- Aza-Matteson Reactions via Controlled Mono-and Double-Methylene Insertions into Nitrogen-Boron Bonds
-
Boron-homologation reactions represent an efficient and programmable approach to prepare alkylboronates, which are valuable and versatile synthetic intermediates. The typical boron-homologation reaction, also known as the Matteson reaction, involves formal carbenoid insertions into C-B bonds. Here we report the development of aza-Matteson reactions via carbenoid insertions into the N-B bonds of aminoboranes. By changing the leaving groups of the carbenoids and altering Lewis acid activators, selective mono- and double-methylene insertions can be realized to access various α- and β-boron-substituted tertiary amines, respectively, from common secondary amines. The derivatization of complex amine-containing bioactive molecules, diverse functionalization of the boronate products, and sequential insertions of different carbenoids have also been achieved.
- Xie, Qiqiang,Dong, Guangbin
-
supporting information
p. 14422 - 14427
(2021/09/29)
-
- Borane-Trimethylamine Complex as a Reducing Agent for Selective Methylation and Formylation of Amines with CO2
-
We report herein that a borane-trimethylamine complex worked as an efficient reducing agent for the selective methylation and formylation of amines with 1 atm CO2 under metal-free conditions. 6-Amino-2-picoline serves as a highly efficient catalyst for the methylation of various secondary amines, whereas in its absence, the formylation of primary and secondary amines was achieved in high yield with high chemoselectivity. Mechanistic studies suggest that the 6-amino-2-picoline-borane catalytic system operates like an intramolecular frustrated Lewis pair to activate CO2.
- Zhang, Yanmeng,Zhang, He,Gao, Ke
-
supporting information
p. 8282 - 8286
(2021/10/25)
-
- Ru-Catalyzed Switchable N-Hydroxyethylation and N-Acetonylation with Crude Glycerol
-
Highly efficient Ru-catalyzed selective C?C or C?O bond cleavage of polyols (e.g., crude glycerol) for N-hydroxyethylation or N-acetonylation of amines was achieved through the hydrogen-borrowing approach. A variety of amines were transformed to the desired amino alcohols/ketones in moderate-to-excellent yields, opening up new avenues for generation of oxygenated pharmaceuticals and fine chemicals from renewable raw materials. The use of new redox-active catalysts containing bisphosphine/thienylmethylamine ligands allows this hydrogen-borrowing system to be operated selectively under both basic and acidic conditions.
- Xin, Zhuo,Jia, Le,Huang, Yuxing,Du, Chen-Xia,Li, Yuehui
-
p. 2007 - 2011
(2020/03/19)
-
- Visible light-mediated Smiles rearrangements and annulations of non-activated aromatics
-
We report the first examples of radical cation Smiles rearrangements. A series of aryloxy alkylamines underwent spontaneous reaction, with the amino group displacing theipso-alkoxy group through substitution, at ambient temperature and under photoactivation by visible light in the presence of an acridinium catalyst (5 mol%). The study was extended to 3-(2-methoxyphenyl)propan-1-amine derivatives, which lack an appropriateipsoleaving group. Here, efficient cyclisations resulted in displacement of the methoxy group and formation of tetrahydroquinolines.
- Lawson, Connor A.,Dominey, Andrew P.,Williams, Glynn D.,Murphy, John A.
-
supporting information
p. 11445 - 11448
(2020/10/12)
-
- Preparation method of methylamine
-
The invention provides a preparation method of methylamine. The preparation method comprises the following step: preparing methylamine by utilizing an amine methylation reaction, wherein in the aminemethylation reaction, the catalyst is dodecyldimethylamine caprolactone. According to the invention, additives required by the reaction are effectively reduced, and the post-treatment process after the reaction is finished is simplified.
- -
-
Paragraph 0040-0046
(2020/12/14)
-
- Direct hydroxyethylation of amines by carbohydrates: Via ruthenium catalysis
-
An efficient and halogen-free catalytic methodology for the synthesis of β-amino alcohols from aromatic amines and biomass-derived carbohydrates is demonstrated for the first time. The activation of C5/C6 sugars by a ruthenium catalyst selectively generates the C2 alkylating reagent glycolaldehyde. The transformation involves metal-catalyzed hydrogen borrowing for the reduction of the imine intermediate. A series of arylamines bearing various substituents were successfully transformed into the desired products in good to excellent yields.
- Jia, Le,Makha, Mohamed,Du, Chen-Xia,Quan, Zheng-Jun,Wang, Xi-Cun,Li, Yuehui
-
p. 3127 - 3132
(2019/06/18)
-
- Practical and regioselective amination of arenes using alkyl amines
-
The formation of carbon–nitrogen bonds for the preparation of aromatic amines is among the top five reactions carried out globally for the production of high-value materials, ranging from from bulk chemicals to pharmaceuticals and polymers. As a result of this ubiquity and diversity, methods for their preparation impact the full spectrum of chemical syntheses in academia and industry. In general, these molecules are assembled through the stepwise introduction of a reactivity handle in place of an aromatic C–H bond (that is, a nitro group, halogen or boronic acid) and a subsequent functionalization or cross-coupling. Here we show that aromatic amines can be constructed by direct reaction of arenes and alkyl amines using photocatalysis, without the need for pre-functionalization. The process enables the easy preparation of advanced building blocks, tolerates a broad range of functionalities, and multigram scale can be achieved via a batch-to-flow protocol. The merit of this strategy as a late-stage functionalization platform has been demonstrated by the modification of several drugs, agrochemicals, peptides, chiral catalysts, polymers and organometallic complexes.
