- Halogenated method of aromatic compound
-
The invention belongs to the field of organic synthesis, and particularly relates to synthesis of aromatic halogens, in particular to arylamine. The invention discloses a synthesis method of a corresponding ortho-halogenated product from aromatic compounds such as carbazole and phenol. The method comprises the following steps: adding a metal sulfonate salt catalyst, aromatic amine, carbazole, phenol and other hydrogen - heteroatom-containing aromatic compound reaction substrates, a halogenation reagent and a reaction solvent at a specific reaction temperature. After the drying agent is dried, the yield of the reaction product and the nuclear magnetic characterization determining structure are determined by column chromatography. The reaction product yield is determined by gas chromatography. By adopting the method, under the cheap metal salt catalyst, a plurality of ortho-substituted brominated and chloro products can be obtained with moderate to excellent yield.
- -
-
Paragraph 0202-0204
(2021/11/10)
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- Synthesis method 5 - halogeno-veratraldehyde
-
The invention belongs to the field of organic chemistry, and in particular relates 5 - to a method for synthesizing halogenated O-veratraldehyde by using 4 - halogenoylguaiacol as a raw material to obtain 2 -hydroxy -3 - methoxy -5 -halogenated mandelic a
- -
-
Paragraph 0061-0064
(2021/11/21)
-
- A synthetic preparation method for small carbags hydrochloric acid
-
The present invention belongs to the field of organic chemistry, relates to a method of synthesizing berberine hydrochloride, comprising: S1: with 5-halo-o-quinoastearaldehyde and piperine ethylamine to obtain N- [2-(3,4-dimethoxyphenyl-5-yl) ethyl] -1- (5-halo-2,3-dimethoxybenzyl) methylimide; S2: to obtain 2- (3,4-diimoxyphenyl) -N- (5-bromo-2,3-dimethoxybenzyl) ethylamine; S3: to obtain 2-(3,4-dimethoxyphenyl) -N- (5-bromo-2 S4: to obtain 12-halogenated berberine derivative; S5: to obtain berberine. The present invention is free from the application of the by-product o-vanillin synthesis of o-resveratal raw material constraints, synthesis of 5- substitute o-resveratal and piperine ethylamine, and the use of the two preparation of berberine hydrochloride, with raw materials readily available, mild reaction conditions, easy to operate, high chemical yield, low cost and other advantages.
- -
-
Paragraph 0164-0166
(2021/12/08)
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- Synthesis and Photoswitching Properties of Bioinspired Dissymmetric I-Pyrone, an Analogue of Cyclocurcumin
-
Cyclocurcumin (CC), a turmeric curcuminoid with potential therapeutic properties, is also a natural photoswitch that may undergo E/Z photoisomerization under UV light. To be further exploited in relevant biological applications, photoactivation under near-infrared (NIR) irradiation is required. Such requirement can be met through opportune chemical modifications, by favoring two-photon absorption (TPA) probability. Herein, a general and efficient synthesis of a biomimetic 2,6-disubstituted-δ-pyrone analogue of CC is described, motivated by the fact that molecular modeling previews an order of magnitude increase of its NIR TPA compared to CC. Three retrosynthetic pathways have been identified (i) via an aryl-oxazole intermediate or via aryl-diynone through (ii) a bottom-up or (iii) a top-down approach. While avoiding the passage through unstable synthons or low-yield intermediate reactions, only the latest approach could conveniently afford the 2,6-disubstituted-I-pyrone analogue of CC, in ten steps and with an overall yield of 18%. The photophysical properties of our biomimetic analogue have also been characterized showing an improved photoisomerization yield over the parent natural compound. The potentially improved nonlinear optical properties, as well as enhanced stability, may be correlated to the enforcement of the planarity of the pyrone moiety leading to a quadrupolar D-π-A-π-D system.
- Pecourneau, Jérémy,Losantos, Raúl,Monari, Antonio,Parant, Stéphane,Pasc, Andreea,Mourer, Maxime
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p. 8112 - 8126
(2021/06/30)
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- Structure-based design, docking and binding free energy calculations of a366 derivatives as spindlin1 inhibitors
-
The chromatin reader protein Spindlin1 plays an important role in epigenetic regulation, through which it has been linked to several types of malignant tumors. In the current work, we report on the development of novel analogs of the previously published lead inhibitor A366. In an effort to improve the activity and explore the structure–activity relationship (SAR), a series of 21 derivatives was synthesized, tested in vitro, and investigated by means of molecular modeling tools. Docking studies and molecular dynamics (MD) simulations were performed to analyze and rationalize the structural differences responsible for the Spindlin1 activity. The analysis of MD simulations shed light on the important interactions. Our study highlighted the main structural features that are required for Spindlin1 inhibitory activity, which include a positively charged pyrrolidine moiety embedded into the aromatic cage connected via a propyloxy linker to the 2-aminoindole core. Of the latter, the amidine group anchor the compounds into the pocket through salt bridge interactions with Asp184. Different protocols were tested to identify a fast in silico method that could help to discriminate between active and inactive compounds within the A366 series. Rescoring the docking poses with MM-GBSA calculations was successful in this regard. Because A366 is known to be a G9a inhibitor, the most active developed Spindlin1 inhibitors were also tested over G9a and GLP to verify the selectivity profile of the A366 analogs. This resulted in the discovery of diverse selective compounds, among which 1s and 1t showed Spindlin1 activity in the nanomolar range and selectivity over G9a and GLP. Finally, future design hypotheses were suggested based on our findings.
