- Innovative Multipodal Ligands Derived from Tr?ger's Bases for the Sensitization of Lanthanide(III) Luminescence
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Herein, the synthesis and characterization of the first family of multipodal ligands with a Tr?ger's base framework designed for the preparation of luminescent lanthanide(III) complexes are reported. Eight ligands were designed and synthesized using diffe
- Barja, Beatriz C.,Bruttomesso, Andrea C.,Eliseeva, Svetlana V.,Petoud, Stéphane,Ramírez, Javier A.,Trupp, Leandro,Vardé, Mariana
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supporting information
p. 16900 - 16909
(2020/11/30)
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- Nickel-Catalyzed Esterification of Amides Under Mild Conditions
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Abstract: The use of ligands to adjust the catalytic activity of the catalyst for esterification of amides is challenge in organic chemistry. In this paper, Nickel(II)-NHC-catalyzed the esterification reaction between N,N-di-Boc amide and alcohols at room temperature have been demonstrated. The imidazolium salt bearing a hydroxyl functionalized side arm showed high effective catalytic activity in the activation of the amide N–C bond in air atmosphere. Graphic Abstract: [Figure not available: see fulltext.].
- Li, Jun-Fei,Wang, Yao-Fang,Wu, Yuan-Yuan,Liu, Wen-Jing,Wang, Jun-Wen
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p. 874 - 880
(2019/11/13)
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- Super electron donor-mediated reductive transformation of nitrobenzenes: A novel strategy to synthesize azobenzenes and phenazines
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The transformation of nitrobenzenes into azobenzenes by pyridine-derived super electron donor 2 is described. This method provides an efficient synthesis of azobenzenes because of not requiring the use of expensive transition-metals, toxic or flammable reagents, or harsh conditions. Moreover, when using 2-fluoronitrobenzenes as substrates, phenazines were found to be obtained. The process affords a novel synthesis of phenazines.
- Nozawa-Kumada, Kanako,Abe, Erina,Ito, Shungo,Shigeno, Masanori,Kondo, Yoshinori
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supporting information
p. 3095 - 3098
(2018/05/22)
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- Mild alkaline hydrolysis of hindered esters in non-aqueous solution
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Sterically hindered esters of carboxylic acids, which are considered very resistant to saponification, were rapidly and efficiently saponified in a non-aqueous medium using NaOH in MeOH/CH2Cl2 (1:9) at room temperature. Furthermore, this reaction protocol was extended and successfully applied to the hydrolysis of tosylates and N-tosyl indoles.
- Theodorou, Vassiliki,Alagiannis, Michalis,Ntemou, Nikoleta,Brentas, Alexios,Voulgari, Pinelopi,Polychronidou, Vasiliki,Gogou, Marina,Giannelos, Marios,Skobridis, Konstantinos
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p. 308 - 319
(2018/11/26)
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- A fast and practical synthesis of tert-butyl esters from 2-tert-butoxypyridine using boron trifluoride·diethyl etherate under mild conditions
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A practical direct preparation of tert-butyl esters from 2-tert-butoxypyridine has been developed. This system features the use of boron trifluoride·diethyl etherate in toluene solvent to rapidly achieve the reaction at room temperature. Using this reaction protocol, a variety of tert-butyl esters were synthesized from several different carboxylic acids at high yields. This practical procedure provides a promising and effective approach to the protection of carboxylic acids with a tert-butyl group.
- La, Minh Thanh,Kim, Hee-Kwon
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p. 3748 - 3754
(2018/05/28)
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- Metal-free radical aromatic carbonylations mediated by weak bases
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We report a new method of metal-free alkoxycarbonylation. This reaction involves the generation of aryl radicals from arenediazonium salts by a very weak base (HCO2Na) under mild conditions. Subsequent radical trapping with carbon monoxide and alcohols gives alkyl benzoates. The conditions (metal-free, 1 equiv. base, MeCN, r.t., 3 h) tolerate various functional groups (I, Br, Cl, CF3, SF5, NO2, ester). Mechanistic studies indicate the operation of a radical aromatic substitution mechanism.
