134895-45-7Relevant academic research and scientific papers
Synthesis of Pinpoint-Fluorinated Polycyclic Aromatic Hydrocarbons: Benzene Ring Extension Cycle Involving Microwave-Assisted SNAr Reaction
Fuchibe, Kohei,Imaoka, Hisanori,Ichikawa, Junji
, p. 2359 - 2363 (2017)
Fluoroarenes bearing no electron-withdrawing groups (non-activated fluoroarenes) readily underwent nucleophilic aromatic substitution with α-cyanocarbanions under microwave irradiation. The sequence (i) formylalkylation involving the cyanoalkylation of fl
Enantioselectivity and diastereoselectivity in the hydrolysis of acylals and structurally related esters of secondary alcohols with Candida rugosa lipase
Angelis, Yiannis S.,Smonou, Ioulia
, p. 2823 - 2826 (1998)
Comparative studies of enantioselectivities and diastereoselectivities in the hydrolysis reactions of acylals and 50:50 threo-erythro mixtures of the eaters of related secondary alcohols with Candida rugosa lipase gave significant information about the reactivity order in the enzymatic hydrolysis of acylals.
Highly Enantioselective Catalytic Kinetic Resolution of α-Branched Aldehydes through Formal Cycloaddition with Homophthalic Anhydrides
Farid, Umar,Aiello, Maria Luisa,Connon, Stephen J.
supporting information, p. 10074 - 10079 (2019/07/18)
A new catalytic methodology was developed to promote an efficient one-pot kinetic resolution of racemic aldehydes with selectivity (s*) of up to 91 (99:1 d.r., >99 % ee) in a cycloaddition reaction with enolizable anhydrides to afford dihydroisocoumarin products (a core prevalent in natural products and molecules of medicinal interest) containing three contiguous stereocentres.
Rhodium-catalyzed asymmetric hydrogenation of β-branched enamides for the synthesis of β-stereogenic amines
Zhang, Jian,Liu, Chong,Wang, Xingguang,Chen, Jianzhong,Zhang, Zhenfeng,Zhang, Wanbin
supporting information, p. 6024 - 6027 (2018/06/18)
Using a rhodium complex of a bisphosphine ligand (R)-SDP, β-branched simple enamides with a (Z)-configuration were hydrogenated to β-stereogenic amines in quantitative yields and with excellent enantioselectivities (88-96% ee).
A simple primary amine catalyst for enantioselective α-hydroxylations and α-fluorinations of branched aldehydes
Witten, Michael R.,Jacobsen, Eric N.
supporting information, p. 2772 - 2775 (2015/06/16)
A new primary amine catalyst for the asymmetric α-hydroxylation and α-fluorination of α-branched aldehydes is described. The products of the title transformations are generated in excellent yields with high enantioselectivities. Both processes can be performed within short reaction times and on gram scale. The similarity in results obtained in both reactions, combined with computational evidence, implies a common basis for stereoinduction and the possibility of a general catalytic mechanism for α-functionalizations. Promising initial results in α-amination and α-chlorination reactions support this hypothesis.
Flow Chemistry Syntheses of Styrenes, Unsymmetrical Stilbenes and Branched Aldehydes
Bourne, Samuel L.,O'Brien, Matthew,Kasinathan, Sivarajan,Koos, Peter,Tolstoy, Paeivi,Hu, Dennis X.,Bates, Roderick W.,Martin, Benjamin,Schenkel, Berthold,Ley, Steven V.
, p. 159 - 172 (2013/03/13)
Two tandem flow chemistry processes have been developed. A single palladium-catalysed Heck reaction with ethylene gas provides an efficient synthesis for functionalised styrenes. Through further elaboration the catalyst becomes multi-functional and performs a second Heck reaction providing a single continuous process for the synthesis of unsymmetrical stilbenes. In addition, the continuous, rhodium-catalysed, hydroformylation of styrene derivatives with syngas affords branched aldehydes with good selectivity. Incorporation of an in-line aqueous wash and liquid-liquid separation allowed for the ethylene Heck reaction to be telescoped into the hydroformylation step such that a single flow synthesis of branched aldehydes directly from aryl iodides was achieved. The tube-in-tube semi-permeable membrane-based gas reactor and liquid-liquid separator both play an essential role in enabling these telescoped flow processes.
MICROWAVE INDUCED SINGLE STEP GREEN SYNTHESIS OF SOME NOVEL 2-ARYL ALDEHYDES AND THEIR ANALOGUES
-
Page/Page column 5, (2012/03/08)
The present invention provides a process for the preparation of some novel 2-aryl and 2,2-diaryl aldehydes and analogues which are privileged intermediates for commercially important nonsteroidal anti-inflammatory drugs including naproxen, flurbiprofen and potent anticancer drug candidates, including phenstatin through a unique single step synthetic methodology utilizing easily available substrates in the form of aryl alkenes as well as environmentally benign aqueous reaction conditions in the form of solvents such as mixtures of water and DMSO or Dioxane and reagents N-bromosuccinimide, N-iodosuccinimide, N-cholorosuccinimide and phase transfer catalyst such as cetyltrimethyl ammonium bromide, N-hexyl ammonium chloride for a reaction time varying from 1 min-30 min, depending upon microwave or conventional heating, without using expensive transition metal catalysts or lewis acids/bases with yield varying from 35-55%, depending upon the solvent and substrate used. The developed method provides a clean and convenient alternative to access a diverse range of medicinally important 2-aryl and 2,2-diaryl aldehyde based scaffolds in lieu of the conventional multistep protocols employing expensive and hazardous transition metal catalysts and lewis acids/bases.
