- Molecular mechanism of micellar catalysis of cross aldol reaction: Effect of surfactant chain length and surfactant concentration
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The importance of alkyl chain length and concentration of quaternary ammonium surfactants (QAS) in the micellar catalysis of cross aldol reaction was investigated. The NaOH-micellar system catalyzed aldol reaction of benzaldehyde and cyclohexanone to α,α′-dibenzylidene cyclohexanone (di condensation/desired product) over mono condensation product was used as model reaction for this study. The C16QAS micellar system (QAS with n-hexadecyl group) gave highest cyclohexanone conversion (90%) to desired product (82%) showing that C16QAS micellar system possesses optimum properties and/or microenvironment for this reaction. Furthermore, the micellar system with high surfactant concentration (C16QAS; >150mM) made the reaction faster giving >99% conversion to selectively desired product (>99%) within 30min The large interface created by C16QAS micelles in the aqueous medium at high surfactant concentration makes the reaction faster by facilitating the interaction of hydrophobic reactants and water soluble catalyst (OH- ions). The activation of benzaldehyde molecules, their localization preferably near the interface and stabilization of enolate ions (reactive intermediates) by micellar system at high surfactant concentration were observed to be promoting the cross reaction selectively to the desired product.
- Vashishtha, Manu,Mishra, Manish,Undre, Sachin,Singh, Man,Shah, Dinesh O.
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- Metal- and Solvent-Free Transesterification and Aldol Condensation Reactions by a Homogenous Recyclable Basic Ionic Liquid Based on the 1,3,5-Triazine Framework
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A new recyclable basic ionic liquid was introduced as an efficient catalyst for aldol condensation and transesterification reactions under environmentally friendly conditions. The catalyst was prepared based on methyl imidazolium moieties bearing hydroxide counter anions via the Hofmann elimination on a 1,3,5-triazine framework. The ionic liquid with two functionalities including anion stabilizer and high basicity, was used as an efficient catalyst for aldol condensation as well as transesterification reaction of a variety of alkyl benzoates. All reactions were performed in the absence of any external reagent, co-catalyst, or solvent, in line with environmental protection. The kinetics isotope effect (KIE) was conducted for the transesterification reaction to elucidate the mechanism and rate determining step (RDS). It worth noted that, the homogeneous catalyst could be recycled from the reaction mixture and reused for several consecutive runs with insignificant drop of basicity and conversion.
- Hu, Yanqiu,Kazemnejadi, Milad,Ren, Mingqi
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p. 775 - 783
(2021/08/30)
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- Highly Enantioselective Iridium-Catalyzed Hydrogenation of Conjugated Trisubstituted Enones
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Asymmetric hydrogenation of conjugated enones is one of the most efficient and straightforward methods to prepare optically active ketones. In this study, chiral bidentate Ir-N,P complexes were utilized to access these scaffolds for ketones bearing the stereogenic center at both the α- and β-positions. Excellent enantiomeric excesses, of up to 99%, were obtained, accompanied with good to high isolated yields. Challenging dialkyl substituted substrates, which are difficult to hydrogenate with satisfactory chiral induction, were hydrogenated in a highly enantioselective fashion.
- Peters, Bram B. C.,Jongcharoenkamol, Jira,Krajangsri, Suppachai,Andersson, Pher G.
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supporting information
p. 242 - 246
(2021/01/13)
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- Redox-Neutral Cobalt(III)-Catalyzed C-H Activation/Annulation of α,β-Unsaturated Oxime Ether with Alkyne: One-Step Access to Multisubstituted Pyridine
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A redox neutral Co(III)-catalyzed annulation of α,β-unsaturated oxime ether with alkyne has been reported. Multisubstituted pyridines were synthesized in good yields without the use of any heavy metal oxidants. The developed methodology tolerates a variety of functional groups. Notably, this transformation has been applied to the late-stage modification of the bioactive molecule dehydropregnenolone.
- Mohanty, Smruti Ranjan,Pati, Bedadyuti Vedvyas,Banjare, Shyam Kumar,Das Adhikari, Gopal Krushna,Ravikumar, Ponneri Chandrababu
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p. 1074 - 1083
(2021/01/14)
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- Ruthenium-catalysed synthesis of chiral exocyclic allylic alcoholsviachemoselective transfer hydrogenation of 2-arylidene cycloalkanones
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An exclusive asymmetric reduction of C=O bonds of 2-arylidene four-, five-, six-, and seven-membered cycloalkanones has been studied systematically. The asymmetric transfer hydrogenation was performed using a robust and commercially available chiral diamine-derived ruthenium complex as a catalyst and HCOOH/Et3N as a hydrogen source under mild conditions, giving 51 examples of chiral exocyclic allylic alcohols in up to 96% yield and 99% ee. This method was also applicable to the gram-scale synthesis of the active intermediates of the anti-inflammatory loxoprofen and natural product (?)-goniomitine.
- Zhang, Kaili,Liu, Qixing,He, Renke,Chen, Danyi,Deng, Zhangshuang,Huang, Nianyu,Zhou, Haifeng
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supporting information
p. 1628 - 1632
(2021/03/09)
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- Activated charcoal-mediated synthesis of chalcones catalyzed by NaOH in water
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A variety of chalcones were synthesized in good yields by the activated charcoal-mediated aldol reactions between benzaldehydes and acetophenones catalyzed by NaOH in water. 2,6-Bis((E)-benzylidene)cyclohexan-1-ones were prepared by the aldol reactions between benzaldehydes and cyclohexanone. Activated charcoal could be recycled five times without the significant decrease of yields.
- Tanemura, Kiyoshi,Rohand, Taoufik
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- Valmet Chiral Schiff-Base Ligands And Their Copper(II) Complexes as Organo, Homogeneous and Heterogeneous Catalysts for Henry, Cyanosilylation and Aldol Coupling Reactions
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Cyanosilylation, aldol coupling and asymmetric Henry reactions were carried out with L- and D-valmet ligands in different configurations: i) coordinated to sodium ions, as organocatalysts, with week base properties, ii) complexes with copper(II), as homogeneous catalysts, and iii) immobilized copper(II) complexes onto graphene oxide (GO) as heterogeneous catalysts. For the reaction of benzaldehyde and nitromethane in water these afforded an asymmetric Henry reaction, with a spectacular increase of the conversion and ee (92.5 and 95.8 %, respectively) after the deposition on GO. Ligand complexed copper was also effective for cyanosilylation and Aldol coupling reaction.
