- Synergetic activation of CO2by the DBU-organocatalyst and amine substrates towards stable carbamate salts for synthesis of oxazolidinones
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The development of an efficient methodology to transform CO2 into valuable chemicals has attracted increasing attention concerning the challenging issues of CO2-utilization. Herein, an efficient approach for the preparation of oxazolidinones from CO2, primary (aliphatic/aromatic) amines and 1,2-dichloroethane (or its derivatives) catalyzed by DBU organo-superbase was achieved with yields of 47-97% under mild conditions (80-100 °C, 12 h, 1.0 MPa CO2). Control experiments demonstrated that the formation of an ion-pair carbamate salt intermediate IS-B derived from the reaction of CO2, DBU (catalyst) and an amine (substrate) was the key step for this three-component reaction. The available DBU-amine-CO2 adduct intermediate (like IS-B-2) with fair stability will evolve into the thermodynamically stable product oxazolidinones upon attack of 1,2-dichloroethane (or its derivatives), along with the regeneration of the DBU catalyst. Alternatively, the decomposition of the DBU-aryl amine-CO2 adduct (like IS-B-1) with relatively poor stability also could result in the competitive substitution reaction of 1,2-dichloroethane (or its derivatives) with the aryl amine. This work provides insights into synergetic CO2-activation by the DBU-catalyst and a nucleophilic amine-substrate via the formation of robust carbamate salt intermediates responsible for the final production of oxazolidinones. This journal is
- Chen, Xiao-Chao,Liu, Ye,Lu, Yong,Yao, Yin-Qing,Zhao, Kai-Chun
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p. 7072 - 7082
(2021/11/17)
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- A Nanocrystal Catalyst Incorporating a Surface Bound Transition Metal to Induce Photocatalytic Sequential Electron Transfer Events
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Heterogeneous photocatalysis is less common but can provide unique avenues for inducing novel chemical transformations and can also be utilized for energy transductions, i.e., the energy in the photons can be captured in chemical bonds. Here, we developed a novel heterogeneous photocatalytic system that employs a lead-halide perovskite nanocrystal (NC) to capture photons and direct photogenerated holes to a surface bound transition metal Cu-site, resulting in a N-N heterocyclization reaction. The reaction starts from surface coordinated diamine substrates and requires two subsequent photo-oxidation events per reaction cycle. We establish a photocatalytic pathway that incorporates sequential inner sphere electron transfer events, photons absorbed by the NC generate holes that are sequentially funneled to the Cu-surface site to perform the reaction. The photocatalyst is readily prepared via a controlled cation-exchange reaction and provides new opportunities in photodriven heterogeneous catalysis.
- Beard, Matthew C.,Chen, Xihan,Han, Chuang,Lin, Yixiong,Martin, Jovan San,Miller, Collin,Wang, Xiaoming,Yamamoto, Nobuyuki,Yan, Yanfa,Yan, Yong,Yazdi, Sadegh,Zeng, Xianghua
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supporting information
p. 11361 - 11369
(2021/08/16)
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- Visible-light-promoted decarboxylative addition cyclization of: N -aryl glycines and azobenzenes to access 1,2,4-triazolidines
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Methods for the synthesis of 1,2,4-triazolidines are scarce. Herein, we report a visible-light-promoted decarboxylative addition cyclization of N-aryl glycines and azobenzenes to access such important compounds. Using commercially available methylene blue (MB) as an organic photocatalyst, the reaction proceeded smoothly in the absence of transition-metal catalysts at ambient temperature, affording the corresponding products, 1,2,4-triaryl 1,2,4-triazolidines, in good to excellent yields. This work demonstrates a new synthetic application of readily available azobenenes and provides a novel strategy for constructing 1,2,4-triazolidines.
- Ma, Ben,Qi, Yanfang,Song, Menghui,Wang, Xi-Cun,Yang, Jingya,Zhou, Hongyan
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supporting information
p. 5806 - 5811
(2021/08/23)
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- Synthesis and antioxidant properties of a novel arylamine antioxidant
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A novel oil-soluble arylamine antioxidant N1,N2-diphenylethane-1,2-diamine (ND) was successfully synthesized, and the potential antioxidant behavior of which had never been reported before. The structure of ND was characterized via nuclear magnetic resonance (1H NMR, 13C NMR) and electron ionization mass spectrometry. The antioxidant performance of ND and its synergistic effect with 2,6-di-tert-butyl-4-methylphenol (BHT) in di-2-ethylhexyl sebacate were evaluated by pressurized differential scanning calorimetry, thermogravimetry analysis, and hot oil oxidation test. All the results indicated that the synthesized antioxidant ND exhibited outstanding antioxidant performance and showed prominent synergistic effect with BHT in ester base oil. Furthermore, the probable synergistic anti-oxidative effect between ND and BHT was discussed, which was mainly induced by the formation of a fresh BHT radical and the regeneration of ND antioxidant.
