- Polyoxometalate-Driven Ease Conversion of Valuable Furfural to trans- N, N-4,5-Diaminocyclopenten-2-ones
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We investigated the catalytic efficacy of silicotungstic acid (H4SiW12O40) polyoxometalate (POM) toward the reaction between furfural and amines that selectively yields trans-N,N-4,5-substituted-diaminocyclopenten-2-ones (trans-DACPs). H4SiW12O40 facilita
- Fountoulaki, Stella,Lykakis, Ioannis N.,Tzani, Marina A.
-
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- Iron-Catalyzed Hydrogen Transfer Reduction of Nitroarenes with Alcohols: Synthesis of Imines and Aza Heterocycles
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A straightforward and selective reduction of nitroarenes with various alcohols was efficiently developed using an iron catalyst via a hydrogen transfer methodology. This protocol led specifically to imines in 30-91% yields, with a good functional group tolerance. Noticeably, starting from o-nitroaniline derivatives, in the presence of alcohols, benzimidazoles can be obtained in 64-72% yields when the reaction was performed with an additional oxidant, DDQ, and quinoxalines were prepared from 1,2-diols in 28-96% yields. This methodology, unprecedented at iron for imines, also provides a sustainable alternative for the preparation of quinoxalines and benzimidazoles.
- Wu, Jiajun,Darcel, Christophe
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p. 1023 - 1036
(2021/01/09)
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- Ru-Catalyzed Carbonylative Murai Reaction: Directed C3-Acylation of Biomass-Derived 2-Formyl Heteroaromatics
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The Murai reaction is a ruthenium-catalyzed transformation leading to alkylated arenes through the C?C bond formation between an alkene and an arene bearing a directing group. Discovered in the nineties, this useful C?H activation based coupling has been the object of intense study since its discovery. After having studied the Murai reaction on 2-formylfurans of biomass derivation, we describe here the carbonylative version applied to 2-formylfurans, 2-formylpyrrols and 2-formylthiophenes. This acylation reaction takes place regioselectively at C3 position of the heterocyclopentadienes thanks to the installation of removable imine directing groups. The transformation can be achieved by treating the two reaction partners with a catalytic amount of Ru3(CO)12, in toluene at 120–150 °C, after CO bubbling, at atmospheric pressure. DFT computations of the full catalytic cycle help in deciphering the mechanism of this transformation, and to rationalize the different behaviors depending on the nature of imine directing groups. (Figure presented.).
- Sala, Roberto,Roudesly, Fares,Veiros, Luis F.,Broggini, Gianluigi,Oble, Julie,Poli, Giovanni
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supporting information
p. 2486 - 2493
(2020/05/06)
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- Non-Bonding Electron Pair versus π-Electrons in Solution Phase Halogen Bond Catalysis: Povarov Reaction of 2-Vinylindoles and Imines
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The non-bonding electron pair (n-pair) of heteroatoms and π-electrons are both efficient halogen bond (XB) acceptors. In solid and gas phase studies, n-pairs generally prevail over π-bonding orbitals as XB acceptors, whereas few studies have been conducte
- Suzuki, Takumi,Kuwano, Satoru,Arai, Takayoshi
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supporting information
p. 3208 - 3212
(2020/07/04)
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- Enantioselective Direct anti-Selective Mannich-type Reactions Catalyzed by 3-Pyrrolidinecarboxylic Acid in the Presence of Potassium Carbonate: Addition of Potassium Carbonate Improves Enantioselectivities
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Mannich-type reactions of cyclohexanone and related six-membered-ring ketones with N-p-methoxyphenyl-protected imines of arylaldehydes catalyzed by 3-pyrrolidinecarboxylic acid in the presence of K2CO3 that afford anti-isomers of the Mannich products with
- Garg, Yuvraj,Tanaka, Fujie
-
supporting information
p. 4542 - 4546
(2020/06/08)
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- Ni-Catalyzed asymmetric reduction of α-keto-β-lactams: via DKR enabled by proton shuttling
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Chiral α-hydroxy-β-lactams are key fragments of many bioactive compounds and antibiotics, and the development of efficient synthetic methods for these compounds is of great value. The highly enantioselective dynamic kinetic resolution (DKR) of α-keto-β-lactams was realized via a novel proton shuttling strategy. A wide range of α-keto-β-lactams were reduced efficiently and enantioselectively by Ni-catalyzed asymmetric hydrogenation, providing the corresponding α-hydroxy-β-lactam derivatives with high yields and enantioselectivities (up to 92% yield, up to 94% ee). Deuterium-labelling experiments indicate that phenylphosphinic acid plays a pivotal role in the DKR of α-keto-β-lactams by promoting the enolization process. The synthetic potential of this protocol was demonstrated by its application in the synthesis of a key intermediate of Taxol and (+)-epi-Cytoxazone. This journal is
- Wang, Fangyuan,Tan, Xuefeng,Wu, Ting,Zheng, Long-Sheng,Chen, Gen-Qiang,Zhang, Xumu
-
supporting information
p. 15557 - 15560
(2020/12/30)
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- Cationic allyl nickel complexes containing N,O-donor labile ligands: Synthesis and molecular characterisation
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Three 2-iminofuran ligands 2-(N-2,6-diisopropylphenylformimino)furan (L1), 2-(N-2,6-dimethylphenylformimino)furan (L2) and 2-(N-4-methoxyphenylformimino)furan (L3) were obtained by condensation reactions of the respective anilines with furfural. The ηsup
- Belkhiria, Marwa,Mechria, Ali,Cruz, Tiago F.C.,Gomes, Clara S.B.,Msaddek, Moncef,Gomes, Pedro T.