- Koziakov, Denis,Jacobi Von Wangelin, Axel
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p. 6715 - 6719
(2017/08/22)
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- Metal-free carbonylations by photoredox catalysis
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The synthesis of benzoates from aryl electrophiles and carbon monoxide is a prime example of a transition-metalcatalyzed carbonylation reaction which is widely applied in research and industrial processes. Such reactions proceed in the presence of Pd or Ni catalysts, suitable ligands, and stoichiometric bases. We have developed an alternative procedure that is free of any metal, ligand, and base. The method involves a redox reaction driven by visible light and catalyzed by eosin Y which affords alkyl benzoates from arene diazonium salts, carbon monoxide, and alcohols under mild conditions. Tertiary esters can also be prepared in high yields. DFT calculations and radical trapping experiments support a catalytic photoredox pathway without the requirement for sacrificial redox partners.
- Majek, Michal,Von Wangelin, Axel Jacobi
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supporting information
p. 2270 - 2274
(2015/02/19)
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- Ultrasound assisted direct oxidative esterification of aldehydes and alcohols using graphite oxide and Oxone
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A sonochemical procedure for direct oxidative esterification of aldehydes and alcohols using graphite oxide and Oxone in an alcoholic solvent is described. Mild reaction conditions, short reaction times, cost-effectiveness, and facile isolation of the products make the present system as a practical method.
- Mirza-Aghayan, Maryam,Zonoubi, Somayeh,Molaee Tavana, Mahdieh,Boukherroub, Rabah
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p. 359 - 364
(2014/10/16)
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- Base-free oxidation of alcohols to esters at room temperature and atmospheric conditions using nanoscale Co-based catalysts
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The direct oxidation of alcohols to esters with molecular oxygen is an attractive and crucial process for the synthesis of fine chemicals. To date, the heterogeneous catalyst systems that have been identified are based on noble metals or have required the addition of base additives. Here, we show that Co nanoparticles embedded in nitrogen-doped graphite catalyze the aerobic oxidation of alcohols to esters at room temperature under base-free and atmospheric conditions. Our Co@C-N catalytic system features a broad substrate scope for aromatic and aliphatic alcohols as well as diols, giving their corresponding esters in good to excellent yields. This apparently environmentally benign process provides a new strategy with which to achieve selective oxidation of alcohols.
- Zhong, Wei,Liu, Hongli,Bai, Cuihua,Liao, Shijun,Li, Yingwei
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p. 1850 - 1856
(2015/03/14)
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- Copper-catalyzed oxidative esterification of aldehydes with dialkyl peroxides: Efficient synthesis of esters of tertiary alcohols
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Copper-catalyzed oxidative esterification of aldehydes with dialkyl peroxides has been developed. This protocol affords a novel approach for the synthesis of carboxylic esters of tertiary alcohols under mild conditions. Depending on the catalyst system, a variety of tertiary esters were produced in good to excellent yields.
- Zhu, Yefeng,Wei, Yunyang
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p. 13668 - 13670
(2013/08/23)
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- MATRIX METALLOPROTEINASE INHIBITORS
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The present invention relates to methyl sulfonamides and N-formamides derivatives of formula (I) and to processes for their syntheses. The invention also relates to pharmacological compositions containing these derivatives and methods of treating asthma, rheumatoid arthritis, COPD, rhinitis, osteoarthritis, psoriatie arthritis, psoriasis, pulmonary fibrosis, pulmonary inflammation, acute respiratory distress syndrome, perodontitis, multiple sclerosis, gingivitis, atherosclerosis, dry eye, neointimal proliferation which leads to restenosis and ischemic heart failure, stroke, renal disease, tumor metastasis, and other inflammatory disorders characterized by over expression and over activation of an matrix metalloproteinase using the compounds.