- Chao, Mianran,Fan, Rong,Zhang, Lulu,Wang, Xiaoyu,Shu, Qianhui,Gao, Jifeng,Chen, Lele,Gong, Peiwei,Shen, Duyi
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p. 1440 - 1445
(2021/09/02)
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- Copper-Catalyzed Propargylation of Nitroalkanes
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Using a commercially available, inexpensive, and abundant copper catalyst system, an efficient α-functionalization of nitroalkanes with propargyl bromides is now established. This mild and robust method is highly functional group tolerant and provides straightforward access to complex secondary and tertiary homopropargylic nitroalkanes. Moreover, the utility of these α-propargylated nitroalkanes is demonstrated through downstream functionalization to biologically relevant, five-membered N-heterocycles such as pyrroles and 2-pyrrolines.
- Kim, Raphael S.,Dinh-Nguyen, Linh V.,Shimkin, Kirk W.,Watson, Donald A.
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supporting information
p. 8106 - 8110
(2020/11/02)
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- B(C6F5)3-Catalyzed Deoxygenative Reduction of Amides to Amines with Ammonia Borane
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The first B(C6F5)3-catalyzed deoxygenative reduction of amides into the corresponding amines with readily accessible and stable ammonia borane (AB) as a reducing agent under mild reaction conditions is reported. This metal-free protocol provides facile access to a wide range of structurally diverse amine products in good to excellent yields, and various functional groups including those that are reduction-sensitive were well tolerated. This new method is also applicable to chiral amide substrates without erosion of the enantiomeric purity. The role of BF3 ? OEt2 co-catalyst in this reaction is to activate the amide carbonyl group via the in situ formation of an amide-boron adduct. (Figure presented.).
- Pan, Yixiao,Luo, Zhenli,Han, Jiahong,Xu, Xin,Chen, Changjun,Zhao, Haoqiang,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
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supporting information
p. 2301 - 2308
(2019/01/30)
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- Synthesis of Arylamines via Non-Aerobic Dehydrogenation Using a Palladium/Carbon-Ethylene System
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The reaction of cyclohexanones with amines proceeded under an ethylene atmosphere in the presence of a catalytic amount of palladium/carbon to afford a variety of arylamines in good to high yields. The present reaction was carried out under completely non-aerobic conditions, and which is in contrast with the previously reported aerobic system. has wide applicability affording a variety of aromatic amines, and co-product of the reaction is only gaseous ethane. Thus, this method is environmentally friendly. This protocol was applied intramolecularly to provide a novel method for the construction of quinoline and isoquinoline compounds. (Figure presented.).
- Shimomoto, Yuya,Matsubara, Ryosuke,Hayashi, Masahiko
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supporting information
p. 3297 - 3305
(2018/08/07)
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- Unmodified Fe3O4 nanostructure promoted with external magnetic field: safe, magnetically recoverable, and efficient nanocatalyst for N- and C-alkylation reactions in green conditions
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Transition metal compounds have emerged as suitable catalysts for organic reactions. Magnetic compounds as soft Lewis acids can be used as catalysts for organic reactions. In this report, the Fe3O4 nanostructures were obtained from Fe2+ and Fe3+-salts, under an external magnetic field (EMF) without any protective agent. The X-ray photoelectron spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy tools were used to characterize these magnetic compounds. The two-dimensional (2-D, it showed nanometric size in the two dimensions, nanorod structure) Fe3O4 compound showed high catalytic activity and stability in N- and C-alkylation reactions. A diverse range of N- and C-alkylation products were obtained in moderate to high yield under green and mild conditions in air. Also the N- and C-alkylation products can be obtained with different selectivity and yield by exposure reactions with EMF. Results of alkylation reactions showed that the presence of Fe(II) and Fe(III) species on the surface of magnetic catalysts (phase structure of magnetic compounds) are essential as very cheap active sites. Also, morphology of magnetic catalysts had influence on their catalytic performances. After the reaction, the catalyst/product(s) separation could be easily achieved with an external magnet and more than 95% of catalyst could be recovered. The catalyst was reused at least four times without any loss of its high catalytic activity for N- and C-alkylation reactions.
- Rafiee, Ezzat,Joshaghani, Mohammad,Abadi, Parvaneh Ghaderi-Shekhi
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p. 2503 - 2522
(2018/01/04)
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- Improved microwave synthesis of unsymmetrical N,N'-diaryl-1,2-aminoethane and imidazolidinium salts as precursors of N-heterocyclic carbenes
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Lithium aluminium hydride reduction of bis-unsymmetric-diaryloxamides 3 is difficult to accomplish especially for the sterically hindered mesityl derivative. Using microwaves LAH reduction of 3a,d was successful in a short time, however, with cleavage of the ether linkage to give compounds 11a,d. Extension of this method enabled the reduction of bis-oxamide derivatives 13 to the corresponding tetraamine derivative 14 which was then converted to the bis-imidazolidinium salt 15. Application of this method led to rapid reduction of unsymmetric N,N'-diaryloxamides 16 to the corresponding N,N'- diarylethylenediamines 17 which were converted to their corresponding imidazolidinium salts 18. the Partner Organisations 2014.
