- Novel and selective palladium-catalyzed annulations of 2-alkynylphenols to form 2-substituted 3-halobenzo[b]furans
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A novel and selective palladium-catalyzed annulation of 2-alkynylphenols method for the synthesis of 2-substituted 3-halobenzo[b]furans is presented. In the presence of PdX2, CuX2, and HEt3NX, 2-substituted 3-halobenzo[b]f
- Liang, Yun,Tang, Shi,Zhang, Xu-Dong,Mao, Li-Qiu,Xie, Ye-Xiang,Li, Jin-Heng
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- Synthesis and in vitro study of nitro- and methoxy-2-phenylbenzofurans as human monoamine oxidase inhibitors
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A new series of 2-phenylbenzofuran derivatives were designed and synthesized to determine relevant structural features for the MAO inhibitory activity and selectivity. Methoxy substituents were introduced in the 2-phenyl ring, whereas the benzofuran moiety was not substituted or substituted at the positions 5 or 7 with a nitro group. Substitution patterns on both the phenyl ring and the benzofuran moiety determine the affinity for MAO-A or MAO-B. The 2-(3-methoxyphenyl)-5-nitrobenzofuran 9 was the most potent MAO-B inhibitor (IC50 = 0.024 μM) identified in this series, whereas 7-nitro-2-phenylbenzofuran 7 was the most potent MAO-A inhibitor (IC50 = 0.168 μM), both acting as reversible inhibitors. The number and position of the methoxyl groups on the 2-phenyl ring, have an important influence on the inhibitory activity. Molecular docking studies confirmed the experimental results and highlighted the importance of key residues in enzyme inhibition.
- Delogu, Giovanna L.,Kumar, Amit,Gatto, Gianluca,Bustelo, Fernando,Saavedra, Lucía M.,Rodríguez-Franco, Maria Isabel,Laguna, Reyes,Vi?a, Dolores
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- Highly Efficient Synthesis of 2-Substituted Benzo[ b ]furan Derivatives from the Cross-Coupling Reactions of 2-Halobenzo[ b ]furans with Organoalane Reagents
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A highly efficient and simple route for the synthesis of 2-substituted benzo[ b ]furans has been developed by palladium-catalyzed cross-coupling reaction of 2-halobenzo[ b ]furans with aryl, alkynyl, and alkylaluminum reagents. Various 2-aryl-, 2-alkynyl-, and 2-alkyl-substituted benzo[ b ]furan derivatives can be obtained in 23-97% isolated yields using 2-3 mol% PdCl 2/4-6 mol% XantPhos as the catalyst under mild reaction conditions. The aryls bearing electron-donating or electron-withdrawing groups in 2-halobenzo[ b ]furans gave products in 40-97% isolated yields. In addition, aluminum reagents containing thienyl, furanyl, trimethylsilanyl, and benzyl groups worked efficiently with 2-halobenzo[ b ]furans as well, and three bioactive molecules with 2-substituted benzo[ b ]furan skeleton were synthesized. Furthermore, the broad substrates scope and the typical maintenance of vigorous efficiency on gram scale make this protocol a potentially practical method to synthesize 2-substituted benzo[ b ]furan derivatives. On the basis of the experimental results, a possible catalytic cycle has been proposed.
- Wen, Chang,Wu, Chuan,Luo, Ruiqiang,Li, Qinghan,Chen, Feng
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supporting information
p. 3847 - 3861
(2021/07/02)
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- Looking for new xanthine oxidase inhibitors: 3-Phenylcoumarins versus 2-phenylbenzofurans
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Overproduction of uric acid in the body leads to hyperuricemia, which is also closely related to gout. Uric acid production can be lowered by xanthine oxidase (XO) inhibitors. Inhibition of XO has also been proposed as a mechanism for improving cardiovascular health. Therefore, the search for new efficient XO inhibitors is an interesting topic in drug discovery. 3-Phenylcoumarins and 2-phenylbenzofurans are privileged scaffolds in medicinal chemistry. Their structural similarity makes them interesting molecules for a comparative study. Methoxy and nitro substituents were introduced in both scaffolds. The current study gives some insights into the synthesis and biological activity of these molecules against this important target. For the best compound of the series, the 3-(4-methoxyphenyl)-6-nitrocoumarin (4), the IC50 value, type of inhibition, cytotoxicity on B16F10 cells and ADME theoretical properties, were determined. Docking studies were also performed in order to better understand the interactions of this molecule with the XO binding pocket. This work is a preliminary screening for further design and synthesis of new non-purinergic derivatives as potential compounds involved in the inflammatory suppression, specially related to gout.