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p. 260 - 265
(2019/01/30)
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- Organocatalytic Mukaiyama Mannich Reactions of 2,5-Bis(trimethylsilyloxy)furan
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The organocatalytic synthesis of densely substituted mono- and bis-?-lactams involving the Mukaiyama Mannich addition of 2,5-bis(trimethylsilyloxy)furan to imines is described. Use of a ditoluenesulfonylimide catalyst produces ?-lactams from monoaddition, whereas a more acidic catalyst (triflic acid) produces fused bis-lactams from double addition. Optimized organocatalytic conditions allow for the selective synthesis of either desired core as well as the one-pot, multicomponent assembly of the trisubstituted monolactams from aldehydes, amines, and bis-trimethylsilyloxyfuran. An examination of chiral acids found these organocatalysts to be highly active and diastereoselective in the monoaddition reaction, albeit with no enantioselectivity.
- Laws, Stephen W.,Howard, Sara Y.,Mato, Raquel,Meng, Shuyu,Fettinger, James C.,Shaw, Jared T.
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supporting information
p. 5073 - 5077
(2019/07/03)
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- Ruthenium-Catalyzed C-H Arylation and Alkenylation of Furfural Imines with Boronates
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A Ru0-catalyzed direct C-H arylation and alkenylation of furfural imines with aryl- or alkenyl-boronates, in the presence of benzylideneacetone as a sacrificial hydride acceptor, is disclosed. This reaction provides access, after hydrolysis, to C3-arylated or vinylated furfural derivatives, and thus valorizes these relevant building-blocks obtained from lignocellulosic biomass. This approach, involving C-H activation by a Ru0/RuII, cycle offers several advantages, notably simple, mild and neutral reaction conditions.
- Siopa, Filipa,Ramis Cladera, Valérie-Anne,Afonso, Carlos Alberto Mateus,Oble, Julie,Poli, Giovanni
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supporting information
p. 6101 - 6106
(2018/09/18)
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- One-pot sequential multicomponent reaction between: In situ generated aldimines and succinaldehyde: Facile synthesis of substituted pyrrole-3-carbaldehydes and applications towards medicinally important fused heterocycles
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An efficient sequential multi-component method for the synthesis of N-Arylpyrrole-3-carbaldehydes has been developed. This reaction involved a proline-catalyzed direct Mannich reaction-cyclization sequence between succinaldehyde and in situ generated Ar/H
- Singh, Anoop,Mir, Nisar A.,Choudhary, Sachin,Singh, Deepika,Sharma, Preetika,Kant, Rajni,Kumar, Indresh
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p. 15448 - 15458
(2018/05/03)
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- A simple method for the synthesis of 1,3-diaminopropan-2-ols derivatives and their ex vivo relaxant activity on isolated rat tracheal rings
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Abstract: A mild and eco-friendly method has been developed for the synthesis of a series of 1,3-diaminopropan-2-ols 8a–n. The epoxide of epichlorohydrin undergoes ring-opening with amines using MgSO4 or mixed metal oxides catalysts under mild
- López, Fabiola I.,de la Cruz, Fabiola N.,López, Julio,Martínez, J. Merced,Alcaraz, Yolanda,Delgado, Francisco,Sánchez-Recillas, Amanda,Estrada-Soto, Samuel,Vázquez, Miguel A.
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p. 1325 - 1335
(2017/05/04)
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- Murai Reaction on Furfural Derivatives Enabled by Removable N,N′-Bidentate Directing Groups
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Furfural and related compounds are industrially relevant building blocks obtained from lignocellulosic biomass. To enhance the added value of these renewable resources, a Ru-catalyzed hydrofurylation of alkenes, involving a directed C?H activation at C3 of the furan ring, was developed. A thorough experimental study revealed that a bidentate amino-imine directing group enabled the desired coupling. Removal of the directing group occurred during the purification step, directly releasing the C3-functionalized furfurals. Development of the reaction as well as optimization and scope of the method were described. A mechanism was proposed on the basis of DFT calculations.