- Ibrahim, Yehia A.,Al-Awadi, Nouria A.,Al-Azemi, Talal F.,John, Elizabeth
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p. 38869 - 38876
(2014/11/08)
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- New phosphine-functionalized NHC ligands: Discovery of an effective catalyst for the room-temperature amination of aryl chlorides with primary and secondary amines
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We report convenient and high-yielding syntheses of new phosphine-functionalized dihydroimidazolium salts and demonstrate their utility as ligand precursors for Buchwald-Hartwig amination. Several examples of the general formula [1-Mes-3-{2-(PR2)phenyl}imidazolidin-2-ylium][BF 4] have been prepared, where phosphines of varying steric and electronic properties (R = Ph (9), Cy (10), 1-Ad (11)) are tethered by an o-phenylene group. The synthesis was not adaptable to N-aryl groups other than mesityl, giving unexpected phosphonium salt species instead. The synthesis was adapted to flexible benzyl-linked variants of the formula [1-Ar-3-{2-(PCy 2)benzyl}imidazolidin-2-ylium][BF4], which allowed more steric variation of the dihydroimidazolium N-aryl group (Ar = Mes (21), Dipp (22)). A preliminary study of these hybrid NHC/P ligands in Buchwald-Hartwig amination catalysis (in situ precatalyst formation) revealed 11 to be the most active of the series. Premixing the isolated free NHC ligand 1-Mes-3-{2-(PAd2)phenyl}imidazolidin-2-ylidene (23) with [Pd(cinnamyl)Cl]2 provided a highly active precatalyst that performed well at room temperature and 1 mol % catalyst loading. The system was shown to have an unprecedented ability to arylate both primary alkylamines (monoarylation) and secondary dialkylamines with aryl chlorides at room temperature. Electron-rich and -poor aryl and heteroaryl halides, as well as those featuring ortho substitution, were well tolerated, while substrates featuring both primary and secondary amine groups were selectively arylated at the NH2 position. Furthermore, a preliminary examination of performance in ammonia arylation and acetone α-arylation showed promising results, giving good conversion and high selectivity for monoarylation in both cases.
- Wheaton, Craig A.,Bow, John-Paul J.,Stradiotto, Mark
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p. 6148 - 6161
(2013/12/04)
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- BippyPhos: A single ligand with unprecedented scope in the Buchwald-Hartwig amination of (hetero)aryl chlorides
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Over the past two decades, considerable attention has been given to the development of new ligands for the palladium-catalyzed arylation of amines and related NH-containing substrates (i.e., Buchwald-Hartwig amination). The generation of structurally diverse ligands, by research groups in both academia and industry, has facilitated the accommodation of sterically and electronically divergent substrates including ammonia, hydrazine, amines, amides, and NH heterocycles. Despite these achievements, problems with catalyst generality persist and access to multiple ligands is necessary to accommodate all of these NH-containing substrates. In our quest to address this significant limitation we identified the BippyPhos/[Pd(cinnamyl)Cl]2 catalyst system as being capable of catalyzing the amination of a variety of functionalized (hetero)aryl chlorides, as well as bromides and tosylates, at moderate to low catalyst loadings. The successful transformations described herein include primary and secondary amines, NH heterocycles, amides, ammonia and hydrazine, thus demonstrating the largest scope in the NH-containing coupling partner reported for a single Pd/ligand catalyst system. We also established BippyPhos/ [Pd(cinnamyl)Cl]2 as exhibiting the broadest demonstrated substrate scope for metal-catalyzed cross-coupling of (hetero)aryl chlorides with NH indoles. Furthermore, the remarkable ability of BippyPhos/[Pd(cinnamyl)Cl] 2 to catalyze both the selective monoarylation of ammonia and the N-arylation of indoles was exploited in the development of a new one-pot, two-step synthesis of N-aryl heterocycles from ammonia, ortho- alkynylhalo(hetero)arenes and (hetero) aryl halides through tandem N-arylation/hydroamination reactions. Although the scope in the NH-containing coupling partner is broad, BippyPhos/[Pd(cinnamyl)Cl]2 also displays a marked selectivity profile that was exploited in the chemoselective monoarylation of substrates featuring two chemically distinct NH-containing moieties.