Regioselective hydroformylation of vinylarenes in aqueous media by a sol-gel entrapped rhodium catalyst
Nairoukh, Zackaria,Blum, Jochanan
scheme or table, p. 129 - 133 (2012/06/18)
Two methods for selective hydroformylation of vinylarenes in aqueous media are described. One method relies on the application of [Rh(cod)Cl]2 and a tertiary phosphane entrapped within an ionic liquid-confined silica sol-gel support. The second method utilizes the same rhodium compound, encaged within ionic-liquid-free hydrophobicized sol-gel. Both methods are best carried out at 50 °C in aqueous emulsions or microemulsions that consist of the substrate, a surfactant, a co-surfactant and >89% water. The optimal H 2/CO ratio is between 1 and 1.1. Both methods allow the reuse of the heterogenized catalyst for several runs. While the regioselectivity and the yield are hardly affected by the electronic nature of the substrates, they are significantly dependent on the reaction temperature, on the surfactant employed, and on the hydrophobicity of the support of the catalyst. Despite the use of H2 in the reactions, no transformation of the organometallic catalyst into metallic nanoparticles could be detected.
MICROWAVE INDUCED SINGLE STEP GREEN SYNTHESIS OF SOME NOVEL 2-ARYL ALDEHYDES AND THEIR ANALOGUES
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Page/Page column 15, (2010/09/17)
The present invention provides a process for the preparation of some novel 2-aryl and 2,2-diaryl aldehydes and analogues which are privileged intermediates for commercially important nonsteroidal anti-inflammatory drugs including naproxen, flurbiprofen and potent anticancer drug candidates, including phenstatin through a unique single step synthetic methodology utilizing easily available substrates in the form of aryl alkenes as well as environmentally benign aqueous reaction conditions in the form of solvents such as mixtures of water and DMSO or Dioxane and reagents N-bromosuccinimide, N- iodosuccinimide, N-cholorosuccinimide and phase transfer catalyst such as cetyltrimethyl ammonium bromide, N-hexyl ammonium chloride for a reaction time varying from 1min- 30min, depending upon microwave or conventional heating, without using expensive transition metal catalysts or lewis acids/bases with yield varying from 35-55 %, depending upon the solvent and substrate used. The developed method provides a clean and convenient alternative to access a diverse range of medicinally important 2-aryl and 2,2- diaryl aldehyde based scaffolds in lieu of the conventional multistep protocols employing expensive and hazardous transition metal catalysts and lewis acids/bases.
Use of a robust dehydrogenase from an archael hyperthermophile in asymmetric catalysis-dynamic reductive kinetic resolution entry into (s)-profens
Friest, Jacob A.,Maezato, Yukari,Broussy, Sylvain,Blum, Paul,Berkowitz, David B.
supporting information; experimental part, p. 5930 - 5931 (2010/07/05)
Described is an efficient heterologous expression system for Sulfolobus solfataricus ADH-10 (Alcohol Dehydrogenase isozyme 10) and its use in the dynamic reductive kinetic resolution (DYRKR) of 2-arylpropanal (Profen-type) substrates. Importantly, among the 12 aldehydes tested, a general preference for the (S)-antipode was observed, with high ee's for substrates corresponding to the NSAIDs (nonsteroidal anti-inflammatory drugs) naproxen, ibuprofen, flurbiprofen, ketoprofen, and fenoprofen. To our knowledge, this is the first application of a dehydrogenase from this Sulfolobus hyperthermophile to asymmetric synthesis and the first example of a DYRKR with such an enzyme. The requisite aldehydes are generated by Buchwald-Hartwig-type Pd(0)-mediated α-arylation of tert-butyl propionate. This is followed by reduction to the aldehyde in one [lithium diisobutyl tert-butoxyaluminum hydride (LDBBA)] or two steps [LAH/Dess-Martin periodinane]. Treatment of the profenal substrates with SsADH in 5% EtOH/phosphate buffer, pH 9, with catalytic NADH at 80 °C leads to efficient DYRKR, with ee's exceeding 90% for 9 aryl side chains, including those of the aforementioned NSAIDs. An in silico model, consistent with the observed broad side chain tolerance, is presented. Importantly, the SsADH-10 enzyme could be conveniently recycled by exploiting the differential solubility of the organic substrate/product at 80 °C and at rt. Pleasingly, SsADH-10 could be taken through several thermal cycles, without erosion of ee, suggesting this as a generalizable approach to enzyme recycling for hyperthermophilic enzymes. Moreover, the robustness of this hyperthermophilic DH, in terms of both catalytic activity and stereochemical fidelity, speaks for greater examination of such archaeal enzymes in asymmetric synthesis.