- Ruffoni, Alessandro,Juliá, Fabio,Svejstrup, Thomas D.,McMillan, Alastair J.,Douglas, James J.,Leonori, Daniele
-
p. 426 - 433
(2019/05/01)
-
- A Multiaddressable Dyad with Switchable Cyan/Magenta/Yellow Colors for Full-Color Rewritable Paper
-
Reversible multicolor displays on solid media created from single-molecule pigments are a long-awaited goal. Herein, a new and simple molecular dyad, which can undergo switchable cyan (C), magenta (M), and yellow (Y) color changes in both solution and the solid state upon exposure to light, water/acid, and nucleophiles, has been designed and synthesized. The stimuli used herein can be applied independent of each other, which is beneficial for color changes without mutual interference. For comparison, mixtures of the two molecular switching motifs that form the basis of the dyad were also studied. The dyad greatly outperforms the corresponding mixed system with respect to reversible color switching on the paper substrate. Its potential for full-color rewritable paper with excellent reversibility has been demonstrated. Legible multicolor prints, that is, high color contrast and resolution, good dispersion, and excellent reversibility, were achieved by using common water-jet and light-based printers. This work provides a very promising approach for the further development of full-color switchable molecules, materials, and displays.
- Qin, Tianyou,Han, Jiaqi,Geng, Yue,Ju, Le,Sheng, Lan,Zhang, Sean Xiao-An
-
supporting information
p. 12539 - 12545
(2018/09/10)
-
- Tailored Cobalt-Catalysts for Reductive Alkylation of Anilines with Carboxylic Acids under Mild Conditions
-
The first cobalt-catalyzed hydrogenative N-methylation and alkylation of amines with readily available carboxylic acid feedstocks as alkylating agents and H2 as ideal reductant is described. Combination of tailor-made triphos ligands with cobalt(II) tetrafluoroborate significantly improved the efficiency, thus promoting the reaction under milder conditions. This novel protocol allows for a broad substrate scope with good functional group tolerance, even in the presence of reducible alkenes, esters, and amides.
- Liu, Weiping,Sahoo, Basudev,Spannenberg, Anke,Junge, Kathrin,Beller, Matthias
-
supporting information
p. 11673 - 11677
(2018/09/10)
-
- Access to α-Amino Acid Esters through Palladium-Catalyzed Oxidative Amination of Vinyl Ethers with Hydrogen Peroxide as the Oxidant and Oxygen Source
-
A novel and convenient palladium catalytic system for the synthesis of α-amino acid esters from simple starting materials is reported. Hydrogen peroxide not only acts as the green oxidant, but also as the oxygen source. This strategy for the conversion of amines and vinyl ethers into highly functionalized and structurally diverse α-amino acid esters is characterized by the simplicity of the experimental procedure, mild reaction conditions, high atom economy, scalability, and practicability.
- Ouyang, Lu,Li, Jianxiao,Zheng, Jia,Huang, Jiuzhong,Qi, Chaorong,Wu, Wanqing,Jiang, Huanfeng
-
p. 15926 - 15930
(2017/11/23)
-
- Preparation method by using amine and imine nitrogen methylation and application thereof
-
The invention discloses a preparation method by using amine and imine nitrogen methylation and application thereof. The preparation method comprises the following steps: A, adding an active carbon loaded platinum catalyst into a Schlenk tube, and after vacuumizing to replace argon, adding a solvent; B, under protection of argon, separately adding phenylsilane, an initial raw material and formic acid; C, stirring the whole reaction system at a certain temperature to react; and D, after reaction, adding ethyl acetate into the system to dilute, stopping the reaction by using a sodium hydroxide aqueous solution, performing extraction with ethyl acetate, separating out an organic phase, drying and filtering the organic phase, and performing rotatable evaporation to remove the solvent. Column chromatography is performed on residues by using ethyl acetate/petroleum ether mixed solvent to obtain a target product, wherein the ethyl acetate and petroleum ether are different in proportion. According to the application of the method in isotope labeled drug synthesis, the dosage of a catalyst is extremely low, the cost is quite low, and the method is suitable for large-scaled production, can be suitable for amine and imine with different substituents, and suitable for realizing methylation conveniently on nitrogen atoms in a natural product structure to prepare drug molecules.