- Crawford, Sarah M.,Lavery, Christopher B.,Stradiotto, Mark
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supporting information
p. 16760 - 16771
(2014/01/06)
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- Addressing challenges in palladium-catalyzed cross-couplings of aryl mesylates: Monoarylation of ketones and primary alkyl amines
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Mor(DalPhos) for Me(sylates): Described are the first examples of ketone mono-α-arylation and primary aliphatic amine monoarylation employing aryl methanesulfonate coupling partners. A range of functionalized aryl mesylates were employed with dialkyl ketones, and also with primary and secondary amines as well as the otherwise challenging coupling partners acetone and methylamine. Ad=adamantyl. Copyright
- Alsabeh, Pamela G.,Stradiotto, Mark
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supporting information
p. 7242 - 7246
(2013/07/26)
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- Controlled acrylate insertion regioselectivity in diazaphospholidine- sulfonato palladium(II) complexes
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Diazaphospholidine-sulfonato Pd(II) complexes [{κ2-P,O-(N- Ar2C2H4N2P)C6H 4SO3}PdMe(L)] 1-L (L = dmso, pyridine, lutidine, or μ-LiCl(solvent); 1a: Ar = Ph, 1b: Ar = 2-MeC6H4, 1c: Ar = 2-MeOC6H4, 1d: Ar = 2,4,6-Me3C 6H2, 1e: Ar = 2,6-iPr2C6H 3, 1f: Ar = 2,6-(p-tolyl)2C6H3) were prepared and structurally characterized. The regioselectivity of methyl acrylate (MA) insertion into the Pd-Me bond is entirely inverted from >93% 1,2-insertion for bulky substituents (1d-f, yielding the insertion products [(PO)Pd{κ2-C,O-CH2CHMeC(O)OMe], 12) to the usual electronically controlled 2,1-insertion (>95%) for the less bulky Ar = Ph (1a, yielding the insertion product [(PO)Pd{κ2-C,O- CHEtC(O)OMe], 11, and β-H elimination product methyl crotonate). DFT studies underline that this is due to a more favorable insertion transition state (2,1- favored by 12 kJ mol-1 over 1,2- for 1a) vs destabilization of the 2,1-insertion transition state in 1d,e. By contrast, MA insertion into the novel isolated and structurally characterized hydride and deuteride complexes [{κ2-P,O-(N-Ar2C 2H4N2P)C6H4SO 3}PdR(lutidine)] (Ar = 2,6-iPr2C6H3; 9e: R = H, 10e: R = D) occurs 2,1-selectively. This is due to the insertion occurring from the isomer with the P-donor and the olefin in trans arrangement, rather than the insertion into the alkyl from the cis isomer in which the olefin is in proximity to the bulky diazaphospholidine. 1a-f are precursors to active catalysts for ethylene polymerization to highly linear polyethylene with M n up to 35 000 g mol-1. In copolymerization experiments, norbornene was incorporated in up to 6.1 mol % into the polyethylene backbone.
- Wucher, Philipp,Roesle, Philipp,Falivene, Laura,Cavallo, Luigi,Caporaso, Lucia,Goettker-Schnetmann, Inigo,Mecking, Stefan
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p. 8505 - 8515
(2013/02/23)
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- Effect of ligand substituents in olefin polymerisation by half-sandwich titanium complexes containing monoanionic iminoimidazolidide ligands-MAO catalyst systems
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Various half-sandwich titanium complexes containing iminoimidazolidide ligands, CpTiCl2[1,3-R2(CH2N)2CN] (1a-d) [R = Ph (a), 2,6-Me2C6H3 (b), cyclohexyl (c), tBu (d)], have been employed as the catalyst precursors for ethylene polymerisation, syndiospecific styrene polymerisation, and copolymerisation of ethylene with 1-hexene in the presence of MAO cocatalyst; 1d showed the highest catalytic activity for ethylene polymerisation whereas 1b showed the highest activity for syndiospecific styrene polymerisation.
- Nomura, Kotohiro,Fukuda, Hiroya,Katao, Shohei,Fujiki, Michiya,Kim, Hyun Joon,Kim, Dong-Hyun,Zhang, Shu
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p. 7842 - 7849
(2011/09/20)
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- Heterogeneous bimetallic Pt-Sn/γ-Al2O3 catalyzed direct synthesis of diamines from N-alkylation of amines with diols through a borrowing hydrogen strategy
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Direct synthesis of diamines has been efficiently realized from the N-alkylation of amines with diols by means of heterogeneous bimetallic Pt-Sn/γ-Al2O3 catalyst (0.5 wt % Pt, molar ratio Pt:Sn = 1:3) through a 'Borrowing Hydrogen' strategy under ligand-free conditions. The present methodology provides an environmentally benign route to diamines.