- Pezzetta, Cristofer,Veiros, Luis F.,Oble, Julie,Poli, Giovanni
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supporting information
p. 8385 - 8389
(2017/06/28)
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- Synthesis and cytotoxic activity of certain trisubstituted azetidin-2-one derivatives as a cis-restricted combretastatin A-4 analogues
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Novel series of 1,3,4-trisubstituted azetidin-2-one derivatives 8a–p were synthesized and proposed as cytotoxic agents acting via inhibition of tubulin at the colchicine binding site. The design of the target compounds was based upon modification in the s
- Elmeligie, Salwa,Taher, Azza. T.,Khalil, Nadia A.,El-said, Ahmed H.
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- Asymmetric Petasis Borono-Mannich Allylation Reactions Catalyzed by Chiral Biphenols
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Chiral biphenols catalyze the asymmetric Petasis borono-Mannich allylation of aldehydes and amines through the use of a bench-stable allyldioxaborolane. The reaction proceeds via a two-step, one-pot process and requires 2–8 mole % of 3,3′-Ph2-BINOL as the optimal catalyst. Under microwave heating the reaction affords chiral homoallylic amines in excellent yields (up to 99 %) and high enantioselectivies (er up to 99:1). The catalytic reaction is a true multicomponent condensation reaction whereas both the aldehyde and the amine can possess a wide range of structural and electronic properties. Use of crotyldioxaborolane in the reaction results in stereodivergent products with anti- and syn-diastereomers both in good diastereoselectivities and enantioselectivities from the corresponding E- and Z-borolane stereoisomers.
- Jiang, Yao,Schaus, Scott E.
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supporting information
p. 1544 - 1548
(2017/02/05)
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- Dimethyl (2-Furyl)-N-(2-Methoxyphenyl)Aminomethylphosphonate Induces Apoptosis in Esophageal Squamous Cancer Cells. Structure Versus Activity of its Selected Analogs
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Cytotoxicities of several new aminophosphonic compounds bearing 2-furyl moiety 2b-d and 3a-c on KYSE 30, 150, and 270 esophageal cancer cell lines are reported here. The qualitative study on correlations between the structure and cytotoxic activity of fur
- Klimczak, Anna Agnieszka,Matusiak, Agnieszka,Lewkowski, Jaroslaw,Bitner, Jan,Szemraj, Janusz,Kontek, Renata
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p. 1088 - 1099
(2015/08/04)
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- Iodine(III)-mediated C-H alkoxylation of aniline derivatives with alcohols under metal-free conditions
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The development of a novel intermolecular oxidative C-H alkoxylation of aniline derivatives is described under metalfree conditions with high reaction rates at ambient temperature. In the presence of an I(III) oxidant, a range of aldehydes, anilines, and alcohol substrates undergo three-component coupling to produce synthetically useful alkoxyl-substituted N-arylimines. The preliminary mechanism investigations revealed that the transformation proceeds via imines as intermediates.
- Jiang, Qing,Wang, Jing-Yu,Guo, Cancheng
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p. 8768 - 8773
(2014/12/12)
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- Synthesis of new N-arylamino(2-furyl)methylphosphonic acid diesters, and in vitro evaluation of their cytotoxicity against esophageal cancer cells
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N-Furfurylideneanilines and N-arylamino(2-furyl)methylphosphonates with tolyl and anisyl moieties were synthesized by the addition of phosphites to azomethine bond of corresponding Schiff bases and their NMR spectroscopic properties were investigated. The
- Klimczak, Anna Agnieszka,Kuropatwa, Agnieszka,Lewkowski, Jaroslaw,Szemraj, Janusz
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p. 852 - 860
(2013/04/23)
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- Phytotoxicity of new furan-derived aminophosphonic acids, N -Aryl furaldimines and 5-nitrofuraldimine
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The aim of this work was to synthesize selected furaldimines and their aminophosphonic derivatives and evaluation the phytotoxicity of new obtained products according to OECD 208 Guideline. Four Schiff bases, N-furfurylidene-p-anisidine (1a), N-furfurylid
- Matusiak, Agnieszka,Lewkowski, Jaroslaw,Rychter, Piotr,Biczak, Robert
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p. 7673 - 7678
(2013/09/02)
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- 1-Butyl-1-methylpyrrolidinium hydrogen sulfate-promoted preparation of 1,5-diaryl-3-(arylamino)-1H-pyrrol-2(5H)-one derivatives
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A convenient preparative approach for synthesis of various 1,5-diaryl-3-(arylamino)-1H-pyrrol-2(5H)-ones promoted by 1-butyl-1- methylpyrrolidinium hydrogen sulfate is developed which involves cyclocondensation of aldehydes with amines and ethyl pyruvate under ambient conditions. Graphical abstract: A convenient preparative approach for synthesis of various 1,5-diaryl-3-(arylamino)-1H-pyrrol-2(5H)-ones promoted by 1-butyl-1-methylpyrrolidinium hydrogen sulfate is developed which involves cyclocondensation of aldehydes with amines and ethyl pyruvate under ambient conditions.[Figure not available: see fulltext.]