- -
-
Paragraph 0158; 0159; 0160; 0161; 0162; 0163
(2017/08/10)
-
- Copper(II)-Catalyzed Selective Reductive Methylation of Amines with Formic Acid: An Option for Indirect Utilization of CO2
-
A copper-catalyzed protocol for reductive methylation of amines and imine with formic acid as a C1 source and phenylsilane as a reductant is reported for the first time, affording the corresponding methylamines in good to excellent yields under mild conditions. This protocol offers an alternative method for indirect utilization of CO2, as formic acid can be readily obtained from hydrogenation of CO2.
- Qiao, Chang,Liu, Xiao-Fang,Liu, Xi,He, Liang-Nian
-
supporting information
p. 1490 - 1493
(2017/03/23)
-
- Betaine Catalysis for Hierarchical Reduction of CO2 with Amines and Hydrosilane To Form Formamides, Aminals, and Methylamines
-
An efficient, sustainable organocatalyst, glycine betaine, was developed for the reductive functionalization of CO2 with amines and diphenylsilane. Methylamines and formamides were obtained in high yield by tuning the CO2 pressure and reaction temperature. Based on identification of the key intermediate, that is, the aminal, an alternative mechanism for methylation involving the C0 silyl acetal and aminal is proposed. Furthermore, reducing the CO2 amount afforded aminals with high yield and selectivity. Therefore, betaine catalysis affords products with a diversified energy content that is, formamides, aminals and methylamines, by hierarchical two-, four- and six-electron reduction, respectively, of CO2 coupled with C?N bond formation.
- Liu, Xiao-Fang,Li, Xiao-Ya,Qiao, Chang,Fu, Hong-Chen,He, Liang-Nian
-
supporting information
p. 7425 - 7429
(2017/06/13)
-
- Palladium-catalyzed intramolecular carbene insertion into C(sp3)-H bonds
-
A palladium-catalyzed carbene insertion into C(sp3)-H bonds leading to pyrrolidines was developed. The coupling reaction can be catalyzed by both Pd0 and PdII, is regioselective, and shows a broad functional group tolerance. This reaction is the first example of palladium-catalyzed C(sp3)-C(sp3) bond assembly starting from diazocarbonyl compounds. DFT calculations revealed that this direct C(sp3)-H bond functionalization reaction involves an unprecedented concerted metalation-deprotonation step. Pd in action: Palladium has been used to catalyze the C(sp3)-H insertion of metal carbenoids derived from α-diazoesters to form pyrrolidines through intramolecular assembly of C(sp3)-C(sp3) bonds. A reaction mechanism involving a metalation-deprotonation step instead of the usual concerted but asynchronous process is proposed.
- Solé, Daniel,Mariani, Francesco,Bennasar, M.-Llu?sa,Fernández, Israel
-
p. 6467 - 6470
(2016/06/01)
-
- Methylation of aromatic amines and imines using formic acid over a heterogeneous Pt/C catalyst
-
We describe here a commercially available Pt/C catalyst capable of catalyzing the methylation of anilines and aromatic imines with formic acid in the presence of a hydrosilane reductant. Both primary aniline and secondary aniline can be methylated. The advantage of this newly described method includes operational simplicity, high TON, ready availability of the catalyst, and also good functional group compatibility.
- Zhu, Lei,Wang, Lian-Sheng,Li, Bojie,Li, Wei,Fu, Boqiao
-
p. 6172 - 6176
(2016/08/19)
-
- Synthetic technology of hydroxyethylaniline ester (III)
-
The invention discloses a synthetic technology of hydroxyethylaniline ester (III). The synthesis process is shown by a chemical equation shown in the description. The technology has the following advantages: 1, the advantage of few instant reaction substances of a micro-channel reactor is used, so the flammable and explosive disadvantages of a hydroxyethylation reaction in a routine kettle are solved, the process safety is increased, and current chemical engineering safety operation requirements are met; and 2, the advantage of high mixing efficiency of the micro-channel reactor is used, the reaction can be carried out under solvent-free conditions when a hydroxyethylation reaction raw material is liquid, and when the excess amount of ethylene oxide is very small, so a reaction solution obtained after the hydroxyethylation reaction ends can be esterified in the micro-channel reactor, serial operation of two-step reactions is realized, and manpower and three wastes are greatly reduced. The technology is a new technology with simplified processes, and accords with environmental protection and safety requirements.
- -
-
Paragraph 0042; 0043; 0056; 0057; 0064
(2016/11/02)
-
- Convenient Reductive Methylation of Amines with Carbonates at Room Temperature
-
Methylation of amines is a fundamental and commonly used reaction in organic synthesis. Many methods are known including various reductive methylations using formaldehyde, formic acid, or carbon dioxide in the presence of reductants. However, several of these methods suffer from limited substrate scope and chemoselectivity because of the different nucleophilicities of substrates. In this respect, the combination of carbonates and hydrosilanes is a valuable methylation source in the presence of Pt-based catalysts. This highly tunable method allows for methylation of both aromatic and aliphatic amines, and chemoselective methylation of aminoalcohols and diamines. Notably, the in situ-formed catalyst can also be used for the reduction of carbonates to methanol at room temperature. Mechanistic insights on intermediates formed during the reaction pathway were obtained by using ESI mass spectrometry.