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Page/Page column 48
(2012/04/10)
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- TARGETING PRODRUGS AND COMPOSITIONS FOR THE TREATMENT OF GASTROINTESTINAL DISEASES
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Provided herein are compounds, compositions and methods for preventing or treating gastrointestinal cancer in a mammal, wherein the method comprises delivering an effective amount of a COX-2 or a similar sulfonamide inhibitor as a prodrug or derivative thereof to the colon, wherein the COX-2 or similar inhibitor is released in- vivo.
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Page/Page column 30-31
(2010/07/09)
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- Rational design of substituted diarylureas: A scaffold for binding to G-quadruplex motifs
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The design and synthesis of a series of urea-based nonpolycyclic aromatic ligands with alkylaminoanilino side chains as telomeric and genomic G-quadruplex DNA interacting agents are described. Their interactions with quadruplexes have been examined by means of fluorescent resonance energy transfer melting, circular dichroism, and surface plasmon resonance-based assays. These validate the design concept for such urea-based ligands and also show that they have significant selectivity over duplex DNA, as well as for particular G-quadruplexes. The ligand-quadruplex complexes were investigated by computational molecular modeling, providing further information on structure-activity relationships. Preliminary biological studies using short-term cell growth inhibition assays show that some of the ligands have cancer cell selectivity, although they appear to have low potency for intracellular telomeric G-quadruplex structures, suggesting that their cellular targets may be other, possibly oncogene-related quadruplexes.
- Drewe, William C.,Nanjunda, Rupesh,Gunaratnam, Mekala,Beltran, Monica,Parkinson, Gary N.,Reszka, Anthony P.,Wilson, W. David,Neidle, Stephen
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supporting information; experimental part
p. 7751 - 7767
(2009/12/07)
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- UREYLENE DERIVATIVES
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The invention concerns compounds of Formula (I) or a salt, solvate or pro-drug thereof. The compounds may be used in therapy, particularly anti-cancer therapy.
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Page/Page column 50
(2008/12/04)
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- Novel C-C bond cleavage from arylacetonitriles in alcohols to aryl carboxylic esters using potassium iodide and catalytic amount of samarium
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A novel way to cleave the carbon-carbon bond from arylacetonitriles in alcohols to their corresponding aryl carboxylic esters using potassium iodide and a catalytic amount of samarium under mild and neutral conditions is described. Useful yields of the reaction can be obtained with electron-deficient subsistent groups in aromatic rings, and the yields are higher when the subsistent group is an electron-withdrawing group (EWG) rather than an electron-donating group (EDG). Products were characterized by IR, 1H NMR, 13C NMR, and MS. Copyright Taylor & Francis Group, LLC.
- Yu, Mingxin,Wen, Weijiang,Wang, Zhiyuan
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p. 2851 - 2857
(2007/10/03)
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- Scope and mechanistic insights into the use of tetradecyl(trihexyl) phosphonium bistriflimide: A remarkably selective ionic liquid solvent for substitution reactions
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A survey of substitution reactions conducted in a phosphonium bistriflimide ionic liquid is presented. The results demonstrate high selectivity favoring substitution over typically competitive elimination and solvolytic processes even when challenging secondary and tertiary electrophiles are employed. The first reports of Kornblum substitution reactions in an ionic liquid are described that proceed with very high chemoselectivity in favor of nitro over nitroso products and elimi nation side products. The structure-reactivity study indicates that these reactions proceed through a narrow spectrum of pathways ranging from straight SN2 to a preassociation pathway along a saddle point that approaches the SN1 limit. The barrier to the formation of dissociated carbocations is attributed to the structural features of this ionic liquid that favor intervention of the associated nucleophile over dissociation, also preventing cross over to E1 processes. The lack of any basic entity in the phosphonium bistriflimide ionic liquid appears to prevent any potential base-mediated elimination reactions, which makes this a highly selective medium for use in general substitution reactions.