- Ghashang, Majid
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p. 2187 - 2195
(2013/06/26)
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- Tetrahydroquinolines and benzazepines through catalytic diastereoselective formal [4 + 2]-cycloaddition reactions between donor-acceptor cyclopropenes and imines
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Regio- and diastereoselective Lewis acid catalyzed cycloaddition reactions between imines and donor-acceptor cyclopropenes generated from silyl-protected enoldiazoacetates provide direct access to stable cyclopropane-fused tetrahydroquinolines and, with cyclopropane ring opening under mild conditions, to 1H-benzazipine derivatives.
- Truong, Phong M.,Mandler, Michael D.,Zavalij, Peter Y.,Doyle, Michael P.
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supporting information
p. 3278 - 3281
(2013/07/26)
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- An efficient three-component synthesis of homoallylic amines catalysed by MgI2 etherate
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A three-component reaction of aldehydes, amines and allyltributylstannane was efficiently carried out to afford the corresponding homoallylic amine derivatives in the presence of 20 mol% of MgI2 etherate [(MgI 2?(OEt2)n] under mild and neutral reaction conditions in good to excellent yields.
- Wang, Yanping,Liu, Yingshuai,Hu, Shenghui,Zhang, Xingxian
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experimental part
p. 21 - 24
(2012/03/27)
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- Construction of highly functional α-amino nitriles via a novel multicomponent tandem organocatalytic reaction: A facile access to α-methylene γ-lactams
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The first tertiary amine-catalyzed multicomponent tandem Strecker-allylic-alkylation (SAA) reaction has been developed, which provides a facile access to functionalized α-amino nitriles, which could be readily converted into α-methylene-γ-butyrolactams. The Royal Society of Chemistry 2012.
- Pan, Feng,Chen, Jian-Ming,Zhuang, Zhe,Fang, Yin-Zhi,Zhang, Sean Xiao-An,Liao, Wei-Wei
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supporting information; experimental part
p. 2214 - 2217
(2012/04/10)
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- New types of reactivity of α,β-unsaturated N,N- dimethylhydrazones: Chemodivergent diastereoselective synthesis of functionalized tetrahydroquinolines and hexahydropyrrolo[3,2-b]indoles
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The indium trichloride-catalyzed reaction between aromatic imines and α,β-unsaturated N,N-dimethylhydrazones in acetonitrile afforded 1,2,3,4-tetrahydroquinolines bearing a hydrazone function at C4 through a one-pot diastereoselective domino process that involves the formation of two C-C bonds and the controlled generation of two stereocenters, one of which is quaternary. This reaction constitutes the first example of an α,β-unsaturated dimethylhydrazone that behaves as a dienophile in a hetero Diels-Alder reaction. The related reaction between anilines, aromatic aldehydes, and methacrolein dimethylhydrazone in CHCl3 with BF 3·Et2O as catalyst afforded polysubstituted 1,2,3,3a,4,8b-hexahydropyrrolo[3,2-b]indoles as major products through a fully diastereoselective ABB′C four-component domino process that generates two cycles, three stereocenters, two C-C bonds, and two C-N bonds in a single operation. Copyright
- Sridharan, Vellaisamy,Ribelles, Pascual,Estevez, Veronica,Villacampa, Mercedes,Ramos, M. Teresa,Perumal, Paramasivan T.,Menendez, J. Carlos
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supporting information; experimental part
p. 5056 - 5063
(2012/05/20)
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- Three-component reactions of CF3-substituted boranes, ethyl diazoacetate and imines
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Aryl(methoxy)(trifluoromethyl)boranes, generated in situ, readily react with ethyl diazoacetate and N-(4- methoxyphenyl)imines to give derivatives of β-amino acids. In this process, the electron-deficient borane reacts with the diazo compound followed by trapping of the intermediate boron enolate by the imine. The final products are predominantly produced as syn isomers.
