- A new method for the synthesis of chalcone derivatives promoted by PPh3/I2under non-alkaline conditions
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A straightforward and general method has been developed for the synthesis of chalcone derivatives by a Claisen-Schmidt reaction in the presence of PPh3/I2 in 1,4-dioxane under reflux temperatures. With the condensation of the aromatic ketone and aldehyde occurring at non-strongly alkaline conditions, our proposed method significantly expands the range of applicable substrates, especially for groups that are unstable under alkaline conditions.
- Xue, Kangsheng,Sun, Guoxiang,Zhang, Yanzhi,Chen, Xubing,Zhou, Yang,Hou, Jinjun,Long, Huali,Zhang, Zijia,Lei, Min,Wu, Wanying
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supporting information
p. 625 - 634
(2020/11/23)
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- Synthesis, characterization and biological evaluation of new 3,5-disubstituted-pyrazoline derivatives as potential anti-Mycobacterium tuberculosis H37Ra compounds
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A total of fourteen pyrazoline derivatives were synthesized through cyclo-condensation reactions by chalcone derivatives with different types of semicarbazide. These compounds were characterized by IR, 1D-NMR (1H, 13C and Distortionless Enhancement by Polarization Transfer-DEPT-135) and 2D-NMR (COSY, HSQC and HMBC) as well as mass spectroscopy analysis (HRMS). The synthesized compounds were tested for their antituberculosis activity against Mycobacterium tuberculosis H37Ra in vitro. Based on this activity, compound 4a showed the most potent inhibitory activity, with a minimum inhibitory concentration (MIC) value of 17 μM. In addition, six other synthesized compounds, 5a and 5c–5g, exhibited moderate activity, with MIC ranges between 60 μM to 140 μM. Compound 4a showed good bactericidal activity with a minimum bactericidal concentration (MBC) value of 34 μM against Mycobacterium tuberculosis H37Ra. Molecular docking studies for compound 4a on alpha-sterol demethylase was done to understand and explore ligand– receptor interactions, and to hypothesize potential refinements for the compound.
- Azmi, Mohamad Nurul,Che Omar, Mohammad Tasyriq,Osman, Hasnah,Parumasivam, Thaigarajan,Supratman, Unang,Wong, Kok Tong
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- C3 amino-substituted chalcone derivative with selective adenosine rA1 receptor affinity in the micromolar range
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Abstract: To identify novel adenosine receptor (AR) ligands based on the chalcone scaffold, herein the synthesis, characterization and in vitro and in silico evaluation of 33 chalcones (15–36 and 37–41) and structurally related compounds (42–47) are reported. These compounds were characterized by radioligand binding and GTP shift assays to determine the degree and type of binding affinity, respectively, against rat (r) A1 and A2A ARs. The chalcone derivatives 24, 29, 37 and 38 possessed selective A1 affinity below 10?μM, and thus, are the most active compounds of the present series; compound 38 was the most potent selective A1 AR antagonist (Ki (r) = 1.6?μM). The structure–affinity relationships (SAR) revealed that the NH2-group at position C3 of ring A of the chalcone scaffold played a key role in affinity, and also, the Br-atom at position C3′ on benzylidene ring B. Upon in vitro and in silico evaluation, the novel C3 amino-substituted chalcone derivative 38—that contains an α,?-unsaturated carbonyl system and easily allows structural modification—may possibly be a synthon in future drug discovery. Graphic abstract: C3 amino-substituted chalcone derivative (38) with C3′ Br substitution on benzylidene ring B possesses selective adenosine rA1 receptor affinity in micromolar range.[Figure not available: see fulltext.]
- Janse van Rensburg, Helena D.,Legoabe, Lesetja J.,Terre’Blanche, Gisella
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p. 1581 - 1605
(2020/11/20)
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- N-Heterocyclic Carbene Catalyzed Synthesis of Trisubstituted Epoxides via Tandem Amidation/Epoxidation Sequence
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A tandem amidation/epoxidation sequence between various substituted chalcones and N,N-dimethylformamide (DMF) for the synthesis of trisubstituted epoxides employing N-heterocyclic carbene catalysis was developed. This reaction was performed under metal-free conditions in the presence of tert-butyl hydroperoxide (TBHP) as the oxidant. Trisubstituted epoxides bearing a ketone and an amide functionality (N,N-dimethyl formyl group) were synthesized starting from a wide range of chalcones in moderate to good yields with excellent diastereoselectivity.
