- Design and synthesis of a novel triptycene-based ligand for modeling carboxylate-bridged diiron enzyme active sites
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A novel triptycene-based ligand with a preorganized framework was designed to model carboxylate-bridged diiron active sites in bacterial multicomponent monooxygenase (BMM) hydroxylase enzymes. The synthesis of the bis(benzoxazole)-appended ligand L1 depicted was accomplished in 11 steps. Reaction of L1 with iron(II) triflate and a carboxylate source afforded the desired diiron(II) complex [Fe2L1(μ-OH)-(μ-O 2CArTol)(OTf)2].
- Li, Yang,Cao, Rui,Lippard, Stephen J.
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- Methylation of 1,8-dihydroxy-9,10-anthraquinone with and without use of solvent-free technique
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A convenient and environmentally friendly solvent-free procedure has been developed for dimethylation of 1,8-dihydroxy-9,10-anthraquinone with excellent yield. A highly selective monomethylation of 1,8-dihydroxy-9,10-anthraquinone in refluxing tetraglyme makes monomethylated peri-dihydroxy-9,10-anthraquinones easily available. Alternatively, irradiation in a domestic microwave oven has been employed for the solvent-free monomethylation of 1,8-dihydroxy-9,10-anthraquinone.
- Sereda, Grigoriy A.,Akhvlediani, David G.
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Read Online
- An efficient synthesis of 9-anthrone lactone derivatives via the Knoevenagel condensation and intramolecular cyclization
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One-step synthesis of 9-anthrone lactone derivatives from 1-acetyloxyanthraquinone with a variety of dicarbonyl substrates in the presence of K2CO3 by Knovenagel condensation and intramolecular cyclization is developed. Possible reaction mechanisms have been investigated using the density functional theory (DFT), which has been widely used in the study of reaction mechanism. The strategy could be useful for the synthesis of the core structure of marine natural product aspergiolide.
- Gao, Liming,Guan, Jing,Lyu, Lili,Ma, Mingliang,Shan, Bin,Tan, Weiqiang,Xia, Yan,Yang, Qipeng,Zhan, Xiuzhi,Zheng, Jifang
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supporting information
(2020/02/15)
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- Efficient reductive Claisen rearrangement of prop-2’-enyloxyanthraquinones and 2’-chloroprop-2’-enyloxyanthraquinones with iron powder in ionic liquids
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A rapid and selective iron-mediated reductive Claisen rearrangement of various prop-2’-enyloxyanthraquinones and 2’-chloroprop-2’-enyloxyanthraquinones to 1-hydroxy-2-(prop-2’-enyl)anthraquinones and anthrafurandiones is presented. All reactions are carried out in a mixture of ionic liquids, [Bzmim]Cl (1-benzyl-3-methylimidazolium chloride) and [Hmim]BF4 (1-methylimidazolium tetrafluoroborate), in short reaction times (5–35 min). Our study showed that 1-(prop-2’-enyloxy)anthraquinone is more active than 1-(2’-chloroprop-2’-enyloxy)anthraquinone to perform this rearrangement.
- Nadali, Samaneh,Khoshroo, Ali,Aghapour, Ghasem
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p. 883 - 895
(2018/06/07)
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- A facile and general approach to 3-((trifluoromethyl)thio)-4 H -chromen-4-one
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A facile and efficient synthetic strategy to 3-((trifluoromethyl)thio)-4H-chromen-4-one was developed. AgSCF3 and trichloroisocyanuric acid were employed here to generate active electrophilic trifluoromethylthio species in situ. This reaction could proceed under mild conditions in a short reaction time and be insensitive to air and moisture.