- Luise, Chiara,Robaa, Dina,Regenass, Pierre,Maurer, David,Ostrovskyi, Dmytro,Seifert, Ludwig,Bacher, Johannes,Burgahn, Teresa,Wagner, Tobias,Seitz, Johannes,Greschik, Holger,Park, Kwang-Su,Xiong, Yan,Jin, Jian,Schüle, Roland,Breit, Bernhard,Jung, Manfred,Sippl, Wolfgang
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-
- Bimetallic photoredox catalysis: Visible light-promoted aerobic hydroxylation of arylboronic acids with a dirhodium(ii) catalyst
-
We report the use of a rhodium(II) dimer in visible light photoredox catalysis for the aerobic oxidation of arylboronic acids to phenols under mild conditions. Spectroscopic and computational studies indicate that the catalyst Rh2(bpy)2(OAc)4 (1) undergoes metal-metal to ligand charge transfer upon visible light irradiation, which is responsible for catalytic activity. Further reactivity studies demonstrate that 1 is a general photoredox catalyst for diverse oxidation reactions.
- Campbell, Michael G.,Chuang, Gary Jing,Liu, Ming-Lun,Miura-Stempel, Emily,Tu, Jing-Wen,Yang, Hsiang-Ming
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p. 2040 - 2047
(2020/03/13)
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- Rapid Bis-Coupling Reactivity with Triarylbismuth Reagents: Synthesis of Structurally Diverse Scaffolds and Step-economic Convergent Synthesis of Quebecol
-
The cross-coupling study of gem-dibromoesters with triarylbismuths as threefold arylating reagents was investigated under palladium-catalyzed conditions. This study using triarylbismuth reagents explored the cross-coupling reactivity with various functionalized gem-dibromoesters. It furnished a variety of multi-functional trisubstituted acrylates embedded with aryl, alkene and alkyne scaffolds in high yields. The present study in turn, provided easy access to various triarylated acrylates and functionalized 1,3-dienyl and 1,3-enyne esters. Further, the established method applied in the step-economic and convergent synthesis of quebecol natural product in good yield.
- Rao, Maddali L. N.,Murty, Venneti N.,Nand, Sachchida
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p. 1629 - 1636
(2020/03/05)
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- Novel pleconaril derivatives: Influence of substituents in the isoxazole and phenyl rings on the antiviral activity against enteroviruses
-
Today, there are no medicines to treat enterovirus and rhinovirus infections. In the present study, a series of novel pleconaril derivatives with substitutions in the isoxazole and phenyl rings was synthesized and evaluated for their antiviral activity against a panel of pleconaril-sensitive and -resistant enteroviruses. Studies of the structure-activity relationship demonstrate the crucial role of the N,N-dimethylcarbamoyl group in the isoxazole ring for antiviral activity against pleconaril-resistant viruses. In addition, one or two substituents in the phenyl ring directly impact on the spectrum of antienteroviral activity. The 3-(3-methyl-4-(3-(3-N,N-dimethylcarbamoyl-isoxazol-5-yl)propoxy)phenyl)-5-trifluoromethyl-1,2,4-oxadiazole 10g was among the compounds exhibiting the strongest activity against pleconaril-resistant as well as pleconaril-susceptible enteroviruses with IC50 values from 0.02 to 5.25 μM in this series. Compound 10g demonstrated markedly less CYP3A4 induction than pleconaril, was non-mutagenic, and was bioavailable after intragastric administration in mice. These results highlight compound 10g as a promising potential candidate as a broad spectrum enterovirus and rhinovirus inhibitor for further preclinical investigations.
- Egorova, Anna,Ekins, Sean,Jahn, Birgit,Kazakova, Elena,Makarov, Vadim,Schmidtke, Michaela
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-
- Mild and Regioselective Bromination of Phenols with TMSBr
-
In this work, an unexpected promoting effect of by-product thioether was observed, leading to a mild and regioselective bromination of phenols with TMSBr. This method can tolerate a series of functional groups such as the reactive methoxyl, amide, fluoro, chloro, bromo, aldehyde, ketone and ester groups, and has the potential to recycle the by-product thioether and isolate the desired product under column chromatography-free conditions. Mechanism studies revealed that O–H···S hydrogen bond may be formed between phenol and by-product thioether. Possibly owing to the steric hindrance effect from by-product thioether, the electrophilic bromination at para-position of phenols is much favorable.
