• Andreas H. Heindl,
• Gastelle Tiétcha,
• Andrey Petrov,
• Zhenpin Lu,
• Christian Logemann and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2018, 14, 618–625, doi:10.3762/bjoc.14.48

• efficiently promotes the IEDDA reaction of 1,2,4,5-tetrazine (6) with 1,4-naphthaquinone (7a) [21]. Therefore, complex B was also tested as catalyst in the IEDDA reaction of 1,2,4,5-tetrazine (6) with 1,4-naphthaquinonic dienophiles 7a–7d. As shown in Table 2, the product 2,3-diaza-9,10-anthraquinone (8a) was

• obtained in 93% yield catalyzed by B while the yield with A was only 76% (Table 2, entry 1). Furthermore, the air-stable bisboron complex B successfully catalyzed the reactions and allowed the synthesis of 2,3-diaza-5,12-naphthacenedione (8b), 6-methoxy-2,3-diaza-9,10-anthraquinone (8c), and 6,7-dimethoxy

• -2,3-diaza-9,10-anthraquinone (8d) in excellent yields (82%, 88%, 95%, respectively) supporting the practicality of this catalyst for IEDDA reactions (Table 2, entry 2–4). Conclusion In summary, we report an air-stable bidentate Lewis acid bisboron complex as an efficient catalyst for IEDDA reaction of

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• used CF3SO2Na as source of the trifluoromethyl group and a catalytic amount of anthraquinone-2-carboxylic acid (AQN-2-CO2H). The scope was achieved on arenes and heteroarenes (10 examples). Once more, electron-rich aromatic compounds were converted into the corresponding trifluoromethylated products in

Pd- and Cu-catalyzed approaches in the syntheses of new cholane aminoanthraquinone pincer-like ligands

• Nikolay V. Lukashev,
• Gennadii A. Grabovyi,
• Dmitry A. Erzunov,
• Alexey V. Kazantsev,
• Gennadij V. Latyshev,
• Alexei D. Averin and
• Irina P. Beletskaya.

Beilstein J. Org. Chem. 2017, 13, 564–570, doi:10.3762/bjoc.13.55

• ). Consequently, this system was used for the synthesis of bis-steroidal arylamines 5a and 5b starting from 24-aminocholanol 3a. Activated chlorinated substrates, such as 1,8- and 1,5-dichloroanthraquinones, are very promising substrates for nucleophilic substitution. For instance, 1,8-dichloro-9,10-anthraquinone

• . Though 5a was not observed in the reaction with 1,3-diiodobenzene, a good yield was obtained with 1,3-dibromobenzene. In fact, the Pd-catalyzed coupling was more efficient [43] than Ullmann-type chemistry (61% from 1,3-dibromobenzene vs 40% from 1,3-diiodobenzene). Since the anthraquinone skeleton is

• yield of 5d (22%). We speculated that the low yield was caused by the presence of an additional hydroxy group in 3b. The formation of the alkoxide anion on the substrate due to the thermodynamically unfavorable equilibrium with Cs2CO3 might promote the destruction of the anthraquinone scaffold. Indeed

A versatile route to polythiophenes with functional pendant groups using alkyne chemistry

• Xiao Huang,
• Li Yang,
• Rikard Emanuelsson,
• Jonas Bergquist,
• Maria Strømme,
• Martin Sjödin and
• Adolf Gogoll

Beilstein J. Org. Chem. 2016, 12, 2682–2688, doi:10.3762/bjoc.12.265

• . The synthetic utility of pyEDOT is demonstrated by the following examples involving a range of pendant groups. The electron acceptor units diethyl terephthalate (DET) and 9,10-anthraquinone (AQ) are of particular interest for their redox chemistry in energy storage applications [34]. Their ester and

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

• up the benzobisfuran motif in 106, the second rearranges the anthraquinone in 106 to the xanthone in 107 and the third is an oxidative ring contraction towards the cyclopentanone in 94 (Scheme 16). After several enzymatic post-PKS modifications, the oxoaverantin (OAVN) cyclase transforms 5