- Xiang, Haoyue,Yang, Chunhao
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supporting information
p. 5686 - 5689
(2015/02/19)
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- Synthesis and enhanced DNA cleavage activities of bis-tacnorthoamide derivatives
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A new metal-free DNA cleaving reagent, bis-tacnorthoamide derivative 1 with two tacnorthoamide (tacnoa) units linked by a spacer containing anthraquinone, has been synthesized from triazatricyclo[5.2.1.04,10]decane and characterized by NMR and mass spectrometry. For comparison, the corresponding compounds mono-tacnorthoamide derivative 2 with one tacnorthoamide unit and 6 with two tacnorthoamide units linked by an alkyl (1,6-hexamethylene) spacer without anthraquinone have also been synthesized. The DNA-binding property investigated via fluorescence and CD spectroscopy suggests that compounds 1 and 2 have an intercalating DNA binding mode, and the apparent binding constants of 1, 2 and 6 are 1.3 × 107 M-1, 0.8 × 10 7 M-1 and 8 × 105 M-1, respectively. Agarose gel electrophoresis was used to assess plasmid pUC19 DNA cleavage activity promoted by 1, 2, 6 and parent tacnoa under physiological conditions, which gives rate constants kobs of 0.2126 ± 0.0055 h-1, 0.0620 ± 0.0024 h-1, 0.040 ± 0.0007 h-1 and 0.0043 ± 0.0002 h-1, respectively. The 50-fold and 15-fold rate acceleration over parent tacnoa is because of the anthraquinone moiety of compound 1 or 2 intercalating into DNA base pairs via a stacking interaction. Moreover, DNA cleavage reactions promoted by compound 1 give 5.3-fold rate acceleration over compound 6, which further demonstrates that the introduction of anthraquinone results in a large enhancement of DNA cleavage activity. In particular, DNA cleavage activity promoted by 1 bearing two tacnoa units is 3.3 times more effective than 2 bearing one tacnoa unit and the DNA cleavage by compound 1 was achieved effectively at a relatively low concentration (0.03 mM). This dramatic rate acceleration suggests the cooperative catalysis of the two positively charged tacnoa units in compound 1. The radical scavenger inhibition study and ESI-MS analysis of bis(2,4-dinitrophenyl) phosphate (BDNPP) and adenylyl(3′-5′) phosphoadenine (APA) cleavage in the presence of compound 1 suggest the cleavage mechanism would be via a hydrolysis pathway by cleaving the phosphodiester bond of DNA.
- Wei, Li,Hu, Hong-Wen,Lu, Guo-Yuan,Shao, Ying,Zhou, Mi
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p. 8484 - 8492,9
(2012/12/13)
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- Photochemistry of 1, n -Dibenzyloxy-9,10-anthraquinones
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Figure presented The photochemistry of a series of 9,10-anthraquinones with multiple benzyloxy substituents was investigated. In polar solvent, the expected Blankespoor oxidative cleavage reaction is the major reaction pathway, but in most cases, several minor products were observed. In nonpolar solvents, the abundance of these minor products increases dramatically. Four types of product were observed with the favored reaction pathway shifting with minor changes in substitution on the anthraquinone. Several types of product require cleavage of the C-O bond on the benzyloxy group and, apparently, follow a photo-Claisen-type mechanism. Others involve the expected 1,5-diradical but do not exhibit the single-electron transfer usually observed in the Blankespoor-type reaction. The results indicate the importance of considering the medium and photoredox behavior in anthraquinone photochemistry.
- Sarma, Saurav J.,Jones, Paul B.
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supporting information; experimental part
p. 3806 - 3813
(2010/08/20)
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- Synthesis and cytotoxic activity of a new series of topoisomerase I inhibitors
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A series of structurally simple analogues of natural topopyrone C were synthesized and tested for cytotoxic and topoisomerase I inhibitory activities. The removal of the hydroxyl groups at the 5 and 9 positions resulted in an increased cytotoxic potency a
- Dallavalle, Sabrina,Gattinoni, Sonia,Mazzini, Stefania,Scaglioni, Leonardo,Merlini, Lucio,Tinelli, Stella,Beretta, Giovanni L.,Zunino, Franco
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p. 1484 - 1489
(2008/09/20)
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- BeCl2 as a new highly selective reagent for dealkylation of aryl-methyl ethers
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An efficient and simple method is introduced for the selective removal of methyl group from poly aryl-methyl ethers, in some important derivatives of benzophenones, xanthones, anthraquinones, aryl esters, benzamides and nitroanisoles with BeCl2.