- Ma, Xiantao,Yu, Jing,Jiang, Mengyuan,Wang, Mengyu,Tang, Lin,Wei, Mengmeng,Zhou, Qiuju
-
supporting information
p. 4593 - 4596
(2019/07/05)
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- Directed Structural Transformations of Coordination Polymers Supported Single-Site Cu(II) Catalysts to Control the Site Selectivity of C-H Halogenation
-
A main difficulty in C-H bond functionalization is to undertake the catalyst control accurately where the reaction takes place. In this work, to achieve highly effective and regioselective single-site catalysts, a three-dimensional (3D) rhombus-like framework of {[Mn(Hidbt)DMF]·H2O}n (1) [H3idbt = 5,5′-(1H-imidazole-4,5-diyl)-bis(2H-tetrazole)] containing coordinated DMF molecules was constructed. For the dissolution-recrystallization structural transformation process, attractive structural transformations proceeded from 1 to a new crystalline species formulated as {[Mn3(idbt)2(H2O)2]·3H2O}n (2) with a 3D windowlike architecture, and then the Mn ions in 2 could be exchanged with Cu ions through cation exchange in a single-crystal to single-crystal fashion to produce the Cu-exchanged product {[Mn2Cu(idbt)2(H2O)2]·3H2O}n (2a), which had a windowlike framework like that of 2. Furthermore, 2 and 2a were used as heterogeneous catalysts for the regioselective C-H halogenation of phenols with N-halosuccinimides (NCS and NBS) to produce the site selective single monohalogenated products. It was found that the catalytic activity and site selectivity of 2a were much higher than those of 2, because the unique structural features of 2a with the uniformly dispersed CuII active centers served as a single-site catalyst with a site-isolated and well-defined platform to promote the C-H halogenation reaction in regiocontrol and guide an orientation that favored the para selectivity during the reaction process.
- Huang, Chao,Zhu, Kaifang,Zhang, Yingying,Shao, Zhichao,Wang, Dandan,Mi, Liwei,Hou, Hongwei
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supporting information
p. 12933 - 12942
(2019/10/11)
-
- A phenol compound high regioselective bromination method
-
The invention discloses a phenol compound high regioselective bromination of the method, the method to trimethyl silane as brominating agent, in order to aryl sulfoxide as activator, with the phenol compound in the 0 - 50 °C lower, in a solvent, the reaction is stirred under an atmosphere of nitrogen at 1 - 12 hours, to realize the phenol compound high regioselective bromination, filtered, extraction columns chromatography separation to obtain the bromo phenol compound. This invention adopts the aryl sulfoxide as activator, sulfoxide substituted Kiev, on the one hand so that the phenol compound bromo the higher selectivity of the reaction region, and when the phenol compound hydroxy alignment not substituted basetime, regional selective para - bromo product, when the phenol compound hydroxy position there is substituted basetime, selective ortho - bromo product obtained; on the other hand if it through the filter, the extraction can be realized at the same time the isolation and purification of the recycling of the by-product, compared with column chromatography, reduces the separation and purification cost.
- -
-
Paragraph 0034; 0035; 0036
(2019/06/05)
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- Regioselective bromination of arenes mediated by triphosgene-oxidized bromide
-
This article first time describes triphosgene (BTC) as an oxidant while the non-toxic and easy-to-handle potassium bromide (KBr) as the source of bromine to the bromination reaction of aromatic substrates. The novel brominating protocol gives excellent para-regioselectivity of the alkoxyl/hydroxyl arenes and high yield, offering good potential of commercial scale applications. The mechanism of “Triphosgene oxidize bromide” was proposed.
- Xu, Yingzhou,Hu, Dufen,Zheng, Hui,Mei, David,Gao, Zhaobo
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supporting information
(2019/08/30)
-
- Design, Synthesis, and Biological Evaluation of Novel Selenium-Containing Isocombretastatins and Phenstatins as Antitumor Agents
-
Two series of structurally related organoselenium compounds designed by fusing the anticancer agent methyl(phenyl)selane into the tubulin polymerization inhibitors isocombretastatins or phenstatins were synthesized and evaluated for antiproliferative acti
- Pang, Yanqing,An, Baijiao,Lou, Lanlan,Zhang, Junsheng,Yan, Jun,Huang, Ling,Li, Xingshu,Yin, Sheng
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p. 7300 - 7314
(2017/09/22)
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- Selenium-containing benzophenone, derivatives and preparation method thereof and application in preparation of antitumor drugs
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The invention discloses selenium-containing benzophenone, derivatives and a preparation method thereof and application in preparation of antitumor drugs. According to the selenium-containing benzophenone and derivatives thereof, an antitumor drug molecule
- -
-
Paragraph 0041-0043
(2017/11/29)
-
- Synthesis and evaluation of selenium-containing indole chalcone and diarylketone derivatives as tubulin polymerization inhibition agents
-
Sixteen new selenium-containing indole chalcone and diarylketone derivatives were synthesized and evaluated as tubulin polymerization inhibitors. Among them, compound 25b exhibited the most potent antiproliferative activities against six human cancer cell lines with IC50 values of 0.004-0.022 μM. A microtubule dynamics assay and an immunofluorescence assay confirmed that 25b could effectively inhibit tubulin polymerization (IC50 = 2.1 ± 0.27 μM). Further cellular mechanism studies revealed that 25b induced G2/M phase arrest, which was further evidenced by the decrease in the mitochondrial membrane potential (MMP).