- Elkin, Pavel K.,Levin, Vitalij V.,Dilman, Alexander D.,Struchkova, Marina I.,Arkhipov, Dmitry E.,Korlyukov, Alexander A.
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supporting information
p. 6216 - 6218,3
(2021/10/12)
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- Chiral phosphoric acid-catalyzed enantioselective three-component Povarov reaction using enecarbamates as dienophiles: Highly diastereo- and enantioselective synthesis of substituted 4-aminotetrahydroquinolines
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A chiral phosphoric acid (5)-catalyzed three-component Povarov reaction of aldehydes 2, anilines 3, and enecarbamates 4 afforded cis-4-amino-2-aryl(alkyl)- 1,2,3,4-tetrahydroquinolines 1 in high yields with excellent diastereoselectivities (>95%) and almost complete enantioselectivities (up to >99% ee). The reaction was applicable to a wide range of anilines bearing electron-donating (OMe) and electron-withdrawing groups (e.g., Cl, CF 3, NO2) and allowed, for the first time, aliphatic aldehydes to be employed in the enantioselective Povarov reaction. With β-substituted acyclic enecarbamates, 2,3,4-trisubstituted 1,2,3,4-tetrahydroquinolines with three contiguous stereogenic centers were produced in excellent diastereo- and enantioselectivities (87 to >99% ee). A detailed study of the active catalytic species allowed us to reduce the catalyst loading from 10% to 0.5% with no deterioration of enantiomeric excess. In addition, mechanistic studies allowed us to conclude unequivocally that the Povarov reaction involving enecarbamate as dienophile proceeded via a stepwise mechanism. The key role of the free NH function of the enecarbamate in the success of this transformation was demonstrated. NMR experiments indicating the catalyst-substrate interaction as well as a linear correlation between catalyst and product ee's were also documented.
- Dagousset, Guillaume,Zhu, Jieping,Masson, Geraldine
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supporting information; experimental part
p. 14804 - 14813
(2011/11/04)
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- Catalyst-free reduction of aldimines with hantzsch esters
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An efficient catalyst-free reduction of aldimines is reported. In the absence of any additional catalysts, a series of N-aromatic aldimines were reduced with Hantzsch esters as the hydrogenation source. Moderate to excellent isolated yields (up to 99 %) were obtained under mild conditions.
- Li, Jianhui,Wang, Zhouyu,Jiang, Zhenju,Jiang, Shengqian,Xiong, Lilin
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experimental part
p. 4101 - 4103
(2012/01/06)
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- Total regioselective transformation of aromatic aziridine 2-carboxamides into 2-aminoamides promoted by active manganese
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(Figure Presented) A novel, totally regioselective transformation of aromatic N-4-methoxyphenylaziridine 2-carboxamides into 2-aminoamides promoted by active manganese (Mn) is reported. a-Amino ketones can be readily obtained by reaction of morpholine-der
- Concellon, Jose M.,Rodriguez-Solla, Humberto,Del Amo, Vicente,Diaz, Pamela
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supporting information; experimental part
p. 2407 - 2410
(2010/06/21)
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- A facile, protic ionic liquid route to N-substituted 5-hydroxy-4-methyl-3- oxoisoindoline-1-carboxamides and N-substituted 3-oxoisoindoline-4-carboxylic acids
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Treatment of highly decorated bicyclo[2.2.1]heptadienes with the protic ionic liquid, TfOH:TEA effected quantitative conversion to the corresponding N-substituted 5-hydroxy-4-methyl-3-oxoisoindoline-1-carboxamides. This approach provides rapid access important chemical space for the rapid development of highly functionalised oxoisoindoline and is highly substrate tolerant.
- Gordon, Christopher P,Byrne, Nolene,McCluskey, Adam
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experimental part
p. 1000 - 1006
(2010/10/18)
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- Convenient synthesis of pyrrolidines by amphiphilic allylation of imines with 2-methylenepropane-1,3-diols
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(Chemical Equation Presented). A straightforward route: The combination of a palladium catalyst and triethylborane promotes the amphiphilic (nucleophilic-electrophilic) allylation of aldimines, prepared in situ from a wide variety of aromatic and aliphatic aldehydes and amines, with commercially available 2-methylenepropane-1,3-diols to provide pyrrolidines (see scheme).
- Kimura, Masanari,Tamaki, Takato,Nakata, Masanori,Tohyama, Katsumi,Tamaru, Yoshinao
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supporting information; experimental part
p. 5803 - 5805
(2009/03/11)
-
- In vitro antifungal activity of polyfunctionalized 2-(hetero)arylquinolines prepared through imino Diels-Alder reactions
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Diverse polyfunctionalized quinolines, easily prepared using Lewis acid-catalyzed imino Diels-Alder reactions between corresponding aldimines, were tested for antifungal properties against standardized as well as clinical isolates of clinically important fungi. Among them, 4-pyridyl derivatives displayed the best activities mainly against dermatophytes. The activity appears not to be related neither to the lipophilicity nor to the basicity of compounds.