• -PKS-derived anthraquinone precursors [155]. (+)-Geodin (189) was the first chlorinated compound isolated from fungi [156]. During its biosynthesis in Aspergillus terreus, the furan-3-one ring is closed by action of the multicopper blue protein dihydrogeodin oxidase on dihydrogeodin (186) (Scheme 26a

From N-vinylpyrrolidone anions to modified paraffin-like oligomers via double alkylation with 1,8-dibromooctane: access to covalent networks and oligomeric amines for dye attachment

• Daniela Obels,
• Melanie Lievenbrück and
• Helmut Ritter

Beilstein J. Org. Chem. 2016, 12, 1395–1400, doi:10.3762/bjoc.12.133

• reactive amino-functionalized oligomers. Further modification of the free amino groups with 1,4-difluoro-9,10-anthraquinone (DFA) yields red-colored oligomeric anthraquinone dyes. The final reaction of DFA-substituted N-VP oligomers with Jeffamine® M 600 leads to blue-colored and branched oligomers with

• poly(ethylene glycol) side chains. Keywords: double alkylation; modified N-vinylpyrrolidone; oligomeric anthraquinone dye; paraffin-like oligomer; radical thiol-ene click reaction; Introduction Poly(N-vinylpyrrolidone) (PVP) is established in daily life due to its high water solubility and

• bonds of 2a were subjected to further modification through a thiol–ene [40][41][42] click reaction with 2-aminoethanethiol hydrochloride yielding oligomer 4 (Scheme 2). Subsequently, the reactivity of the primary amino groups in 4 was proven by the attachment of 1,4-difluoro-9,10-anthraquinone (DFA

Regiodefined synthesis of brominated hydroxyanthraquinones related to proisocrinins

• Joyeeta Roy,
• Tanushree Mal,
• Supriti Jana and
• Dipakranjan Mal

Beilstein J. Org. Chem. 2016, 12, 531–536, doi:10.3762/bjoc.12.52

• cyclohexenones 13/36 in the presence of LiOt-Bu to give brominated anthraquinones 14/38 in good yields. Darzens condensation of 30 was shown to give chain-elongated anthraquinone 32. Alkaline hydrolysis of 38 furnished 39 representing desulfoproisocrinin F. Keywords: brominated anthraquinones; Darzens

• inhibitory activity against human tumor cell lines SF-268, MCF-7, and NCI-H460, with IC50 values of 7.11, 6.64, and 7.42 μM, respectively [12]. Proisocrinins A–F (6–11), recently isolated from the stalked crinoid Proisocrinus ruberrimus (Figure 1) are the first water soluble natural anthraquinone pigments

• the bromoanthraquinone scaffolds of proisocrinins 6–11. Results and Discussion First synthetic route Anthraquinone 14 was proposed to be synthesized by the Hauser annulation of cyanophthalide 12 and cyclohexenone 13 (Scheme 1). A functional group manipulation of 14 was expected to give anthraquinone

Recent highlights in biosynthesis research using stable isotopes

• Jan Rinkel and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2015, 11, 2493–2508, doi:10.3762/bjoc.11.271

• . on the anthraquinone crysophanol, for which different folding modes in fungi (F type folding) and in bacteria (S type, “Streptomyces” type) were found by isotopic labeling experiments for one and the same compound [30]. As an additional concluding remark of this chapter, the role of isotopic labeling

Aggregation behaviour of amphiphilic cyclodextrins: the nucleation stage by atomistic molecular dynamics simulations

• Giuseppina Raffaini,
• Antonino Mazzaglia and
• Fabio Ganazzoli

Beilstein J. Org. Chem. 2015, 11, 2459–2473, doi:10.3762/bjoc.11.267

• for instance the wormlike micelles formed by the cetyltrimethylammonium cations, investigated at various salt concentrations to assess their stability against rupture in smaller spherical micelles [36], or more recently a bilayer of aCDs functionalized through an anthraquinone moiety mimicking a small

Syntheses of 2-substituted 1-amino-4-bromoanthraquinones (bromaminic acid analogues) – precursors for dyes and drugs