- Borges, Fernanda,Delogu, Giovanna L.,Era, Benedetta,Fais, Antonella,Gatto, Gianluca,Kumar, Amit,Matos, Maria J.,Pintus, Francesca,Uriarte, Eugenio
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p. 774 - 780
(2020/07/07)
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- Fabrication of an amyloid fibril-palladium nanocomposite: A sustainable catalyst for C-H activation and the electrooxidation of ethanol
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Amyloids are highly ordered nanofibrils and their tensile strength is similar to that of steel, which makes them resistant to extreme pH and temperature. Based on this rationale, we demonstrate a facile synthesis of palladium, copper, platinum, gold and silver nanocomposites using α-Synuclein (α-Syn) fibrils as a template. We showed that an α-Syn-fibril-palladium nanoparticles (α-Syn-PdNPs) composite can be used as a heterogeneous catalyst in C-H bond activation and the electrooxidation of ethanol. The study demonstrated α-Syn-PdNPs to be a superior heterogeneous catalyst for the synthesis of pharmaceutically valuable benzofuran, naphthofuran, coumarin and N-arylindole via C-H activation. Further, the electrooxidation of ethanol using α-Syn-PdNPs displayed an electrochemically active surface area of 160.6 m2 g-1, which is much higher than the previously reported values for supported Pd nanocomposites.
- Jayarajan, Ramasamy,Kumar, Rakesh,Gupta, Jagriti,Dev, Gayathri,Kadu, Pradeep,Chatterjee, Debdeep,Bahadur, Dhirendra,Maiti, Debabrata,Maji, Samir K.
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supporting information
p. 4486 - 4493
(2019/03/06)
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- Method for synthesizing benzofuranol derivative by nickel-catalysis of phenethynyl phenol under microwave irradiation
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The invention discloses a method for synthesizing a benzofuranol derivative by nickel-catalysis of phenethynyl phenol under microwave irradiation; a catalytic amount of catalyst nickel chloride, ligand 1,10-phenanthroline(1,10-Phen), auxiliary catalyst po
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Paragraph 0025; 0029
(2018/09/11)
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- Strategy for Overcoming Full Reversibility of Intermolecular Radical Addition to Aldehydes: Tandem C-H and C-O Bonds Cleaving Cyclization of (Phenoxymethyl)arenes with Carbonyls to Benzofurans
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An intermolecular addition of carbon radicals enabled by a cascade radical coupling strategy is developed. It includes an intermolecular alkyl radical addition to a carbonyl group followed by an intramolecular alkoxy radical addition to haloarenes and produces substituted benzofurans in high yields. The radical nature of this reaction is explored by radical trapping experiments and EPR analysis. The mechanism is investigated by KIE experiments and control experiments. This method could provide rapid and practical access to the key intermediate of TAM-16, a safe and potent antibacterial agent for treating tuberculosis, and, therefore, is of great importance for organic synthesis and the pharmaceutical industry.
- Zheng, Hong-Xing,Shan, Xiang-Huan,Qu, Jian-Ping,Kang, Yan-Biao
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supporting information
p. 3310 - 3313
(2018/06/11)
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- Mechanistic Insights on Orthogonal Selectivity in Heterocycle Synthesis
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Recently, we have developed a method for catalytic regioselective synthesis of 2-substituted and 3-substituted benzofurans starting from phenols. The choice of reacting partner, olefin versus α,β-unsaturated acid, is critical to dictate the isomeric product formation. Instances are known where these olefinic partners did not complement each other and yield a similar outcome. In the current work, we have addressed this paradox with emphasis on (a) the origin of orthogonal selectivity and (b) the key requirements to expect complementary behavior. Experimental and computational studies provided important mechanistic insights. Electrostatic compatibility during migratory insertion and the positioning of the carboxylic acid moiety in catalytic steps are found to exert a paramount impact in determining the regioselectivity. The study offers a predictable single component tuning tool to control the regioselectivity.