- Melendez Gomez, Carlos M.,Kouznetsov, Vladimir V.,Sortino, Maximiliano A.,Alvarez, Sandra L.,Zacchino, Susana A.
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body text
p. 7908 - 7920
(2009/04/11)
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- Synthesis of new cholesteryl and adenosinyl esters of 2-furyl-N- phenylaminophosphonous acids
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The synthesis of novel 2-furyl N-arylaminomethanephosphonous acids 2a, b and their cholesteryl and adenosinyl esters 3a, b and 4a, b, respectively, is presented. Copyright Taylor & Francis Group, LLC.
- Lewkowski, Jaroslaw,Karpowicz, Rafl,Skowronski, Romuald,Stronka-Lewkowska, Ewa
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experimental part
p. 1455 - 1460
(2009/05/07)
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- Arthrobacter sp.: a lipase of choice for the kinetic resolution of racemic arylazetidinone precursors of taxanoid side chains
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The native strain of Arthrobacter sp. (MTCC 5125) bearing a lipase has been found to be the most effective in the kinetic resolution of racemic arylazetidinones for producing cis-(3R,4S)-3-acetoxy-1-(4-methoxyphenyl)-4-phenyl-2-azetidinone, cis-(3R,4S)-3-
- Anand, Naveen,Kapoor, Munish,Ahmad, Khursheed,Koul, Surrinder,Parshad, Rajinder,Manhas, Kuldip S.,Sharma, Rattan L.,Qazi, Ghulam N.,Taneja, Subhash C.
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p. 1059 - 1069
(2008/01/07)
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- Cu(OTf)2 or Et3N-catalyzed three-component condensation of aldehydes, amines and cyanides: a high yielding synthesis of α-aminonitriles
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Copper(II) triflate or Et3N have been found to catalyze, under ambient conditions, the addition of a cyanide anion, such as trimethylsilyl cyanide or acetone cyanohydrin, onto in situ generated imines, furnishing α-aminonitriles in excellent yi
- Paraskar, Abhimanyu S.,Sudalai, Arumugam
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p. 5759 - 5762
(2007/10/03)
-
- Nickel-catalyzed multi-component connection reaction of isoprene, aldimines (lactamines), and diphenylzinc
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Ni(acac)2 catalyzes the four-component connection reaction of diphenylzinc, isoprene, aromatic aldehydes, and aromatic amines in this order and provides stereochemically homogeneous (E)-1-arylamino-1-aryl-3-methyl-5-phenyl-3-pentenes (1) in excellent yields. Aliphatic aldehydes react similarly and give (E)-1-arylamino-1-alkyl-3-methyl-5-phenyl-3-pentenes (1) in slightly reduced yields. When the alkyl groups are bulky, in addition to 1 are formed (E)-1-arylamino-1-alkyl-4-methyl-5-phenyl-3-pentenes (1′) as the minor products. Lactamines prepared in situ from five- and six-membered lactols and aromatic amines are more reactive than alkyl aldehyde aldimines and furnish (E)-4-arylamino-6-methyl-8-phenyl-6-octen-1-ols (4) and (E)-5-arylamino-7-methyl-9- phenyl-7-nonen-1-ols (5), respectively, in good yields with excellent E-stereoselectivity.