• Enas M. Malik,
• Younis Baqi and
• Christa E. Müller

Beilstein J. Org. Chem. 2015, 11, 2326–2333, doi:10.3762/bjoc.11.253

• , Postal Code 123, Muscat, Oman 10.3762/bjoc.11.253 Abstract Anthraquinone (AQ) derivatives play a prominent role in medicine and also in textile industry. Bromaminic acid (1-amino-4-bromoanthraquinone-2-sulfonic acid) is an important precursor for obtaining dyes as well as biologically active compounds

• through the replacement of the C4-bromo substituent with different (ar)alkylamino residues. Here we report methods for the synthesis of bromaminic acid analogues bearing different substituents at the 2-position of the anthraquinone core. 1-Aminoanthraquinone was converted to its 2-hydroxymethyl

• 1-amino-2,4-dibromoanthraquinone directly from 1-aminoanthraquinone in excellent yields (94–100%) and high purities. The synthesized brominated AQs are valuable precursors for the preparation of AQ drugs and dyes. Keywords: anthraquinone; bromaminic acid; drug synthesis; dyes; intermediates

Design and synthesis of propellane derivatives and oxa-bowls via ring-rearrangement metathesis as a key step

• Sambasivarao Kotha and
• Rama Gunta

Beilstein J. Org. Chem. 2015, 11, 1727–1731, doi:10.3762/bjoc.11.188

• from readily accessible starting materials such as p-benzoquinone, 1,4-naphthoquinone and 1,4-anthraquinone. Keywords: allylation; propellane derivatives; quinones; ring-rearrangement metathesis; Introduction The synthesis of complex target structures requires bond-disconnection analysis of the

• -quinones (p-benzoquinone, 1,4-naphthoquinone or 1,4-anthraquinone) with a freshly cracked cyclopentadiene. To realize the synthetic strategy (Figure 1) to various propellane derivatives [29][30][31] and oxa-bowls, we commenced with the preparation of a known DA adduct 3a [32]. Subsequent allylation of 3a

• established on the basis of 1H and 13C NMR spectral data and further supported by HRMS data. Next, another DA adduct 3c was prepared from readily available starting materials. In this regard, 1,4-anthraquinone was prepared from quinizarin (1,4-dihydroxyanthraquinone) by using the literature procedure [34] and

Single-molecule conductance of a chemically modified, π-extended tetrathiafulvalene and its charge-transfer complex with F₄TCNQ

• Raúl García,
• M. Ángeles Herranz,
• Edmund Leary,
• M. Teresa González,
• Gabino Rubio Bollinger,
• Marius Bürkle,
• Linda A. Zotti,
• Yoshihiro Asai,
• Fabian Pauly,
• Juan Carlos Cuevas,
• Nicolás Agraït and
• Nazario Martín

Beilstein J. Org. Chem. 2015, 11, 1068–1078, doi:10.3762/bjoc.11.120

• viologen [5][6], aniline [7][8], thiophene [9], anthraquinone [10] and ferrocene [11] have been previously studied. However, a particularly suitable redox-active molecule for molecular electronics is the well-known electron donor tetrathiafulvalene (TTF) molecule. Pristine TTF, as well as the

• anthracene and anthraquinone OPE derivatives showed a difference of approximately two orders of magnitude between their respective conductance values [36]. This would fit with our hypothesis that the conductance of the neutral exTTF molecule, which has a similar bonding pattern to anthraquinone, is below our

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

The Ugi four-component reaction as a concise modular synthetic tool for photo-induced electron transfer donor-anthraquinone dyads

• Sarah Bay,
• Gamall Makhloufi,
• Christoph Janiak and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 1006–1016, doi:10.3762/bjoc.10.100

• Strukturchemie, Universitätsstraße 1, D-40225 Düsseldorf, Germany 10.3762/bjoc.10.100 Abstract Phenothiazinyl and carbazolyl-donor moieties can be covalently coupled to an anthraquinone acceptor unit through an Ugi four-component reaction in a rapid, highly convergent fashion and with moderate to good yields