- Sharghi, Hashem,Tamaddon, Fatemeh
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p. 13623 - 13640
(2007/10/03)
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- 2-Anthracenonyl acetic acids as 5-lipoxygenase inhibitors
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The synthesis of 2-substituted anthracenonyl acetic acid (2-AA) derivatives is described. The key step is the Marschalk reaction of 1-hydroxy-8-methoxy-anthracenedione with glycolic acid. After protection of the resulting 2-anthracenonyl acetic acid derivative, the 2-monoalkylated derivatives are selectively obtained by direct alkylation. The methodology proves quite general and allows for the introduction of various substituents onto the 2-position of the carboxylic side chain. Reduction of the anthracenediones proceeds with concomitant protecting group removal and proves final 2-AA products in good yields. The results of initial biological studies demonstrate enhanced 5-lipoxygenase inhibition compared to anthralin.
- Prinz, Helge,Mueller, Klaus
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p. 262 - 266
(2007/10/03)
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- Novel anthraquinone inhibitors of human leukocyte elastase and cathepsin G
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A large series of variously substituted anthraquinones has been synthesized and assayed for inhibitory capacity against human leukocyte elastase (HLE) and cathepsin G (CatG), two serine proteinases implicated in diseases characterized by the abnormal degradation of connective tissue, such as pulmonary emphysema and rheumatoid arthritis. It was found that 2-alkyl- 1,8-dihydroxyanthraquinone analogues are competitive inhibitors of HLE with IC50 values ranging from 4 to 10 μM, and also inhibit CatG with IC50 values ranging from 25 to 55 μM. Consequently, analogues containing the 2- alkyl-1-hydroxy-8-methoxyanthraquinone substitution pattern inhibit HLE to the same magnitude as for the compounds above, but show very little inhibition of CatG. Anthraquinones containing long, hydrophobic n-butyl carbonate moieties in the 1- and 8-positions in conjunction with a third hydrophobic substituent in the 2- or 3-position are highly selective for HLE, with K(i) values in the range of 10-7 M. All of the inhibitors described are completely reversible, with no evidence of acyl-enzyme formation detected.
- Zembower,Kam,Powers,Zalkow
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p. 1597 - 1605
(2007/10/02)
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- A FORMAL TOTAL SYNTHESIS OF AKLAVINONE VIA A BLOCKED ANTHRAQUINONE TAUTOMER
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An advanced intermediate in the Kishi synthesis of aklavinone was prepared.Juglone was converted into enone 4.Quinone 6 was then prepared from 4 by Michael addition and elimination of PhSOH and HCN.
- Kraus, George A.,Walling, John A.
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p. 1873 - 1876
(2007/10/02)
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- A VICARIOUS AROMATIC SUBSTITUTION APPROACH TO AKLAVINONE FROM CHRYSAZIN
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The cheap, available dye-intermediate 1,8-dihydroxyanthraquinone (2) is converted efficiently to a useful aklavinone precursor (3).A Mitsunobu alkylation-Claisen rearrangement sequence and an unprecedented vicarious aromatic substitution on an anthraquino
- Murphy, Raymond A.,Cava, Michael P.
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p. 803 - 806
(2007/10/02)
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- ANTHRAQUINONE DYE INTERMEDIATES AS PRECURSORS OF AKLAVINONE-TYPE ANTHRACYCLINONES
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The commercially available dye intermediates 1-hydroxyanthraquinone, 1-amino-2-methylanthraquinone and 1,8-dihydroxyanthraquinone (chrysazin) have been elaborated in a regiospecific manner into tetracyclic ketonitriles.The latter are potential precursors
- Cava, Michael P.,Ahmed, Zareen,Benfaremo, Nicholas,Murphy, Raymond A.,O'Malley, Gerard J.