- Li, Yuehui,Sorribes, Iván,Vicent, Cristian,Junge, Kathrin,Beller, Matthias
-
p. 16759 - 16763
(2015/11/16)
-
- Cu-catalyzed oxidative Povarov reactions between N-alkyl N-methylanilines and saturated oxa- and thiacycles
-
Cu-catalyzed oxidative Povarov reactions between N,N-dialkylanilines and saturated oxa- or thiacycles with tert-butyl hydroperoxide (TBHP) are described; notably, the reactions use neither [4π] nor [2π]-motifs as the initial reagents. The use of cheap alkane-based substances as building units is of mechanistic and practical interest as two inert sp3 C-H bonds are activated.
- Kawade, Rahul Kisan,Huple, Deepak B.,Lin, Rong-Jing,Liu, Rai-Shung
-
p. 6625 - 6628
(2015/04/14)
-
- Boron-Catalyzed N-Alkylation of Amines using Carboxylic Acids
-
A boron-based catalyst was found to catalyze the straightforward alkylation of amines with readily available carboxylic acids in the presence of silane as the reducing agent. Various types of primary and secondary amines can be smoothly alkylated with good selectivity and good functional-group compatibility. This metal-free amine alkylation was successfully applied to the synthesis of three commercial medicinal compounds, Butenafine, Cinacalcet. and Piribedil, in a one-pot manner without using any metal catalysts.
- Fu, Ming-Chen,Shang, Rui,Cheng, Wan-Min,Fu, Yao
-
supporting information
p. 9042 - 9046
(2015/08/03)
-
- A Direct C-H/Ar-H Coupling Approach to Oxindoles, Thio-oxindoles, 3,4-Dihydro-1 H-quinolin-2-ones, and 1,2,3,4-Tetrahydroquinolines
-
A copper(II)-catalysed approach to oxindoles, thio-oxindoles, 3,4-dihydro-1H-quinolin-2-ones, and 1,2,3,4-tetrahydroquinolines via formal C-H, Ar-H coupling is described. In a new variant, copper(II) 2-ethylhexanoate has been identified as an inexpensive and efficient catalyst for this transformation, which utilises atmospheric oxygen as the re-oxidant. Copper(II) 2-ethylhexanoate: The synthesis of oxindoles, thio-oxindoles, 3,4-dihydro-1H-quinolin-2-ones, and 1,2,3,4-tetrahydroquinolines from linear precursors by direct C-H, Ar-H coupling by using a single copper catalyst is reported (see scheme; DIPEA=diisopropylethylamine, EWG=electron-withdrawing group). The cyclisations are simple to perform, run open to the air, are moisture insensitive, and use an inexpensive catalyst.
- Hurst, Timothy E.,Gorman, Ryan M.,Drouhin, Pauline,Perry, Alexis,Taylor, Richard J. K.
-
supporting information
p. 14063 - 14073
(2016/02/18)
-
- General catalytic methylation of amines with formic acid under mild reaction conditions
-
A general catalytic protocol for the methylation of amines has been developed applying, for the first time, formic acid as the C1 building block and silanes as reducing agents. A broad range of aromatic and aliphatic, both primary and secondary, amines has been converted to the corresponding tertiary amines including [N-13C]-labelled drugs in good to excellent yields under mild conditions. Methylation made easy: A general catalytic protocol for the methylation of amines has been developed applying, for the first time, formic acid as the C1 building block and silanes as reducing agents. A broad range of aromatic and aliphatic, both primary and secondary, amines has been converted to the corresponding tertiary amines, including [N-13C]-labelled drugs, in good to excellent yields at mild conditions (see scheme; dppp=(1,3-bis(diphenylphosphino)propane)).
- Sorribes, Ivan,Junge, Kathrin,Beller, Matthias
-
supporting information
p. 7879 - 7883
(2014/07/07)
-
- Selective methylation of amines with carbon dioxide and H2
-
Put a label on it: Carbon dioxide with H2 is shown to be an efficient and selective methylation reagent for aromatic and aliphatic amines (see scheme; acac=acetylacetonate, triphos = 1,1,1- tris(diphenylphosphanylmethyl)ethane). A variety of functionalized amines including 13C-labelled drugs were obtained with good yields and functional-group tolerance. Copyright
- Li, Yuehui,Sorribes, Ivan,Yan, Tao,Junge, Kathrin,Beller, Matthias
-
supporting information
p. 12156 - 12160
(2013/12/04)
-
- Novel ROS-activated agents utilize a tethered amine to selectively target acute myeloid leukemia
-
This study explores the possible use of reactive oxygen-activated DNA modifying agents against acute myeloid leukemia (AML). A key amine on the lead agent was investigated via cytotoxicity assays and was found necessary for potency. The two best compounds were screened via the NCI-60 cell panel. These two compounds had potency between 200 and 800 nM against many of the leukemia cancer cell types. Subsequent experiments explored activity against a transformed AML model that mimics the molecular signatures identified in primary AML patient samples. A lead compound had an IC50 of 760 nM against this AML cell line as well as a therapeutic index of 7.7 ± 3 between the transformed AML model cell line and non-cancerous human CD34+ blood stem/progenitor cells (UCB). The selectivity was much greater than the mainstays of AML treatment: doxorubicin and cytarabine. This manuscript demonstrates that this novel type of agent may be useful against AML.