- Wang, Liandi,He, Wei,Wu, Kaikai,He, Songbo,Sun, Chenglin,Yu, Zhengkun
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supporting information; experimental part
p. 7103 - 7107
(2012/01/05)
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- Structure-Analytical Investigations of P-Substituted 1,3,2- Diazaphospholidines
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2-Diphenylphosphanyl-1,3,2-diazaphospholidines were prepared via metathesis from 2-chloro-1,3,2-diazaphospholidines and LiPPh2. For some of the products, symmetrisation to tetraphenyldiphosphane and 2,2′-bis-1,3,2- diazaphospholidinyls was observed. Most of the derivatives were characterised by single-crystal X-ray diffraction, which showed that all compounds studied feature elongated exocyclic P-Cl or P-P-bonds, respectively. The extent of this bond lengthening is in the P-phosphanyl-substituted species similar and in the P-chloro-derivatives less pronounced than in corresponding CC-unsaturated 1,3,2-diazaphospholenes. Structure correlation involving comparison of exocyclic P-X and endocyclic P-N distances suggests that n(N)/σ(P-X) hyperconjugation contributes strongly to the bond lengthening and induces a perceptible weakening of the P-P bonds in 2-diphenylphosphanyl-1,3,2- diazaphospholidines, which should render these compounds interesting substrates for P-P bond activation reactions. Copyright
- Puntigam, Oliver,Hajdok, Imre,Nieger, Martin,Niemeyer, Mark,Strobel, Sabine,Gudat, Dietrich
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scheme or table
p. 988 - 994
(2011/09/12)
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- N-Heterocyclic phosphenium cations: Syntheses and cycloaddition reactions
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A series of trifluoromethanesulfonate (OTf) salts of N-heterocyclic phospheniums (NHP) bearing phenyl (1a), para-methoxyphenyl (1b), 2,6-diisopropylphenyl (1c) and mesityl (1d) substituents is reported. The compounds 1b-d are made by a modification to a literature procedure that improves the overall yields for 1c and 1d by 15 and 23%, respectively. Two unwanted side-products in the synthesis of 1d, the diammonium salt, [(2,6-iPr-C6H3)N(H)2CH2CH 2N(H)2(2,6-iPr-C6H3)]Cl2 (4) and the bisphosphine (2,6-iPr-C6H3)N(PCl 2)CH2CH2N(PCl2)(2,6-iPr-C 6H3) (5), are crystallographically characterized, as is the intermediate cyclic chlorophosphine, C1PN(4-OMe-C6H 4)CH2CH2N(4-OMe-C6H4) (3b). The phenyl-substituted NHP 1a is fully characterized, including by X-ray crystallography, for the first time; this compound contains a short P-O contact of 2.1850(14) A Cycloaddition reactions of 1a-d with 2,3-dimethyl-1,3- butadiene give the expected spirocyclic phospholeniums, 7,8-dimethyl-1,4-diaryl- 1,4-diaza-5-phopshoniaspiro[4.4]non-7-ene, as their OTf salts (6a-d), while reactions with N,N′-dimesityl-1,4-diaza-1,3-butadiene give, except in the case of 1c, which is too bulky to react, the aza analogues, 1,4-dimesityl-6,9- diaryl-1,4,6,9-tetraaza-5-phosphoniaspiro[4.4]non-2-ene (7a, 7b and 7d). The sterically congested 7d is in thermal equilibrium with 1d and free diazadiene, and undergoes a substitution reaction with 2,3-dimethyl-1,3-butadiene to give 6d.
- Caputo, Christine A.,Price, Jacquelyn T.,Jennings, Michael C.,McDonald, Robert,Jones, Nathan D.
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p. 3461 - 3469
(2008/09/21)
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- Palladium-catalyzed amination of aryl and heteroaryl tosylates at room temperature
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Mild palladium-catalyzed aminations of aryl tosylates and the first aminations of heteroaryl tosylates are described. In the presence of the combination of L2Pd(0) (L = P(o-tol)3) and the hindered Josiphos ligand CyPF-t-Bu, a variety of primary alkylamines and arylamines react with both aryl and heteroaryl tosylates at room temperature to form the corresponding secondary arylamines in high yields with complete selectivity for the monoarylamine. These reactions at room temperature occur in many cases with catalyst loadings of 0.1 mol % and 0.01 mol % in one case, constituting the most efficient aminations of aryl tosylates by nearly 2 orders of magnitude. This catalyst is made practical by the development of a convenient method to synthesize the L2Pd(0) precursor. This complex is stable to air as a solid. In contrast to conventional relative rates for reactions of aryl sulfonates, the reactions of aryl tosylates are faster than parallel reactions of aryl triflates, and the reactions of aryl tosylates are faster than parallel or competitive reactions of aryl chlorides. Copyright
- Ogata, Tokutaro,Hartwig, John F.
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supporting information; experimental part
p. 13848 - 13849
(2009/02/07)
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- New osmium-based reagent for the dihydroxylation of alkenes
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The cis dihydroxylation of alkenes is most efficiently accomplished by reaction with osmium tetroxide. Recently, the expense and toxicity of osmium tetroxide have led to a number of attempts to harness alternative osmium-based reagents, including microencapsulation and solid support techniques. We describe here the development of a new nonvolatile, stable, and recoverable osmium-based reagent devised for the stoichiometric cis dihydroxylation of alkenes. Although attempts to make this new dihydroxylation work with catalytic amounts of this reagent were unsuccessful, we did develop a sensitive test for free osmium tetroxide leached from the reagent in situ: this test may well have uses in probing future applications of derivatized osmium reagents.
- Donohoe, Timothy J.,Harris, Robert M.,Butterworth, Sam,Burrows, Jeremy N.,Cowley, Andrew,Parker, Jeremy S.
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p. 4481 - 4489
(2015/09/24)
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- Synthesis and evaluation of antiinflammatory and analgesic activity of some new 1,3-diphenyl-2-aryltetrahydroimidazoles
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In an effort to search for new antiinflammatory and analgesic agents, some new tetrahydroimidazole derivatives 2a-2g have been synthesized via condensation of 1,2-dianilinoethane with various aldehydes. Characterization of the newly synthesized compounds has been done on the basis of 1H NMR and mass spectral data. The resulting compounds have been evaluated for their antiinflammatory activity. The activity of compounds 2b and 2c is excellent and comparable to indomethacin. All these compounds have been tested for their analgesic activity also and their LD50 determined. Compounds 2b and 2c show a comparable activity with aspirin. The MTD for all the compounds is found to be >1800 mg/kg.