- Arora, Zinnia,Eftemie, Diana-Ioana,Spinciu, Adela,Maxim, C?t?lin,Hanganu, Ana-Maria,Tudorache, Madalina,Cojocaru, Bogdan,Pavel, Octavian D.,Granger, Pascal,Andruh, Marius,Parvulescu, Vasile I.
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p. 4634 - 4644
(2021/09/08)
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- Synthesis of 1H-isochromenes, 4H-chromenes, and ortho-aminocarbonitrile tetrahydronaphthalenes from the same reactants by using metal-free catalyst
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A facile and rapid multicomponent synthesis of pharmaceutically diverse 1H-isochromenes, 4H-chromenes, and ortho-aminocarbonitrile tetrahydronaphthalenes has been developed from benzaldehyde, malononitrile, and cyclohexanone. Three different methods from the same reactants, solvent, temperature, and catalyst lead to three products with excellent yields. All the reactions were followed with the Michael addition and cyclization. In this study, morpholine was used as an active metal-free base catalyst that increases the yields of products and decreases the time of reactions.
- Naeimi, Hossein,Mohammadi, Somaye
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supporting information
p. 50 - 59
(2019/12/27)
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- Functionalized CoFe2O4/lamellar mesopore silica anchored to melamine nanocomposite as a novel catalyst for synthesis of 4H-chromenes under mild conditions
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In this research, it was displayed an efficient method for the one-pot reaction of cyclohexanone, benzaldehyde and malononitrile for the synthesis of 4H-chromenes by using CoFe2O4/lamellar mesopore silica anchored to melamine as a magnetic nanocatalyst. This nanocatalyst was prepared in several steps and discriminated by XRD, FT-IR, SEM, VSM, TGA and BET techniques. The catalyst has a large active base site that has functionalized in both the surface and the pore of nanostructure. The advantages of magnetic nanocatalyst were simple accessible, heterogeneous nanocatalyst, easy work up and reusability. The various derivatives of 4H-chromenes were synthesized in the presence of CoFe2O4/lamellar mesopore silica/melamine magnetic nanocatalyst with the excellent yields and appropriate times. The products were identified by the melting point, FT-IR, 1H NMR, 13C NMR and C.H.N techniques.
- Mohammadi, Somaye,Naeimi, Hossein
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- Synthesis of hexahydrophenanthridines via the tandem reaction of benzynes
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A tandem insertion-cyclization reaction between carbocyclic β–amino ketones and benzynes has been described, producing hexahydrophenanthridines in moderate to high yields.
- Li, Wen-Juan,Pian, Ji-Xin,Gu, Cheng-Zhi,Dai, Bin,He, Lin
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- Rhodium-catalyzed asymmetric hydrogenation of exocyclic α,β-unsaturated carbonyl compounds
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A highly enantioselective hydrogenation of exocyclic α,β-unsaturated carbonyl compounds catalyzed by Rh/bisphosphine-thiourea (ZhaoPhos) has been developed, giving the corresponding α-chiral cyclic lactones, lactams and ketones with high yields and excellent enantioselectivities (up to 99% yield and 99% ee). Remarkably, the hydrogen bond between the substrate and the catalyst plays a critical role in this transformation. The synthetic utility of this protocol has been demonstrated by efficient synthesis of chiral 3-(4-fluorobenzyl)piperidine, a key chiral fragment of bioactive molecules.
- Yang, Jiaxin,Li, Xiuxiu,You, Cai,Li, Shuailong,Guan, Yu-Qing,Lv, Hui,Zhang, Xumu
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supporting information
p. 856 - 859
(2020/02/15)
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- Novel chalcones derivatives with potential antineoplastic activity investigated by docking and molecular dynamics simulations
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Glioblastoma is an aggressive primary tumor of the central nervous system (CNS). Is the most aggressive among infiltrative gliomas arising from the CNS. This tumor has low patient survival rate and several studies aiming at developing new drugs have increased. Patients with this cancer type face significant morbidity and mortality. This study evaluated the antineoplastic activity of synthetic chalcones (3a-3f) using in vitro glioblastoma models and molecular modeling. Cytotoxicity assay showed that Astrocitoma Hospital Ofir Loyola No 1 (AHOL1) and Uppsala 87 neoplastic glioblastoma lines (U87) cellular viability were significantly reduced compared to Healthy human fibroblasts cell lines (AN27) when exposed to chalcones. Interaction with the serine amino acid was present in the most promising and the reference binder docking, suggesting its importance inhibiting cell growth. Comparative analysis between the reference ligands and the molecules showed that the amino acid LYS352 present in all fittings, suggesting that this is the main amino acid for interaction with tubulin and are consistent with those in cytotoxicity assay, suggesting antineoplastic potential in glioblastoma. Long trajectory molecular dynamics studies were also carried out in order to investigate stability and conformations amongst the chalcones bound tubulin as well, in comparison to doxorubicin (here used as control), however future studies are needed to further assess the mechanism of inhibition of chalcones used in this investigation. Communicated by Ramaswamy H. Sarma.
- Neto, Raimundo de A. M.,Santos, Cleydson B. R.,Henriques, Shayanne V. C.,Machado, Letícia de O.,Cruz, Jorddy N.,da Silva, Carlos H. T. de P.,Federico, Leonardo B.,Oliveira, Edivaldo H. C. de,de Souza, Michel P. C.,da Silva, Patrícia N. B.,Taft, Carlton A.,Ferreira, Irlon M.,Gomes, Madson R. F.
