- Regio- and stereoselective synthesis of bromoalkenes by homolytic hydrobromination of alkynes with hydrogen bromide
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Homolytic hydrobromination of terminal and internal alkynes with a commercially available solution of hydrogen bromide in acetic acid has been investigated for regio- and stereoselective synthesis of bromoalkenes. Under an aerobic atmosphere at room temperature, the reaction of ethynylarenes with a small excess of HBr efficiently gave (2-bromoethenyl)arenes with good to high E-selectivity. (Alk-1-ynyl)arenes, or internal alkynes bearing both phenyl and alkyl groups at the sp-carbons also underwent the air-initiated hydrobromination to exhibit high Z-selectivity under kinetic conditions using a half equivalent of HBr.
- Kinoshita, Hidenori,Kumaki, Wataru,Miura, Katsukiyo
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- A Simplified Protocol for the Stereospecific Nickel-Catalyzed C-S Vinylation Using NiX 2 Salts and Alkyl Phosphites
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A Ni-catalyzed C-S cross-coupling using only NiI 2 (0.5-2.5 molpercent) and P(O i Pr) 3 (2.0-10.0 molpercent) is reported. Using an air-stable Ni(II) precatalyst, and a cheap and commercially available ligand, a scalable and robust method was developed to cross-couple various thiophenols and styryl bromides, including some sterically encumbered thiols, an α-bromocinnamaldehyde as well as a thiolation-cyclization.
- Larin, Egor M.,Lautens, Mark,Marchese, Austin D.,Mirabi, Bijan
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p. 311 - 319
(2019/12/28)
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- Design, synthesis and biological evaluation of novel uracil derivatives bearing 1, 2, 3-triazole moiety as thymidylate synthase (TS) inhibitors and as potential antitumor drugs
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Research on thymidylate synthase inhibitors has been a hot spot for anticancer drug development. Here, based on the structures and pharmacological properties of two types of TS inhibitors, through a molecular assembly principle of drugs design, we designed and synthesized a series of 30 novel uracil derivatives as TS inhibitors. The antiproliferative ability of these compounds was evaluated against four cancer cell lines (A549, OVCAR-3, SGC-7901, and HepG2) by the MTT assay. Most of them showed excellent activities against all the tested cell lines. Furthermore, hTS assay results showed that these compounds have the unique ability to inhibit hTS activity in vitro. Notably, compound 13j exhibited the most potent activity against A549 cells (IC50 = 1.18 μM) and extremely prominent enzyme inhibition (IC50 = 0.13 μM), which was superior to the pemetrexed (PTX, IC50 = 3.29 μM and IC50 = 2.04 μM). Flow cytometric analysis showed the compound 13j could inhibit A549 cells proliferation by arresting the cell cycle in the G1/S phase, then induced the cell apoptosis. Further western blot analysis showed that compound 13j could down-regulate the cycle checkpoint proteins cyclin D1 and cyclin E to inhibit the cell cycle progression, and then induce intrinsic apoptosis by activating caspase-3, and reducing the ratio of bcl-2/bax. All of these results demonstrated that this new structure has potential drug-making properties and provides new ideas for drug development.
- Lu, Guo-qing,Li, Xin-yang,Mohamed O, Kamara,Wang, Depu,Meng, Fan-hao
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p. 282 - 296
(2019/03/27)
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- TsNBr2 promoted decarboxylative bromination of α,β-unsaturated carboxylic acids
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A rapid process for decarboxylative bromination of α,β-unsaturated carboxylic acids have been developed using N,N-dibromo-p-toluenesulfonamide (TsNBr2). Treatment of cinnamic acids with TsNBr2 in presence of potassium carbonate in acetonitrile produces corresponding β-bromostyrenes at room temperature. Exclusive formation of (E)-β-bromostyrenes was observed in a stereoselective manner within a very short period of time (5–15 min). This method was further extended for obtaining 1-bromoalkynes from corresponding propiolic acids. Instantaneous formation of bromoalkynes was observed when the reaction was carried out in presence of DBU as a base in acetonitrile at room temperature. A wide variety of cinnamic acids and propiolic acids could be converted to corresponding β-bromostyrenes and 1-bromoalkynes respectively under mild reaction condition with high to excellent yield.
- Hazarika, Debojit,Phukan, Prodeep
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supporting information
p. 4593 - 4596
(2018/11/23)
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- FARNESOID X RECEPTOR AGONISTS AND USES THEREOF
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Described herein are compounds that are farnesoid X receptor agonists, methods of making such compounds, pharmaceutical compositions and medicaments comprising such compounds, and methods of using such compounds in the treatment of conditions, diseases, or disorders associated with farnesoid X receptor activity.