- Zhang, Shun,An, Baijiao,Li, Jiayan,Hu, Jinhui,Huang, Ling,Li, Xingshu,Chan, Albert S. C.
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supporting information
p. 7404 - 7410
(2017/09/25)
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- Lewis Acid-Mediated Site-Selective Synthesis of Oxygenated Biaryls from Methoxyphenols and Electron-Rich Arenes
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A rapid, efficient, and metal-free Lewis acid-mediated methodology has been developed for the site-selective synthesis of unsymmetrical oxygenated biaryls. This simple and efficient methodology furnished highly oxygenated and functionalized unsymmetrical biaryls in good to excellent yields by the direct oxidative coupling of electron-rich arenes to the α-position of carbonyl functionality of in situ generated masked benzoquinones.
- Sharma, Shivangi,Parumala, Santosh Kumar Reddy,Peddinti, Rama Krishna
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p. 9367 - 9383
(2017/09/22)
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- Rapid Access to Benzofuran-Based Natural Products through a Concise Synthetic Strategy
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A concise strategy is described for the synthesis of ailanthoidol (1), egonol (2), homoegonol (3), demethoxyegonol (4), demethoxyhomoegonol (5), and stemofuran A (6). This approach involves a Pd-catalysed domino cyclization/coupling process using triarylbismuth reagents for the generation of the benzofuran core. Subsequent structural modifications then give the final targets. The high yielding synthesis of the recently isolated natural products egonol-9(Z)-12(Z)-linoleate (2a), 7-demethoxyegonol-9(Z)-12(Z)-linoleate (4a), and 7-demethoxy-egonol-9(Z)-oleate (4b) are also reported.
- Rao, Maddali L. N.,Murty, Venneti N.
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p. 2177 - 2186
(2016/05/09)
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- Synthesis of the carbon skeleton of the griseorhodins
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A synthetic strategy to access the carbon skeleton of the griseorhodin family of natural products has been developed. The key step involved the acid-mediated spirocyclisation of a highly functionalised dihydroxyketone. The delicate electronic balance betw
- Atkinson, Darcy J.,Furkert, Daniel P.,Brimble, Margaret A.
-
-
- Unprecedented 8,9′-neolignans: Enantioselective synthesis of possible stereoisomers for structural determination
-
(+)-Wutaienin (3) and its C-7 methyl ether (4), isolated from Zanthoxylum wutaiense, were found to be unprecedented 8,9′-neolignans containing an (S)-2-(1,1-dimethyl-1-hydroxymethyl)-7-methoxydihydrobenzofuran skeleton. Wutaienin (3) was present in the pl
- Takahashi, Masato,Suzuki, Noriyuki,Ishikawa, Tsutomu,Huang, Hung-Yi,Chang, Hsun-Shuo,Chen, Ih-Sheng
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supporting information
p. 2585 - 2589
(2015/02/05)
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- Visible-light photoredox catalysis enabled bromination of phenols and alkenes
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A mild and efficient methodology for the bromination of phenols and alkenes has been developed utilizing visible light-induced photoredox catalysis. The bromine was generated in situ from the oxidation of Br- by Ru(bpy)33+, both of which resulted from the oxidative quenching process.