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- Novel racemic chiral organic boron nitrogen fluorescent compound and preparation method thereof (by machine translation)
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The novel chiral organic boron nitride fluorescent compound, is characterized in that, takes a cheap,readily available monoiodobenzene derivative, carboxylic acid derivative as a raw material, to react at a certain temperature with a common organic solvent as a reaction solvent, for a certain time, high yield, to selectively obtain a novel chiral organic boron nitrogen fluorescent compound . The catalyst, can be recovered, at a certain temperature for a certain period of time for a certain period of time to produce a novel chiral organic boron-nitrogen fluorescent compound with low cost,and a high yield, and selectivity, can be, obtained at a certain temperature for a certain period, of time with a certain period of time and high yield. (by machine translation)
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Paragraph 0118-0125
(2020/05/05)
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- Catalytic activity of Mg-Al hydrotalcites and derived mixed oxides for imination reactionsviaan oxidative-dehydrogenation mechanism
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The catalytic activities of Mg-Al hydrotalcites and derived Mg-Al mixed oxides were studied for the imination of benzylic substrates (benzyl amine and benzyl alcohol), with aniline as a model reaction, to establish a green and cost-effective catalytic (precious metal free) process for imination and tandem reactions utilizing alcohols as reagents. The Mg-Al mixed oxide (Mg/Al ratio = 3.0) was found to be an efficient catalyst for imination reactions to synthesize cross-imines with high selectivity as well as for tandem reactions of alcohols. Basic sites of catalysts adsorb benzylic substrates through the hydrogen of their functional groups (-NH2/-OH) and activate (weaken) benzylic C-H bonds for hydride elimination. Thus, basic sites catalyze the reaction by activating benzylic substrates for oxidative-dehydrogenation (i.e., deprotonation followed by hydride elimination with the help of oxygen) to produce reactive imine/carbonyl intermediates, which undergo subsequent nucleophilic reactions with amine.
- Vala, Naresh,Joshi, Pradyuman A.,Mishra, Manish
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p. 8859 - 8868
(2020/06/08)
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- Tuning the Product Selectivity of the α-Alkylation of Ketones with Primary Alcohols using Oxidized Titanium Nitride Photocatalysts and Visible Light
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The direct α-alkylation of ketones with alcohol to synthesize important α-alkylated ketones and enones is an attractive procedure for C-C bond formation. High reaction temperatures are always needed for heterogeneous catalysis using non-noble metals, and switching product selectivity in one catalysis system remains a great challenge. In the present study, a visible-light-driven procedure for this reaction is proposed, using oxidized TiN photocatalysts under mild conditions, whereby the product selectivity can be well-tuned. Oxidized TiN photocatalysts with tunable surface N/O ratios were successfully synthesized through the facile and flexible thermal oxidation treatment of low-cost TiN nanopowder. The α-alkylation of acetophenone with benzyl alcohol to form the two important compounds chalcone and dihydrochalcone occurred even at room temperature and almost complete conversion was achieved at 100 °C under visible light. The proportion of the two products can be well-tuned by switching the surface N/O ratio of the synthesized photocatalysts. Visible light is demonstrated to affect the surface N/O ratio of the photocatalysts and contribute to tuning the product selectivity. Light intensity and action spectrum study proves that the generation of energetic charge carriers results in the observed activities under visible light, based on interband transitions of TiN or the ligand-to-metal charge transfer (LMCT) effect of the surface complex formed on TiO2. Thermal energy can be coupled with light energy within this photocatalytic system, which will facilitate the full use of solar energy. Different sequential reaction mechanisms on TiN and TiO2 are proposed to be responsible for the tunable product selectivity. The wide reaction scope, the fine conversion at a low light intensity, and the favorable reusability of photocatalysts prove the great application potential of this visible-light-driven procedure for the α-alkylation of ketones with primary alcohols.
- Li, Peifeng,Su, Haijia,Xiao, Gang,Zhao, Yilin
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p. 3640 - 3649
(2020/04/09)
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- RhIII-Catalyzed Synthesis of Highly Substituted 2-Pyridones using Fluorinated Diazomalonate
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A RhIII-catalyzed strategy was developed for the rapid construction of highly substituted 2-pyridone scaffolds using α,β-unsaturated oximes and fluorinated diazomalonate. The reaction proceeds through direct, site-selective alkylation based on migratory insertion and subsequent cyclocondensation. A wide substrate scope with different functional groups was explored. The requirement of fluorinated diazomalonate was explored for this transformation. The developed methodology was further extended with the synthesis of the bioactive compound.
- Das, Debapratim,Sahoo, Gopal,Biswas, Aniruddha,Samanta, Rajarshi
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supporting information
p. 360 - 364
(2020/01/25)
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- Establishing the correlation between catalytic performance and N→Sb donor-acceptor interaction: Systematic assessment of azastibocine halide derivatives as water tolerant Lewis acids
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A series of organoantimony(iii) halide complexes with a tetrahydrodibenzo[c,f][1,5]azastibocine framework were synthesized and employed as water tolerant Lewis acid catalysts. The results of a systematic structure-activity relationship study demonstrated that the strength of N→Sb donor-acceptor interaction could be synergistically modulated by tuning the properties of the nitrogen substituents and halogen atoms adjacent to the central antimony atom, and consequently resulted in distinct catalytic performances towards organic reactions such as Mannich, cross-condensation, cyclization-aromatization and epoxide aminolysis reaction. The fluorinated organoantimony(iii) derivatives were found to be more active than those of the chlorinated, brominated and iodinated analogues, owing to the use of an Sb-F moiety as a hydrogen bond acceptor. By comparison, the compound 6-cyclohexyl-12-fluoro-5,6,7,12-tetrahydrodibenzo[c,f][1,5] azastibocine (1d) is found to exhibit the highest catalytic activity, together with facile reusability in scale enlarged synthesis.
- Lei, Jian,Peng, Lingteng,Qiu, Renhua,Liu, Yongping,Chen, Yi,Au, Chak-Tong,Yin, Shuang-Feng
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supporting information
p. 8478 - 8487
(2019/06/19)
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- Green synthesis of dissymmetric bisarylidene derivatives of cyclohexanone analogues under ultrasonic conditions
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Abstract: A new procedure is developed for the synthesis of dissymmetric bisarylidene derivatives of two cyclohexanone analogues. Under mild ultrasonic/organocatalytic conditions, the first aldehyde reacts with the ketone to give the monoarylidene intermediate which subsequently condenses with the second aldehyde upon addition of NaOH/MeOH to the reaction mixture. Both condensations proceed in one pot, and high yields of the corresponding products are obtained in relatively short time periods. It was shown that the method is useful for the synthesis of monoarylidene counterparts as well. Graphical abstract: [Figure not available: see fulltext.].
