- Cobalt-catalyzed Divergent Markovnikov and Anti-Markovnikov Hydroamination
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Catalytic hydroamination of the readily available alkenes is among the most straightforward means to construct diverse alkyl amines. To this end, the facile access to both regioselectivity, i.e., Markovnikov or anti-Markovnikov hydroamination, with minimum reaction-parameter alternation, remains challenging. Herein, we report a cobalt-catalyzed highly selective and divergent Markovnikov and anti-Markovnikov hydroamination of alkenes, in which the switch of regioselectivity is achieved simply by the variation of the addition sequence of 9-BBN.
- Zhang, Xiang-Gui,He, Zi-Xin,Guo, Peng,Chen, Zheng,Ye, Ke-Yin
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supporting information
p. 22 - 26
(2022/01/04)
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- Direct conversion of secondary propargyl alcohols into 1,3-di-arylpropanoneviaDBU promoted redox isomerization and palladium assisted chemoselective hydrogenation in a single pot operation
-
Palladium(ii)acetate is found to be an efficient catalyst for the single-step conversion of secondary propargyl alcohols to 1,3-diarylpropanone derivatives under mild basic conditions. The reaction is believed to proceedviaredox isomerisation of secondary propargyl alcohols followed by chemoselective reduction of an enone double bond with formic acid as an adequate hydrogen donor. A large number of 1,3-diarylpropanone derivatives may readily be prepared from a milligram to a multigram scale.
- Bera, Mrinal K.,Chandra, Shubhadeep,De, Rimpa,Savarimuthu, S. Antony
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p. 17871 - 17877
(2021/10/12)
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- Visible-Light Decatungstate/Disulfide Dual Catalysis for the Hydro-Functionalization of Styrenes
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We describe an efficient photoredox system, relying on decatungstate/disulfide catalysts, for the hydrofunctionalization of styrenes. In this methodology the use of disulfide as a cocatalyst was shown to be crucial for the reaction efficiency. This photoredox system was employed for the hydro-carbamoylation, -acylation, -alkylation, and -silylation of styrenes, giving access to a large variety of useful building blocks and high-value molecules such as amides and unsymmetrical ketones from simple starting materials.
- Prieto, Alexis,Taillefer, Marc
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supporting information
p. 1484 - 1488
(2021/03/08)
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- Selective catalytic synthesis of α-alkylated ketones and β-disubstituted ketones via acceptorless dehydrogenative cross-coupling of alcohols
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Herein, a phosphine-free pincer ruthenium(III) catalyzed β-alkylation of secondary alcohols with primary alcohols to α-alkylated ketones and two different secondary alcohols to β-branched ketones are reported. Notably, this transformation is environmentally benign and atom efficient with H2O and H2 gas as the only byproducts. The protocol is extended to gram-scale reaction and for functionalization of complex vitamin E and cholesterol derivatives.
- Bhattacharyya, Dipanjan,Sarmah, Bikash Kumar,Nandi, Sekhar,Srivastava, Hemant Kumar,Das, Animesh
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supporting information
p. 869 - 875
(2021/02/06)
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- Iron-catalyzed chemoselective hydride transfer reactions
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A Diaminocyclopentadienone iron tricarbonyl complex has been applied in chemoselective hydrogen transfer reductions. This bifunctional iron complex demonstrated a broad applicability in mild conditions in various reactions, such as reduction of aldehydes over ketones, reductive alkylation of various functionalized amines with functionalized aldehydes and reduction of α,β-unsaturated ketones into the corresponding saturated ketones. A broad range of functionalized substrates has been isolated in excellent yields with this practical procedure.
- Coufourier, Sébastien,Ndiaye, Daouda,Gaillard, Quentin Gaignard,Bettoni, Léo,Joly, Nicolas,Mbaye, Mbaye Diagne,Poater, Albert,Gaillard, Sylvain,Renaud, Jean-Luc
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supporting information
(2021/06/07)
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- Efficient cleavage of tertiary amide bonds: Via radical-polar crossover using a copper(ii) bromide/Selectfluor hybrid system
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A novel approach for the efficient cleavage of the amide bonds in tertiary amides is reported. Based on the selective radical abstraction of a benzylic hydrogen atom by a CuBr2/Selectfluor hybrid system followed by a selective cleavage of an N-C bond, an acyl fluoride intermediate is formed. This intermediate may then be derivatized in a one-pot fashion. The reaction proceeds under mild conditions and exhibits a broad substrate scope with respect to the tertiary amide moiety as well as to nitrogen, oxygen, and carbon nucleophiles for the subsequent derivatization. Mechanistic studies suggest that the present reaction proceeds via a radical-polar crossover process that involves benzylic carbon radicals generated by the selective radical abstraction of a benzylic hydrogen atom by the CuBr2/Selectfluor hybrid system. Furthermore, a synthetic application of this method for the selective cleavage of peptides is described. This journal is
- Maruoka, Keiji,Matsumoto, Akira,Wang, Zhe
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p. 12323 - 12328
(2020/12/08)
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- Visible-Light-Promoted Photocatalyst-Free Hydroacylation and Diacylation of Alkenes Tuned by NiCl2·DME
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Herein, we describe a visible light-promoted hydroacylation strategy that facilitates the preparation of ketones from alkenes and 4-acyl-1,4-dihydropyridines via an acyl radical addition and hydrogen atom transfer pathway under photocatalyst-free conditions. The efficiency was highlighted by wide substrate scope, good to high yields, successful scale-up experiments, and expedient preparation of highly functionalized ketone derivatives. In addition, this protocol allows for the synthesis of 1,4-dicarbonyl compounds through alkene diacylation in the presence of NiCl2·DME.