- Devi, E. Sankari,Pavithra, Thangavel,Tamilselvi,Nagarajan, Subbiah,Sridharan, Vellaisamy,Maheswari, C. Uma
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supporting information
p. 3576 - 3580
(2020/04/20)
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- Retro-Corey-Chaykovsky Epoxidation: Converting Geminal Disubstituted Epoxides to Ketones
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Corey-Chaykovsky epoxidation has been widely applied in the conversion of aldehydes and ketones to epoxides with sulfonium and sulfoxonium ylides. The reverse transformation is realized for conversion of geminal disubstituted epoxides to ketones in the presence of DABCO in refluxing mesitylene. The method is a weak basic transformation from epoxides to ketones with loss of a methylene group and can be applied as an alternative strategy of the acid-catalyzed Meinwald rearrangement or oxidation for conversion of epoxides to carbonyl compounds.
- Li, Siqi,Li, Pingfan,Xu, Jiaxi
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- Organocatalytic asymmetric vinylogous 1,4-addition of α,α-Dicyanoolefins to chalcones under a bio-based reaction media: Discovery of new Michael adducts with antiplasmodial activity
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The organocatalysed asymmetric vinylogous Michael addition of α,α-dicyanoolefins to α,β-unsaturated aldehydes and ketones have been reported in the last decade, however, chalcones have been poorly explored. Moreover, a considerable part of the publications in this theme still employs undesirable solvents, such as toluene and THF, with concerns related to health and environmental safety. We report herein the use of a bifunctional catalyst derived from a Cinchona alkaloid to perform the enantio- and diastereoselective Michael addition of α,α-dicyanoolefins to chalcones using 2-MeTHF as solvent. The Michael adducts were obtained in moderate to good yields and were evaluated for their antiplasmodial and cytotoxic activity.
- Martelli, Lorena S.R.,Vieira, Lucas C.C.,Paix?o, Márcio W.,Zukerman-Schpector, Julio,de Souza, Juliana O.,Aguiar, Anna Caroline C.,Oliva, Glaucius,Guido, Rafael V.C.,Corrêa, Arlene G.
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supporting information
p. 3530 - 3542
(2019/05/24)
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- Visible Light-Induced Aerobic Epoxidation of α,β-Unsaturated Ketones Mediated by Amidines
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An aerobic photoepoxidation of α,β-unsaturated ketones driven by visible light in the presence of tetramethylguanidine (3b), tetraphenylporphine (H2TPP), and molecular oxygen under mild conditions was revealed. The corresponding α,β-epoxy ketones were obtained in yields of up to 94% in 96 h. The reaction time was shortened to 4.6 h by flow synthesis. The mechanism related to singlet oxygen was supported by experiments and density functional theory (DFT) calculations.
- Wu, Yufeng,Zhou, Guangli,Meng, Qingwei,Tang, Xiaofei,Liu, Guangzhi,Yin, Hang,Zhao, Jingnan,Yang, Fan,Yu, Zongyi,Luo, Yi
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p. 13051 - 13062
(2018/10/25)
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- Transition-Metal-Free Catalytic Formal Hydroacylation of Terminal Alkynes
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Although hydroacylation is a very useful reaction for producing ketones from aldehydes with 100% atom efficiency, classical Rh-catalyzed hydroacylation presents several problems, including the need for transition metal catalysts, unwanted decarbonylation of aldehydes, and difficulty in regioselectivity control. However, formal hydroacylation utilizing the nucleophilicity of terminal alkynes can avoid these problems. In this work, we have achieved transition-metal-free formal hydroacylation of terminal alkynes using an Mg3Al-CO3-layered double hydroxide as a heterogeneous catalyst. This system was applicable to the efficient synthesis of α,β-unsaturated ketones with various substituents, and the catalyst can be reused without a significant loss of catalytic performance.
- Yatabe, Takafumi,Mizuno, Noritaka,Yamaguchi, Kazuya
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p. 11564 - 11569
(2018/11/23)
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- High pressure-assisted low-loading asymmetric organocatalytic conjugate addition of nitroalkanes to chalcones
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The application of high pressure (up to 9 kbar) allows for relatively fast (1-5 h) and highly enantioselective 1,4-addition of nitromethane and 2-nitropropane to chalcones at room temperature with substantial reduction of catalyst loading (0.2-1 mol% of cinchona alkaloid-based thioureas and squaramides). Various γ-nitroketones were obtained at 9 kbar with high yield and enantioselectivity (up to 98%), whereas in control experiments at atmospheric pressure usually only a small amount (10%) of products were formed after 20 h.