- Zhao, Yating,Li, Zhe,Yang, Chao,Lin, Run,Xia, Wujiong
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p. 622 - 627
(2014/04/17)
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- Asymmetric synthesis and anti-protozoal activity of the 8,4′-oxyneolignans virolin, surinamensin and analogues
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The asymmetric synthesis of 8,4′-oxyneolignans (-)-virolin, (-)-surinamensin and a number of analogues has been achieved. A divergent synthesis was used, with all compounds being elaborated from a single chiral aldehyde derived from ethyl lactate. In the
- Rye, Claire E.,Barker, David
-
p. 240 - 248
(2013/03/28)
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- A novel p-terphenyl derivative inducing cell-cycle arrest and apoptosis in MDA-MB-435 cells through topoisomerase inhibition
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A novel series of p-terphenyl derivatives (1-4, 1a-4a) was successfully synthesized and their in vitro anticancer activities were evaluated. Compound 1, showing the best antiproliferative activity with IC50 1 μM against MDA-MB-435 cells, was further investigated. Compound 1 brought about a remarkable accumulation of MDA-MB-435 cells in G2/M phase prior to the induction of apoptosis. Further antitumor mechanism study indicated that compound 1, which inhibited the enzyme activity of Topo I and Topo IIα by interfering predominantly with the enzyme, could be topoisomerase suppressors instead of poisons. We conclude that compound 1 represents a novel class of Topo catalytic suppressors for developing new chemotherapeutic agents.
- Qiu, Jin,Zhao, Baobing,Shen, Yan,Chen, Wang,Ma, Yudao,Shen, Yuemao
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p. 192 - 202
(2013/10/01)
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- Vanadate-dependent bromoperoxidases from Ascophyllum nodosum in the synthesis of brominated phenols and pyrroles
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Bromoperoxidases from the brown alga Ascophyllum nodosum, abbreviated as VBrPO(AnI) and VBrPO(AnII), show 41% sequence homology and differ by a factor of two in the percentage of α-helical secondary structures. Protein monomers organize into homodimers for VBrPO(AnI) and hexamers for VBrPO(AnII). Bromoperoxidase II binds hydrogen peroxide and bromide by approximately one order of magnitude stronger than VBrPO(AnI). In oxidation catalysis, bromoperoxidases I and II turn over hydrogen peroxide and bromide similarly fast, yielding in morpholine-4-ethanesulfonic acid (MES)-buffered aqueous tert-butanol (pH 6.2) molecular bromine as reagent for electrophilic hydrocarbon bromination. Alternative compounds, such as tribromide and hypobromous acid are not sufficiently electrophilic for being directly involved in carbon-bromine bond formation. A decrease in electrophilicity from bromine via hypobromous acid to tribromide correlates in a frontier molecular orbital (FMO) analysis with larger energy gaps between the π-type HOMO of, for example, an alkene and the σ*Br,X-type LUMO of the bromination reagent. By using this approach, the reactivity of substrates and selectivity for carbon-bromine bond formation in reactions mediated by vanadate-dependent bromoperoxidases become predictable, as exemplified by the synthesis of bromopyrroles occurring naturally in marine sponges of the genera Agelas, Acanthella, and Axinella. The Royal Society of Chemistry.
- Wischang, Diana,Radlow, Madlen,Hartung, Jens
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p. 11926 - 11940
(2013/09/02)
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- Bromination of phenols in bromoperoxidase-catalyzed oxidations
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Phenol and ortho-substituted derivatives furnish products of selective para-bromination, if treated with sodium bromide, hydrogen peroxide, and the vanadate(V)-dependent bromoperoxidase I from the brown alga Ascophyllum nodosum. Relative rates of bromination in morpholine-4-ethane sulfonic acid (MES)-buffered aqueous tert-butanol (pH 6.2) increase by a factor 32, as the ortho-substituent in a phenol changes from F via Cl, OCH3, C(CH 3)3, and H to CH3. The polar effect in phenol bromination by the enzymatic method, according to a Hammett-correlation (ρ=-3), compares to reactivity of molecular bromine under identical conditions (ρ=-2). Hypobromous acid is not able to electrophilically substitute bromine for hydrogen at pH 6.2 in aqueous tert-butanol. The tribromide anion behaves in MES-buffered aqueous tert-butanol as electrophile (ρ~-3), showing a similar polar effect in phenol bromination as molecular bromine.
- Wischang, Diana,Hartung, Jens
-
supporting information
p. 9456 - 9463
(2012/11/07)
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- A short-step asymmetric synthesis of dehydrodiconiferyl alcohol via C-H insertion reaction
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A rhodium-catalyzed intramolecular C-H insertion reaction using a chiral auxiliary and a chiral catalyst was employed to achieve double asymmetric induction of a trans-disubstituted dihydrobenzofuran ring, as the key reaction of a stereoselective synthesis of (-)-dehydrodiconiferyl alcohol in 13 steps from commercially available guaiacol. Georg Thieme Verlag Stuttgart · New York.
- Matsumoto, Shogo,Asakawa, Tomohiro,Hamashima, Yoshitaka,Kan, Toshiyuki
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supporting information; experimental part
p. 1082 - 1084
(2012/06/15)
-
- Simple and improved regioselective brominations of aromatic compounds using N-benzyl-N,N-dimethylanilinium peroxodisulfate in the presence of potassium bromide under mild reactions conditions
-
A simple, efficient, and mild method for the selective bromination of some activated aromatic compounds using N-benzyl-N,N-dimethylanilinium peroxodisulfate in the presence of potassium bromide in non-aqueous solution is reported. The results obtained revealed good to excellent selectivity between the ortho and para positions of phenols and methoxyarenes.