- Zhao, Xinxin,Li, Bing,Xia, Wujiong
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p. 1056 - 1061
(2020/02/15)
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- Sustainable and Selective Alkylation of Deactivated Secondary Alcohols to Ketones by Non-bifunctional Pincer N-heterocyclic Carbene Manganese
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A sustainable and green route to access diverse functionalized ketones via dehydrogenative–dehydrative cross-coupling of primary and secondary alcohols is demonstrated. This borrowing hydrogen approach employing a pincer N-heterocyclic carbene Mn complex displays high activity and selectivity. A variety of primary and secondary alcohols are well tolerant and result in satisfactory isolated yields. Mechanistic studies suggest that this reaction proceeds via a direct outer-sphere mechanism and the dehydrogenation of the secondary alcohol substrates plays a vital role in the rate-limiting step.
- Lan, Xiao-Bing,Ye, Zongren,Liu, Jiahao,Huang, Ming,Shao, Youxiang,Cai, Xiang,Liu, Yan,Ke, Zhuofeng
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p. 2557 - 2563
(2020/05/04)
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- Chemoselective Hydrosilylation of the α,β-Site Double Bond in α,β- And α,β,γ,δ-Unsaturated Ketones Catalyzed by Macrosteric Borane Promoted by Hexafluoro-2-propanol
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The B(C6F5)3-catalyzed chemoselective hydrosilylation of α,β- and α,β,γ,δ-unsaturated ketones into the corresponding non-symmetric ketones in mild reaction conditions is developed. Nearly 55 substrates including those bearing reducible functional groups such as alkynyl, alkenyl, cyano, and aromatic heterocycles are chemoselectively hydrosilylated in good to excellent yields. Isotope-labeling studies revealed that hexafluoro-2-propanol also served as a hydrogen source in the process.
- Zhan, Xiao-Yu,Zhang, Hua,Dong, Yu,Yang, Jian,He, Shuai,Shi, Zhi-Chuan,Tang, Lei,Wang, Ji-Yu
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p. 6578 - 6592
(2020/07/17)
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- Arylation of Aldehydes to Directly Form Ketones via Tandem Nickel Catalysis
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A nickel-catalyzed arylation of both aliphatic and aromatic aldehydes proceeds with air-stable (hetero)arylboronic acids, with an exceptionally wide substrate scope. The neutral condition tolerates acidic hydrogen and sensitive polar groups and also preserves α-stereocenters of some chiral aldehydes. Interestingly, this nickel(0) catalysis does not follow common 1,2-insertion of arylmetal species to aldehydes and β-hydrogen elimination.
- Lei, Chuanhu,Zhu, Daoyong,Tangcueco, Vicente Iii Tiu,Zhou, Jianrong Steve
-
supporting information
p. 5817 - 5822
(2019/08/26)
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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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- Ligand-controlled phosphine-free Co(II)-catalysed cross-coupling of secondary and primary alcohols
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Cobalt(II) complexes (5 mol% Co) bearing phosphine-free N?N?N pincer ligands efficiently catalyze C–C coupling of secondary and primary alcohols to selectively form α-alkylated ketones with a good functional group compatibility using NaOH (20 mol%) as a base at 120 °C. The NH group on the N?N?N–Co(II) precatalyst controls the activity and selectivity. This simple catalytic system is involved in the synthesis of quinolones via the dehydrogenative annulation of 2-aminobenzyl alcohols with secondary alcohols.
- Zhang, Shi-Qi,Guo, Bin,Xu, Ze,Li, Hong-Xi,Li, Hai-Yan,Lang, Jian-Ping
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- Electrochemical 1,4-reduction of α,β-unsaturated ketones with methanol and ammonium chloride as hydrogen sources
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A sustainable, chemoselective 1,4-reduction of α,β-unsaturated ketones by means of an electrochemical method is presented, wherein the extremely inexpensive ammonium chloride (NH4Cl) is applied as the only additive. The reaction proceeds smoothly in the air at ambient temperature. Mechanistic studies reveal that both NH4Cl and solvent methanol work as hydrogen donors.