- Bell-Horwath, Tiffany R.,Vadukoot, Anish K.,Thowfeik, Fathima Shazna,Li, Guorui,Wunderlich, Mark,Mulloy, James C.,Merino, Edward J.
-
supporting information
p. 2951 - 2954
(2013/06/27)
-
- ROS-Activated Compounds as Selective Anti-Cancer Therapeutics
-
Provided are compounds according to the following Formula I: The Formula I compounds are activated in the presence of reactive oxygen species (ROS) and are therefore selective anti-cancer therapeutics for cancers associated with elevated ROS. Also provided are methods and pharmaceutical compositions for treating cancers associated with increased ROS.
- -
-
Paragraph 0122
(2013/09/12)
-
- Copper(II)-acid co-catalyzed intermolecular substitution of electron-rich aromatics with diazoesters
-
The intermolecular aromatic substitution of N,N-dialkylanilines and alkoxybenzenes with diazoesters is shown to proceed in the presence of catalytic amounts of both copper(II) salt and acid (Lewis or Br?nsted). This method is a mild and rare metal-free C-C bond formation reaction between aromatic (sp2) and aliphatic (sp3) carbons.
- Tayama, Eiji,Ishikawa, Moe,Iwamoto, Hajime,Hasegawa, Eietsu
-
supporting information; experimental part
p. 5159 - 5161
(2012/10/07)
-
- Free-radical hydroxymethylation of ketimines generated in situ: A one-pot multicomponent synthesis of β,β-disubstituted-β-aminoalcohols
-
We report how an acidic TiCl4-Zn/t-BuOOH system is able to promote the one-pot multicomponent synthesis of β,β-disubstituted- β-aminoalcohols via nucleophilic addition of a hydroxymethyl radical to activated ketimines generated in situ in methanol solvent. While ketimines are generally recognized as less reactive and less stable when compared with aldimines, Ti(IV) plays a key role in facilitating their formation and in enhancing their electrophilic character. As a consequence, the reaction occurs at room temperature and under non-anhydrous conditions in just 1 h, without requiring either the preformation of the ketimine or protection of the amino group. The scope of the reaction is widely explored and a possible mechanism is discussed.
- Rossi, Bianca,Pastori, Nadia,Clerici, Angelo,Punta, Carlo
-
p. 10151 - 10156,6
(2020/09/02)
-
- Efficient radical domino approach to β-aminoalcohols from arylamines and alcohols triggered by Ti(III)/t-BuOOH
-
We report that an aqueous Ti(III)/t-BuOOH system promotes the efficient domino radical reaction of arylamines with alcohol cosolvents leading to β-aminoalcohols in good yields, in less than ten minutes at room temperature. The free-radical mechanism accor
- Spaccini, Raffaele,Ghilardi, Alessandra,Pastori, Nadia,Clerici, Angelo,Punta, Carlo,Porta, Ombretta
-
supporting information; experimental part
p. 2044 - 2052
(2010/04/26)
-
- Copper(II) triflate catalyzed intermolecular aromatic substitution of N,N-disubstituted anilines with diazo esters
-
The intermolecular aromatic substitution of N,N-disubstituted anilines with diazo esters is achieved under mild conditions in the presence of a catalytic amount of copper(II) triflate (up to 89 % yield). The scope and limitations regarding substrates, diazo esters, and ligands in this reaction are described. The intermolecular aromatic substitution of N,N-disubstituted anilines with diazo esters is shown to proceed under mild conditions in the presence of a catalytic amount of copper(II) triflate/ligand complex(up to 89 % yield). The scope and limitations regarding substrates, diazoesters, and ligands in this reaction are described. Copyright
- Tayama, Eiji,Yanaki, Tomoyo,Iwamoto, Hajime,Hasegawa, Eietsu
-
supporting information; experimental part
p. 6719 - 6721
(2011/02/28)
-
- Ruthenium-catalyzed /V-alkylation of amines and sulfonamides using borrowing hydrogen methodology
-
The alkylation of amines by alcohols has been achieved using 0.5 mol percent [Ru(p-cymene)CI2]2 with the bidentate phosphines dppf or DPEphos as the catalyst. Primary amines have been converted into secondary amines, and secondary amines into tertiary amines, including the syntheses of Piribedil, Tripelennamine, and Chlorpheniramine. A/-Heterocyclization reactions of primary amines are reported, as well as alkylation reactions of primary sulfonamides. Secondary alcohols requiremore forcing conditions than primary alcohols but are still effective a lkylating agents in the presence of this catalyst.
