136618-42-3Relevant articles and documents
ZWITTERIONIC CATALYSTS FOR (TRANS)ESTERIFICATION: APPLICATION IN FLUOROINDOLE-DERIVATIVES AND BIODIESEL SYNTHESIS
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Paragraph 0015; 0028, (2021/01/29)
An amide/iminium zwitterion catalyst has a catalyst pocket size that promotes transesterification and dehydrative esterification. The amide/iminium zwitterions are easily prepared by reacting aziridines with aminopyridines. The reaction can be applied a wide variety of esterification processes including the large-scale synthesis of biodiesel. The amide/iminium zwitterions allow the avoidance of strongly basic or acidic condition and avoidance of metal contamination in the products. Reactions are carried out at ambient or only modestly elevated temperatures. The amide/iminium zwitterion catalyst is easily recycled and reactions proceed in high to quantitative yields.
A metal-free iodine-mediated conversion of hydroxamates to esters
Ghosh, Subhankar,Banerjee, Jeet,Ghosh, Rajat,Chattopadhyay, Shital K.
, p. 1353 - 1360 (2020/03/30)
A metal-, oxidant-, and additive-free conversion of hydroxamates to esters have been achieved using molecular iodine as the reagent using a novel but not-so-explored heron-type rearrangement. The reaction proceeds with almost equal facility with substrates having either electron-donating or electron-withdrawing substituent. Similarly, α,?-unsaturated, and sterically hindered ortho-substituted hydroxamates also undergo the desired transformation smoothly.
Amide/Iminium Zwitterionic Catalysts for (Trans)esterification: Application in Biodiesel Synthesis
Lam, Ying-Pong,Ng, Wing-Hin,Tan, Fei,Tse, Ying-Lung Steve,Wang, Xinyan,Yeung, Ying-Yeung
, p. 8083 - 8092 (2019/08/26)
A class of zwitterionic organocatalysts based on an amide anion/iminium cation charge pair has been developed. The zwitterions are easily prepared by reacting aziridines with aminopyridines. They are catalytically applicable to transesterifications and dehydrative esterifications. Mechanistic studies reveal that the amide anion and iminium cation work synergistically in activating the reaction partners, with the iminium cationic moiety interacting with the carbonyl substrates through nonclassical hydrogen bonding. The reaction can be applied to large-scale synthesis of biodiesel under mild conditions.
O-Benzylation of Carboxylic Acids Using 2,4,6-Tris(benzyloxy)-1,3,5-triazine (TriBOT) under Acidic or Thermal Conditions
Yamada, Kohei,Yoshida, Saki,Fujita, Hikaru,Kitamura, Masanori,Kunishima, Munetaka
, p. 7997 - 8002 (2015/12/24)
Two methods for the synthesis of benzyl esters from carboxylic acids using the O-benzylating reagent 2,4,6-tris(benzyloxy)-1,3,5-triazine (TriBOT) have been developed. The reactions were conducted either in the presence of a catalytic amount of TfOH at room temperature (acidic conditions) or in the absence of TfOH at 180-230 C (thermal conditions). Interestingly, the O-benzylation of hydroxy carboxylic acids under the two conditions afforded different products: The dibenzylated product under acidic conditions and the hydroxy ester under thermal conditions. In addition to these results, other evidence indicated that the former reaction proceeds through an SN1-type mechanism, and the latter by an SN2-type mechanism. Two methods for the O-benzylation of carboxylic acids using TriBOT have been developed under either acidic or thermal conditions. The O-benzylation of hydroxy carboxylic acids afforded the dibenzylated product under acidic conditions and the hydroxy ester under thermal conditions. The former reaction proceeds through an SN1-type mechanism and the latter by an SN2-type mechanism.
Organocatalyzed anodic oxidation of aldehydes
Finney, Eric E.,Ogawa, Kelli A.,Boydston, Andrew J.
supporting information; experimental part, p. 12374 - 12377 (2012/09/05)
A method for the catalytic formation of electroauxiliaries and subsequent anodic oxidation has been developed. The process interfaces N-heterocyclic carbene-based organocatalysis with electro-organic synthesis to achieve direct oxidation of catalytically generated electroactive intermediates. We demonstrate the applicability of this method as a one-pot conversion of aldehydes to esters for a broad range of aldehyde and alcohol substrates. Furthermore, the anodic oxidation reactions are very clean, producing only H2 gas as a result of cathodic reduction.
N- (2 { [1-PHENYL-1H-INDAZ0L-4-YL] AMINO} PROPYL) -SULFONAMIDE DERIVATIVES AS NON-STEROIDAL GLUCOCORTICOID RECEPTOR LIGANDS FOR THE TREATMENT OF INFLAMMATIONS
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Page/Page column 59-60, (2009/07/17)
The present invention provides compounds of formula (I): a process for their preparation, to pharmaceutical compositions comprising the compounds and the preparation of said compositions, to intermediates, and to use of the compounds for the manufacture o
INDAZOLES AS GLUCOCORTICOID RECEPTOR LIGANDS
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Page/Page column 42, (2009/05/28)
The present invention provides compounds of formula (I): a process for their preparation, to pharmaceutical compositions comprising the compounds and the preparation of said compositions, to intermediates, and to use of the compounds for the manufacture o
Design of branched and chiral solvatochromic probes: Toward quantifying polarity gradients in dendritic macromolecules
Milosevic, Petar,Hecht, Stefan
, p. 5023 - 5026 (2007/10/03)
(Chemical Equation Presented) A pair of chiral, branched monomer building blocks, consisting of a solvatochromic probe and a spectroscopically inactive volume dummy, has been developed. The probe can selectively be excited, and its fluorescence characteristics provide information about local polarity. Incorporation of these monomers into high-generation polyester dendrimers should enable a detailed investigation of the polarity/density profile in dendritic architectures and ultimately allow for the realization of energy gradients from one chromophore building block only.
Solid-phase synthesis of potential protein tyrosine phosphatase inhibitors via the Ugi four-component condensation
Li, Zhengong,Yeo, Su Ling,Pallen, Catherine J.,Ganesan
, p. 2443 - 2446 (2007/10/03)
A library of 108 α,α-difluoromethylenephosphonic acids was prepared by Ugi four-component condensation using Rink-NH2 resin, 4- [(diethoxyphosphinyl)difluoromethyl]benzoic acid, and a set of 18 aldehydes and 6 isonitriles. Following resin cleavage, the diethylphosphonate esters were hydrolyzed with trimethylsilyl bromide to yield the free acids which were assayed for inhibition of PTPα, PTPβ and PTPε.
Synthesis of 10-(hydroxymethyl)-5,10-dideaza-5,6,7,8-tetrahydrofolic acid, a potent new analogue of DDATHF (Lometrexol)
Taylor,Yoon
, p. 7096 - 7098 (2007/10/02)
A synthesis of 10-(hydroxymethyl)-5,10-dideaza-5,6,7,8-tetrahydrofolic acid [as a mixture of four diastereomers] is described. Substantial cytotoxicity was observed for this new analogue of DDATHF (Lometrexol).