- Khan,Gupta, Monica
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p. 2086 - 2090
(2007/10/03)
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- Study on synthesis, characterization and biological activity of some new nitrogen heterocycle porphyrins
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Seven new nitrogen heterocycle porphyrins, 5,10,15,20-tetra[4-(N-pyrrolidinyl)phenyl]porphine (TBPPH2), 5,10,15,20-tetra[4-(4′-ethylpiperazinyl)phenyl]porphine (TEPPH2), 5,10,15,20-tetra [4-(4′-butylpiperazinyl)phenyl]porphine (TUPPH2), 5,10,15,20-tetra[4-(4′-heptylpiperazinyl) phenyl]porphine (THPPH2), 5-[4-(4′-ethylpiperazinyl)phenyl]-10,15,20-triphenylporphine (MEPPH2), 5-[4-(4′-buthylpiperazinyl)phenyl]-10,15,20-triphenylporphine (MUPPH2) and piperazine bridge porphine dimer N,N′-di(5,10,15,20-tetraphenylporphinato)piperazine (DiPPH2) have been synthesized by the direct condensation of nitrogen heterocycle substituted benzaldehydes with pyrrole. Each porphine bears one or four substituted pyrrolidine or piperazine moieties that have been used as drugs. Their structures were characterized by elementary analysis, MS, 1H NMR, IR and UV-vis. These nitrogen heterocycle porphyrins aggregates in water and THF solution were studied by the spectrophotofluorimetry. The anticancer activity of these porphines for the liver cancer cells, the stomach tumor cells and the nasopharyngeal carcinoma cancer cells were tested by the MTT assay. Compared with cis-platinum (cis-Pt) and 5-Fluorouracil (5-Fu), the nitrogen heterocycle porphyrins have the better biological activity and might have potential application in medicine.
- Guo, Can-Cheng,Li, He-Ping,Zhang, Xiao-Bing
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p. 1745 - 1751
(2007/10/03)
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- Reaction of 1,2-dibromoethane with primary amines: Formation of N,N′-disubstituted ethylenediamines RNH-CH2CH2-NHR and homologous polyamines RNH-[CH2CH2NR]n-H
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The reaction of primary amines RNH2 (R: Me, Et, iPr, tBu and Ph) with 1,2-dibromoethane gave N,N′-disubstituted ethylenediamines R-NH-CH2CH2-NH-R (1) in yields ranging from 10% (1a; R=Me) to 70% (1d, R=tBu; 1e, R=Ph). Pipe
- Denk, Michael K.,Krause, Mike J.,Niyogi, Debyani F.,Gill, Nachhattarpal K.
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p. 7565 - 7570
(2007/10/03)
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- C-H activation with elemental sulfur: Synthesis of cyclic thioureas from formaldehyde aminals and S8
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The C-H activation of cyclic formaldehyde aminals LCH2 (L = RNCH2CH2CH2-NR and RNCH2CH2-NR, R = Me, Et, iPr, tBu, or Ph) with S8 proceeds at unusually low temperatures (T 2S. The reaction constitutes a new, solvent-free method for the synthesis of thioureas that eliminates the toxic and highly flammable CS2. For R = tBu, the ionic carbenium thiocyanates [LCH]+ SCN- dominate the product spectrum and the respective thioureas are obtained in low yield. The reactivity of the analogous sulfur and oxygen ring systems towards S8 was investigated. 1,3-Dithiolane is cleanly converted into 1,3-dithiolane-2-thione (S8, 14 d, 190°C) and resembles the cyclic formaldehyde aminals in this respect. 1,3-Dioxolane (L = OCH2CH2O) is completely inert towards sulfur even under forceful reaction conditions (190°C, 14 d). The formation of thioureas from aminals was investigated at the CBS-4 and B3LYP/6-31G(d) levels of theory.
- Denk, Michael K.,Gupta, Shilpi,Brownie, John,Tajammul, Sabiha,Lough, Alan J.
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p. 4477 - 4486
(2007/10/03)
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- Ruthenium-catalyzed heteroannulation of anilines with alkanolammonium chlorides leading to indoles
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Anilines react with alkanolammonium chlorides in an aqueous medium (H2O-dioxane) at 180°C in the presence of a catalytic amount of a ruthenium catalyst together with SnCl2·2H2O to afford the corresponding indoles in moderate to good yields. Especially, when triisopropanolammonium chloride is employed to react with anilines, 2-methylindoles are formed regioselectively. The presence of SnCl2·2H2O is necessary for the effective formation of indoles. A reaction pathway involving alkanol group transfer from alkanolamines to anilines, N-alkylation of anilines by anilinoalkanols and heteroannulation of 1,2-dianilinoalkanes is proposed for this catalytic process.