- Maji, Arun,Reddi, Yernaidu,Sunoj, Raghavan B.,Maiti, Debabrata
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p. 10111 - 10118
(2018/10/20)
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- Tandem Sonogashira-Hagihara coupling/cycloisomerization reactions of ethynylboronic acid MIDA ester to afford 2-heterocyclic boronic acid MIDA esters: A concise route to benzofurans, indoles, furopyridines and pyrrolopyridines
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A one-pot process that provides direct access to 2-heterocyclic MIDA (N-methyliminodiacetic acid) boronates has been developed. The reaction of 2-iodophenols or 2-iodoanilines with ethynylboronic acid MIDA ester readily afforded 2-substituted heterocyclic compounds. Amidine and phosphazene bases, especially TMG (1,1,3,3-tetramethylguanidine) assumed an important role in the tandem Sonogashira-Hagihara coupling/cycloisomerization reactions.
- Sakurai, Yohji
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p. 1322 - 1336
(2017/07/18)
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- Copper pincer complexes as advantageous catalysts for the heteroannulation of ortho-halophenols and alkynes
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A new, non-symmetrical copper(II) pincer complex catalyzes much more efficiently the formation of benzofuran by the reaction between ortho-iodophenols and alkynes. The lowest catalyst loadings are realized for this reaction, and bromo- and chlorophenols are heteroannulated for the first time. Strong evidence for hydrophenoxylation and intramolecular halogen atom-transfer steps catalyzed by this remarkably active, recyclable homogeneous catalyst is provided.
- Moure, Maria Jesus,Sanmartin, Raul,Dominguez, Esther
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p. 2070 - 2080
(2014/07/07)
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- Palladium-catalyzed synthesis of benzofurans and coumarins from phenols and olefins
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Triple C-H functionalization: Palladium-catalyzed synthesis of benzofurans and coumarins by reacting phenols and unactivated olefins is described. The reaction comprises sequential C-H functionalization and shows diverse functional group compatibility. Preliminary mechanistic studies shed light into the possible mechanisms. Copyright
- Sharma, Upendra,Naveen, Togati,Maji, Arun,Manna, Srimanta,Maiti, Debabrata
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supporting information
p. 12669 - 12673
(2013/12/04)
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- An efficient tandem elimination-cyclization-desulfitative arylation of 2-(gem-dibromovinyl)phenols(thiophenols) with sodium arylsulfinates
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An efficient tandem elimination-cyclization-desulfitative arylation of 2-(gem-dibromovinyl)phenols(thiophenols) with sodium arylsulfinates has been developed. In the presence of TBAF-PdCl2-Cu(OAc)2-NEt 3, the reactions gen
- Chen, Wei,Li, Pinhua,Miao, Tao,Meng, Ling-Guo,Wang, Lei
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supporting information
p. 420 - 424
(2013/02/23)
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- A highly efficient tandem reaction of 2-(gem-dibromovinyl) phenols(thiophenols) with organosilanes to 2-arylbenzofurans (thiophenes)
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2-Arylbenzofurans(thiophenes) were prepared through an efficient tandem elimination-intramolecular addition-Hiyama cross-coupling reaction. In the presence of tetra-(n-butyl)ammonium fluoride (TBAF), palladium(II) acetate [Pd(OAc)2] and triphenylphosphine (PPh3), the reaction of 2-(gem-dibromovinyl)phenols(thiophenols) with phenyl(trialkoxy)silanes proceeded smoothly and generated the corresponding products with good yields in one-pot. It should be noted that TBAF plays an important role in the tandem reaction. Copyright
- Liu, Jie,Chen, Wei,Ji, Yong,Wang, Lei
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experimental part
p. 1585 - 1592
(2012/07/14)
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- Sequential and one-pot reactions of phenols with bromoalkynes for the synthesis of (Z)-2-bromovinyl phenyl ethers and benzo[ b ]furans
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Benzo[b]furans were prepared in one pot based on the addition/palladium- catalyzed C-H bond functionalization of phenols with bromoalkynes. The addition reactions of phenols to bromoalkynes generated (Z)-2-bromovinyl phenyl ethers in high yields with excellent regio- and stereoselectivity. The obtained (Z)-2-bromovinyl phenyl ethers subsequently proceeded by intramolecular cyclization to afford 2-substituted benzo[b]furans in good yields through palladium-catalyzed direct C-H bond functionalizations. It is important to note that the transformation of phenols with bromoalkynes into benzo[b]furans could be carried out in one pot with a simple and efficient tandem procedure.