- Hamid, M. Haniti S. A.,Allen, C. Liana,Lamb, Gareth W.,Maxwell, Aoife C.,Maytum, Hannah C.,et al.
-
supporting information; experimental part
p. 1766 - 1774
(2009/07/25)
-
- A new one-pot, four-component synthesis of 1,2-amino alcohols: TiCl 3/t-BuOOH-mediated radical hydroxymethylation of imines
-
(Chemical Equation Presented) An amine, an aldehyde, and methanol can be readily assembled in one pot under very mild conditions through a free-radical multicomponent reaction by using an aqueous acidic TiCl3/t-BuOOH system to afford 1,2-amino alcohols in fair to excellent yields.
- Clerici, Angelo,Ghilardi, Alessandra,Pastori, Nadia,Punta, Carlo,Porta, Ombretta
-
supporting information; experimental part
p. 5063 - 5066
(2009/05/31)
-
- Synthesis of β-amino alcohols from aromatic amines and alkylene carbonates using Na-Y zeolite catalyst
-
A simple, efficient, and environmentally benign methodology for the synthesis of β-amino alcohols from aromatic amines and alkylene carbonates in the presence of the highly active and reusable solid base catalyst Na-Y zeolite is demonstrated. Georg Thieme Verlag Stuttgart.
- Shivarkar, Anandkumar B.,Gupte, Sunil P.,Chaudhari, Raghunath V.
-
p. 1374 - 1378
(2007/10/03)
-
- Reversal of aryl bromide reactivity in Pd-catalysed aryl amination reactions promoted by a hemilabile aminophosphine ligand
-
Incorporation of a hemilabile amino group with a bulky, electron-rich phosphorus ligand led to a reversal in the order of aryl bromide reactivity in Pd-catalysed aryl amination reactions.
- Parisel, Sebastien L.,Adrio, Luis Angel,Pereira, Adriana Amoedo,Pérez, Marta Marino,Vila, José M.,Hii, King Kuok
-
p. 9822 - 9826
(2007/10/03)
-
- Thermotropic side-chain liquid crystalline copolymers containing both mono- And bisazobenzene mesogens: Synthesis and properties
-
The synthesis of a novel series of copolymers containing push-pull bisazobenzene (BAz) and monoazobenzene (MAz) groups with various N-alkyl donor groups and with spacers of two and four methylene units is presented, and the effects of the structural variables on the mesomorphic properties of the polymers are investigated. The copolymer with very short spacer (n = 2) and bulky N-ethyl group exhibits liquid crystalline (LC) properties when the BAz content is at least 30 mol %. Replacing the N-ethyl group with N-methyl increases the tendency toward smectic mesomorphism and expands the mesophases stability. If the flexible spacer is extended to four methylene units, the glass transition temperature (Tg) decreases strongly, whereas the isotropization temperature (Ti) is only slightly affected. X-ray diffraction investigations reveal an orthogonal partial bilayer smectic phase in which the mesogens are interdigitated. Annealing the BAz polymer films above Tg brings about the out-of-plane (homeotropic) orientation of chromophores and the formation of H-aggregates.
- Cojocariu, Cristina,Rochon, Paul
-
p. 9526 - 9538
(2008/02/01)
-
- A controlled supramolecular approach toward cation-specific chemosensors: Alkaline earth metal ion-driven exciton signaling in squaraine tethered podands
-
Three different squaraine tethered bichromophoric podands 3a-c with one, two, and three oxygen atoms in the podand chain and an analogous monochromophore 4a were synthesized and characterized. Among these, the bichromophores 3a-c showed high selectivity toward alkaline earth metal cations, particularly to Mg2+ and Ca2+ ions, whereas they were optically silent toward alkali metal ions. From the absorption and emission changes as well as from the Job plots, it is established that Mg2+ ions form 1:1 folded complexes with 3a and 3b whereas Ca2+ ions prefer to form 1:2 sandwich dimers. However, 3c invariably forms weak 1:1 complexes with Mg2+, Ca2+, and Sr2+ ions. The signal output in all of these cases was achieved by the formation of a sharp blue-shifted absorption and strong quenching of the emission of 3a-c. The signal transduction is achieved by the exciton interaction of the face-to-face stacked squaraine chromophores of the cation complex, which is a novel approach of specific cation sensing. The observed cation-induced changes in the optical properties are analogous to those of the "H" aggregates of squaraine dyes. Interestingly, a monochromophore 4a despite its binding, as evident from 1H NMR studies, remained optically silent toward Mg2+ and Ca2+ ions. While the behavior of 4a toward Mg2+ ion is understood, its optical silence toward Ca2+ ion is rationalized to the preferential formation of a "Head-Tail-Tail-Head" arrangement in which exciton coupling is not possible. The present study is different from other known reports on chemosensors in the sense that cation-specific supramolecular host-guest complexation has been exploited for controlling chromophore interaction via cation-steered exciton coupling as the mode of signaling.