- McNulty, James,Nair, Jerald J.,Cheekoori, Sreedhar,Larichev, Vladimir,Capretta, Alfredo,Robertson
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p. 9314 - 9322
(2007/10/03)
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- A mild esterification process in phosphonium salt ionic liquid
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A general, high yielding procedure is described for the esterification of carboxylic acids through carboxylate alkylation in phosphonium salt ionic liquid.
- McNulty, James,Cheekoori, Sreedhar,Nair, Jerald J.,Larichev, Vladimir,Capretta, Alfredo,Robertson, Al J.
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p. 3641 - 3644
(2007/10/03)
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- Synthesis, structure-activity relationship, and p210bcr-abl protein tyrosine kinase activity of novel AG 957 analogs
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A series of novel, sterically hindered lipophilic analogs of AG 957 was designed and synthesized as potential protein tyrosine kinase (PTK) inhibitors. The in vitro activity, in vivo anti-leukemia activity, and pharmacology of these PTK inhibitors were studied. Some aspects of the structure-activity relationship associated with the carboxylic acid, phenol ring, and linker modifications are discussed. We have demonstrated that the 1,4-hydroquinone moiety is essential for activity and that sterically hindered esters contribute to enhanced in vivo efficacy. Adaphostin (NSC 680410) has emerged as the improved compound with the maximum in vivo anti-leukemia hollow fiber activity, concordant with the original lead compound AG 957. Currently, adaphostin is undergoing preclinical toxicology studies.
- Kaur, Gurmeet,Narayanan, Ven L.,Risbood, Prabhakar A.,Hollingshead, Melinda G.,Stinson, Sherman F.,Varma, Ravi K.,Sausville, Edward A.
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p. 1749 - 1761
(2007/10/03)
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- New selenyl linker for solid-phase synthesis of dehydropeptides
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A novel linker possessing selenocyanate and masked carboxylic acid was developed for the solid-phase synthesis of dehydropeptides. This linker was used to demonstrate the synthesis of the model compound of RGD-conjugated dehydropeptide.
- Nakamura, Kazuhiko,Ohnishi, Yuki,Horikawa, Eiji,Konakahara, Takeo,Kodaka, Masato,Okuno, Hiroaki
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p. 5445 - 5448
(2007/10/03)
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- Disubstituted lavendustin a analogs and pharmaceutical compositions comprising the analogs
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Disubstituted lavendustin A analogs that are PTK inhibitors having antiproliferative activity are described. Preferred compounds of the present invention, without limitation, satisfy either Formula 1 or Formula 2. Currently preferred compounds ,based on in vivo biological activity, are 4'-adamantylbenzoate-1'-N-1,4-dihydroxybenzylamine and 4'-adamantylmethylbenzoate-1'-N-1,4-dihydroxybenzylamine. The present invention also provides pharmaceutical compositions comprising effective amounts of disubstituted lavendustin A analogs. Such compositions also may comprise other active ingredients, other materials conventionally used in the formulation of pharmaceutical composition, and mixtures thereof. The compounds and compositions of the present invention can be used for treating subjects to, for example, inhibit the proliferation of living cells in the treatment of proliferative diseases.
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- Selective oxidation of aromatic aldehydes to arenecarboxylic acids using ebselen-tert-butyl hydroperoxide catalytic system
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It has been found that aromatic aldehydes with electron-withdrawing as well as electron-donating substituents are oxidized to arenecarboxylic acids using tert-butyl hydroperoxide in the presence of ebselen (2-phenylbenzisoselenazol-3(2H)-one) as a catalyst. The reaction is highly chemoselective and formation of phenols, being the products of competitive Baeyer-Villiger rearrangement, is marginal. It has been assumed that this rearrangement is inhibited by steric hindrance of the electron-deficient oxygen atom in the transient tetrahedral intermediate.