- Wang, Shihua,Li, Pinhua,Yu, Lin,Wang, Lei
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p. 5968 - 5971
(2011/12/15)
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- Microwave-assisted efficient synthesis of 2-arylbenzo[b]furans and 2-ferrocenylbenzo[b]furans from readily prepared propargylic alcohols and o-iodophenols
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A simple, efficient and expeditious method for synthesis of 2-arylbenzo[b]furans and 2- ferrocenylbenzo[b]furans from readily prepared propargylic alcohols, o-iodophenols and silica gel with the catalyst of PdCl2(PPh3)2 (2 mol%)/CuI (2mol%) and microwave-promoted Sonogashira coupling/cyclization reaction is developed. The methodology can produce good to excellent yields. In addition, this method can also be completed in one-pot with iodobenzene, 2-methyl-3-butyn-2-ol and 2-iodo-4-methylphenol as reactants. Indian Academy of Sciences.
- Wu, Liansheng,Shi, Xiaokang,Xu, Xiaoyun,Liang, Fen,Huang, Guosheng
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experimental part
p. 697 - 702
(2012/07/03)
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- Efficient synthesis of 5-nitro-benzo[b]furans via 2-bromo-4-nitro-phenyl acetates
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Acetylation/Sonogashira cross-coupling reaction/cyclization has been carried out in one-pot using a Na2PdCl4/2-(di-tert-butylphosphino)-N-phenylindole/CuI system in TMEDA to give 5-nitro-2-substituted benzo[b]furans in excellent yields. We also describe the extension of this method to 4-EWG-2-bromo-phenols obtaining 2,5-disubstituted-benzo[b]furans in good yields.
- Bochicchio, Antonella,Chiummiento, Lucia,Funicello, Maria,Lopardo, Maria Teresa,Lupattelli, Paolo
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experimental part
p. 2824 - 2827
(2010/07/04)
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- Simple, convenient, and efficient synthesis of 2-aryl-substituted benzo[b]furans
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A simple, convenient, and efficient one-pot method for the preparation of benzofuran is reported. Sonogashira coupling reaction of aryl iodides with 2-methyl-3-butyn-2-ol was used as an acetylene source in the presence of Pd(PPh3)2Cl2 and CuI. Deprotection of the acetylene moiety in the same pot using a strong base and the second Sonogashira coupling/cyclization of and substituted o-iodophenols led to the formation of the appropriate benzo[b]furans. These protocols also can be used in the synthesis of natural products and indoles. Copyright Taylor & Francis Group, LLC.
- Jiang, Yong,Gao, Botao,Huang, Wenjuan,Liang, Yongmin,Huang, Guosheng,Ma, Yongxiang
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experimental part
p. 197 - 204
(2009/04/07)
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- Efficient synthesis of benzofurans utilizing [3,3]-sigmatropic rearrangement triggered by N-trifluoroacetylation of oxime ethers: Short synthesis of natural 2-arylbenzofurans
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A new synthetic method for the preparation of benzofurans has been developed. The key step of this method is the [3,3]-sigmatropic rearrangement of N-trifluoroacetyl-ene-hydroxylamines, which was triggered by acylation of oxime ethers. TFAA has been proved to be the best reagent to induce [3,3]-sigmatropic rearrangement for the synthesis of cyclic or acyclic dihydrobenzofurans. On the other hand, the TFAT-DMAP system is found to be the most effective for constructing various benzofurans. Synthetic utility of this reaction is demonstrated by the short synthesis of natural benzofurans without protection of the hydroxy group. The synthesis of Stemofuran A was accomplished via condensation of ketones with aryloxyamine and subsequent reaction with TFAT-DMAP in a four-step synthesis with 72% overall yield. Similarly, Eupomatenoid 6 and Coumestan were synthesized through the reaction of oxime ether with TFAT-DMAP. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Takeda, Norihiko,Miyata, Okiko,Naito, Takeaki
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p. 1491 - 1509
(2008/09/19)
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- Novel anti-inflammatory and analgesic heterocyclic amidines that inhibit nitrogen oxide (NO) production
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Heterocyclic amidines with anti-inflammatory and analgesic activity that inhibit nitrogen oxide production, of formula (I): in which: G1 and G2 are hydrogen, halogen, hydroxyl, C1-C4 alkoxy, C1-C4 alkyl, and an amidino substituent of formula Q, provided that, for each compound of formula (I), only one of the two substituents G1 or G2 is an amidino substituent of formula Q: and in which the substituents W, Y and X are combined to form 9- or 10-membered bicyclic heteroaromatic derivatives containing up to 2 hetero atoms in the same ring; and Z is an aryl or heteroaryl group, a linear or branched C1-C6 alkyl or alkenyl chain, a C1-C4 alkyl-aryl group or a C1-C4 alkyl-heteroaryl group.