- Cho, Chan Sik,Kim, Jin Hwang,Kim, Tae-Jeong,Shim, Sang Chul
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p. 3321 - 3329
(2007/10/03)
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- Synthesis of indole from aniline and ethylene glycol with Pb(II) catalysts
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Various catalysts for the direct synthesis of indole from ethylene glycol and aniline have been reported. It was found that in Pb(II) catalysts, the selectivities of indole are greatly influenced by the ligands; some of these, such as PbI2-KI and PbI2-BaI2, provide indole in high yields. The catalytic activities of lead halides and binary systems were investigated regarding the effects of the ligands of Pb(II): recycling of the catalyst was tested.
- Seto,Imanari
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p. 3139 - 3141
(2007/10/02)
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- A convenient one-pot synthesis of symmetric secondary and tertiary vicinal diamines
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A convenient one-pot synthesis of symmetric vicinal diamines utilizing sodium borohydride/trifluoroacetic acid reduction methodology is described.
- Nutaitis
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p. 1081 - 1085
(2007/10/02)
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- A Novel Method for the Synthesis of Symmetrical Vicinal Tertiary and Secondary Diamines
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A variety of symmetrical vicinal tertiary and secondary diamines are readily prepared in good to excellent yields by either Grignard reaction or reduction of the glyoxal bisproducts with benzotriazole and secondary or primary amines.
- Katritzky, Alan R.,Fan, Wei-Qiang,Fu, Cong
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p. 3209 - 3213
(2007/10/02)
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- 2-Propanol derivatives as corrosion inhibitors
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New composition comprises a functional fluid in contact with ferrous metal and a corrosion inhibiting amount of at least one compound of formula (I) STR1 or a derivative thereof in which R1, R2 and R3 are, independently, hydrogen, a C1 -C15 straight or branched chain alkyl residue, a C5 -C12 cycloalkyl residue, a C6 -C15 aryl residue or C7 -C12 alkaryl residue, and R4 and R5 are, independently, hydrogen, 2-hydroxyethyl or 2-hydroxypropyl with the provisos that (a) R4 and R5 are not simultaneously hydrogen, (b) when R4 and R5 are each --CH2 --CH2 --OH, R1 and R2 are not simultaneously hydrogen and R3 is not a pentyl residue and (c) that polyalkylene and phenol or polycarboxylic ester co-additives are absent; as well as salts thereof. Some of the compounds of formula I are new.
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- Corrosion inhibiting composition
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A composition, in contact with a corrodable metal surface, which composition comprises: (a) an aqueous-based or oil-based system; and (b) as inhibitor for protecting the metal surface against corrosion, at least one compound having the formula I: STR1 as well as salts or partial esters thereof wherein: n is 0 or an integer ranging from 1 to 20, R is a straight or branched chain C4 -C30 alkyl group, optionally interrupted by one, two or three oxygen atoms or substituted by one, two or three hydroxy groups, a C5 -C12 cycloalkyl group, a C6 -C10 aryl group optionally substituted by one, two or three C1 -C12 alkyl groups, or a C7 -C13 aralkyl group which is optionally substituted by a hydroxyl group; R1 is H or a straight- or branched chain C1 -C4 alkyl group; R2 is H, a straight or branched chain C1 -C4 alkyl group or CO2 H; R3 is H, a straight or branched chain C1 -C4 alkyl group, --CH2 CO2 H or --CH2 CH2 CO2 H; R4 is H, a straight or branched chain C1 -C4 alkyl group or CO2 H; R5 is H, a straight or branched chain C1 -C4 alkyl group, CH2 CO2 H or CH2 CH2 CO2 H; provided that at least one group R4 must be CO2 H, with the provisio, that compositions comprising an oil-based system and a compound having the formula STR2 wherein R, R1 and R2 are hydrogen or alkyl radicals, having a total from 10 to 38 C-atoms, are excluded.
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- Triazole-organodithiophosphate reaction product additives for functional fluids
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New reaction products, useful as additives for functional fluids, are obtained by reacting, at elevated temperature, (A) a triazole having the formula IA or IB: STR1 wherein R7 is hydrogen or a C1 -C20 alkyl residue; R8 and R9 are the same or different and each is C1 -C20 alkyl, C3 -C20 alkenyl, C5 -C12 cycloalkyl, C7 -C13 aralkyl, C6 -C10 aryl or R8 and R9, together with the nitrogen atom to which they are attached, form a 5-, 6- or 7-membered heterocyclic residue or R8 and R9 is each a residue of formula: wherein X is O, S or N(R12), R12 is hydrogen or C1 -C20 alkyl, "alkylene" is a C1 -C12 alkylene residue and n is 0 or an integer from 1 to 6; R10 is hydrogen, C1 -C20 alkyl or C6 -C10 aryl or C7 -C18 alkyl phenyl; and R11 is hydrogen, C1 -C20 alkyl or a residue --CH2 NR8 R9 wherein R8 and R9 have their previous significance; with (B) an organodithiophosphate having the formula: STR2 in which R13 is a C1 -C20 alkyl or C7 -C18 alkyl phenyl or C7 -C13 aralkyl group, M is a metal ion of Group IA, IB, IIA, IIB, VB, VIB, VIIB or VIII of the Periodic System of Elements, and y is the valency of M.
