- Electrochemical Switching of Lariat Ethers: Enhanced Cation Binding by One- and Two-electron Reduction of an Anthraquinone Sidearm
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The first example of cation binding enhancement by electrochemical switching in a lariat ether, accomplished by one- or two-electron reduction of a quinone sidearm, is presented.
- Echegoyen, Luis,Gustowski, Deborah A.,Gatto, Vincent J.,Gokel, George W.
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- Regioselectivity of Alkoxyisobenzofuran-Aryne Cycloadditions
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The cycloaddition reactions of some unsymmetrical arynes with 1-ethoxy-3-(trimethylsilyl)isobenzofuran and a naphthofuran analogue were examined for prospective regioselectivity.The arynes, generated by lithium tetramethylpiperidide induced dehydrohalogenation of the appropriate haloaromatics, were 3-bromo, 3-chloro, 3-methoxy, and 3-methylbenzyne, 3,4-pyridyne, and 1,2-naphthalyne.Regioselectivities ranged from nil (50/50 isomer ratio with 3,4-pyridyne) to modest (ca. 80/20).The products are bridgehead trimethylsilylated ketals, which undergo a novel acid-catalyzed rearrangement to 9-alkoxy-10-anthracenes.These position-differentiated anthracenediol analogues are thought to be formed by ring opening, followed by Brook rearrangement.Isomeric ketal pairs were found to react at different rates, and this selective decomposition was used to isolate one of the cycloadduct isomers from the reaction of 3-bromobenzyne.Lithium-bromine exchange followed by methylation was used to determine its structure, and this information in turn was used to clarify the mechanism of the acid-catalyzed reaction.
- Pollart, Daniel J.,Rickborn, Bruce
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- Characterization of TnmH as an O-Methyltransferase Revealing Insights into Tiancimycin Biosynthesis and Enabling a Biocatalytic Strategy to Prepare Antibody-Tiancimycin Conjugates
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The enediynes are among the most cytotoxic molecules known, and their use as anticancer drugs has been successfully demonstrated by targeted delivery. Clinical advancement of the anthraquinone-fused enediynes has been hindered by their low titers and lack of functional groups to enable the preparation of antibody-drug conjugates (ADCs). Here we report biochemical and structural characterization of TnmH from the tiancimycin (TNM) biosynthetic pathway, revealing that (i) TnmH catalyzes regiospecific methylation at the C-7 hydroxyl group, (ii) TnmH exhibits broad substrate promiscuity toward hydroxyanthraquinones and S-alkylated SAM analogues and catalyzes efficient installation of reactive alkyl handles, (iii) the X-ray crystal structure of TnmH provides the molecular basis to account for its broad substrate promiscuity, and (iv) TnmH as a biocatalyst enables the development of novel conjugation strategies to prepare antibody-TNM conjugates. These findings should greatly facilitate the construction and evaluation of antibody-TNM conjugates as next-generation ADCs for targeted chemotherapy.
- Adhikari, Ajeeth,Teijaro, Christiana N.,Yan, Xiaohui,Chang, Chin-Yuan,Gui, Chun,Liu, Yu-Chen,Crnovcic, Ivana,Yang, Dong,Annaval, Thibault,Rader, Christoph,Shen, Ben
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supporting information
p. 8432 - 8441
(2020/09/23)
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- Pyrazine compound and application thereof
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The invention discloses a pyrazine compound and application thereof. In particular, the present invention provides a compound represented by the formula (I), wherein the extractant composed of the compound has a high extraction rate for lithium ions, and the organic phase is easy to enrich lithium-7 isotopes, so as to realize the extraction and separation of lithium isotopes.
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Paragraph 0165; 0167-0168
(2019/07/04)
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- Synthesis method of anthraquinone derivatives and tetracenedione derivatives through benzannulation reaction
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The present invention relates to a method for synthesizing anthraquinone derivatives and tetracene dione derivatives through a benzannulation reaction, which presents a novel synthesis method, capable of processing synthesis easily, conveniently, and efficiently under mild conditions by an organic catalyst. The synthesis method uses an L-proline catalyst which is nontoxic, economical and easily available, compared to conventional production methods, thereby providing the anthraquinone derivatives and the tetracene dione derivatives through the one-pot benzannulation reaction of an α, β-unsaturated aldehyde compound, various 1,4-naphthoquinone compounds or 1,4-anthracenedione compounds. Various forms of anthraquinone derivatives or tetracene dione derivatives prepared by the synthesis method can be widely used for synthesis of natural products, dyes, and pharmaceutical products.COPYRIGHT KIPO 2017
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Paragraph 0029-0030; 0044
(2017/08/09)
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- Organocatalyzed benzannulation for the construction of diverse anthraquinones and tetracenediones
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An efficient one-pot synthesis of anthraquinones and tetracenediones was achieved vial-proline catalyzed [4+2] cycloaddition of in situ generated azadiene from α,β-unsaturated aldehydes and 1,4-naphthoquinones or 1,4-anthracenedione in good to excellent yield. This protocol constitutes an unprecedented tandem benzannulation that allows one-pot construction of diverse anthraquinones and tetracenediones in the presence of organocatalysts. This methodology was applied successfully to the synthesis of naturally occurring molecules and photochemically interesting phenanthrenequinone derivatives.