- Huang, Binbin,Li, Yanan,Yang, Chao,Xia, Wujiong
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supporting information
p. 6731 - 6734
(2019/06/17)
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- Cobalt-Catalyzed Chemoselective Transfer Hydrogenation of C=C and C=O Bonds with Alkanols
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An environmentally benign protocol of chemoselective transfer hydrogenation of C=C and C=O bonds with alkanols under base-free conditions is developed by this study, wherein the cobalt- bidentate phosphine catalyst precursor is commercially available and
- Jiang, Biao-Lin,Ma, Shuang-Shuang,Wang, Meng-Liang,Liu, Dian-Sheng,Xu, Bao-Hua,Zhang, Suo-Jiang
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p. 1701 - 1706
(2019/03/08)
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- Nonbifunctional Outer-Sphere Strategy Achieved Highly Active α-Alkylation of Ketones with Alcohols by N-Heterocyclic Carbene Manganese (NHC-Mn)
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The unusual nonbifunctional outer-sphere strategy was successfully utilized in developing an easily accessible N-heterocyclic carbene manganese (NHC-Mn) system for highly active α-alkylation of ketones with alcohols. This system was efficient for a wide range of ketones and alcohols under mild reaction conditions, and also for the green synthesis of quinoline derivatives. The direct outer-sphere mechanism and the high activity of the present system demonstrate the potential of nonbifunctional outer-sphere strategy in catalyst design for acceptorless dehydrogenative transformations.
- Lan, Xiao-Bing,Ye, Zongren,Huang, Ming,Liu, Jiahao,Liu, Yan,Ke, Zhuofeng
-
supporting information
p. 8065 - 8070
(2019/10/11)
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- Iron-Catalyzed Chemoselective Reduction of α,β-Unsaturated Ketones
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An iron-catalyzed chemo- and diastereoselective reduction of α,β-unsaturated ketones into the corresponding saturated ketones in mild reaction conditions is reported herein. DFT calculations and experimental work underline that transfer hydride reduction is a more facile process than hydrogenation, unveiling the fundamental role of the base.
- Lator, Alexis,Gaillard, Sylvain,Poater, Albert,Renaud, Jean-Luc
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supporting information
p. 5770 - 5774
(2018/03/26)
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- Transition-Metal-Free Highly Chemoselective and Stereoselective Reduction with Se/DMF/H2O System
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A novel metal-free reduction system, in which H2Se (or HSe-) produced in situ from Se/DMF/H2O acts as the active reducing species, has been developed. By using water as an inexpensive, safe, and environmentally friendly surrogate as the hydrogen donor, this new reduction system incorporating Se/DMF/H2O displayed high selectivity and good activity in the reduction of α,β-unsaturated ketones and alkynes. Therefore, this reduction system has great potential to be a general and practical reduction methodology in organic transformation.
- Li, Hong-Chen,An, Cui,Wu, Ge,Li, Guo-Xing,Huang, Xiao-Bo,Gao, Wen-Xia,Ding, Jin-Chang,Zhou, Yun-Bing,Liu, Miao-Chang,Wu, Hua-Yue
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supporting information
p. 5573 - 5577
(2018/09/12)
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- Switchable Chemoselective Transfer Hydrogenations of Unsaturated Carbonyls Using Copper(I) N-Donor Thiolate Clusters
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Unsaturated alcohols and saturated carbonyls are important chemical, pharmaceutical, and biochemical intermediates. We herein report an efficient transfer hydrogenation protocol in which conversion of unsaturated carbonyl compounds to either unsaturated alcohols or saturated carbonyls was catalyzed by Cu(I) N-donor thiolate clusters along with changing hydrogen source (isopropanol or butanol) and base (NaOH or K2CO3). Mechanistic studies supported by DFT transition state modeling indicate that such a chemoselectivity can be explained by the relative concentrations of Cu(I) monohydride and protonated Cu(I) hydride complexes in each catalytic system.
- Zhang, Meng-Juan,Tan, Da-Wei,Li, Hong-Xi,Young, David James,Wang, Hui-Fang,Li, Hai-Yan,Lang, Jian-Ping
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p. 1204 - 1215
(2018/02/09)
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- Iridium(III)- benzoxazolyl and benzothiazolyl phosphine ligands catalyzed versatile alkylation reactions with alcohols and the synthesis of quinolines and indole
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A series of benzoxazolyl and benzothiazolyl phosphine ligands 4a-4g were synthesized and characterized, which prepared from commercially available 2-aminophenol/2-aminobenzenethiol and 2-bromobenzaldehyde via cyclization and phosphination. The representative ligands 4c and 4e were determined by single-crystal X-ray diffraction. The corresponding iridium complexes could be generated in situ when [Cp*IrCl2]2 (Cp* = pentamethylcyclopentadienyl) encountered ligands. The molecular structures of complexes 5c and 5e were crystallographically characterized. The dihedral angles of N (1)-C (1)-C (8)-C (9) showed an increasing twist compared with the corresponding ligand. The iridium (III) catalysts were screened, [Cp*IrCl2]2/4a proved to be the optimal catalyst, which exhibited efficient catalytic activity toward versatile alkylations including ketones, secondary alcohols and amines with primary alcohols. Additionally, the synthesis of quinolines from ketones with 2-aminobenzyl alcohol by intermolecular cyclization and indole from 2-(2-aminophenyl)ethanol by intramolecular cyclization were achieved under the optimized conditions.