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p. 4767 - 4776
(2007/10/02)
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- Selective Dealkylation of Methoxyanthraquinones via Difluoro1,O9>boron Chelates: Synthesis of Hydroxymethoxyanthraquinones
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1,8-, 1,5- 1,2-, and 1,4-Dimethoxyanthraquinones have been treated with boron trifluoride-diethyl ether to give difluoro(anthraquinonato)boron chelates (1a-d) respectively. 1,4,5-Trimethoxyanthraquinone was similarly converted separately in benzene and toluene into the mono- (2) and bis-difluoroboron(3)-chelates respectively, and 2,2',4,4'-tetramethoxybenzophenone was converted by BF3*Et2O in toluene into the boron adduct (4).Treatment of these derivatives, (1a-d) and (2)-(4), with methanol gave the following uncomplexed derivatives in good yield respectively: 1-hydroxy-8-methoxyanthraquinone, 1-hydroxy-5-methoxyanthraquinone, 1-hydroxy-2-methoxyanthraquinone, 1-hydroxy-4-methoxyanthraquinone, 4-hydroxy-1,5-dimethoxyanthraquinone, 1,4-dihydroxy-5-methoxyanthraquinone, and 2-hydroxy-2',4,4'-trimethoxybenzophenone.
- Preston, Peter N.,Winwick, Thomas,Morley, John O.
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p. 1439 - 1441
(2007/10/02)
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- Selective Demethylation of Di- and Tri-methoxyanthraquinones via Aryloxydifluoroboron Chelates. Synthesis of 4-Hydroxy-1,5-dimethoxyanthraquinone and 1,4-Dihydroxy-5-methoxyanthraquinone
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Methoxyanthraquinone derivatives react with boron trifluoride-diethyl ether to give mono- and bis-difluoroboron chelates which, in methanol, are converted into hydroxyanthraquinones; an extension of this method is described for the synthesis of 2-hydroxy-2',4,4'-trimethoxybenzophenone.
- Preston, Peter N.,Winwick, Thomas,Morley, John O.
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- Regiospecific Synthesis of Quinizarin and Naphthazarin Derivatives by Cycloaddition
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The diene (E)-1,1,4-trimethoxybuta-1,3-diene underwent regiospecific cycloaddition to derivatives of 2(3)-chloro-1,4-naphthoquinone.The resulting adducts were aromatized to give 1,4-dioxygenated anthraquinones.The latter were obtained as derivatives of quinizarin dimethyl ether or of quinizarin monomethyl ether depending on the conditions of aromatization.Cycloaddition of the diene to non-halogenated naphthoquinones proceeded similarly, orientation being controlled by substituents in the benzenoid ring.Analogous reaction of the diene with benzoquinones gave 5,8-dioxygenated naphthoquinones (naphthazarins), generally in limited yield.The procedure has been applied to synthesis of the mould metabolites helminthosporin and cynodontin
- Cameron, Donald W.,Feutrill, Geoffrey I.,McKay, Peter G.
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p. 2095 - 2109
(2007/10/02)
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- REGIOSPECIFIC SYNTHESIS OF QUINIZARIN DERIVATIVES BY CYCLOADDITION
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Cycloaddition of (E)-1,1,4-trimethoxy-1,3-butadiene (1) to naphthoquinones affords regiospecific syntheses of derivatives of 1,4-dihydroxyanthraquinone including the mould metabolites helminthosporin (21) and cynodontin (22).
- Cameron, Donald W.,Feutrill, Geoffrey I.,McKay, Peter G.
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p. 701 - 702
(2007/10/02)
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