- Ghasemnejad-Bosra, Hassan,Ramzanian-Lehmali, Farhad,Jafari, Somaye
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experimental part
p. 685 - 692
(2012/01/16)
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- Anodic coupling of guaiacol derivatives on boron-doped diamond electrodes
-
The anodic treatment of guaiacol derivatives on boron-doped diamond electrodes (BDD) provides a direct access to nonsymmetrical biphenols, which would require a multistep sequence by conventional methods. Despite the destructive nature of BDD anodes they
- Kirste, Axel,Schnakenburg, Gregor,Waldvogel, Siegfried R.
-
supporting information; experimental part
p. 3126 - 3129
(2011/08/03)
-
- Facile p-toluenesulfonic acid-promoted para-selective monobromination and chlorination of phenol and analogues
-
para-Regioselective bromination of phenol and analogues, promoted by p-toluenesulfonic acid, is achieved in high to excellent yields at room temperature with N-bromosuccinimide. Chlorination with N-chlorosuccinimide and catalysed by p-toluenesulfonic acid also gives para-chlorinated phenol analogues in good yields at room temperature. para-Bromination of phenol, promoted by p-toluenesulfonic acid, is achieved in excellent yields at room temperature with N-bromosuccinimide. p-Toluenesulfonic acid is also effective as a promoter of para-chlorination with N-chlorosuccinimide.
- Bovonsombat, Pakorn,Ali, Rameez,Khan, Chiraphorn,Leykajarakul, Juthamard,Pla-On, Kawin,Aphimanchindakul, Suraj,Pungcharoenpong, Natchapon,Timsuea, Nisit,Arunrat, Anchalee,Punpongjareorn, Napat
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experimental part
p. 6928 - 6935
(2010/10/01)
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- Bromination of aromatic compounds using ammonium bromide and oxone
-
A simple, efficient and mild method for the selective bromination of activated aromatic compounds using ammonium bromide as the source of bromine and Oxone as the oxidant in methanol or water as solvent is reported. The reaction proceeds at ambient temperature in yields ranging from moderate to excellent without a catalyst. Georg Thieme Verlag Stuttgart.
- Arunkumar, MacHarla,Rohitha, Chozhiyath Nappunni,Kulkarni, Shivanand Janardhan,Narender, Nama
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experimental part
p. 1629 - 1632
(2010/06/20)
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- An efficient formal synthesis of the human telomerase inhibitor (±)-γ-rubromycin
-
Balancing act: The correct balance of electronic factors in the naphthazarin and isocoumarin fragments facilitates the acid-mediated spiroketalization step to afford the key densely functionalized spiroketal (see picture; EOM=ethoxymethyl) in the formal s
- Rathwell, Dominea C. K.,Yang, Sung-Hyun,Tsang, Kit Y.,Brimble, Margaret A.
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scheme or table
p. 7996 - 8000
(2010/01/16)
-
- Kumada-Corriu cross coupling route to the anti-cancer agent combretastatin A-4
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A short and efficient synthesis of the anticancer agent combretastatin A-4 was accomplished from inexpensive starting materials using the iron-catalyzed cross-coupling of a Grignard reagent and a bromostilbene as the key step. Copyright Taylor & Francis Group, LLC.
- Camacho-Davila, Alejandro A.
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p. 3823 - 3833
(2008/12/23)
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- A practical highly selective oxybromination of phenols with dioxygen
-
A simple, low cost and highly selective method for the synthesis of mono-bromophenols from phenol and electron-rich phenolic compounds has been developed. Bromide ions are used as halogenating agents, dioxygen as a final oxidant, and Cu(OAc)2 as a catalyst.
- Menini, Luciano,Parreira, Luciana A.,Gusevskaya, Elena V.
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p. 6401 - 6404
(2008/02/12)
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- Bromination of some aromatic compounds with potassium bromide in the presence of benzyltriphenylphosphonium peroxodisulfate
-
A simple, efficient, and mild method for selective bromination of some activated aromatic compounds using potassium bromide in the presence of benzyltriphenylphosphonium peroxodisulfate in nonaqueous solution is reported. The results obtained revealed good to excellent selectivity between ortho and para positions of phenols and methoxyarenes. Copyright Taylor & Francis Group, LLC.
- Tajik, Hassan,Mohammadpoor-Baltork, Iraj,Albadi, Jalal
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p. 323 - 328
(2007/10/03)
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- A convenient and regioselective oxidative bromination of electron-rich aromatic rings using potassium bromide and benzyltriphenylphosphonium peroxymonosulfate under nearly neutral reaction conditions
-
Regioselective oxidative bromination of electron-rich aromatic rings has been studied using potassium bromide as a bromine source in the presence of benzyltriphenylphosphonium peroxymonosulfate as oxidant under nearly neutral reaction conditions. In most cases we obtained monobrominated derivatives regioselectively and in good to high yields without the aid of strong acids.