• these novel donor–acceptor dyads. In addition, the X-ray structure of a phenothiazinyl–anthraquinone dyad supports short donor–acceptor distances by an intramolecular π-stacking conformation, an important assumption also implied in the calculations of the Gibbs energies according to the Weller

• moieties C60 fullerene [43][44][45], and quinones, such as 9,10-anthraquinone as a potential two electron acceptor, have been commonly used in Do–Acc arrangements [46][47][48][49][50][51]. In previous studies phenothiazine–anthraquinone couples have been introduced into peptide scaffolds [52][53][54] and

Nonanebis(peroxoic acid): a stable peracid for oxidative bromination of aminoanthracene-9,10-dione

• Vilas Venunath Patil and
• Ganapati Subray Shankarling

Beilstein J. Org. Chem. 2014, 10, 921–928, doi:10.3762/bjoc.10.90

• acid and oxidative bromination of amino-anthracene-9,10-dione have not been reported in literature. This oxidation strategy allowed us to brominate various amino anthraquinone derivatives in good yield and at ambient temperature. Result and Discussion The oxidant, nonanebis(peroxoic acid) was

Multigramme synthesis and asymmetric dihydroxylation of a 4-fluorobut-2E-enoate

• James A. B. Laurenson,
• John A. Parkinson,
• Jonathan M. Percy,
• Giuseppe Rinaudo and
• Ricard Roig

Beilstein J. Org. Chem. 2013, 9, 2660–2668, doi:10.3762/bjoc.9.301

• by increasing the ligand or osmium concentrations. Sharpless has reported that the (DHQ)2AQN and (DHQD)2AQN ligands based on the anthraquinone core, (Figure 2), are superior ligands for olefins bearing heteroatoms in the allylic position [27]. An asymmetric dihydroxylation reaction was performed

Flexible synthesis of anthracycline aglycone mimics via domino carbopalladation reactions

• Markus Leibeling and
• Daniel B. Werz

Beilstein J. Org. Chem. 2013, 9, 2194–2201, doi:10.3762/bjoc.9.258

• . Subsequent aromatization of the C-ring and several additional steps generated the daunomycin aglycon 6 and the corresponding isodaunomycin aglycone (dependent on the regioisomers) in a total of 16 steps. In 2003, Saá published a concise route to anthraquinone derivatives by using an intramolecular dehydro

• annulated cycles and their possible modification, whereupon the main focus was the preparation of several D-ring derivatives. The anthraquinone moiety 11 should be formed within the last steps of the synthetic approach by benzylic oxidation of compound 12 (Scheme 3). The terminal silyl group and the silyl

• described before. To install the anthraquinone moiety it was necessary to reprotect the alcohol functionalities. It has proven challenging to install the TBS protecting group at the substrates, particular for the galactose-derived derivatives 12b which could be obtained in only poor yield [47][48][49]. For

The chemistry of isoindole natural products

• Klaus Speck and
• Thomas Magauer

Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243

• . This motif is found in its intact or modified form in indolocarbazoles, macrocyclic polyketides (cytochalasan alkaloids), the aporhoeadane alkaloids, meroterpenoids from Stachybotrys species and anthraquinone-type alkaloids. Concerning their biological activity, molecular structure and synthesis, we

• first oxidized and chlorinated by an FADH2-dependent halogenase to give 205, which after extension by the polyketide synthase gives the polyketides 206 and 207, respectively. The intermolecular condensation of these two components yields chlorizidine A (208) [155]. Anthraquinone-type alkaloids

Synthesis of 2,3-dihydronaphtho[2,3-d][1,3]thiazole-4,9-diones and 2,3-dihydroanthra[2,3-d][1,3]thiazole-4,11-diones and novel ring contraction and fusion reaction of 3H-spiro[1,3-thiazole-2,1'-cyclohexanes] into 2,3,4,5-tetrahydro-1H-carbazole-6,11-diones

• Lidia S. Konstantinova,
• Kirill A. Lysov,
• Ljudmila I. Souvorova and
• Oleg A. Rakitin