- Mojtahedi, Mohammad M.,Afshinpoor, Leila,Karimi, Fatemeh,Abaee, M. Saeed
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p. 209 - 217
(2019/01/30)
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- RuPHOX-Ru-Catalyzed Selective Asymmetric Hydrogenation of Exocyclic α,β-Unsaturated Pentanones
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A RuPHOX-Ru catalyzed selective asymmetric hydrogenation of exocyclic α,β-unsaturated ketones has been developed, furnishing the corresponding chiral exocyclic allylic alcohols in high yields and with up to >99.5percent ee. The reaction could be performed on a gram scale with a relatively low catalyst loading (up to 10000 S/C) without any loss in reaction activity and enantioselectivity. The resulting hydrogenated products could be easily transformed to several biologically active compounds with high asymmetric performance. The asymmetric protocol provides an efficient methodology for the synthesis of chiral exocyclic allylic alcohols.
- Li, Jing,Liu, Delong,Liu, Yangang,Lu, Yufei,Wang, Yanzhao,Zhang, Wanbin,Zhu, Yue
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supporting information
(2019/08/26)
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- Stereodivergent Access to Enantioenriched Epoxy Alcohols with Three Stereogenic Centers via Ruthenium-Catalyzed Transfer Hydrogenation
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The resolution technique of stereodivergent reaction on racemic mixtures (stereodivergent RRM) was employed for the first time in ruthenium complex catalyzed transfer hydrogenation of racemic epoxy ketones, providing a new and very simple method that allows access to enantioenriched epoxy alcohols with three stereogenic centers in a one-step fashion. The protocol features simple reaction conditions, practical operation, ability to scale up, and broad group tolerance.
- Zhao, Zhifei,Bagdi, Prasanta Ray,Yang, Shuang,Liu, Jinggong,Xu, Weici,Fang, Xinqiang
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supporting information
p. 5491 - 5494
(2019/08/01)
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- An access to α, β-unsaturated ketones via dual cooperative catalysis
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A dual cooperative organocatalytic approach for the synthesis of α, β-unsaturated ketones is described. This one pot transformation is realized via a domino Knoevenagel-Michael-retro Michael reaction sequence. Various aliphatic ketones reacted smoothly with aromatic as well as aliphatic aldehydes in presence catalytic amount of Meldrum's acid and bifunctional amine. The highlights of this protocol are the easy availability of catalysts, high selectivity, and functional group tolerance. The reaction proved to highly E-selective with no side products emanating from self-condensation, unlike the base-mediated reactions.
- Syamala, Lakshmi V.R. Babu,Khopade, Tushar M.,Warghude, Prakash K.,Bhat, Ramakrishna G.
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supporting information
p. 88 - 91
(2018/12/05)
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- Bovine serum albumin-catalysed cross aldol condensation: Influence of ketone structure
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Bovine serum albumin (BSA) catalyses the cross aldol condensation and proved to be catalytically active at mild temperature and in ethanol, a cheap and green solvent, contrasting with the strong or expensive reaction media usually employed for this reaction. We herein report the reaction of a set of ketones (butanone, 3-pentanone, cyclopentanone and cyclohexanone) with benzaldehyde and p-nitrobenzaldehyde which provided high conversions (77–95%) of the corresponding enones (isolated in a range of yields from 19% to 74%). Parameters assayed to achieve these conversion values were solvent, ketone/aldehyde molar ratio and temperature. In this procedure only cyclohexanone gave the bis-enone, by-product of the conventional aldol condensation, in low amount even at high benzaldehyde/cyclohexanone molar excess. Under the assayed conditions null or low ketol amounts were observed, except for the reaction of cyclopentanone and p-nitrobenzaldehyde. Moreover, kinetic data of BSA-catalysed aldol condensation of cyclohexanone and p-nitrobenzaldehyde suggest an ordered bi bi mechanism for enone formation; an enamine mechanism involving residues of the catalytic cavity exhibiting abnormal pKa values is also proposed.
- Ardanaz, Sebastián M.,Borucki, Estefanía L.,Velez Rueda, Ana J.,Parisi, Gustavo,Iribarren, Adolfo M.,Iglesias, Luis E.
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- Reaction condition controlled nickel(ii)-catalyzed C-C cross-coupling of alcohols
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The challenge in the C-C cross-coupling of secondary and primary alcohols using acceptorless dehydrogenation coupling (ADC) is the difficulty in accurately controlling product selectivities. Herein, we report a controlled approach to a diverse range of β-alkylated secondary alcohols, α-alkylated ketones and α,β-unsaturated ketones using the ADC methodology employing a Ni(ii) 4,6-dimethylpyrimidine-2-thiolate cluster catalyst under different reaction conditions. This catalyst could tolerate a wide range of substrates and exhibited a high activity for the annulation reaction of secondary alcohols with 2-aminobenzyl alcohols to yield quinolines. This work is an example of precise chemoselectivity control by careful choice of reaction conditions.
- Zhang, Meng-Juan,Li, Hong-Xi,Young, David J.,Li, Hai-Yan,Lang, Jian-Ping
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supporting information
p. 3567 - 3574
(2019/04/14)
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- Design, synthesis and biological evaluation of novel dihydropyrimidine-2-thione derivatives as potent antimicrobial agents: Experimental and molecular docking approach
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Introduction: Dihydropyrimidine scaffold represent an important class of pharmacologically active nitrogen containing heterocyclic compounds. A wide range of molecules with dihydropyrimidine moieties have important role in medicinal chemistry on account of their potential biological activities. Methodology: A series of 3,4-dihydropyrimidine-2(1H)-thione derivatives have been designed and synthesized in a concise way through condensation of variously substituted chalcones with thiourea in alkaline alcoholic solutions. In order to investigate their biological significance, these compounds were tested for their in vitro antimicrobial potential against various bacterial and fungal strains. Moreover, the experimental results were supported by molecular docking studies. Results and Discussion: The newly synthesized compounds were characterized by the usual spectroscopic techniques In case of antibacterial activity, the compounds 5 (40.3±0.44 mm), 12 and 13 (almost 35 mm) exhibited highest zone of inhibitions against Methicillin-resistant Staphylococcus auerus (MRSA) bacterial strain as compared to the standard drug Cefixime. These compounds displayed moderate to good activities against all attempted fungal strains. In docking analysis, it has been observed that compounds 8 (-6.4017 Kcal/mol) and 10 (-6.1319 Kcal/mol) revealed significant binding affinity against penicillin binding protein (PDB ID: 1VQQ), while compounds 1 (-143.23 Kcal/mol) and 2 (-146.99 Kcal/mol) showed best activity for shikimate dehydrogenase (PDB ID: 3DON). Conclusion: In conclusion, we have designed, synthesized and characterized an interesting series of biologically active dihydropyrimidine derivatives. Remarkably, most of the synthesized compounds were found more active against all tested bacterial strains in comparison to the standard drug Cefixime as manifested by experimental as well as theoretical results.