- Adibi, Hadi,Hajipour, Abdol R.,Hashemi, Majid
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p. 1255 - 1259
(2007/10/03)
-
- Copper(II) bromide: A simple and selective monobromination reagent for electron-rich aromatic compounds
-
Copper(II) bromide was found to be a simple and efficient reagent for monobromination of electron-rich aromatic compounds at room temperature. The reaction proceeded smoothly with phenols, aryl alkyl ethers, and aromatic amines to afford the corresponding monobrominated product selectively in moderate to good yields. Copyright Taylor & Francis Group, LLC.
- Bhatt, Suchitra,Nayak, Sandip K.
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p. 1381 - 1388
(2008/02/01)
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- N-octylquinolinium tribromide: A task specific quinoline based ionic liquid as a new brominating agent
-
The N-octylquinolinium tribromide has been synthesized and explored as a new efficient brominating agent. It has high active bromine content per molecule and shows a remarkable reactivity towards various substrates. No organic solvent has been used during any stage of the reaction. The N-octylquinolinium tribromide is stable for months and acts as a safe source of bromine for complete bromination of phenols, aromatic amines, alkenes and alkynes.
- Kaushik,Polshettiwar, Vivek
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p. 2542 - 2545
(2007/10/03)
-
- Total synthesis of lamellarins D, L, and N
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Total synthesis of cytotoxic marine alkaloids, lamellarins D, L, and N, has been achieved by using Hinsberg-type pyrrole synthesis and palladium-catalyzed Suzuki-Miyaura coupling of the 3,4-dihydroxypyrrole bistriflate 6 as the key reactions. The total yields of lamellarins D, L, and N from the common intermediate 6 are 54, 58, and 50%, respectively.
- Fujikawa, Naotaka,Ohta, Takeshi,Yamaguchi, Tomohiro,Fukuda, Tsutomu,Ishibashi, Fumito,Iwao, Masatomo
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p. 594 - 604
(2007/10/03)
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- Efficient halogenation of aromatic systems using N-halosuccinimides in ionic liquids
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A simple, rapid and highly regioselective green protocol has been developed for the halogenation of aromatic systems with N-halosuccinimides using room temperature ionic liquids (ILs) as novel and recyclable reaction media to produce the corresponding halogenated aromatic compounds in high to quantitative yields. N-Halosuccinimides show enhanced reactivity in ionic liquids thereby reducing the reaction times dramatically and improving the yields substantially.
- Yadav,Reddy,Reddy,Basak,Narsaiah
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- Total synthesis of (S)-(+)-imperanene. Effective use of regio- and enantioselective intramolecular carbon-hydrogen insertion reactions catalyzed by chiral dirhodium(II) carboxamidates
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The total synthesis of (S)-(+)-imperanene, a natural product found in Chinese medicine, has been completed in 12 steps from a commercially available cinnamic acid. The key step is highly enantioselective carbon-hydrogen insertion from a diazoacetate using a chiral dirhodium(II) carboxamidate catalyst. An elimination process essential to the construction has been optimized to avoid intramolecular Friedel-Crafts alkylation.
- Doyle, Michael P.,Hu, Wenhao,Valenzuela, Marcela V.
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p. 2954 - 2959
(2007/10/03)
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- Intermolecular Diels-Alder reactions of brominated masked o-benzoquinones with electron-deficient dienophiles. A detour method to synthesize bicyclo[2.2.2]octenones from 2-methoxyphenols
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Intermolecular Diels-Alder reactions of masked o-benzoquinones, i.e., 6,6-dimethoxy-2,4-cyclohexadienones 5-7 and 21-24 generated from 2-methoxyphenols 1-3 and 17-20, respectively, with electron-deficient dienophiles leading to highly functionalized bicyclo[2.2.2]octenones are described. The masked o-benzoquinones (MOBs) 5-7 underwent Diels-Alder cycloadditions with methyl acrylate, methyl methacrylate, and methyl vinyl ketone to provide bicyclo[2.2.2]octenones 13a-c to 15a-c (direct method) in low to moderate yields with the concomitant formation of considerable amounts of dimers 9-11. To retard dimerization and to improve the yields of the requisite bicyclo[2.2.2]octenones, a detour method comprised of sequential bromination of 2-methoxyphenols 1-4, oxidation and Diels-Alder reaction, and debromination has been developed. The oxidation of bromophenols 17-20 produced MOBs 21-24 which are stable enough to be isolated. The MOBs 21-24 underwent cycloaddition with electron-deficient dienophiles in a very efficient manner to afford the corresponding cycloadducts 25a-c to 28a-c in good to high yields without self-dimerization. When the cycloadducts 25a-c to 28a-c were treated with either Bu3SnH/AIBN or tributylammonium formate-palladium reagent, the corresponding debrominated products 13a-c to 16a-c were obtained in high to excellent yields. In general, the cycloadducts 13a-c to 15a-c were obtained in 20-40% higher yields via the detour method than those via the direct method. In both routes, the Diels-Alder reactions proceeded in a highly regio- and stereoselective manner to furnish a single cycloadduct in each case.