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Page/Page column 21-22
(2010/02/13)
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- Novel anti-inflammatory and analgesic heterocyclic amidines that inhibit nitrogen oxide (NO) production
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Heterocyclic amidines with anti-inflammatory and analgesic activity that inhibit nitrogen oxide production, of formula (I): in which:G1 and G2 are hydrogen, halogen, hydroxyl, C1-C4 alkoxy, C1-C4 alkyl, and an amidino substituent of formula Q, provided that, for each compound of formula (I), only one of the two substituents G1 or G2 is an amidino substituent of formula Q: and in which the substituents W, Y and X are combined to form 9- or 10-membered bicyclic heteroaromatic derivatives containing up to 2 hetero atoms in the same ring; andZ is an aryl or heteroaryl group, a linear or branched C1-C6 alkyl or alkenyl chain, a C1-C4 alkyl-aryl group or a C1-C4 alkyl-heteroaryl group.
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Page/Page column 30
(2010/02/13)
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- Sonogashira cross-coupling reactions catalysed by copper-free palladium zeolites
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A heterogeneous copper-free [Pd(NH3)4]2+/ (NH4)Y catalyst was employed to achieve the heterogeneous Sonogashira reaction of aryl halides with terminal alkynes. Several reaction parameters like solvent, base and temperature were evaluated. When optimised, the coupling reaction of bromobenzene with phenylacetylene gave a 45% yield of diphenylacetylene within 3 h using only 1 mol % Pd. This catalyst was successfully applied to the coupling reaction of a range of aryl iodides and bromides: aryl iodides and activated aryl bromides gave almost quantitative yields and non-activated aryl bromides led to reasonable yields (20% to 45%). This heterogeneous [Pd(NH3)4]2+/(NH 4)Y catalyst was shown to be efficient, stable towards leaching and recyclable for the copper-free Sonogashira reaction.
- Djakovitch, Laurent,Rollet, Patrick
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p. 1782 - 1792
(2007/10/03)
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- Pd/C mediated synthesis of 2-substituted benzo[b]furans/nitrobenzo[b] furans in water
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An efficient synthesis of 2-alkyl/aryl substituted benzo[b]furans/nitrobenzo[b]furans in water has been accomplished via Pd/C catalyzed reaction of o-iodophenols with terminal alkynes in the presence of PPh3, CuI and prolinol. This method can t
- Pal, Manojit,Subramanian, Venkataraman,Yeleswarapu, Koteswar Rao
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p. 8221 - 8225
(2007/10/03)
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- Chemistry of aminophenols. Part 3: First synthesis of nitrobenzo[b]furans via a coupling-cyclization approach
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The first synthesis of 4-, 5-, and 6-nitrobenzo[b]furans has been achieved via the Sonogashira cross-coupling reaction of 2-iodonitrophenol acetates prepared from commercially available and inexpensive 2-aminonitrophenols. The obtained 2-alkynylnitropheno
- Dai, Wei-Min,Lai, Kwong Wah
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p. 9377 - 9380
(2007/10/03)
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- Compounds derived from 3-(benzofuran-5-yl)oxazolidin-2-one, preparation method therefor and therapeutical use thereof
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PCT No. PCT/FR96/01731 Sec. 371 Date May 8, 1998 Sec. 102(e) Date May 8, 1998 PCT Filed Nov. 5, 1996 PCT Pub. No. WO97/17346 PCT Pub. Date May 15, 1997Compounds derived from 3-(benzofuran-5-yl) oxazolidin-2-one, of general formula (I) in which: R1 represe
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- Alkylaminoalkyl derivatives of benzofuran, benzothiophene, indole and indolizine, process for their preparation and compositions containing them
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The subject of the invention is benzofuran, benzothiophene, indole or indolizine compounds of general formula: STR1 in which: Het represents one of the groups: STR2 in which T,T' and T"represent particularly a group: STR3 R and Ra, identical or different, represent X represent --O-- or --S-- Y represents a radical STR4 These compounds are useful as medecines particularly for the treatment of pathological syndroms of the cardio-vascular system.
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