- Mughal, Ehsan Ullah,Sadiq, Amina,Hamayun, Muhammad,Zafar, Muhammad Naveed,Fatima, Nighat,Yameen, Muhammad Arfat,Muhammad, Syed Aun,Mumtaz, Amara,Ahmed, Ishtiaq,Fatima, Tehseen
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p. 1189 - 1201
(2018/11/01)
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- Divergent synthesis of novel dienylbenzothiazoles and arylidenedibenzoxazepines and evaluation of their antiproliferative and cytotoxic properties
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Background: Dibenzo-oxazepine and Benzothiazole derivatives are used as antipsychotics, anticancer, antibacterial and anti-inflammatory agents. Methods: Arylidene derivatives of 1,2,3,4-Tetrahydro-Dibenzo[b,f][1,4]Oxazepine and 2-[2-Chloro-Cyclohex-1-enyl]- Benzothiazoles were synthesized by reacting benzylidene derivative of chloroaldehyde with 2-aminophenol and 2-aminothiophenol respectively. Benzylidene derivative of chloroaldehyde was prepared by Vilsmeier reaction of 2-benzylidenecyclohexanone derivatives, which were obtained from the condensation of various aromatic aldehydes with cyclohexanone. Results: Benzylidene derivatives of 1,2,3,4-Tetrahydro-Dibenzo[b,f][1,4]Oxazepine 6a-g exhibited promising antiproliferative activity with GI50 values in the micromolar range. The compounds containing halo, alkyl and alkoxyl groups as substituents on the benzylidine ring have been found to be very effective cytotoxic agents. Conclusion: This study identified dibenzo-oxapine as a prospective pharmacophore which set the stage for thorough exploration of this compound class as cytotoxic agents.
- Kathiravan,Muthukumaran,Dhatchanamoorthy,Shanmuganathan,Venugopal
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p. 314 - 322
(2018/04/20)
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- Synthesis, molecular modeling studies and evaluation of antifungal activity of a novel series of thiazole derivatives
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In the search for new antifungal agents, a novel series of fifteen hydrazine-thiazole derivatives was synthesized and assayed in vitro against six clinically important Candida and Cryptococcus species and Paracoccidioides brasiliensis. Eight compounds showed promising antifungal activity with minimum inhibitory concentration (MIC) values ranging from 0.45 to 31.2 μM, some of them being equally or more active than the drug fluconazole and amphotericin B. Active compounds were additionally tested for toxicity against human embryonic kidney (HEK-293) cells and none of them exhibited significant cytotoxicity, indicating high selectivity. Molecular modeling studies results corroborated experimental SAR results, suggesting their use in the design of new antifungal agents.
- Lino, Cleudiomar Inácio,Gon?alves de Souza, Igor,Santos Teixeira, Iasmin Natália,Maltarollo, Vinícius Gon?alves,de Oliveira, Renata Barbosa,Borelli, Beatriz Martins,Silvério Matos, Thelma Tirone,Johann, Susana,Ramos, Jonas Pereira,Maria de Souza Fagundes, Elaine,de Oliveira Fernandes, Philipe
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p. 248 - 260
(2019/03/12)
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- A Ferrocene-Based NH-Free Phosphine-Oxazoline Ligand for Iridium-Catalyzed Asymmetric Hydrogenation of Ketones
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A new type of ferrocene-based phosphine-oxazoline ligand has been prepared over a few simple steps. An iridium complex of this ligand is air stable and exhibits excellent performance for the asymmetric hydrogenation of simple ketones (up to 98% yield, up to 99% ee, and 20?000 S/C). Exo-α,β-unsaturated cyclic ketones could be regiospecifically hydrogenated to give chiral allylic alcohols with good results. This study indicates that P,N-ligands can also efficiently promote Ir-catalyzed asymmetric hydrogenation without NH-hydrogen-bonding assistance.
- Wang, Yanzhao,Yang, Guoqiang,Xie, Fang,Zhang, Wanbin
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supporting information
p. 6135 - 6139
(2018/09/27)
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- Synthesis and cytotoxicity evaluation of novel asymmetrical mono-carbonyl analogs of curcumin (AMACs) against vero, HeLa, and MCF7 cell lines
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A series of novel asymmetrical mono-carbonyl analogs of curcumin (AMACs) were synthesized and evaluated for cytotoxic activity using BSLT and MTT assay against Vero, HeLa, and MCF7 cell lines. The structures of the synthesized compounds were confirmed by FTIR,1H-NMR,13C-NMR, and mass spectral data. The results of the cytotoxicity evaluation showed that the synthesized compounds exhibited moderate to very high toxic activity in BSLT (LC50 value 29.80–1704.23 μM); most of the compound exhibited cytotoxic activity against HeLa cell lines, which is comparable to the activity of cisplatin (IC50 value 40.65–95.55 μM), and most of the compound tested against MCF7 cell lines exhibited moderate to very high cytotoxic activity (IC50 value 7.86–35.88 μM). However, the selectivity index (SI) of the compounds was low (1–1.96). Among the synthesized compounds, compound 1b was the most cytotoxic and selective against MCF7 cell lines. It could be considered for further development to obtain the more active and selective chemotherapeutic agents against breast cancer.
- Prasetyaningrum, Pekik Wiji,Bahtiar, Anton,Hayun, Hayun
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- Synthesis of symmetrical and unsymmetrical triarylpyrylium ions: Via an inverse electron demand Diels-Alder reaction
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BF3·OEt2 mediated inverse electron demand Diels-Alder (IEDDA) reaction of chalcones with aryl acetylenes is reported for the synthesis of symmetrical and unsymmetrical 2,4,6-triarylpyrylium ions. The protocol provides an effective one-pot method for the utilization of readily available simple substrates under mild reaction conditions leading to a diverse array of pyrylium ions in moderately good yield.