- Wójtowicz, Halina,Brza?szcz, Monika,Kloc, Krystian,M?ochowski, Jacek
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p. 9743 - 9748
(2007/10/03)
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- A new reagent for the convenient synthesis of t-butyl esters from t-butanol
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An alumina-supported reagent has been prepared to synthesize the t-butyl esters from t-butanol. The method requires less time, mild conditions, and involves simplified work-up. Yield of the products is also high.
- Karmakar,Das
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p. 535 - 537
(2007/10/03)
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- Improved ester interchange catalysts
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(equation presented) Mixed alkoxide/aryloxide clusters are long-lived and milder than previously reported ester interchange catalysts. They completely transform difficult substrates in a single synthetic operation with lower catalyst and reagent ester loadings. In addition to superior activities, these mixed clusters are kinetically less basic toward enolizable esters.
- Kissling, Rebecca M.,Gagne, Michel R.
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p. 4209 - 4212
(2007/10/03)
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- Template-constrained cyclic peptide analogues of somatostatin: Subtype-selective binding to somatostatin receptors and antiangiogenic activity
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β-Turns are a common secondary structure motif found in proteins that play a role in protein folding and stability and participate in molecular recognition interactions. Somatostatin, a peptide hormone possessing a variety of therapeutically-interesting b
- Suich, Daniel J.,Mousa, Shaker A.,Singh, Gurke,Liapakis, George,Reisine, Terry,Degrado, William F.
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p. 2229 - 2241
(2007/10/03)
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- α,α-difluorophosphonomethyl azobenzene derivatives as photoregulated phosphoamino acid analogs. 1. Design and synthesis
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A series of novel, photoregulated phosphoamino acid analogs based on an azobenzene core bearing an α,α-difluoromethylphosphonate as a hydrolytically stable phosphate isostere have been prepared with N-Fmoc protection for use in peptide synthesis. Classes of reagents analogous to both phosphotyrosine and phosphoserine/threonine were prepared by a common route employing a nitrosoarene/aniline condensation to form the azo linkage and the Cu(I)-promoted coupling of an iodoarene with (diethylphosphono)difluoromethyl cadmium bromide (Burton's method) to introduce the phosphonate moiety.
- Park, Seung Bum,Standaert, Robert F.
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p. 6557 - 6560
(2007/10/03)
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- Liquid-Phase Hydrogenation of p-Nitrobenzoic Acid Esters on Palladium Catalysts
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Hydrogenation of some p-nitrobenzoic esters on palladium catalysts (conventional heterogeneous Pd/C and Pd/Al2O3 and polymeric AV-17-8-Pd and AN-1-Pd) is studied. The maximum rate of the hydrogenation reaction was observed in methanol at t = 55°C and PH2 = 0.1 MPa. MNDO calculations of some electronic characteristics of p-nitrobenzoic ester molecules were performed. A two-parameter correlation between the hydrogenation rate constant, the charge of the nitro group, and the steric substituent constant was found for the reaction conducted on the AV-17-8-Pd and AN-1-Pd catalysts.
- Morogina,Nasibulin,Klyuev
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p. 251 - 255
(2007/10/03)
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- Convenient preparations of t-butyl esters and ethers from t-butanol
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A one-pot preparation of t-butyl esters and ethers is described that proceeds from the carboxylic acid or alcohol and t-butanol using only anhydrous magnesium sulfate and catalytic sulfuric acid as additional reagents. The method affords t-butyl esters and ethers in good yields and is applicable to a variety of substrates.
- Wright, Stephen W.,Hageman, David L.,Wright, Ann S.,McClure, Lester D.