- Cholewiak, Agnieszka,Adamczyk, Kamil,Kopyt, Micha?,Kasztelan, Adrian,Kwiatkowski, Piotr
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supporting information
p. 4365 - 4371
(2018/06/22)
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- One-Pot Synthesis of α,β-Unsaturated Esters, Ketones, and Nitriles from Alcohols and Phosphonium Salts
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A general method for the synthesis of α,β-unsaturated esters, ketones, and nitriles is successfully achieved by a one-pot copper-catalyzed oxidation with O 2 in air as oxidant. The solvent mixture of acetonitrile and formamide (1:1) is optimized to ensure the oxidation of alcohols, deprotonation of phosphonium salt, and Wittig reaction occur efficiently in one pot. A broad range of substrates has been explored for this process, including three electron-withdrawing group (CO 2 Et, COPh, CN) functionalized phosphonium salts. They reacted not only with benzylic and heteroaromatic alcohols, but also with aliphatic alcohols, forming the corresponding α,β-unsaturated esters, ketones, and nitriles in moderate to excellent yields.
- Ding, Weijie,Hu, Juan,Jin, Huile,Yu, Xiaochun,Wang, Shun
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p. 107 - 118
(2017/09/28)
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- CBr4 as a Halogen Bond Donor Catalyst for the Selective Activation of Benzaldehydes to Synthesize α,β-Unsaturated Ketones
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CBr4 has been employed as a halogen bond donor catalyst for the selective activation of aldehyde, to achieve an efficient solvent- and metal-free CC bond forming reaction in the presence of strong acid sensitive groups such as methoxy, cyanide, ester, and ketal for the synthesis of α,β-unsaturated ketones. This unique capability of CBr4 to act as a halogen bond donor has been explored and established using UV-vis as well as IR spectroscopy. Moreover, this unprecedented methodology enables the synthesis of the pharmaceutically important molecule licochalcone A.
- Kazi, Imran,Guha, Somraj,Sekar, Govindasamy
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supporting information
p. 1244 - 1247
(2017/03/14)
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- Silver-catalyzed decarboxylative cross-coupling of α-keto acids with alkenes giving approach to chalcones
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A silver-catalyzed decarboxylative cross-coupling of α-keto acids with alkenes is reported. The method, with a wide range of substrate tolerance and mild operational conditions, can produce various chalcone derivatives in moderate to high yields from easily available starting materials.
- Wu, Shang,Yu, Hongheng,Hu, Qinzheng,Yang, Quanlu,Xu, Shouwang,Liu, Tian
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p. 4763 - 4765
(2017/12/01)
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- Chiral octahedral complexes of Co(iii) as catalysts for asymmetric epoxidation of chalcones under phase transfer conditions
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Stereochemically inert and positively charged chiral complexes of Co(iii) were shown to catalyze the asymmetric epoxidation of chalcones with H2O2 under phase transfer conditions. The reaction products had enantiomeric purities of up to 55%. It was also shown that complex 1a I- catalyzed the coupling reaction of a resulting epoxide with CO2 (conversion 72%).
- Larionov, Vladimir A.,Markelova, Elina P.,Smol'yakov, Alexander F.,Savel'yeva, Tat'yana F.,Maleev, Victor I.,Belokon, Yuri N.
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p. 72764 - 72771
(2015/09/15)
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- Synthesis of chalcones via domino dehydrochlorination/Pd(OAc)2-catalyzed Heck reaction
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A new method has been developed for the cross-coupling of aryl halides with β-chloroalkyl aryl ketones and their ester and amide analogs through a domino dehydrochlorination/Pd(OAc)2- catalyzed Heck reaction sequence. The enone intermediates generated in situ reduced the occurrence of side reactions and therefore enhanced the efficiency of the reaction. This reaction exhibited good tolerance to various functional groups on both substrates and provides rapid access to a wide range of chalcone derivatives.