- Fathimath Salfeena,Basavaraja,Ashitha,Kumar, V. Praveen,Varughese, Sunil,Suresh, Cherumuttathu H.,Sasidhar
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supporting information
p. 12463 - 12466
(2018/11/20)
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- Acid/Base-Co-catalyzed Direct Oxidative α-Amination of Cyclic Ketones: Using Molecular Oxygen as the Oxidant
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A novel acid/base-co-catalyzed direct intermolecular α-amination of various cyclic ketones has been developed for the first time. The reaction employs molecular oxygen as the sole oxidant under metal-free conditions. The reaction tolerates a wide range of various anilines, especially primary diamine derivatives, and provides a simple and efficient method for the constructions of α-amino enones and benzodiazepine derivatives in a single step. (Figure presented.).
- Li, Yi-Jin,Zhang, Lu,Yan, Na,Meng, Xiang-He,Zhao, Yu-Long
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supporting information
p. 455 - 461
(2017/12/04)
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- In vitro and in silico evaluations of diarylpentanoid series as α-glucosidase inhibitor
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A series of thirty-four diarylpentanoids derivatives were synthesized and evaluated for their α-glucosidase inhibitory activity. Eleven compounds (19, 20, 21, 24, 27, 28, 29, 31, 32, 33 and 34) were found to significantly inhibit α-glucosidase in which compounds 28, 31 and 32 demonstrated the highest activity with IC50 values ranging from 14.1 to 15.1 μM. Structure-activity comparison shows that multiple hydroxy groups are essential for α-glucosidase inhibitory activity. Meanwhile, 3,4-dihydroxyphenyl and furanyl moieties were found to be crucial in improving α-glucosidase inhibition. Molecular docking analyses further confirmed the critical role of both 3,4-dihydroxyphenyl and furanyl moieties as they bound to α-glucosidase active site in different mode. Overall result suggests that diarylpentanoids with both five membered heterocyclic ring and polyhydroxyphenyl moiety could be a new lead design in the search of novel α-glucosidase inhibitor.
- Leong, Sze Wei,Abas, Faridah,Lam, Kok Wai,Yusoff, Khatijah
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p. 302 - 309
(2018/01/03)
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- Synthesis and biological evaluation of novel active arylidene derivatives of 5,6-dihydro-4H-cyclopenta[b]- and 4,5,6,7-tetrahydrobenzo[b]-thiophene-2-carboxylic acid
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A series of novel arylidene derivatives of 5,6-dihydro-4H-cyclopenta[b]-thiophene-2-carboxylic acid and 4,5,6,7-tetrahydrobenzo[b]-thiophene-2-carboxylic acid were synthesized by reacting benzylidene derivatives of chloro aldehyde with 2-mercaptoacetic acid. Benzylidene derivatives of chloro aldehyde were prepared from Vilsmeier reaction of 2-benzylidenecyclopentanone and 2-benzylidenecyclohexanone derivatives, obtained from condensation of various aromatic aldehydes with cyclopentanone and cyclohexanone. All synthesized compounds were characterized by nuclear magnetic resonance (NMR), infrared (IR), and mass spectroscopy and X-ray single-crystal analysis. The synthesized compounds were screened for their in?vitro antimicrobial and antifungal activity. Good antimicrobial activity, especially against methicillin-resistant Staphylococcus aureus, was observed for most of the compounds tested. In particular, compound 9f emerged as an effective antibacterial agent and may be a potential candidate for future drug discovery and development.
- Kathiravan,Venugopal,Muthukumaran
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p. 2315 - 2331
(2017/03/22)
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- Enantioselective and Diastereoselective Conjugate Radical Additions to α-Arylidene Ketones and Lactones
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A highly stereoselective conjugate radical addition to arylidene ketones and lactones has been developed. The conjugate radical additions using chiral salen Lewis acids proceeds with up to 99:1 dr and 87% ee in good to excellent chemical yields.
- Zhao, Changjia,Sibi, Mukund P.
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supporting information
p. 2971 - 2975
(2017/10/30)
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- Tuning the Reactivity of Functionalized Diallylic Alcohols: Br?nsted versus Lewis Acid Catalysis
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The chemodivergent reactivity of bifunctional, enol thioether-containing diallylic alcohols in acidic medium is disclosed, highlighting the difference between strong Lewis acid and mild Br?nsted acid catalysis. In the presence of bismuth(III) triflate, allylic alcohol activation affords diversely substituted cyclopentenones in a Nazarov-type electrocyclization, whereas activation of the thioenol ether by p-toluenesulfonic acid provides an entry to α-sulfenylated β,γ-unsaturated ketones. Both methods represent a facile access to the corresponding products under mild conditions, using inexpensive and non-toxic catalytic systems.
- Lempenauer, Luisa,Du?ach, Elisabet,Lemière, Gilles
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supporting information
p. 10285 - 10288
(2017/08/07)
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- Phase-vanishing method applied to condensation reactions using TiCl4
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The phase-vanishing (PV) method using perfluorohexanes as the phase screen was applied to the aldol condensation using TiCl4 as the Lewis acid. A special test tube was used, in which an interface between the fluorous and organic layers was stirred, and cyclohexanone was treated with two equivalents of benzaldehyde derivatives under PV conditions to afford corresponding 2,6-dibenzylidencyclohexanone in good yields. The formyl-methylenation of ketones with triethylamine using TiCl4 was also demonstrated by the PV method.