- Huang, Shuang,Wu, Si-Peng,Zhou, Quan,Cui, He-Zhen,Hong, Xi,Lin, Yue-Jian,Hou, Xiu-Feng
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- Phosphine-Free NNN-Manganese Complex Catalyzed α-Alkylation of Ketones with Primary Alcohols and Friedl?nder Quinoline Synthesis
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Herein, we report a very simple and inexpensive catalytic system based on Earth's abundant transition metal manganese and on a bench-stable phosphine-free NNN-pincer ligand for an atom-efficient α-alkylations of ketones with primary alcohols via hydrogen-autotransfer C?C bond formation protocol. The precatalyst could be generated in situ and could be activated by using catalytic amount of base under milder conditions. A range of ketones were efficiently diversified with a broad range of primary alcohols in good to excellent isolated yields. Remarkably, this catalyst could also be employed for the synthesis of quinoline derivatives using 2-aminobenzyl alcohol as an alkylating agent. The later reaction is highly benign producing only hydrogen and water as byproducts. (Figure presented.).
- Barman, Milan K.,Jana, Akash,Maji, Biplab
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supporting information
p. 3233 - 3238
(2018/07/31)
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- Manganese-Catalyzed α-Alkylation of Ketones, Esters, and Amides Using Alcohols
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Herein we report the manganese-catalyzed C-C bond-forming reactions via α-alkylation of ketones, amides, and esters, using primary alcohols. β-Alkylation of secondary alcohols by primary alcohols to obtain α-alkylated ketones is also reported. The reactions are catalyzed by a (iPr-PNP)Mn(H)(CO)2 pincer complex under mild conditions in the presence of (catalytic) base liberating water (and H2 in the case of secondary alcohol alkylation) as the sole byproduct.
- Chakraborty, Subrata,Daw, Prosenjit,Ben David, Yehoshoa,Milstein, David
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p. 10300 - 10305
(2018/10/20)
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- NNN pincer Ru(II)-complex-catalyzed α-alkylation of ketones with alcohols
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A series of novel ruthenium(II) complexes supported by a symmetrical NNN ligand were prepared and fully characterized. These complexes exhibited good performance in transfer hydrogenation to form new C-C bonds using alcohols as the alkylating agents, generating water as the only byproduct. A broad range of substrates, including (hetero)aryl- or alkyl-ketones and alcohols, were well tolerated under the optimized conditions. Notably, α-substituted methylene ketones were also investigated, which afforded α-branched steric hindrance products. A potential application of α-alkylation of methylene acetone to synthesize donepezil was demonstrated, which provided the desired product in 83% yield. Finally, this catalytic system could be applied to a one-pot double alkylation procedure with sequential addition of two different alcohols. The current protocol is featured with several characteristics, including a broad substrate scope, low catalyst (0.50 mol %) loadings, and environmental benignity.
- Cao, Xiao-Niu,Wan, Xiao-Min,Yang, Fa-Liu,Li, Ke,Hao, Xin-Qi,Shao, Tian,Zhu, Xinju,Song, Mao-Ping
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p. 3657 - 3668
(2018/04/14)
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- Acid fluorides as acyl electrophiles in suzuki–miyaura coupling
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The first palladium-catalyzed construction of ketones through Suzuki–Miyaura reaction by using acid fluorides is described. In contrast to typical acyl electrophiles such as acid chlorides, acid fluorides are uncommon acyl electrophiles to use in boron-based coupling reactions, probably due to a high level of stability toward nucleophiles. This first attempt to use acid fluorides as a coupling partner with boronic acids allowed highly functional group tolerance and a wide substrate scope while affording various ketones in effective yields.
- Ogiwara, Yohei,Sakino, Daisuke,Sakurai, Yuka,Sakai, Norio
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supporting information
p. 4324 - 4327
(2018/08/28)
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- Alkylation of Ketones Catalyzed by Bifunctional Iron Complexes: From Mechanistic Understanding to Application
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Cyclopentadienone iron dicarbonyl complexes were applied in the alkylation of ketones with various aliphatic and aromatic ketones and alcohols via the borrowing hydrogen strategy in mild reaction conditions. DFT calculations and experimental works highlight the role of the transition metal Lewis pairs and the base. These iron complexes demonstrated a broad applicability in mild conditions and extended the scope of substrates.
- Seck, Charlotte,Mbaye, Mbaye Diagne,Coufourier, Sébastien,Lator, Alexis,Lohier, Jean-Fran?ois,Poater, Albert,Ward, Thomas R.,Gaillard, Sylvain,Renaud, Jean-Luc
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p. 4410 - 4416
(2017/11/20)
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- Hydrogen autotransfer and related dehydrogenative coupling reactions using a rhenium(i) pincer catalyst
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A novel rhenium complex bearing a non-innocent PNP pincer ligand was prepared. This novel catalyst is active in hydrogen autotransfer reactions to form new C-C and C-N bonds. More specifically, valuable alkylations of ketones and sulfonamides with primary alcohols are herein presented. In addition, the first examples of rhenium-catalysed synthesis of pyrroles are described by dehydrogenative coupling of diols, amines and ketones.