- Somai Magar, Krishna Bahadur,Xia, Likai,Lee, Yong Rok
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supporting information
p. 8592 - 8595
(2015/05/20)
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- Synthesis of functionalized 1,4-dihydro-9,10-anthraquinones and anthraquinones by ring closing metathesis using Grubbs' catalyst
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A general and straightforward synthesis of anthraquinones was developed, in which diallylation of 1,4-naphthoquinones, followed by Ring Closing Metathesis (RCM) of the resulting diallylnaphthoquinones with Grubbs' catalyst and subsequent dehydrogenation using Pd/C afforded the desired anthraquinones with regiocontrol of substituents and in good yields.
- Van Nguyen, Tuyen,D'Hooghe, Matthias,Pattyn, Siegfried,De Kimpe, Norbert
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p. 1913 - 1916
(2007/10/03)
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- A New Convenient Synthesis of Alkoxyanthracenes from Alkoxy-9,10- anthraquinones
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Methoxy-9,10-anthraquinones with mono-, di- and tetraether groups at different positions 1a-h can be directly reduced to the corresponding methoxyanthracenes 3a-h in moderate to good yields by zinc in refluxing acetic acid. Under similar conditions, ethyl 1′-anthracenoxyacetate (3i) with the ester group unaffected and 1,8-oxybis(ethyleneoxyethyleneoxy)anthracene (5) were also conveniently synthesized in 65 and 70% yields, respectively.
- Lu, Lingang,Chen, Qiyin,Zhu, Xiaozhang,Chen, Chuanfeng
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p. 2464 - 2466
(2007/10/03)
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- Intramolecular reactivity of 1-alkoxyanthronylidenes. Disproportionation (set) of carbene-derived 1,5-biradicals
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Photolyses of 1-alkoxy-9-diazoanthrones 12 in benzene induce abstraction of hydrogen from the side chain, followed by cyclization (→ 15 → 16) or disproportionation (→ 17 + 18) of the intervening biradicals 20. In alcohols, reduction of triplet anthronylidenes (314 → 21 → 22) competes with the formation of 20, and intramolecular electron transfer of 20 leads eventually to the acetals 24.
- Gotzhein, Frank,Kirmse, Wolfgang
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p. 6675 - 6678
(2007/10/03)
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- Preparation of Anthraquinones from 10-Hydroxy-9-anthracenecarbonitriles Obtained from a Novel Aryne Annulation Reaction
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A new method for brief regioselective synthesis of anthraquinones via the reaction of anions of ethyl cyanoacetate or the anions of 2-(carbethoxyaryl)acetonitriles with arynes is described.
- Bhawal, Baburao M.,Khanapure, Subhash P.,Zhang, Hongming,Biehl, Edward R.
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p. 2846 - 2849
(2007/10/02)
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- Diels-Alder reactions between dienamides and quinones: Stereochemistry of the cycloadditions and cytotoxic activity of the adducts
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Tetrahydronaphthoquinones and tetrahydroanthraquinones bearing an amido group have been prepared by Diels-Alder reactions between (E)-1-(N-carbobenzyloxyamino)-1,3-butadiene (2) or (E)-1-(N-benzoyl-N-benzylamino)-1,3-butadiene (5) and benzoquinone or 5-substituted naphthoquinones. The stereochemistry of the cycloadditions was investigated. A high regioselectivity was observed in the reaction of the diene carbamate 2 with 5-methoxy and 5-acetoxy naphthoquinones. This latter gave the unexpected 1,8-regioisomer 3d. The cycloadditions of the dienamide 5 with naphthoquinones 1 (R = OH, OMe, OAc) are regiospecific. Assignment of the structure of the tetrahydroanthraquinone 6b is in good agreement with the known directing effect of the 5-hydroxy group of juglone 1b in analogous Diels-Alder reactions. With 5-methoxy and 5-acetoxy naphthoquinones, the opposite regiochemistry observed is consistent with the electron-donating influence of the methoxy or acetoxy group, making the C-3 carbon atom more electron deficient. Aromatization of the adducts 6b and 7c was accompanied by an unusual elimination of the amido moiety. Thus, 1-hydroxy and 1-methoxy anthraquinones were obtained. Reactions of the dienes 2 and 5 with benzoquinone gave the tetrahydronaphthoquinones 9 and 10 with an endo stereospecificity. Oxidation of 9 by activated manganese dioxide gave the naphthoquinone 11. These compounds were submitted to in vitro cytotoxic assays towards murine L 1210 leukemia cells and clonogenic human tumor cell line MDA-MB 231. The naphthoquinone derivatives 9, 10 and 11 had significant activities with IC50 ≤ 0.4 μg/ml towards these two tumor cell systems.