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- Synthesis of 1,3-Disubstituted Diazolidines
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Symmetrical and unsymmetrical 1,3-diaminoethanes 1 are obtained by the reduction of N,N'-disubstituted oxamides 4 with lithium aluminum hydride.The oxamides 4 are readily produced by treatment of diethyl oxalate with primary amines.The 1,3-diaminoethanes 1 lead to 1,3-diazolidines 2 on treatment with formaldehyde.
- Lambert, Joseph B.,Huseland, Dave E.,Wang, Gen-tai
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p. 657 - 658
(2007/10/02)
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- Extremely Reactive C=C-Double Bonds, IV. Unusual Reactions with Thiophenol, 1,2-Ethanedithiol, and other Sulfur Compounds
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Reactions of thiophenol and 1,2-ethanedithiol with imidazolidine derivatives lead to solvolysis with opening or conversion of the imidazolidine system as well as to hydrogenation, partly without a change in the ring system .Benzophenone diaryl dithioacetals are reduced to aryl benzhydryl sulfides by thiophenol . 1,1',3,3'-Tetraphenyl-Δ2,2'-biimidazolidine (9) desulfurates thioacetic acid, dibenzoyl disulfide, and dixanthogen .
- Schoenberg, Alexander,Singer, Erich,Stephan, Werner
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p. 3388 - 3399
(2007/10/02)
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- Extremely Reactive C=C-Double Bonds, II. 1,3-Diphenyl-2-imidazolidineselenone from 1,1',3,3'-Tetraphenyl-Δ2,2'-biimidazolidine and Selenium
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1,1',3,3'-Tetraphenyl-Δ2,2'-biimidazolidine (1) reacts with metallic selenium to form 1,3-diphenyl-2-imidazolidineselenone (6).The actions of powdered copper, ethyliodide, thiophenol, phenyl magnesiumbromide, phenylisocyanate, and lithium alanate on 6 are described.Some of the unusual mechanisms of these reactions are discussed.
- Schoenberg, Alexander,Singer, Erich,Stephan, Werner
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p. 2068 - 2073
(2007/10/02)
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- CONTROLLED CHEMILUMINESCENCE DURING THE OXIDATION OF TETRAARYL-Δ2,2'-BIIMIDAZOLIDINES BY TRIPLET OXYGEN IN THE PRESENCE OF FLUORESCERS
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Tetraaryl-Δ2,2'-biimidazolidines (3) are stable compounds in the solid state.In solution they react with triplet oxygen.In the presence of fluorescers chemiluminescence is observed.The intensity and lifetime of the chemiluminescence depends on the substituents at the aryl groups and on the solvent.
- Roeterdink, F.,Scheeren, J. W.,Laarhoven, W. H.
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p. 2307 - 2310
(2007/10/02)
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- General-Acid-Catalyzed Imidazolidine Ring Opening. Hydrolysis of Symmetrical and Unsymmetrical 1,3-Imidazolidines of p-Dimethylaminocinnamaldehyde
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Rate constants have been obtained for ring opening of a series of symmetrical and unsymmetrical 1,3-imidazolidines of p-dimethylaminocinnamaldehyde in H2O at 30 deg C.Ring opening of the N,N'-diphenyl derivative is catalyzed by hydronium ion (kH = 2290 M-1 s-1), and gives rise to a cationic Schiff base with λmax 505 nm.The reaction is considerably slower in D2O than in H2O, kH/kD = 3.0.At pH greater than 6 ring opening is pH independent (k0' = 1.8 10-2 s-1).Ring opening of the N,N'-dimethylimidazolidine to a species with λmax 480 nm is hydronium ion catalyzed (kH = 2 109 M-1 s-1) and pH independent at pH values above 11.5.The unsymmetrical N-isopropyl-N'-phenyl derivative opens to give a species with λmax 480 nm and with rate constants that are similar to those for the N,N'-dimethyl substituted compound (kH = 4 107 M-1 s-1).Consequently, this species must be the N-isopropyl Schiff base resulting from breaking of the C-N phenyl bond.General acid catalysis of ring opening was observed in trimethylamine buffer.Only at pH values less than 6 does C-N isopropyl bond breaking become competitive, giving the N-phenyl Schiff base (λmax 512 nm).The interconversion of Schiff bases (480 -> 512 nm) is general acid catalyzed by buffer acids or a kinetic equivalent.Thus, ring-opening reactions of imidazolidines have been directly monitored, and general acid catalysis has been observed.It can be concluded that, in reactions of the neutral species and hydronium ion, or a general acid, the imidazolidine ring opens preferentially to give the most stable carbonium ion with expulsion of the least basic nitrogen.In the reaction of the unsymmetrical imidazolidine at low pH when there are two protons in the transition state, either C-N bond may break, and the C-N phenyl Schiff base is the favored product.These results are discussed in relation to reactions of N5,N10-methylenetetrahydrofolic acid.
- Fife, Thomas H.,Pellino, August M.
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p. 3062 - 3071
(2007/10/02)
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