- Arunkumar, Easwaran,Chithra, Parayali,Ajayaghosh, Ayyappanpillai
-
p. 6590 - 6598
(2007/10/03)
-
- ANILINO LIVER X-RECEPTOR MODULATORS
-
The present invention is directed to selective LXR modulators, small molecule compounds corresponding to Formula I and is further directed to a process of treating a condition in a mammal that is modulated by LXR using a therapeutically effective dose of a compound of Formula I.
- -
-
-
- Synthesis and characterization of a series of azobenzene-containing side-chain liquid crystalline polymers
-
A series of poly{4′-{(X-methacryloyloxyalkylene)methylamino}-4-nitroazobenzene} (pXMAN, where X is the number of methylene units and varies from 2 to 12) polymers with liquid crystalline (LC) properties was synthesized. When annealed above their Tg values, the whole series of polymers exhibits a stable smectic A mesophase while only the material with the shorter spacer, p2MAN, presents a smectic phase followed by a nematic phase. The spacing of the smectic layers was determined by X-ray diffraction, revealing intermolecular reorganization by interdigitation of the side-chain mesogens since the smectic layer spacing was larger than a fully extended side chain but less than two extended chains. This behavior is confirmed by temperature dependent aggregation as observed by UV-visible spectroscopy during the transition from an amorphous state to a liquid crystalline phase. The stability of the mesophase is enhanced by intermolecular interactions as argued by enthalpic and thermochromic considerations. Systematic photoinduced birefringence measurements on the various states reveal that the maximum and remnant levels of birefringence decrease with increasing the spacer length and with decreasing the glass transition temperature of the considered liquid crystalline polymer.
- Freiberg, Stephan,Lagugne-Labarthet, Francois,Rochon, Paul,Natansohn, Almeria
-
p. 2680 - 2688
(2007/10/03)
-
- New photosensitive methacrylate monomers with 4-aminoazobenzene type chromophore group
-
Photosensitive methacrylate monomers, derivatives of azobenzene, were synthesized. The route of syntheses was based on coupling of diazonium salts of sulfathiazole, sulfomethoxazole, sulfadiazine, 4-aminobenzoic acid and 4-nitroaniline with N-alkyl-N-[2-(methacryloyloxy)ethyl]aniline. The trans?cis isomerization of the monomers in DMSO solution was investigated by UV-VIS spectroscopy recording their spectra during illumination and thermal recovery periods. It was found that except for nitro derivatives the yield of trans-cis isomerization was ca. 50% and that the reverse reaction was a result of thermal relaxation. The spectroscopic studies were accompanied by quantum chemical calculations.
- Janik,Kucharski,Kubainska,Lyko
-
p. 241 - 252
(2007/10/03)
-
- A facile preparation of ethanolamines by direct irradiation of some carbonyl compounds in N,N-dimethylaniline
-
Direct irradiation of some carbonyl compounds in N,N-dimethylaniline, without solvent, with 300 nm UV light afforded ethanolamines as the major product in moderate yields.
- Kim, Sung Sik,Mah, Yoon Jung,Kim, Ae Rhan
-
p. 8315 - 8317
(2007/10/03)
-
- New rhodium complexes with P,N-ligands possessing a hydroxy or methoxy group. Synthesis, characterization and application to hydroformylation of styrene
-
Two new cationic rhodium(I) complexes containing a phosphino amino alcohol ligand and a methoxy amino phosphine, respectively, have been prepared. According to IR and NMR data the ligands are P,N-bonded and coordination of the hydroxy or the methoxy group to the metal does not take place. The complexes were applied to the hydroformylation of styrene and displayed a quantitative chemoselectivity for aldehydes with a very good branched:linear ratio. The reaction rate is higher using the complex possessing the methoxy group as opposed to the hydroxy group.
- Kostas, Ioannis D.,Screttas, Constantinos G.