- Adachi, Yusuke,Kuniyoshi, Kenji,Matsubara, Hiroshi
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p. 100 - 105
(2017/04/10)
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- Synthesis and biological activities of some new C-Aminomethylation of 5H-5-Aryl-6,7,8,9-tetrahydrothiazolo[2,3-b]quinazolin-3(2H)-one and 6H-6-Aryl-2,3,7,8,9,10-hexahydrothiazino[2,3-b]quinazolin-4(3H)-one
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The synthesis of 5H-5-aryl-6,7,8,9-tetrahydrothiazolo[2,3-b]quinazolin-3(2H)-one and 6H-6-aryl-2,3,7,8,9,10-hexahydrothiazino[2,3-b]quinazolin-4(3H)-one, reaction between 4-aryl-3,4,5,6,7,8-hexahydroquinazolin-2-thione and methyl chloroacetate and ethyl β-bromo propionate. The Mannich reaction on 5H-5-aryl-6,7,8,9-tetrahydrothiazolo[2,3-b]quinazolin-3(2H)-one and 6H-6-aryl-2,3,7,8,9,10-hexahydrothiazino[2,3-b]quinazolin-4(3H)-one in ethanol, aqueous formaldehyde and different secondary amines yielded a single product C-Mannich base in each case. The obtained C-Mannich bases (compounds VIII and X) have been characterized on the basis of analytical spectral data. These C-Mannich bases have been screened for their antibacterial, antifungal, anti-inflammatory and analgesic activities.
- Kumaraswamy, Damerakonda,Mallareddy
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p. 2231 - 2235
(2016/07/21)
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- BF3·Et2O mediated one-step synthesis of N-substituted-1,2-dihydropyridines, indenopyridines and 5,6-dihydroisoquinolines
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A simple and efficient one-pot synthesis of N-substituted-1,2-dihydropyridines, indenopyridines and 5,6-dihydroisoquinolines by a BF3·Et2O mediated novel methodology, from easily available α,β-unsaturated ketones/arylidene ketones, phenyl acetylenes and substituted nitriles, has been described. This novel annulation provides quick access to complex polycyclic frameworks with an excellent substrate scope.
- Fathimath Salfeena,Ashitha,Sasidhar
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supporting information
p. 10165 - 10169
(2016/11/17)
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- The cascade synthesis of α,β-unsaturated ketones via oxidative C-C coupling of ketones and primary alcohols over a ceria catalyst
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We herein report the oxidative C-C coupling of ketones and primary alcohols to produce α,β-unsaturated ketones in the absence of base additives. This cascade synthetic reaction was conducted at 150 °C in 12 h using a heterogeneous CeO2 catalyst. The conversion of acetophenone reached 74% with 89% selectivity to chalcone. A correlation between the CeO2 crystal plane and catalytic performance is established as the catalytic activities decrease in the sequence of (110) > (111) > (100). Characterization using Raman spectroscopy, CO2 temperature-programmed desorption (CO2-TPD), and in situ active site-capping tests has shown that the unusual catalysis of the CeO2 catalyst is attributed to the coexistence of basic and redox active sites. These sites synergistically catalyze the oxidation of alcohols to aldehydes and the aldol condensation to ketones. Moreover, the CeO2 catalyst can be reused several times after calcination to remove the surface-adsorbed substances.
- Zhang, Zhixin,Wang, Yehong,Wang, Min,Lu, Jianmin,Zhang, Chaofeng,Li, Lihua,Jiang, Jingyang,Wang, Feng
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p. 1693 - 1700
(2016/04/05)
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- Chemoselective Claisen-Schmidt bis-substitutional condensation catalyzed by an alkoxy-bridged dinuclear Ti(IV) cluster
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The highly efficient and chemoselective α,α′-bis-substitution of alkanones is important in organic synthesis. Herein, a dimeric titanium cluster, Ti2Cl2(OPri)6·2HOPri (Ti2), is used in the Claisen-Schmidt condensation reaction, for the selectively activation of symmetrical ketones containing α,α′-methylene groups and production of α,α′-bis-substituted alkanones in high efficiency and chemoselectivity. The high efficiency and chemoselectivity can be extended to a variety of typical alkanones and aromatic aldehydes. Both of the oxo-bridged dimeric motif of Ti2 and the ionic Ti-Cl bond are responsible for the high efficiency and chemoselectivity.
- Wu, Yufei,Hou, Jie,Liu, Yuliang,Zhang, Mingfu,Tung, Chen-Ho,Wang, Yifeng
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p. 1511 - 1516
(2016/03/01)
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- Thiazole compounds with activity against Cryptococcus gattii and Cryptococcus neoformans in vitro
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Human cryptococcosis can occur as a primary or opportunistic infection and develop as an acute, subacute, or chronic, systemic infection involving different host organs. We evaluated the antifungal activity of thirteen compounds against Cryptococcus gattii and Cryptococcus neoformans in vitro, by assessing the toxicity of the compounds showing the greatest antifungal activity in VERO cells and murine macrophages. From these results, four compounds were considered promising for further studies because they displayed low cytotoxicity and significant antifungal activity. The heterocyclic compounds 1b, 1c, 1d, and 1m have antifungal activity levels between that of amphotericin B and fluconazole in vitro. The death curve of Cryptococcus spp. treated with these four compounds was similar to the curve obtained for amphotericin B, in that we observed a significant reduction in cell viability within the first 24 h of treatment. Additionally, we found that there was no effect when these compounds were combined with amphotericin and fluconazole, except for 1c, which antagonized the effect of amphotericin B against C. gattii, also reflected in the reduction of the post-antifungal effect (PAFE); however, this interaction did not alter the ergosterol content. The results shown in this paper reveal the discovery of novel thiazole compounds, which are easy to synthesize, and with potentially exhibit antifungal activity, and display low cytotoxicity in normal mammalian cells. These compounds can be used as prototypes for the design of new antifungal drugs against C. gattii and C. neoformans.
- Pereira de Sá, Nívea,Lino, Cleudiomar Inácio,Fonseca, Nayara Cristina,Borelli, Beatriz Martins,Ramos, Jonas Pereira,Souza-Fagundes, Elaine Maria,Rosa, Carlos Augusto,Santos, Daniel Assis,Barbosa De Oliveira, Renata,Johann, Susana
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p. 233 - 242
(2015/08/24)
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- A magnetic solid sulfonic acid modified with hydrophobic regulators: An efficient recyclable heterogeneous catalyst for one-pot aza-Michael-type and Mannich-type reactions of aldehydes, ketones, and amines
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Two convenient green protocols for the synthesis of β-amino ketones have been developed which involve one-pot aza-Michael-type and Mannich-type reactions of a series of aldehydes, ketones, and amines in the presence of a catalytic amount of the magnetic solid sulfonic acid catalyst, Fe3O4@SiO2@Me&Et-PhSO3H, at room temperature. The catalyst can be reused four times without loss of activity.