- Piehl, Patrick,Pe?a-López, Miguel,Frey, Anna,Neumann, Helfried,Beller, Matthias
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supporting information
p. 3265 - 3268
(2017/03/20)
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- Isolation and Characterization of Regioisomers of Pyrazole-Based Palladacycles and Their Use in α-Alkylation of Ketones Using Alcohols
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Regioisomers of 3,5-diphenyl-1-(4-(trifluoromethyl)phenyl)-1H-pyrazole-based palladacycles (1 and 2) were synthesized by the aromatic C-H bond activation of N/3-aryl ring. The application of these regioisomers as catalysts to enable the formation of α-alkylated ketones or quinolines with alcohols using a hydrogen borrowing process is evaluated. Experimental results reveal that palladacycle 2 is superior over palladacycle 1 to catalyze the reaction under similar reaction conditions. The reaction mechanisms for the palladacycles 1 and 2 catalyzed α-alkylation of acetophenone were studied using density functional theoretical (DFT) methods. The DFT studies indicate that palladacycle 2 has an energy barrier lower than that of palladacycle 1 for the alkylation reaction, consistent with the better catalytic activity of palladacycle 2 seen in the experiments. The palladacycle-phosphine system was found to tolerate a wide range of functional groups and serves as an efficient protocol for the synthesis of α-alkylated products under solvent-free conditions. In addition, the synthetic protocol was successfully applied to prepare donepezil, a drug for Alzheimer's disease, from simple starting materials.
- Mamidala, Ramesh,Samser, Shaikh,Sharma, Nishant,Lourderaj, Upakarasamy,Venkatasubbaiah, Krishnan
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supporting information
p. 3343 - 3351
(2017/09/18)
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- Borylation and selective reduction of α,β-unsaturated ketones under mild conditions catalyzed by Cu nanoparticles
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An effective strategy for synthesis of Cu nanoparticles is designed, these nanoparticles have high catalytic activity in conjugate addition of B2(pin)2and α,β-unsaturated ketones. The reaction of protodeboration can proceed with adding NaOtBu. In this way, a new method to reduce the conjugated alkenes of α,β-unsaturated ketones is developed with organoboranes as intermediates. Cu nanocrystals also have excellent performance in gram-scale reaction and recycling experiment. A possible mechanism is proposed.
- Zhou, Xin-Feng,Sun, Yu-Yang,Wu, Ya-Dong,Dai, Jian-Jun,Xu, Jun,Huang, Yu,Xu, Hua-Jian
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p. 5691 - 5698
(2016/08/23)
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- Manganese-Catalyzed Hydrogen-Autotransfer C?C Bond Formation: α-Alkylation of Ketones with Primary Alcohols
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A novel catalytic hydrogen-autotransfer protocol for the atom-efficient α-alkylation of ketones with readily available alcohols is presented. The use of manganese complexes bearing non-innocent PNP pincer ligands enabled the functionalization of a broad range of valuable ketones, including 2-oxindole, estrone 3-methyl ether, and testosterone. Mechanistic investigations suggest the participation of an intramolecular amidate-assisted alcohol-dehydrogenation process.
- Pe?a-López, Miguel,Piehl, Patrick,Elangovan, Saravanakumar,Neumann, Helfried,Beller, Matthias
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supporting information
p. 14967 - 14971
(2016/11/25)
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- Method for synthesizing alpha-alkyl ketone
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The invention discloses a method for synthesizing alpha-alkyl ketone. The method comprises the following steps: adding ketone, a compound alcohol, an iridium complex catalyst, an alkali and a solvent tert-amyl alcohol in a reaction container, carrying out a refluxing reaction on the above obtained reaction mixture in air for several hours, cooling the obtained reaction product to room temperature, carrying out rotary evaporation to remove the solvent, and carrying out column separation to obtain the target compound. The meta-organic bifunctional iridium complex is used, only 0.1 equivalent carbonate is added in the reaction process, and the reaction is carried in air for 6h, so obvious advantages are displayed; and the reaction accords with green chemistry requirements, and has wide development prospect.
- -
-
Paragraph 0150; 0151; 0152; 0153; 0154
(2016/10/07)
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- Chemoselective biohydrogenation of α,β- and α,β,γ,δ-unsaturated ketones by the marine-derived fungus Penicillium citrinum CBMAI 1186 in a biphasic system
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To broaden the range of applicability of a reduction reaction mediated by the marine fungal strain Penicillium citrinum CBMAI 1186 to organic chemical processes, the ability of whole mycelia to grow in biphasic mixtures with organic solvents was tested with acetone, ethyl acetate, n-butanol, dichloromethane, n-hexane and toluene. n-Hexane was the least toxic solvent according to the amount of mycelial mass grown in an artificial sea water medium mixed with each solvent. Therefore, whole hyphae of P. citrinum CBMAI 1186 were used as biocatalysts in the chemoselective biotransformation of the carbon-carbon double bond in α,β-, di-α,β-, and mono-α,β,γ,δ-unsaturated ketones (3a, 3c-f) in a biphasic system of phosphate buffer and n-hexane (9:1). Only the di-α,β,γ,δ-unsaturated ketone (3b) was not biocatalyzed under these conditions. In general, there were good conversions of saturated ketones by the enoate reductase enzymes of P. citrinum CBMAI 1186.