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Paragraph 00437
(2017/04/11)
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- H-β-zeolite catalyzed synthesis of β-bromostyrenes from styrene bromohydrins
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Synthesis of β-bromostyrenes from styrene bromohydrins using H-β-zeolite as catalyst under moderate conditions is reported. The catalyst could be regenerated and reused up to three consecutive cycles.
- Pappula, Venkatanarayana,Donthiri, Ramachandra Reddy,Darapaneni, Chandra Mohan,Subbarayappa, Adimurthy
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supporting information
p. 1793 - 1795
(2014/03/21)
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- Decarboxylative bromination of cinnamic acids by 2-iodoxybenzoic acid with tetrabutylammonium bromide
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The decarboxylative bromination of cinnamic acids using the hypervalent iodine reagent 2-iodoxybenzoic acid with tetrabutylammonium bromide is described, providing good to excellent yields of bromostyrenes. Bromostyrenes are useful coupling components in a wide range of transition metal-catalysed coupling reactions.
- Han, Jianlei,Wei, Yuping
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experimental part
p. 247 - 248
(2012/09/22)
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- A novel method for bromodecarboxylation of α,β-unsaturated carboxylic acids using catalytic sodium nitrite
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A first novel synthetic utility of catalytic sodium nitrite in combination with aqueous HBr, for bromo decarboxylation of α,β-unsaturated carboxylic acid is described. α,β-Unsaturated carboxylic acid compounds successfully converted into corresponding bromo compounds. The advantages of this protocol are shorter reaction time and moderate to good yields.
- Telvekar, Vikas N.,Takale, Balaram S.
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experimental part
p. 2394 - 2396
(2011/05/09)
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- Microwave-assisted Pd/Cu-catalyzed C-8 direct alkenylation of purines and related azoles: An alternative access to 6,8,9-trisubstituted purines
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An efficient microwave-assisted palladium/copper comediated C-8 direct alkenylation of purines with styryl bromides has been developed. The method is regioselective, functional group tolerant, rapid, and compatible with other related azoles. Combined with
- Vabre, Roxane,Chevot, Franciane,Legraverend, Michel,Piguel, Sandrine
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experimental part
p. 9542 - 9547
(2011/12/22)
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- Novel system for decarboxylative bromination of α,β-unsaturated carboxylic acids with diacetoxyiodobenzene
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A simple and mild method for the conversion of varieties of α,β-unsaturated carboxylic acids to the corresponding bromoalkenes using diacetoxyiodobenzene (IBD) in combination with tetraethyl-ammonium bromide (TEAB) at room temperature is discussed. Advantages of this system are short reaction time, easy work up and gave good to excellent yields.
- Fursule, Ravindra Abhykumar,Patil, Pravin Onkar,Shewale, Bharti Devaji,Kosalge, Satish Bhaskar,Deshmukh, Prashant Krishnarao,Patil, Dilip Ashok
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experimental part
p. 1243 - 1245
(2010/08/06)
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- An efficient microwave-promoted route to (Z)-stilbenes from trans-cinnamic acids: Synthesis of combretastatin A-4 and analogues
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cis-Stilbenes were synthesized from trans-cinnamic acids, involving ethylenic-bond bromination and a subsequent one-pot microwave-promoted stereoselective debrominative decarboxylation-Suzuki cross-coupling strategy. This sequence represents a useful way to prepare a variety of combretastatin A-4 derivatives.
- Bazin, Marc-Antoine,Jouanne, Marie,El-Kashef, Hussein,Rault, Sylvain
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experimental part
p. 2789 - 2794
(2010/03/03)
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- Stereoselective direct copper-catalyzed alkenylation of oxazoles with bromoalkenes
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(Chemical Equation Presented) A copper-catalyzed direct alkenylation of oxazoles with bromoalkenes has been developed. The method is both regio- and stereoselective and tolerates a variety of functional groups. A wide range of 2-E-vinyl-substituted oxazoles were obtained in high yields including the highly fluorescent alkaloid annuloline.
- Besselievre, Francois,Piguel, Sandrine,Mahuteau-Betzer, Florence,Grierson, David S.
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supporting information; experimental part
p. 4029 - 4032
(2009/06/18)
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- A novel system for decarboxylative bromination
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A simple and mild method for decarboxylative bromination of α,β-unsaturated carboxylic acids has been developed using diphosphorus tetraiodide in combination with tetraethylammonium bromide (TEAB) at room temperature. High yields of the corresponding bromoalkenes were obtained.