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p. 7345 - 7348
(2007/10/03)
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- Quinazoline antifolate thymidylate synthase inhibitors: Replacement of glutamic acid in the C2-methyl series
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The synthesis of a series of analogues of the potent thymidylate synthase (TS) inhibitor N-[4[N-[(3,4-dihydro-2-methyl-4-oxo-6-quinazolinyl)methyl]-N- prop-2-ynylamino]benzoyl]-L-glutamic acid (ICI 198583, 1) is described in which the glutamic acid residu
- Marsham,Jackman,Barker,Boyle,Pegg,Wardleworth,Kimbell,O'Connor,Calvert,Hughes
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p. 994 - 1004
(2007/10/02)
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- A Simple, Powerful, and Efficient Method for Transesterification
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Aromatic and α,β-unsaturated methyl esters undergo efficient transesterification at ambient temperature or below with primary, secondary, or (particularly) tertiary alcohols in the presence of butyl-lithium in tetrahydrofuran solution.
- Meth-Cohn, Otto
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p. 695 - 697
(2007/10/02)
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- Observation of a Stable Hemiortho Ester Anion. Acidity Constant for a Tetrahedral Intermediate
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Pinacol mono-p-nitrobenzoate (POH) undergoes a rapid, reversible cyclization in base producing an anionic tetrahedral intermediate (TO-), the conjugate base of 2-(p-nitrophenyl)-2-hydroxy-4,4,5,4-tetramethyl-1,3-dioxolane (TOH).Presence of the anion is established by changes in UV spectra and by the rate behavior exhibited in the hydrolysis of the ester to pinacol and p-nitrobenzoate.Rate constants in base do not rise as rapidly as expected as the ester form is converted to the unreactive TO-.Interconversion of POH and TO- occurs in a typical acid:base manner, and UV spectral analysis in base provides Kb= ->/->=0.7.The equilibrium constant K0=/ for cyclization of the pinacol ester to the neutral hemiortho ester TOH is 8*10-4, this has been measured as the ratio of forward and reverse rate constants.Combination of Kb and K0 provides a value Ka=->+>/ for the acidity constant of the tetrahedral intermediate of 10-10.4.This number is compared with estimates of tetrahedral intermediate acidity based on substituent effects and free energy correlations, and excellent agreement is noted.
- McClelland, Robert A.,Seaman, N. Esther,Cramm, David
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p. 4511 - 4515
(2007/10/02)
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- Esterification of Aromatic Carboxylic Acids with Alcohols Using 2-Chloro-3,5-dinitropyridine as a Condensing Agent
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The reaction of 2-chloro-3,5-dinitropyridine (CDNP) with carboxylic acids and alcohols was examined, and it was found that CDNP was a useful condensing agent.Various esters were prepared in good yields.
- Takimoto, Seiji,Abe, Naomi,Kodera, Yasushi,Ohta, Hiroshi
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p. 639 - 640
(2007/10/02)
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- Esterification of Carboxylic Acids with Alcohols Using Benzenesulphonyl and Methanesulphonyl Chlorides
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The role of benzene- and methane-sulphonyl chlorides as coupling agents in the esterification of carboxylic acids with alcohols has been investigated.Hindered tertiary alcohols require initial conversion of the acid to the mixed acid-anhydride with benzenesulphonyl chloride.It is necessary to adjust molar ratios for esterification with secondary alcohols so that the intermediate formed is the symmetrical acid anhydride, since mixed acid-anhydrides also give the sulphonates of the alcohols wihich are difficult to separate from the esters.
- Dharmaratne, H. R. W.,Gunatilaka, A. A. Leslie,Sotheeswaran, S.
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- Esterification of Carboxylic Acids by Alcohols with 2-Chloro-1,3,5-trinitrobenzene as Condensing Agent
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When mixtures of carboxylic acids or their sodium salts and alcohols were treatment with 2-chloro-1,3,5-trinitrobenzene in the presence of pyridine under mild conditions, the corresponding carboxylic esters were formed.The yields and the rates of the ester formation depended on the types of the acids and the alcohols used.
- Takimoto, Seiji,Inanaga, Junji,Katsuki, Tsutomu,Yamaguchi, Masaru
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p. 1470 - 1473
(2007/10/02)
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