- Ferreira, Irlon M.,Meira, Eloá B.,Rosset, Isac G.,Porto, André L.M.
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- Palladium-Catalyzed Desulfitative Oxidative Coupling between Arenesulfinic Acid Salts and Allylic Alcohols: A Strategy for the Selective Construction of β-Aryl Ketones and Aldehydes
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An efficient palladium-catalyzed desulfitative oxidative coupling of sodium arylsulfinites for highly region-selective Heck-type reaction of allylic alcohols has been developed. The compatibility of the functionalities of -I, -Br, and -F would explore further postfunctionalization of the C-X bonds. This method provides a new and straightforward protocol for the synthesis of β-aryl ketones and aldehydes. The deuterium labeling experiments indicated that this transformation may proceed via a [1, 2-H] shift process.
- Liao, Jianhua,Zhang, Zhenming,Tang, Xiaodong,Wu, Wanqing,Guo, Wei,Jiang, Huanfeng
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p. 8903 - 8909
(2015/09/15)
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- Cobalt-catalyzed intermolecular hydroacylation of olefins through chelation-assisted imidoyl C-H activation
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A low-valent cobalt catalyst generated from cobalt(II) bromide, a diphosphine ligand, and zinc powder promotes intermolecular hydroacylation of olefins using N-3-picolin-2-yl aldimines as aldehyde equivalents, which affords, upon acidic hydrolysis, ketone products in moderate to good yields with high linear selectivity. The reaction is applicable to styrenes, vinylsilanes, and aliphatic olefins as well as to various aryl and heteroaryl aldimines. The cobalt catalysis features a distinctively lower reaction temperature (60 °C) compared with those required for the same type of transformations catalyzed by rhodium complexes (typically 130-150°C).
- Yang, Junfeng,Seto, Yuan Wah,Yoshikai, Naohiko
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p. 3054 - 3057
(2015/05/20)
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- Transition metal free chemoselective reduction of α,β-unsaturated ketones to saturated ketones using tosyl hydrazide as a hydrogen donor
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An efficient, inexpensive and simple method for the reduction of various α,β-unsaturated ketones to corresponding saturated ketones using tosyl hydrazide as a hydrogen donor in DMF using calcium oxide powder has been reported. A variety of enones underwen
- Girish, Yarabally R.,Raghavendra, Kanchipura R.,Nagaraja, Dasappa,Kumar, Kothanahally S. Sharath,Shashikanth, Sheena
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p. 181 - 184
(2015/03/04)
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- Catalyst-free dehydrative α-alkylation of ketones with alcohols: Green and selective autocatalyzed synthesis of alcohols and ketones
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Direct dehydrative α-alkylation reactions of ketones with alcohols are now realized under simple, practical, and green conditions without using external catalysts. These catalyst-free autocatalyzed alkylation methods can efficiently afford useful alkylated ketone or alcohol products in a one-pot manner and on a large scale by Ci£C bond formation of the in situ generated intermediates with subsequent controllable and selective Meerwein-Pondorf-Verley-Oppenauer-type redox processes. Plain and simple: The title reaction has been realized under simple and practical conditions without using external catalysts, and can afford alkylated ketone or alcohol products in a one-pot manner and on a large scale. The reaction proceeds by Ci£C bond formation of the in situ generated intermediates with subsequent controllable and selective Meerwein-Pondorf-Verley-Oppenauer-type redox processes. Copyright
- Xu, Qing,Chen, Jianhui,Tian, Haiwen,Yuan, Xueqin,Li, Shuangyan,Zhou, Chongkuan,Liu, Jianping
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p. 225 - 229
(2014/01/17)
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- Rhodium(I)-catalyzed arylation of β-chloro ketones and related derivatives through domino dehydrochlorination/conjugate addition
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Highly efficient arylations of β-chloro ketones and their ester and amide derivatives were achieved by means of domino dehydrochlorination/Rh(I)- catalyzed conjugate addition. In situ generated vinyl ketones and their analogues were identified as the reaction intermediates. The present synthetic protocol provides a concise route to (chiral) β-aryl ketones, esters, and amides. Copyright
- Jiang, Quanbin,Guo, Tenglong,Wang, Qingfu,Wu, Ping,Yu, Zhengkun
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supporting information
p. 1874 - 1880
(2013/07/19)
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- Chemoselective transfer hydrogenation of α,β-unsaturated ketones catalyzed by pincer-Pd complexes using alcohol as a hydrogen source
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A pincer-Pd complex was utilized in the chemoselective transfer hydrogenation of α,β-unsaturated ketones using n-BuOH as a hydrogen source and solvent. Good to excellent yields were obtained for various substrates even with reducible groups. Based on deuterium-labeling experiments, the reaction mechanism is proposed to occur via a pincer-Pd-hydride intermediate.