- Movassagh, Barahman,Tahershamsi, Leili,Mobaraki, Akbar
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p. 1851 - 1854
(2015/03/30)
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- Alginic acid aerogel: A heterogeneous Br?nsted acid promoter for the direct Mannich reaction
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We demonstrate that highly dispersed alginic acid aerogel beads can function as heterogeneous promoters for Br?nsted acid catalyzed reactions. The activity displayed by alginic acid, benchmarked in the three-component direct Mannich reaction, depended on its morphology, with the aerogel formulation providing distinct advantages over other forms.
- Pettignano, Asja,Bernardi, Luca,Fochi, Mariafrancesca,Geraci, Lorenzo,Robitzer, Mike,Tanchoux, Nathalie,Quignard, Fran?oise
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supporting information
p. 4222 - 4226
(2015/06/16)
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- One-pot sequential 1,4- and 1,2-reductions of α,β-unsaturated δ-lactones to the corresponding δ-lactols with CuCl and NaBH 4 in methanol
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An efficient, one-pot method for the highly chemoselective synthesis of δ-lactols from α,β-unsaturated δ-lactones using CuCl and NaBH4 in methanol was developed. Georg Thieme Verlag Stuttgart. New York.
- Matsumoto, Yasunobu,Yonaga, Masahiro
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supporting information
p. 1764 - 1768
(2014/08/05)
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- Phosphoric acid mediated tautomerism of imines: Addition of a secondary enamine intermediate to aldehydes
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A phosphoric acid derivative has been shown to promote the addition between an imine and several aldehyde substrates through an enamine intermediate to give cross-aldol condensation products. The reaction scope and preliminary mechanistic investigations will be presented.
- Davis, Lindsey O.,Putri, Marcella A.,Meyer, Caitlin L.,Durant, Christopher P.
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p. 3100 - 3103
(2014/05/20)
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- Molecular mechanism of micellar catalysis of cross aldol reaction: Effect of surfactant chain length and surfactant concentration
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The importance of alkyl chain length and concentration of quaternary ammonium surfactants (QAS) in the micellar catalysis of cross aldol reaction was investigated. The NaOH-micellar system catalyzed aldol reaction of benzaldehyde and cyclohexanone to α,α′
- Vashishtha, Manu,Mishra, Manish,Undre, Sachin,Singh, Man,Shah, Dinesh O.
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p. 143 - 154
(2015/02/05)
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- Modified calcium oxide as stable solid base catalyst for Aldol condensation reaction
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A highly efficient and stable solid-base catalyst for Aldol condensation was prepared by modifying commercial CaO with benzyl bromide in a simple way. It was found that modified CaO can effectively catalyse the Aldol condensation of cyclohexanone and benzaldehyde, as well as various benzaldehydes, to produce 2-benzylidenecyclohexanone with a good selectivity and high yield. Higher yield of 95.8% was obtained over modified CaO after 3 h, which is short compared with the yield of 92.1% after 12 h over commercial CaO. The influence of several reaction parameters, such as temperature, catalyst loading, was investigated. The humidity test over modified CaO reveals that the basic centres of modified CaO are stable for CO2 and moisture. From the results of Fourier transform-infrared (FT-IR) and Thermogravity analysis (TG) characterization, the modifier was bonded on surface of CaO chemically and almost no Ca(OH) 2 formed during the modification process. The type of aldehyde has great influence on the yield of aldol condensation.
- Tang, Ying,Xu, Jingfang,Gu, Xuefan
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p. 313 - 320
(2013/07/26)
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- Ultrasound mediation for efficient synthesis of monoarylidene derivatives of homo- and heterocyclic ketones
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Ultrasonic irradiation was efficiently used for high yield synthesis of monoarylidene derivatives of cyclic systems directly from the reaction of ketone with various aldehydes under solvent-free conditions. Reactions took place rapidly in the presence of catalytic amounts of pyrrolidine, while no significant formation of the undesired bis by-products was observed. Moreover, the procedure was applicable to both homo- and heterocyclic ketones.
- Mojtahedi, Mohammad M.,Abaee, M. Saeed,Samianifard, Mehdieh,Shamloo, Akram,Padyab, Masoomeh,Mesbah, A. Wahid,Harms, Klaus
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p. 924 - 930
(2013/03/13)
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- Fe3O4 nanoparticles as an efficient and magnetically recoverable catalyst for the synthesis of α β-unsaturated heterocyclic and cyclic ketones under solvent-free conditions
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An efficient and green procedure has been developed for the synthesis of monoarylidenes of cyclic and heterocyclic ketones. The reaction was carried out under solvent-free conditions in the presence of a catalytic amount of nanosized magnetite (Fe3O4). The catalyst was easily removed by using an external magnet. The structures of the products were deduced from their 1H NMR, 13C NMR, and infrared spectroscopy and mass spectrometry. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
- Alishiri, Tooba,Oskooei, Hossein A.,Heravi, Majid M.
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p. 3357 - 3362
(2013/10/01)
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- Mixed Cu(ii)-Bi(iii) metal organic framework with a 2D inorganic subnetwork and its catalytic activity
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The very dense (d = 4.359 g cm-3) three dimensional (3D) hybrid heterometallic framework Bi3O2Cu(OH)(pdc)2 (pdc3-:3,5-pyrazoledicarboxylate), 1, features a 2D inorganic subnetwork representing an unprecedented topological type, and is an effective catalyst for the diastereoselective synthesis of E-α,β-unsaturated ketones.
- Shi, Fa-Nian,Silva, Ana Rosa,Yang, Ting-Hai,Rocha, Joao
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p. 3776 - 3779
(2013/06/05)
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- Clean borrowing hydrogen methodology using hydrotalcite supported copper catalyst
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The catalytic activity of Mg-Al hydrotalcite supported copper catalyst was investigated for clean CC and CN bond forming reactions using alcohols as alkylating agent via borrowing hydrogen methodology. The catalyst showed excellent conversion of ketone and amine substrates (71-99%) to alkylated products with high selectivity in alkylation reactions.
- Dixit, Manish,Mishra, Manish,Joshi, Pradyuman A.,Shah, Dinesh O.
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