- Guo, Tenglong,Jiang, Quanbin,Yu, Likun,Yu, Zhengkun
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- Copper-catalyzed oxidative transformation of secondary alcohols to 1,5-disubstituted tetrazoles
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A mild and convenient oxidative transformation of secondary alcohols to 1,5-disubstituted tetrazoles is uncovered by employing trimethylsilyl azide (TMSN3) as a nitrogen source in the presence of a catalytic amount of copper(II) perchlorate hexahydrate [Cu(ClO4)2 .6 H2O] (5 mol%) and 2,3-dichloro-5,6-dicyano-para- benzoquinone (DDQ) (1.2 equiv.) as an oxidant. This reaction is performed under ambient conditions and proceeds through C-C bond cleavage.
- Rokade, Balaji V.,Gadde, Karthik,Prabhu, Kandikere Ramaiah
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supporting information
p. 946 - 950
(2014/04/03)
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- Montmorillonite clay-promoted, solvent-free cross-aldol condensations under focused microwave irradiation
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An environmentally benign, clean and general protocol was developed for the synthesis of aryl and heteroaryl trans-chalcones. This method involved solvent-free reaction conditions under microwave irradiation in the presence of a clay-based catalyst, and afforded the target compounds in good yields and short reaction times. Furthermore, the same conditions allowed the synthesis of symmetrical, diarylmethylene-a,a-unsaturated ketones from aromatic aldehydes and ketones.
- Rocchi, Damiano,Gonzalez, Juan F.,Menendez, J. Carlos
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supporting information
p. 7317 - 7326
(2014/07/08)
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- Tin(II) chloride mediated coupling reactions between alkynes and aldehydes
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Tin(II) chloride, which is insensitive to water and air, mediated the coupling reaction between alkynes and aldehydes as a Lewis acid in nitromethane to produce (E)-α,β-unsaturated ketones by a skeletal transformation in which one alkynic carbon atom changed into an oxo carbon atom accompanied by the cleavage of a C=O bond in the starting aldehydes. This coupling reaction was promoted by a catalytic amount of a primary or secondary alkanol. The coupling reaction between 1-deuterio-2-phenylethyne and benzaldehyde with BuOH afforded 1,3-diphenyl-2-deuterio-2-propenone (2-deuteriation: 94 % D), whereas the coupling reaction between phenylethyne and benzaldehyde with BuOD afforded 1,3-diphenyl-2-propenone (2-deuteriation: 0 % D). Because almost no exchange between hydrogen and deuterium at the 2-position of 1,3-diphenyl-2-propenone occurs in either of the reactions, the coupling reaction between alkynes and aldehydes with tin(II) chloride is presumed to proceed by nucleophilic addition of alkynes to aldehydes. The cleavage of the C-O single bond generated by the nucleophilic addition might be induced by the strong oxophilicity of tin. Coupling reactions occur between alkynes and aldehydes mediated by tin(II) chloride as a Lewis acid to produce (E)-α,β-unsaturated ketones by a skeletal transformation in which an alkynic carbon atom changes into an oxo carbon atom accompanied by cleavage of the C=O bond in the starting aldehydes. This coupling reaction is promoted by a catalytic amount of a primary or secondary alkanol. Copyright
- Masuyama, Yoshiro,Takamura, Wataru,Suzuki, Noriyuki
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p. 8033 - 8038
(2014/01/06)
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- Amberlyst-15 and Amberlite-200C: Efficient catalysts for aldol and cross-aldol condensation under ultrasound irradiation
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This paper presents an improved synthesis of trans-chalcones and α,α′-bis(arylmethylidene) cycloalkanones under ultrasound irradiation in the presence of commercial acid-resins as catalysts in solvent free conditions. Several trans-chalcones and α,α′- bis(arylmethylidene) cycloalkanones were synthesized in good yields and excellent selectivity in a short reaction time.