- Kojima, Keisuke,Kimura, Masanari,Ueda, Satoshi,Tamaru, Yoshinao
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p. 7512 - 7520
(2007/10/03)
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- (+)-(S,S)-pseudoephedrine as a chiral auxiliary in asymmetric Mannich reactions: Scope and limitations
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The Mannich reaction of variously substituted (+)-(S,S)-pseudoephedrine amides with either enolizable and nonenolizable imines smoothly afforded a series of β-substituted α-alkyl-β-amino amides with full stereochemical control. These Mannich adducts have
- Iza, Ainara,Vicario, Jose L.,Carrillo, Luisa,Badia, Dolores
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p. 4065 - 4074
(2008/03/11)
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- Nickel catalyzed stereoselective conjugate addition of dimethylzinc upon aldimines across 1,3-dien-8-ynes and 1,3-dien-9-ynes
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Ni(acac)2 catalyzes the five-component connection reaction of Me2Zn, alkynes, diene (of 1,3-dien-8-ynes and 1,3-dien-9-ynes), aldehydes and anisidine to furnish cyclic dienyl amines anti-2 with high remote 1,5-diastereoselectivity. T
- Kimura, Masanari,Mori, Masahiko,Mukai, Nahoko,Kojima, Keisuke,Tamaru, Yoshinao
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p. 2813 - 2815
(2008/09/19)
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- Efficient ruthenium-catalyzed aerobic oxidation of amines by using a biomimetic coupled catalytic system
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Efficient aerobic oxidation of amines was developed by the use of a biomimetic coupled catalytic system involving a ruthenium-induced dehydrogenation. The principle for this aerobic oxidation is that the electron transfer from the amine to molecular oxygen occurs stepwise via coupled redox systems and this leads to a low-energy electron transfer. A substrate-selective ruthenium catalyst dehydrogenates the amine and the hydrogen atoms abstracted are transported to an electron-rich quinone (2a). The hydroquinone thus formed is subsequently reoxidized by air with the aid of an oxygen-activating [Co(salen)]-type complex (27). The reaction can be used for the preparation of ketimines and aldimines in good to high yields from the appropriate corresponding amines. The reaction proceeds with high selectivity, and the catalytic system tolerates air without being deactivated. The rate of the dehydrogenation was studied by using quinone 2a as the terminal oxidant. A catalytic cycle in which the amine promotes the dissociation of the dimeric catalyst 1 is presented.
- Samec, Joseph S. M.,Ell, Alida H.,Baeckvall, Jan-E.
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p. 2327 - 2334
(2007/10/03)
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- Silica gel supported sodium hydrogen sulfate as an efficient and reusable heterogeneous catalyst for the synthesis of imines in solvent-free conditions under microwave irradiation
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This synthesis of imines has been carried out efficiently by the condensation of carbonyl compounds with amines in the presence of silica gel supported sodium hydrogen sulfate (NaHSO4.SiO2) as a heterogeneous catalyst under microwave irradiation in solvent-free conditions. NaHSO4.SiO2 can be recovered and re-used up to ten times by simple washing with diethyl ether after each use and activated in an oven at 120°C for 1 h, thus rendering the process more economical.
- Gopalakrishnan, Mannathusamy,Sureshkumar, Purushothaman,Kanagarajan, Vijayakumar,Thanusu, Jeyaraman,Govindaraju, Ramalingam
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p. 299 - 303
(2007/10/03)
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- Palladium-catalyzed allylation of imines with allyl alcohols
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(Chemical Equation Presented) A catalytic system, Pd(OAc)2 (10 mol %)-P(n-Bu)3 (20 mol %)-Et3B (360 mol %), promotes allylic alcohols to undergo the allylation of anisidineimines of aromatic and aliphatic aldehydes and furnishes homoallylamines in good to moderate yields. The reaction shows unique stereoselectivity, giving anti-isomers selectively.
- Shimizu, Masamichi,Kimura, Masanari,Watanabe, Toshiya,Tamaru, Yoshinao
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p. 637 - 640
(2007/10/03)
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- Nickel-catalyzed four-component connection of oraganoaluminium (organozinc), isoprene, aldehydes and amines: Stereo- and regioselective synthesis of trisubstituted (E)-homoallylamines
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Ni(acac)2 catalyzes the four-component connection reaction of trimethylaluminium (or diphenylzinc), isoprene, aromatic aldehydes and p-anisidine in this order and provides (E)-1-aryl-1-(p-methoxyphenyl)amino-3- methyl-3-hexenes (or (E)-1-aryl-1
- Kojima, Keisuke,Kimura, Masanari,Tamaru, Yoshinao
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p. 4717 - 4719
(2007/10/03)
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- Microwave-assisted rapid and simplified hydrogenation
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Catalytic transfer hydrogenation has been conducted under microwave irradiation in open vessels using high-boiling solvents such as ethylene glycol (bp 198 °C) as the microwave energy transfer agent. Reduction of double bonds and hydrogenolysis of several functional groups were carried out safely and rapidly (3-5 min) at about 110-130 °C with 10% Pd/C as an efficient catalyst and ammonium formate as the hydrogen donor. Diverse types of β-lactam synthons were prepared by the reduction of ring substituents containing alkene and alkylidene groups or conjugated unsaturated esters. Cleavage of the β-lactam ring by hydrogenolysis of the N-C4 bond of 4- aryl-2-azetidinones was a facile reaction with 10% Pd/C as the catalyst; but no ring scission occurred when Raney nickel catalyst was employed. Dehalogenation of aromatic compounds was also successful with ammonium formate and Pd/C catalyst. Hydrogenolysis of phenylhydrazone of methyl benzoylformate gave the methyl ester of phenylglycine in excellent yield. The techniques described here for microwave assisted hydrogenation are safe, rapid, and efficient and are suitable for research investigation as well as for undergraduate and high school laboratory exercises.