- Lai, Chien-Hsun,Shen, Yi-Ling,Wang, Min-Nen,Rao, N. S. Kameswara,Liao, Chun-Chen
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p. 6493 - 6502
(2007/10/03)
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- Stereoselective synthesis of the neolignan, (+ )-dehydrodiconiferyl alcohol.
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A stereo controlled synthesis of the biologically active neolignan, (+)-dehydrodiconiferyl alcohol (1) was achieved. This synthetic method was also efficient for preparing its enantiomer and other derivatives with biological activity.
- Okazaki,Shuto
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p. 1134 - 1140
(2007/10/03)
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- Transition metal-catalyzed oxidations. 11 : Para-selective chlorination and bromination of phenols with tert-butyl hydroperoxide and TiX(OiPr)3
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Mononuclear phenols 1-4 are chlorinated or brominated with high para-selectivity and in good yields to the halides 5-11 with the TiXn(OiPr)m/TBHP system (X = Cl or Br). WILEY-VCH Verlag GmbH, 1999.
- Krohn, Karsten,Rieger, Hagen,Steingroever, Klaus,Vinke, Ingeborg
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- N-Bromosuccinimide as a Regioselective Nuclear Monobrominating Reagent for Phenols and Naphthols
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A wide range of substituted phenols and naphthols were regioselectively monobrominated with N-bromosuccinimide, at para position in acetonitrile and at ortho position in carbon disulfide, under mild conditions in good yields. Methylphenols afforded only nuclear bromination products.
- Carre?o, M. Carmen,García Ruano, José L.,Sanz, Gema,Toledo, Miguel A.,Urbano, Antonio
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p. 1241 - 1242
(2007/10/03)
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- Regioselective Bromination of O-β-Glycosylated Aromatics
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The quasi quantitative and regioselective bromination of O-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)phenols is described.The orientating effect of the glycoside group is compared with those of other oxygenated groups and its usefulness illustrated with
- Mabic, Stephane,Lepoittevin, Jean-Pierre
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p. 1705 - 1708
(2007/10/02)
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- Selective para-Bromination of Phenols via a Regenerable Polymer-bound Tetraalkylammonium Tribromide
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Amberlyst-A26 resin in its tribromide form effects para-bromination of phenols with high yields and selectivity; the resin is easily recovered by filtration and can be reconverted into the tribromide form by addition of bromine.
- Smith, Keith,James, D. Martin,Matthews, Ian,Bye, Martin R.
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p. 1877 - 1878
(2007/10/02)
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- Synthesis of compounds of interest in proton transfer spectroscopy
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A new series of compounds has been prepared for use in proton transfer spectroscopy. The complexes 6a-6d have been converted into the fully characterised perchlorates 7a-7d and the corresponding anhydro bases 8a-8d.
- Barton,Ozbalik,Sas
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p. 8043 - 8052
(2007/10/02)
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- Bromation regioselective en serie aromatique. I: Monobromation en position para de phenols et d'amines aromatiques par le tribromure de tetrabutylammonium
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The reaction of tetrabutylammonium tribromide (TBABr3) with phenols and aromatic amines in aprotic and non-basic solvents at 20 deg C gives exclusively the corresponding para-brominated compounds in high yields.A mechanism involving electrophilic substitution by the tribromide anion Br3- itself is suggested to account for the results, especially the regioselective para bromination.Key words: bromination, tetrabutylammonium tribromide, phenols, aromatic amines.
- Berthelot, Jacques,Guette, Catherine,Desbene, Paul-Louis,Basselier, Jean-Jacques,Chaquin, Patrick,Masure, Daniel
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p. 2061 - 2066
(2007/10/02)
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- Halogenation Using Quaternary Ammonium Polyhalides. IV. Selective Bromination of Phenols by Use of Tetraalkylammonium Tribromides
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Reaction of phenols with calculated amounts of benzyltrimethylammonium tribromide or tetrabutylammonium tribromide in dichloromethane-methanol for 0.5-1 h under mild conditions gave, selectively, the objective mono-, di-, or tribromophenols in good yields.
- Kajigaeshi, Shoji,Kakinami, Takaaki,Okamoto, Tsuyoshi,Nakamura, Hiroko,Fujikawa, Masahiro
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p. 4187 - 4189
(2007/10/02)
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