- Lahyani, Achraf,Chtourou, Manef,Frikha, Mohamed Hédi,Trabelsi, Mahmoud
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p. 1296 - 1301
(2013/06/27)
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- Chemoselectivity in the reaction of 2-diazo-3-oxo-3-phenylpropanal with aldehydes and ketones
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The chemoselectivity in the reaction of 2-diazo-3-oxo-3-phenylpropanal (1) with aldehydes and ketones in the presence of Et3N was investigated. The results indicate that 1 reacts with aromatic aldehydes with weak electron-donating substituents and cyclic ketones under formation of 6-phenyl-4H-1,3-dioxin-4-one derivatives. However, it reacts with aromatic aldehydes with electron-withdrawing substituents to yield 1,3-diaryl-3-hydroxypropan-1-ones, accompanied by chalcone derivatives in some cases. It did not react with linear ketones, aliphatic aldehydes, and aromatic aldehydes with strong electron-donating substituents. A mechanism for the formation of 1,3-diaryl-3-hydroxypropan-1-ones and chalcone derivatives is proposed. We also tried to react 1 with other unsaturated compounds, including various olefins and nitriles, and cumulated unsaturated compounds, such as N,N′-dialkylcarbodiimines, phenyl isocyanate, isothiocyanate, and CS2. Only with N,N′-dialkylcarbodiimines, the expected cycloaddition took place. Copyright
- Zhang, Jiantao,Xu, Jiaxi
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p. 1733 - 1739
(2013/10/21)
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- Investigation of chalcones and benzochalcones as inhibitors of breast cancer resistance protein
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Breast cancer resistance protein (BCRP/ABCG2) belongs to the ATP binding cassette family of transport proteins. BCRP has been found to confer multidrug resistance in cancer cells. A strategy to overcome resistance due to BCRP overexpression is the investigation of potent and specific BCRP inhibitors. The aim of the current study was to investigate different multi-substituted chalcones for their BCRP inhibition. We synthesized chalcones and benzochalcones with different substituents (viz. OH, OCH3, Cl) on ring A and B of the chalcone structure. All synthesized compounds were tested by Hoechst 33342 accumulation assay to determine inhibitory activity in MCF-7 MX and MDCK cells expressing BCRP. The compounds were also screened for their P-glycoprotein (P-gp) and Multidrug resistance-associated protein 1 (MRP1) inhibitory activity in the calcein AM accumulation assay and were found to be selective towards inhibition of BCRP. Substituents at position 2′ and 4′ on chalcone ring A were found to be essential for activity; additionally there was a great influence of substituents on ring B. Presence of 3,4-dimethoxy substitution on ring B was found to be optimal, while presence of 2- and 4-chloro substitution also showed a positive effect on BCRP inhibition.
- Juvale, Kapil,Pape, Veronika F.S.,Wiese, Michael
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experimental part
p. 346 - 355
(2012/03/09)
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- Continuous-flow hydration-condensation reaction: Synthesis of αβ-unsaturated ketones from alkynes and aldehydes by using a heterogeneous solid acid catalyst
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A simple, practical and efficient continuous-flow hydration-condensation protocol was developed for the synthesis of α,β-unsaturated ketones starting from alkynes and aldehydes by employing a heterogeneous catalyst in a flow microwave. The procedure presents a straightforward and convenient access to valuable differently substituted chalcones and can be applied on multigram scale.
- Rueping, Magnus,Bootwicha, Teerawut,Baars, Hannah,Sugiono, Erli
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supporting information; experimental part
p. 1680 - 1687
(2012/02/04)
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- Ferrocenyl chalcones versus organic chalcones: A comparative study of their nematocidal activity
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A series of 30 organic chlacones and 33 ferrocenyl (Fc) chalcones were synthesized and characterized by melting point, elemental analysis, spectroscopy (1H NMR and FTIR) and, in two cases, by X-ray crystallography. The biological activity of each compound (10-4 M in DMSO) against the model nematode Caenorhabditis elegans was examined in terms of % mortality (percent nematodes that died) and % fecundity (percent nematodes that reproduced) and compared to that obtained for the control medium (1% DMSO) over a 14-day period. Detailed conformational analyses for two Fc-chalcones (studied also by X-ray crystallography) were performed via molecular modeling studies. In general, the organic chalcones were found to be less polar than their Fc analogs. Some structure-activity relationships (SARs) were determined: (a) The nematocidal activities of the organic chalcones in this series were found to be much greater than those of their ferrocenyl analogs. (b) The position of the carbonyl group played a central role in the biological activity of both classes of chalcones studied. (c) For both classes of chalcones, lipophilicity of a compound seemed to play a significant role in its nematocidal activity. (d) The planarity of a ferrocenyl-chlacone seems to play a role in its activity.