- Ding, Boqiang,Zhang, Zhenfeng,Liu, Yangang,Sugiya, Masashi,Imamoto, Tsuneo,Zhang, Wanbin
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supporting information
p. 3690 - 3693
(2013/08/23)
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- Lithium tert-butoxide mediated α-alkylation of ketones with primary alcohols under transition-metal-free conditions
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LiOtBu was found to efficiently promote the α-alkylation reaction of ketones with primary alcohols, without the addition of any transition metal catalyst.
- Liang, Yu-Feng,Zhou, Xin-Feng,Tang, Shi-Ya,Huang, Yao-Bing,Feng, Yi-Si,Xu, Hua-Jian
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p. 7739 - 7742
(2013/06/27)
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- Study on comparison of reducing ability of three organic hydride compounds
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Selective reduction of three kinds of substrates were studied to evaluate the reducing abilities of N,N-dimethyl-benzimidazolidine (DMBI), 2-phenylbenzimidazoline (PBI) and 2-phenylbenzothiazoline (PBT). As hydride donors, these three five-membered heterocyclic compounds performed different reducing abilities depending on the substrates.
- Feng, Yi-Si,Yang, Chun-Yan,Huang, Qiang,Xu, Hua-Jian
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experimental part
p. 5053 - 5059
(2012/07/28)
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- Carbon-carbon bond formation between secondary alcohols and aldehydes under ruthenium-catalyzed redox shuttle
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Secondary alcohols are coupled with aldehydes in dioxane in the presence of a catalytic amount of a ruthenium catalyst along with KOH to give coupled ketones or coupled secondary alcohols depending on the molar ratio of secondary alcohols to aldehydes and the presence (or absence) of a sacrificial hydrogen acceptor. Copyright
- Cho, Chan Sik,Kim, Bok Tae,Yoon, Nam Sik
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experimental part
p. 695 - 698
(2012/01/05)
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- Synthesis and olefination of carbonyl compounds using solid-supported reagents
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The development and application of three new solid-supported reagents for use in the synthesis or olefination of carbonyl compounds are described. The reagents include the Weinreb amide, Mukaiyama's S-2-pyridyl thioate and a Peterson methylenation reagent. As solid-supports p-benzyl alcohol resin, Wang resin and Merrifield resin (1-2% crosslinked polystyrene) have been used. The Royal Society of Chemistry.
- Hansen, Anne-Lene L.,Murray, Anthony,Tanner, David
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p. 4497 - 4505
(2008/09/18)
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- Branch-selective intermolecular hydroacylation: Hydrogen-mediated coupling of anhydrides to styrenes and activated olefins
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(Chemical Equation Presented) Branching out with hydrogen: Hydrogenation of symmetric or mixed carboxylic anhydrides in the presence of styrenes or activated olefins generates intermolecular hydroacylation products. The use of cationic rhodium catalysts ligated by triphenylarsine (Ph3As) results in the formation of branched coupling products as single regioisomers in high yields (see scheme; cod = cycloocta-1,5-diene, ArF = 3,5-(CF 3)2C6H3).
- Hong, Young-Taek,Barchuk, Andriy,Krische, Michael J.
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p. 6885 - 6888
(2007/10/03)
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- A ruthenium-catalyzed one-pot method for α-alkylation of ketones with aldehydes
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Ketones react with an array of aldehydes in dioxane at 80 °C in the presence of a catalytic amount of RuCl2(PPh3)3 along with KOH to give the corresponding α-alkylated ketones in moderate to good yields. A reaction pathway involving base-catalyzed cross-aldol reaction between ketones and aldehydes to form α,β-unsaturated ketones and regioselective reduction of carbon-carbon double bond of α,β-unsaturated ketones is proposed for this catalytic process.
- Cho, Chan Sik,Shim, Sang Chul
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p. 4329 - 4332
(2007/10/03)
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- Easy α-alkylation of ketones with alcohols through a hydrogen autotransfer process catalyzed by RuCl2(DMSO)4
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The electrophilic α-alkylation of ketones with alcohols is accomplished by a hydrogen autotransfer process catalyzed by RuCl2(DMSO)4. The reaction can produce either simple alkylated ketones or α,β-unsaturated ketones just by choosing the appropriate starting ketones (methyl ketones or bicyclic methylenic ketones, respectively), as well as quinolines (by using 2-aminobenzyl alcohol derivatives) or the corresponding alcohol derivatives by the addition of an extra equivalent of the initial alcohol. In the last case, after the above alkylation process reduction of the carbonyl compound takes place. A mechanistic study seems to indicate that the process goes through the oxidation of the alcohols with ruthenium (after a previous deprotonation) to yield the corresponding aldehyde and a ruthenium hydride intermediate. In turn, the aldehyde suffers a classical aldol reaction with the starting ketone to form the corresponding α,β-unsaturated ketone, which finally is reduced through a Michael-type addition by the aforementioned ruthenium hydride intermediate.