Beilstein J. Org. Chem. 2013, 9, 577–584, doi:10.3762/bjoc.9.62

• naphthoquinones 3 we studied a reaction of 4 with a mixture of S2Cl2 and Hünig’s base in THF. After treatment of anthraquinone 4a with S2Cl2 (9 equiv) and Hünig’s base (5 equiv) in THF at 0 °C for 72 h with subsequent 2 h heating under reflux we isolated, along with the chlorinated product 9a, orange crystals 10a

• , mp 183–185 °C. Microanalysis and mass-spectrometry data allowed the establishment of its molecular formula as C19H15NO2S2, suggesting the presence of two sulfur atoms inserted into the final product instead of four hydrogen atoms. The 1H NMR spectrum showed that both the anthraquinone ring and butyl

• then extended to other anthraquinone derivatives 4. Fused anthraquinonothiazole-2-thiones 10 were isolated in yields ranging from moderate to low together with chlorinated products 9 (with higher yields in most cases). To confirm the structure of anthraquinonothiazoles 10 we treated thiazole 2c with

Polymerization of novel methacrylated anthraquinone dyes

• Christian Dollendorf,
• Susanne Katharina Kreth,
• Soo Whan Choi and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 453–459, doi:10.3762/bjoc.9.48

• anthraquinone dyes has been synthesized by nucleophilic aromatic substitution reactions and subsequent methacrylation. Thereby, green 5,8-bis(4-(2-methacryloxyethyl)phenylamino)-1,4-dihydroxyanthraquinone (2), blue 1,4-bis(4-((2-methacryloxyethyl)oxy)phenylamino)anthraquinone (6) and red 1-((2-methacryloxy-1,1

• -dimethylethyl)amino)anthraquinone (12), as well as 1-((1,3-dimethacryloxy-2-methylpropan-2-yl)amino)anthraquinone (15) were obtained. By mixing of these brilliant dyes in different ratios and concentrations, a broad color spectrum can be generated. After methacrylation, the monomeric dyes can be covalently

• . Keywords: anthraquinone; monomeric dyes; red; green; blue dyes; polymer; Introduction Anthraquinone and its derivatives bearing hydroxy and amino moieties are of remarkable importance in pharmacological, biochemical and dye industries [1][2]. They have been described as important compounds for decades [3

Electron and hydrogen self-exchange of free radicals of sterically hindered tertiary aliphatic amines investigated by photo-CIDNP

• Martin Goez,
• Isabell Frisch and
• Ingo Sartorius

Beilstein J. Org. Chem. 2013, 9, 437–446, doi:10.3762/bjoc.9.46

• anthraquinone (AQ) and xanthone (XA) or benzophenone (BP) were investigated by time-resolved photo-CIDNP (photochemically induced dynamic nuclear polarization) experiments. By varying the radical-pair concentration, it was ensured that these measurements respond only to self-exchange reactions of the free amine

• ) and triisopropylamine (TIPA). The hindrance is due to a stereoelectronic effect with DABCO [21], and due to overcrowding with TIPA [22]. As sensitizers, we have chosen 9,10-anthraquinone (AQ) on one hand and xanthone (XA) or benzophenone (BP) on the other; with triethylamine, these are typical

• -resolved CIDNP in sensitized (sensitizers xanthone (XA), benzophenone (BP), or anthraquinone (AQ)) photoreactions of 1,4-diazabicyclo[2.2.2]octane (DABCO). Shown are the relative CIDNP intensities (integrals) Irel (DABCO) of the 12 equivalent amine protons (s, 2.64 ppm) as functions of the delay t between

Cyclodextrin-induced host–guest effects of classically prepared poly(NIPAM) bearing azo-dye end groups

• Gero Maatz,
• Arkadius Maciollek and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 1929–1935, doi:10.3762/bjoc.8.224

• Polymers bearing dyes, such as azo, stilbene, anthraquinone or fluorescence dyes, in the main or side chain have been widely described and investigated [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. A few examples of dyes located at the end group of polymers are prepared preferably under anionic or