- Attar, Saeed,O'Brien, Zachary,Alhaddad, Hasan,Golden, Melissa L.,Calderón-Urrea, Alejandro
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supporting information; experimental part
p. 2055 - 2073
(2011/04/27)
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- Synthesis, characterization, antiamoebic activity and cytotoxicity of novel series of pyrazoline derivatives bearing quinoline tail
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The cyclization of chalcones (1a-1j) with 2-(quinolin-8-yloxy) acetohydrazide (2) under basic condition led to the formation of new compounds, pyrazoline derivatives (3a-3j). In vitro antiamoebic activity was performed against HM1: IMSS strain of Entamoeba histolytica. The results showed that the compounds 3d, 3g, 3h, and 3j exhibited promising antiamoebic activity (IC 50 = 0.05 μM, 0.31 μM, 0.06 μM, 0.29 μM) respectively than the standard drug metronidazole (IC50 = 1.84 μM). The toxicological studies of these compounds on human breast cancer MCF-7 cell line showed that all the compounds 3d, 3g, 3h, 3j and metronidazole were nontoxic at the concentration range of 1.56-50 μM.
- Hayat, Faisal,Salahuddin, Attar,Umar, Sadiq,Azam, Amir
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experimental part
p. 4669 - 4675
(2010/10/19)
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- Screening of biological activities of a series of chalcone derivatives against human pathogenic microorganisms
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In an effort to develop new antimicrobial agents, a series of chalcone derivatives, 3-60, were prepared by Claisen-Schmidt condensation of appropriate acetophenones and 2-furyl methyl ketones with appropriate aromatic aldehydes, furfural, and thiophene-2-carbaldehyde in an aqueous solution of NaOH and EtOH at room temperature. The synthesized compounds were characterized by means of their IR- and NMR-spectral data, and elemental analysis. All compounds were tested for their antibacterial and antifungal activities by the disc diffusion method. For the most active compounds, also minimum inhibitory concentrations (MICs) were determined.
- Karaman, Isa,Gezegen, Hayreddin,Guerdere, M. Burcu,Dingil, Alparslan,Ceylan, Mustafa
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experimental part
p. 400 - 408
(2010/09/04)
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- A palladium catalyzed atom-efficient cross-coupling reactivity of triarylbismuths with α,β-unsaturated acyl chlorides
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An atom-efficient cross-coupling reactivity of triarylbismuths (1 equiv) was demonstrated by cross-coupling reaction with 3 equiv of α,β-unsaturated acyl chlorides under palladium catalysis in the synthesis of a series of functionalized α, β-unsaturated ketones in high isolated yields.
- Rao, Maddali L.N.,Venkatesh, Varadhachari,Jadhav, Deepak N.
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p. 2494 - 2498
(2008/09/21)
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- Application of ferrocenyl substituted aziridinylmethanols (FAM) as chiral ligands in enantioselective conjugate addition of diethylzinc to enones
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Easily available ferrocenyl substituted aziridinylmethanol FAM-4a complexes with nickel and catalyzes the enantioselective diethylzinc addition to various enones with enantiomeric excesses reaching 80%. The ligand can be recovered and used without losing its activity. The sense of induction was found to be dependent on the configuration of the aziridine ring.
- Isleyen, Alper,Dogan, Oezdemir
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p. 679 - 684
(2007/10/03)
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- Mechanochemical aminochlorination of electron-deficient olefins with chloramine-T promoted by (diacetoxyiodo)benzene
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A direct and convenient procedure for the solvent-free mechanochemical aminochlorination of electron-deficient olefins promoted by (diacetoxyiodo) benzene [PhI(OAc)2] was described using commercially available and cheap chloramine-T as a nitrogen and chlorine source. The vicinal chloramine derivatives were obtained in high regio- and stereoselectivity with good yields. PhI(OAc)2 was superior to metal salts for the aminochlorination of electron-deficient olefins.
- Wang, Guan-Wu,Wu, Xue-Liang
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p. 1977 - 1982
(2008/09/17)
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- The ortho effect: Copper-catalyzed highly enantioselective 1,4-conjugate addition of diethylzinc to chalcones
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The copper-catalyzed enantioselective 1,4-conjugate addition of diethylzinc to chalcones was investigated in the presence of a catalytic amount of N,P-ferrocenyl ligands with central and planar chirality under mild conditions (0 °C→rt). It was found that chalcones with ortho-substituents (from ortho-substituted benzaldehydes and acetophenone/substituted acetophenones) led to a dramatic improvement in the enantioselectivities. The (R)- and (S)-antipodes of the addition reaction were obtained with up to 92% ee after this transformation.