- Martínez, Ricardo,Ramón, Diego J.,Yus, Miguel
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p. 8988 - 9001
(2007/10/03)
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- [Ru(DMSO)4] Cl2 catalyzes the α-alkylation of ketones by alcohols
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The electrophilic α-alkylation of ketones with alcohols was accomplished by a [Ru(DMSO)4]Cl2 catalyzed process, water being the only wasted material. The reaction can be successfully governed to produce either the expected ketones or their related alcohols only by changing the reaction conditions. When 2-aminobenzyl alcohol was used, a cyclization process took place to yield 2,3-disubstituted quinolines.
- Martínez, Ricardo,Brand, Gabriel J.,Ramón, Diego J.,Yus, Miguel
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p. 3683 - 3686
(2007/10/03)
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- Phase-vanishing method: Friedel-Crafts acylation of thiophene with tin tetrachloride and its application to convenient parallel synthesis
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Phase-vanishing (PV) method was applied to Friedel-Crafts acylations of aromatic compounds with tin tetrachloride as a Lewis acid. The reaction proceeded smoothly and acylation products were obtained in good yield. Parallel, four different Friedel-Crafts acylation reactions were carried out successfully based on the present PV method.
- Matsubara, Hiroshi,Yasuda, Shinji,Ryu, Ilhyong
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p. 247 - 249
(2007/10/03)
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- Amino derivatives of phenyl alkyl thiophene as inhibitors of bone resorption. Structure-activity relationship
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Metabolism of arachidonic acid through the 5-lipoxygenase (LO) pathway generates compounds that stimulate osteoclastic bone resorption; since LO metabolites might play a role in bone loss due to excessive resorption it was tried to develop a series of antiresorptive agents starting from an already known LO inhibitor. Of the 35 compounds synthesized, 11 strongly inhibited (10 μmol/l) retinoic acid-induced bone resorption in cultured mouse calvariae; they were also tested for their effect on LO activity using rat peritoneal neutrophils, but no correlation could be drawn between inhibition of LO and bone resorption. Other pathways, still to be identified, must therefore be targeted by these compounds even though LO inhibition might contribute to their effects on bone. Two compounds selected for further studies were found active on parathyroid hormone-induced osteolysis, while they had no effect on basal resorption; they must, therefore, act at some key point in the process of activation of osteoclastic resorption. This series of compounds may represent a new way for the treatment of bone loss due to excessive resorption.
- Wierzbicki, Michel,Boussard, Marie-Francoise,Sauveur, Frederic,Kirsch, Gilbert,Sabatini, Massimo,Lesur, Christophe,Trodjman, Charles,Bonnet, Jacqueline
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p. 840 - 849
(2007/10/03)
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- Thiophene compounds, compositions and use
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1. New thiophene compounds of the formula: STR1 in which: X represents hydrogen, halogen, C1 -C5 alkyl or alkoxy or dialkylamino; n represents 1 or 2; a represents an integer of from 2 to 6; b represents 2 or 3; c represents 1 or 2,
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- Synthesis and Antifungal Activity of a Series of Novel 1,2-Disubstituted Propenones
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To find an antifungal agent other than those of the imidazole and triazole series, a new class of 1,2-disubstituted propenones I and II was prepared and tested for antifungal activity.Comparison of the structure-activity relationships showed that the conjugated structure of carbonyl and exomethylene groups in I and II plays an important role in potent antifungal acivity.However, it is noteworthy that compounds 53, 54, and 56, which have a hydroxymethyl or methoxymethyl group instead of an exo-methylene group in I, also showed potent activity.Although many compounds exhibited strong antifungal activity in vitro, none showed activity in vivo of oral efficacy against subacute systemic candidiasis in mice. '
- Ogata, Masaru,Matsumoto, Hiroshi,Kida, Shiro,Shimizu, Sumio,Tawara, Katsuya,Kawamura, Yoshimi
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p. 1497 - 1502
(2007/10/02)
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- MODERN FRIEDEL-CRAFTS CHEMISTRY XVI. REACTION OF THIOPHENE WITH BIFUNCTIONAL MOLECULES UNDER DIFFERENT FRIEDEL-CRAFTS CATALYSTS: ATTEMPTED SYNTHESIS OF CYCLOPENTA THIOPHENES AND DIHYDROBENZO THIOPHENES
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The reaction of thiophene (1) with 3-chloropropionyl chloride (2), 4-chlorobutyryl chloride (3), crotonyl chloride (4) and cinnamoyl chloride (5) under different Friedel-Crafts catalysts (AlCl3/CH3NO2, FeCl3, and AlCl3/CS2) was investigated.The cyclic products 4,5-dihydro-6H-4-methylcyclopenta-thiophen-6-one, 5,6-dihydrobenzothiophen-7(4H)one and 4-phenyl-6H-cyclopentathiophen-6-one were formed.The different behaviors of compounds (2-5) towards thiophene were discussed.
- El-Khagawa, Ahmed M.,El-Zohry, Maher F.,Ismail, Mohamed T.
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