-
-
- Dynamics of anilinium radical α-heterolytic fragmentation processes. Electrofugal group, substituent, and medium effects on desilylation, decarboxylation, and retro-aldol cleavage pathways
-
A single electron transfer (SET) photosensitization technique in conjunction with time-resolved, laser spectroscopy has been employed to generate and kinetically analyze decay processes of anilinium radicals derived by one-electron oxidation of α-anilinocarboxylates, β- anilinoalcohols, and α-anilinosilanes. In this manner, the rates of unimolecular decarboxylation of aniliniumcarboxylate radicals were determined to be in the range 106 - 107 s-1 and dependent upon solvent polarity, the nature of the metal cation, and substituents on the aniline ring, nitrogen, and α-carbon. In addition, kinetic analysis of base-induced retro-aldol fragmentations of cation radicals arising by SET oxidation of β- anilinoalcohols has shown that they occur with bimolecular rate constants which vary from 104 to 105 M-1 s1. These values are close to those for α-deprotonation reactions of related N,N-dialkylanilinium radicals. The retro-aldol fragmentation rates, like those for α-decarboxylation, also vary in a patterned way with changes in arene ring, nitrogen, and α- and β- carbon substituents. An investigation of the dynamics of methanol-promoted reactions of α-(trimethylsilyl)methyl-substituted anilinium radicals, has demonstrated that a change in the nitrogen substituent from alkyl to acyl causes an ca. 10-fold increase in the desilylation rate. Parallel photochemical studies have been conducted to gain chemical evidence to support assignment of the anilinium radical decay pathways in the LFP experiments and to demonstrate the preparative consequences of the kinetic results. First, clean formation of products derived by coupling of the (N- methylanilino)methyl radical in photochemical reactions of 1,4- dicyanobenzene with either tetra-n-butylammonium N-methyl-N-phenylglycinate or β-(N-methyl-N-phenyl)aminoethanol shows that the respective decarboxylation and retro-aldol cleavage processes occur with exceptionally high efficiencies. Second, in accord with the high rates observed for aminium radical decarboxylation and base-induced retro-aldol fragmentation, tethered cyclohexenone - α-aminocarboxylates and - β-aminoethanols undergo high- yielding SET-promoted photocyclization reactions under both direct and SET- sensitized conditions. Last, results which depict how the rates of aminium radical α-fragmentation correlate with quantum efficiencies of SET-promoted reactions of tertiary amines and amides have come from a study of photocyclization reactions of N-(aminoethyl)- and (amidoethyl)phthalimides. The quantum yields for these SET-promoted processes are observed to vary with the electrofugal group and nitrogen substituent in the manner predicted on the basis of the LFP-determined fragmentation rates.
- Su, Zhuoyi,Mariano, Patrick S.,Falvey, Daniel E.,Yoon, Ung Chan,Oh, Sun Wha
-
p. 10676 - 10686
(2007/10/03)
-
- SYNTHESIS OF BAPTA-AM ANALOGUES CAPABLE OF ENHANCING THE VASCULAR PRODUCTION OF PROSTACYCLIN
-
About 30 analogues of BAPTA-AM, a potential antithrombotic agent, have been synthesized and tested for their effect on the production of prostacyclin.None of them was found to be a better enhancher of the production of prostacyclin by aortic endothelial cells than BAPTA-AM itself.The enhancing effect can be produced by compounds unable to chelate Ca2+, thus confirming that it is not related to their buffering capacity for free Ca2+.
- Heilporn, S.,Broeders, F.,Daloze, D.,Braekman, J. C.,Boeynaems, J. M.
-
p. 309 - 320
(2007/10/02)
-
- Direct Substitution of Aromatic Ethers by Lithium Amides. A New Aromatic Amination Reaction
-
Reaction of lithiated dialkylamines with methoxy aromatics in refluxing THF leads to products resulting from a direct ipso-substitution.Especially with lithiated secondary amines high conversions and selectivities are achieved.Sulfonyl-substituted aromatics react equally well, but halogenated aromatics give rise to side-products arising from a competing pathway via aryne intermediates.The scope and mechanistic implications of this novel nucleophilic amination reaction are described.
- Hoeve, Wolter ten,Kruse, Chris, G.,Luteyn, Jan M.,Thiecke, Janet R. G.,Wynberg, Hans
-
p. 5101 - 5106
(2007/10/02)
-
- Ruthenium Complex Catalyzed N-Heterocyclization. Indoles from Aminoarenes and Glycols.
-
N-Methylaniline reacted with ethylene glycol in the presence of a homogenous ruthenium catalyst (1 molpercent based on ethylene glycol) to give 1-methylindole in 51percent yield.Similarly, aniline reacted with 2,3-butanediol affording 2,3-dimethylindole in 58percent yield.The yields of indoles were affected by the molar ratio of aminoarene to glycol.
- Tsuji, Yasushi,Huh, Keun-Tae,Watanabe, Yoshihisa
-
p. 377 - 380
(2007/10/02)
-
- REACTION PATHS OF 1,3-OXAZOLINIUM SALTS WITH STABILIZED CARBANIONS
-
Reaction of stabilized carbanions with 3-methyl-2-phenyl-1,3-oxazolinium triflate occurs both C5 and C2 sites with a regioselectivity depending partially on steric effects.The reaction at C2 site can result in the formation of 1,4-oxazepin derivatives.
- Dreme, Martine,Perchec, Pierre Le,Garapon, Jacques,Sillion, Bernard
-
-
- PREPARATION DE SELS D'AMINOALKYLPHOSPHONIUMS
-
Three synthetic methods have been applied to prepare amino phosphonium salts: (C6H5)3P+-(CH2)n-N-.The best ways have been determined for different n values and different substituents on the nitrogen atom.In all cases, yields are better with n=3, but no intramolecular stabilization has been detected.
- Dantas, T. N. de Castro,Laval, J. P.,Lattes, A.
-
-
- Aminopiperidines, their production and the pharmaceutical compositions incorporating them
-
This invention relates to 4-aminopiperidines and more precisely to 4-aminopiperidines the nitrogen atom of the piperidine ring is substituted with an aryl lower alkyl side-chain. This invention also relates to processes for producing the same. This invention further extends to pharmaceutical compositions and to the method of using the same.
- -
-
-