- Liu, Lan-Tao,Wang, Min-Can,Zhao, Wen-Xian,Zhou, Yan-Li,Wang, Xiao-Dan
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p. 136 - 141
(2007/10/03)
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- Efficient coupling reactions of arylalkynes and aldehydes leading to the synthesis of enones
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Ionic liquids such as 1-butyl-3-methyl-1H-imidazolium 4- methylbenzenesulfonate (BmimOTs) and its 1-ethyl analogue EmimOTs are novel effective and recyclable media for acid-catalyzed coupling reaction, of aromatic alkynes with aldehydes affording (E)-enones (Scheme 1, Table) with simple recovery and easy workup due to the absence of volatile organic solvents. This transformation avoids the use of moisture-sensitive and heavy-metal Lewis acids.
- Xu, Li-Wen,Li, Lyi,Xia, Chun-Gu,Zhao, Pei-Qing
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p. 3080 - 3084
(2007/10/03)
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- Ytterbium triflate promoted coupling reaction between aryl alkynes and aldehydes
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A simple and efficient solvent-free coupling reaction affording regioselectively trans-α,β-enones from aryl alkynes and aldehydes catalysed by Yb(OTf)3 hydrate is described.
- Curini, Massimo,Epifano, Francesco,Maltese, Federica,Rosati, Ornelio
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p. 552 - 554
(2007/10/03)
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- FeCl3·6H2O catalysed condensation of aldehydes and ketones in ionic liquid: A novel green synthesis of chalcones
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Using iron(III) chloride hexahydrate as a catalyst, chalcones were efficiently prepared from acetophenone and benzaldehyde in ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) for the first time. Compared with the known methods, this novel access to chalcones has the advantage of being a green process together with good yields and mild reaction conditions.
- Zhang, Xinying,Niu, Hongying,Wang, Jianji
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- A new solvent-free synthesis of α,β-unsaturated ketones from acetals with aryl ketones under microwave irradiation
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A new, rapid and efficient method for the synthesis of α,βunsaturated ketones under microwave irradiation conditions is described. The process involves the reaction of acetals with aryl ketones in the absence of solvent using Lewis acids as catalysts under microwave irradiation to afford the α,βunsaturated ketones in good to excellent isolated yields. The reaction mechanism is briefly discussed.
- Huang, Danfeng,Wang, Jin-Xian,Hu, Yulai,Zhang, Yumei,Tang, Jing
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p. 971 - 979
(2007/10/03)
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- A facile deamination of aziridines using N2O4 under very mild conditions
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Various aziridines reacted with N2O4 (2 eq) in the presence of Et3N (1 or 2 eq) in dry THF to give the corresponding ethylenes in good to excellent yields at (-23 °C or -43 °C) in 10 min under Ar.
- Lee, Kieseung,Kim, Yong Hae
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p. 1241 - 1248
(2007/10/03)
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- Solution phase synthesis of a spiro[pyrrolidine-2,3'-oxindole] library via a three component 1,3-dipolar cycloaddition reaction
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A combinatorial library of 26,500 spiro[pyrrolidine,-2,3-oxindoles] was prepared in a single-compound format by a facile intermolecular 1,3-dipolar cycloaddition. An azomethine ylide, generated by the decarboxylative condensation of an isatin 1 with an α-amino acid 2, was trapped by a transchalcone 3 to afford heterocycles of the general structure 4. The regio- and stereochemistry of a representative product was determined by single crystal X-ray structure.
- Fokas, Demosthenes,Ryan, William J.,Casebier, David S.,Coffen, David L.
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p. 2235 - 2238
(2007/10/03)
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- 3-[2-(4-Anisidino)phenyl]-1-phenyl-1-propiophenones and propanols
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The invention relates to novel 1-(4-R1 O-phenyl)-2-(4-R2 -phenyl)-6-R3 -1,2,3,4-tetrahydroquinolines having anti-fertility and hypocholesterolemic activities, to their preparation, and to novel intermediates therefor.
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- Certain 1,2-diphenyl-1,2,3,4-tetrahydroquinoline compounds
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The invention relates to novel 1-(4-R1 O-phenyl)-2-(4-R2 -phenyl)-6-R3 -1,2,3,4-tetrahydroquinolines having antifertility and hypocholesterolemic activities, to their preparation, and to novel intermediates therefor.
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