- Chigr,Fillion,Rougny,Berlion,Riondel,Beriel
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p. 688 - 691
(2007/10/02)
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- METAL TEMPLATE ORTHO-ACYLATION OF PHENOLS; A NEW GENERAL APPROACH TO ANTHRACYCLINONES
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Direct and mild synthesis of dihydroxyanthraquinones including 4-demethoxy-7-deoxydaunomycinone 8 from ortho-phthaloyl dichloride and hydroquinone derivatives is described.
- Sartori, Giovanni,Casnati, Giuseppe,Bigi, Franca,Robles, Pasquale
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p. 1533 - 1536
(2007/10/02)
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- Electrochemical Switching in Anthraquinone-Substituted Carbon-Pivot Lariat Ethers and Podands: Chain Length Effects in Geometric and Electronic Cooperativity
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A series of 1-substituted anthraquinones has been synthesized, most often by nucleophilic aromatic substitution on 1-chloroanthraquinone.They have the following structures and were prepared in the indicated yields where E is -CH2CH2- and Aris the 1-substitued anthraquinone: 1, Ar-OCH3, (48percent); 2, Ar-OEOEOCH3 (61percent); 3, Ar-OEOEOEOCH3 (61percent); 4, Ar-OEOEOEOEOCH3 (65percent); 5, Ar-OEOEOEOEOEOCH3 (14percent); 6, Ar-OEOEOEO-Ar (66percent); 7, Ar-O-CH2-15-crown-5 (39percent).Both one- and two-electron time-resolved redox couples (using cyclic voltammetry) are observed for the various systems when 0-1.0 equiv of Li+, Na+, or K+ are added.The electrochemical behavior is complex and is accounted for by a combinations of electronic steric factors.
- Gustowski, Deborah A.,Delgado, Milargos,Gatto, Vincent J.,Echegoyen, Luis,Gokel, George W.
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p. 7553 - 7560
(2007/10/02)
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- REACTIONS OF 1-ACETOXY-9,10-ANTHRAQUINONES WITH THE FORMATION OF DERIVATIVES OF 1,10-ANTHRAQUINONE AND 10-ANTHRONE
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The action of alkali-metal alkoxides on 1-acetoxy-9,10-anthraquinone and its nitro and amino derivatives under mild conditions leads to the formation of the corresponding 9,9-dialkoxy-1-hydroxy-10-anthrones.For the 4-amino-substituted 1-acetoxyanthraquinones the intermediately formed 4-amino-substituted 9-alkoxy-1,10-anthraquinones were isolated.The structures of the 9,9-dialkoxy-1-hydroxy-10-anthrones were proved by their chemical transformations.
- Popov, S. I.,Volosenko, V. P.
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p. 127 - 131
(2007/10/02)
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- Process for the production of methoxyanthraquinones
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A process for the production of methoxyanthraquinones of high purity by reaction of nitroanthraquinones with methanol and alkali, in the presence of alkali-resistant nitrous acid inhibitors.
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- A New Route to Anthraquinones
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The lithium salts derived from position 3 of phthalides react with arynes to form adducts, which, upon aerial oxidation, produce anthraquinones in moderate to good yields.Substituted phthalides and arynes also participate in this general reaction.The addition to unsymmetrically substituted arynes shows regioselectivity, whilst the availability of a new general route to phthalides extends the scope of this reaction.
- Dodsworth, David J.,Calcagno, Maria-Pia,Ehrmann, E. Ursula,Devadas, Bhatt,Sammes, Peter G.
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p. 2120 - 2124
(2007/10/02)
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- Restricted Rotation Involving the Tetrahedral Carbon. XXXV. Stereodynamics of 9-(3,5-Dimethylbenzyl)styrene Derivatives
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Stereodynamics of a variety of 9-(3,5-dimethylbenzyl)triptycene derivatives was studied.Atropisomerism about the bridgehead-to-methylene bond was realized in a triply peri-substituted derivative, 8,13-dichloro-1,4-dimethyl-9-(3,5-dimethylbenzyl)triptycene: the activation enthalpy for the ap--> +/-sc conversion was 26.4 kcal/mol.Barriers to rotation about the bridgehead-to-methylene bond in a variety of triply, doubly, and singly peri-substituted derivatives were obtained by DNMR method.DNMR behavior of the diastereotopic m-methyl groups in the benzyl moiety revealed the dual mechanisms of the methyl exchange process; rotation about the methylene-to-aryl bond by 180 deg without rotation about the bridgehead-to-methylene bond ("isolated rotation (IR)") and rotation about the methylene-to-aryl bond by 180 deg synchronous with rotation about the bridgehead-to-methylene bond by 120 deg ("gear motion (GM)").The GM process predominates in peri-unsubstituted derivatives, while the IR process predominates in triply peri-substituted ones.
- Yamamoto, Gaku,Oki, Michinori
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p. 473 - 480
(2007/10/02)
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- Process for producing high purity methoxyanthraquinones
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Methoxyanthraquinones are produced from the corresponding nitroanthraquinones by reacting a nitroanthraquinone with methanol and an alkali in a reaction medium chiefly comprising methanol at a temperature of 50°-130° C under atmospheric or superatmospheric pressure in the presence of molecular oxygen wherein the dissolved oxygen concentration of the reaction medium is maintained at a value of at least 1 ppm.
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