- Telvekar, Vikas N.,Chettiar, Somsundaram N.
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p. 4529 - 4532
(2008/02/03)
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- Mild and efficient method for decarboxylative bromination of α,β-unsaturated carboxylic acids with Dess-Martin periodinane
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A simple and mild method for decarboxylative bromination of α,β-unsaturated carboxylic acids has been developed using Dess-Martin Periodinane (DMP) in combination with tetraethylammonium bromide (TEAB) at room temperature. High yields of the corresponding bromoalkenes were obtained. Georg Thieme Verlag Stuttgart.
- Telvekar, Vikas N.,Arote, Nitin D.,Herlekar, Omkar P.
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p. 2495 - 2497
(2007/10/03)
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- Synthesis of (Z)-1-bromo-1-alkenes and terminal alkynes from anti-2,3-dibromoalkanoic acids by microwave-induced reaction
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(Z)-1-Bromo-1-alkenes were stereoselectively prepared in high yields in a short reaction time by microwave irradiation of the corresponding anti-2,3-dibromoalkanoic acids in a Et3N/DMF system. A one-pot synthesis of terminal alkynes and enynes from 2,3-dibromoalkanoic acids were also developed by microwave-induced reaction.
- Kuang, Chunxiang,Yang, Qing,Senboku, Hisanori,Tokuda, Masao
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p. 4043 - 4052
(2007/10/03)
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- A one-pot synthesis of terminal alkynes from anti-3-aryl-2,3- dibromopropanoic acids under microwave irradiation
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A facile one-pot synthesis of terminal alkynes was achieved by microwave irradiation of a mixture of anti-3-aryl-2,3-dibromopropanoic acids, Et 3N and DMF and subsequent irradiation in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). This method requires short reaction time (1-2 min) and gives terminal alkynes in high yields. Copyright
- Kuang, Chunxiang,Senboku, Hisanori,Tokuda, Masao
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- Synthesis of functionalized vinyl boronates via ruthenium-catalyzed olefin cross-metathesis and subsequent conversion to vinyl halides
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Functionalized vinyl pinacol boronates suitable for Suzuki cross-coupling reactions are synthesized using ruthenium-catalyzed olefin cross-metathesis of 1-propenyl pinacol boronate and various alkenes, including functionalized and 1,1-disubstituted alkenes. The resultant boronate cross products are stereoselectively transformed into predominantly Z-vinyl bromides and E-vinyl iodides. The vinyl bromides may be synthesized in a two-step, one-pot synthesis from a variety of olefins, resulting in a Z-selective formal vinyl bromide cross-metathesis reaction.
- Morrill, Christie,Grubbs, Robert H.
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p. 6031 - 6034
(2007/10/03)
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- Facile and stereoselective synthesis of (E)-vinyl bromides by microwave-induced reaction of 1,1-dibromoalkenes using a diethyl phosphonate/EtONa/EtOH system
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(E)-Vinyl bromides were readily prepared from 1,1-dibromoalkenes by microwave irradiation within 1 min using a diethyl phosphonate/EtONa/EtOH system. This method utilizes cheap and environmentally friendly reagents, requires only a short reaction time, and gives (E)-vinyl bromides in high stereoselectivities and high yields.
- Kuang, Chunxiang,Senboku, Hisanori,Tokuda, Masao
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p. 1491 - 1496
(2007/10/03)
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- Convenient and stereoselective synthesis of (Z)-1-bromo-1-alkenes by microwave-induced reaction
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(Z)-1-Bromo-1-alkenes were stereoselectively prepared in high yields in a short reaction time (0.2-1.0 min) by microwave irradiation of the corresponding 2,3-dibromoalkanoic acids in DMF in the presence of triethylamine.
- Kuang, Chunxiang,Senboku, Hisanori,Tokuda, Masao
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p. 3893 - 3896
(2007/10/03)
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- Synthesis of the Substituted Z-1-Bromo-1-alkenes and Arylacetylenes from 2,3-Dibromocarboxylic Acids
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Stereoselectivity was studied of simultaneous debromination-decarboxylation of dibrominated cinnamic and acrylic acids. The best selectivity in formation of Z-vinyl bromides was achieved with the use of organic nitrogen bases. The 1-bromo-1-alkenes were converted into the corresponding acetylenes.
- Matveeva,Erin,Kurz
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p. 1065 - 1067
(2007/10/03)
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