- Banik, Bimal K.,Barakat, Khaled J.,Wagle, Dilip R.,Manhas, Maghar S.,Bose, Ajay K.
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p. 5746 - 5753
(2007/10/03)
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- Anti-tumor compounds, pharmaceutical compositions, methods for preparation thereof and for treatment
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The present invention is directed to novel taxanes useful as chemotherapeutic agents or their precursors. Processes for preparing the novel taxanes include coupling reactions, in the presence of a base, of baccatin of formula (III) or (IV) STR1 with β-lac
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- Synthesis and structure-activity relationships of novel 2',2'-difluoro analogues of docetaxel
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To investigate the role of the 2'-hydroxy group at the C-13 side chain of docetaxel in the antitumor activity, we prepared several 2',2'-difluoro derivatives of docetaxel and evaluated their cytotoxicity against mouse leukemia and human tumor cell lines a
- Uoto, Kouichi,Ohsuki, Satoru,Takenoshita, Haruhiro,Ishiyama, Takashi,Iimura, Shin,Hirota, Yasuhide,Mitsui, Ikuo,Terasawa, Hirofumi,Soga, Tsunehiko
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p. 1793 - 1804
(2007/10/03)
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- Anti-tumor compounds, pharmaceutical compositions, methods for preparation thereof and for treatment
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The present invention is directed to novel taxanes useful as chemotherapeutic agents or their precursors. Processes for preparing the novel taxanes include coupling reactions, in the presence of a base, of baccatin of formula (III) or (IV) STR1 with β-lac
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- Stereoselectivity in the Condensation Reactions between Malate Enolate and Imines to 2-Pyrrolidinone Derivatives
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Enolate dianion of diethyl (S)-malate was stereoselectively condensed with nonenolizable N-arylimines to give 2-pyrrolidinone derivatives.The presence of HMPA changes the diastereoselectivity of this cyclization reaction.
- Ha, Deok-Chan,Yun, Kyeong-Soon,Park, Hye-Sang,Choung, Won-Keun,Kwon, Young-Eun
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p. 8445 - 8448
(2007/10/02)
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- Process for the production of chiral hydroxy-β-lactams and hydroxyamino acids derived therefrom
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The reaction between a hydroxyacetic acid derivative bearing an oxygen protecting group and a chiral auxiliary group and an imine produces chiral β-lactams. Hydrolysis of the chiral β-lactams produces chiral amino acid analogs.
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- Ester-imine condensation mediated by potassium tert-butoxide: Synthesis of β-lactams and 3,4-dihydropyridin-2-ones
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The utility of the weak base potassium tert-butoxide has been successfully demonstrated in the synthesis of β-lactams and 3,4-dihydropyridin-2-ones starting from esters and imines.
- Cainelli,Panunzio,Giacomini,Di Simone,Camerini
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p. 805 - 808
(2007/10/02)
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- Intramolecular Diels-Alder Reaction with Furans: Effect of the Substitution Pattern Reinvestigated
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Intramolecular Diels-Alder reactions occurred smoothly when N-(α-cyanofurfuryl)arylamines 2a-g and N-furfurylarylamines 7a-d were treated with maleic anhydride and fumaroyl chloride-triethylamine respectively, to afford the corresponding cycloadducts 4 an
- Prajapati, Dipak,Borthakur, Dipak R.,Sandhu, Jagir S.
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p. 1197 - 1200
(2007/10/02)
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- New and efficient approaches to the semisynthesis of taxol and its C-13 side chain analogs by means of β-lactam synthon method
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Highly efficient chiral ester enolate-imine condensation giving 3-hydroxy-4-aryl-β-lactams with excellent enantiomeric purity is successfully applied to the asymmetric synthesis of the enantiomerically pure taxol C-13 side chain, N-benzoyl-(2R,3S)-3-phenyl-isoserine and its analogs. (3R,4S)-N-benzoyl-3-(1-ethoxyethoxy)-4-phenyl-2-azetidinone readily derived from the 3-hydroxy-4-phenyl-β-lactam is coupled with protected baccatin IIIs, followed by deprotection to give optically pure taxol and 10-deacetyl-7,10-bis(Troc)-taxol in good yields. Fully assigned 1H, 13C, and 2D (COSY and HETCOR) NMR spectra of taxol thus synthesized are shown and discussed.
- Ojima, Iwao,Habus, Ivan,Zhao, Mangzhu,Zucco, Martine,Park, Young Hoon,Sun, Chung Ming,Brigaud, Thierry
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p. 6985 - 7012
(2007/10/02)
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