91083-82-8Relevant academic research and scientific papers
Photo-induced energy transfer relay of N-heterocyclic carbene catalysis: an asymmetric α-fluorination/isomerization cascade
Jiang, Xinhang,Li, En,Chen, Jiean,Huang, Yong
supporting information, p. 729 - 732 (2021/02/05)
The geometric configuration of olefin products is often driven by thermodynamic control in synthesis. Methods enabling switching of cis/trans selectivity are rare. Recently, photosensitized approaches have emerged as a powerful tool for accomplishing this task. In this report, we report an in situ isomerization of an N-heterocyclic carbene (NHC)-bound intermediate by a photo-induced energy transfer process that leads to selective access of chiral allylic fluorides with a cis-olefin geometry. In the absence of a photocatalyst or light, the reaction proceeds smoothly to give (E)-olefin products, while the (Z)-isomer can be obtained under photosensitizing conditions. Preliminary mechanistic experiments suggest that an energy transfer process might be operative. This journal is
Design, synthesis, modelling studies and biological evaluation of 1,3,4-oxadiazole derivatives as potent anticancer agents targeting thymidine phosphorylase enzyme
Bajaj, Shalini,Kumar, Maushmi S.,Tinwala, Hussain,YC, Mayur
, (2021/04/12)
A series of novel 1,3,4-oxadiazole derivatives with substituted phenyl ring were designed and synthesized with an objective of discovering newer anti-cancer agents targeting thymidine phosphorylase enzyme (TP). The 1,3,4-oxadiazole derivatives were synthesized by simple and convenient methods in the lab. Chemical structure of the all the synthesized compounds were characterized by IR, 1H NMR and mass spectral methods and evaluated for cytotoxicity by MTT method against two breast cancer cell lines (MCF-7 and MDA-MB-231). Further, results of TP assay identified that 1,3,4-oxadiazole molecules displayed anti-cancer activity partially by inhibition of phosphorylation of thymidine. The TP assay identified SB8 and SB9 as potential inhibitors with anti-cancer activity against both the cell lines. The molecular docking studies recognized the orientation and binding interaction of molecule at the active site amino acid residues of TP (PDB: 1UOU). Acute toxicity studies of compound SB8 at the dose of 5000 mg/kg has identified no signs of clinical toxicity was observed. The SARs study of synthesized derivatives revealed that the substitution of phenyl ring with electron withdrawing group at ortho position showed significant TP inhibitory activity compared to para substitution. The experimental data suggests that 1,3,4-oxadiazole with substituted phenyl can be taken as a lead for the design of efficient TP inhibitors and active compounds which can be taken up for further studies.
Intramolecular Cyclization of Vinyldiazoacetates as a Versatile Route to Substituted Pyrazoles
Drikermann, Denis,G?rls, Helmar,Kerndl, Valerie,Vilotijevic, Ivan
supporting information, p. 1158 - 1162 (2020/07/20)
Vinyldiazo compounds undergo a thermal electrocyclization to form pyrazoles in yields of up to 95percent. The reactions are operationally simple, use readily available starting materials, require no intervention of a catalyst, and enable the synthesis of mono-, di- A nd tri-substituted pyrazoles. With the ability to produce highly substituted pyrazoles and the flexibility in installing various types of substituents, this method constitutes a new entry to this valuable heterocyclic scaffold and may be of interest to all branches of the chemical industry.
An Enzymatic Platform for the Highly Enantioselective and Stereodivergent Construction of Cyclopropyl-δ-lactones
Chandgude, Ajay L.,Fasan, Rudi,Liu, Ningyu,Ren, Xinkun
supporting information, p. 21634 - 21639 (2020/09/23)
Abiological enzymes offers new opportunities for sustainable chemistry. Herein, we report the development of biological catalysts derived from sperm whale myoglobin that exploit a carbene transfer mechanism for the asymmetric synthesis of cyclopropane-fused-δ-lactones, which are key structural motifs found in many biologically active natural products. While hemin, wild-type myoglobin, and other hemoproteins are unable to catalyze this reaction, the myoglobin scaffold could be remodeled by protein engineering to permit the intramolecular cyclopropanation of a broad spectrum of homoallylic diazoacetate substrates in high yields and with up to 99 % enantiomeric excess. Via an alternate evolutionary trajectory, a stereodivergent biocatalyst was also obtained for affording mirror-image forms of the desired bicyclic products. In combination with whole-cell transformations, the myoglobin-based biocatalyst was used for the asymmetric construction of a cyclopropyl-δ-lactone scaffold at a gram scale, which could be further elaborated to furnish a variety of enantiopure trisubstituted cyclopropanes.
Synthesis of Allylboranes via Cu(I)-Catalyzed B-H Insertion of Vinyldiazoacetates into Phosphine-Borane Adducts
Drikermann, Denis,M??el, Robert S.,Al-Jammal, Walid K.,Vilotijevic, Ivan
, p. 1091 - 1095 (2020/02/15)
Cu(I) catalysts enable C-B bond formation via direct insertion of vinyldiazoacetates into B-H bonds of borane-phosphine Lewis adducts to form phosphine-protected allylboranes under mild conditions. The resulting allylborane-phosphine Lewis adducts can be used in the diastereoselective allylation of aldehydes directly without the need for removal of the phosphine. The allylation reaction proceeds with high diastereoselectivity and yields 5,6-disubstituted dihydropyranones after treatment with an appropriate acid.
BICYCLIC KETONE COMPOUNDS AND METHODS OF USE THEREOF
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Page/Page column 79; 80, (2019/02/02)
The invention provides novel compounds having the general formula (I): (I) wherein R1, the A ring and the B ring are as described herein, pharmaceutical compositions including the compounds, and methods of using the compounds.
Stereoselective Ring-Opening of gem-Difluorocyclopropanes: An Entry to Stereo-defined (E,E)- and (E,Z)-Conjugated Fluorodienes
Specklin, Simon,Fenneteau, Johan,Subramanian, Parthasarathi,Cossy, Janine
supporting information, p. 332 - 336 (2018/01/17)
The ring-opening of gem-difluorocyclopropyl acetaldehydes producing selectively (E,E)- and (E,Z)-conjugated fluorodienals is described. Two stereo-divergent methods are presented to access both stereoisomers from a common precursor, in high yield and selectivity. The mechanistic aspect of these transformations is discussed.
Selective Palladium-Catalyzed Carbonylation of Alkynes: An Atom-Economic Synthesis of 1,4-Dicarboxylic Acid Diesters
Liu, Jiawang,Dong, Kaiwu,Franke, Robert,Neumann, Helfried,Jackstell, Ralf,Beller, Matthias
supporting information, p. 10282 - 10288 (2018/08/03)
A class of novel diphosphine ligands bearing pyridine substituents was designed and synthesized for the first time. The resulting palladium complexes of L1 allow for chemo- and regioselective dialkoxycarbonylation of various aromatic and aliphatic alkynes affording a wide range of 1,4-dicarboxylic acid diesters in high yields and selectivities. Kinetic studies suggest the generation of 1,4-dicarboxylic acid diesters via cascade hydroesterification of the corresponding alkynes. Based on these investigations, the chemo- and regioselectivities of alkyne carbonylations can be controlled as shown by switching the ligand from L1 to L3 or L9 to give α,β-unsaturated esters.
A highly efficient Pd/CuI-catalyzed oxidative alkoxycarbonylation of α-olefins to unsaturated esters
Maffei, Mathias,Giacoia, Gabriele,Mancuso, Raffaella,Gabriele, Bartolo,Motti, Elena,Costa, Mirco,Della Ca’, Nicola
, p. 435 - 443 (2016/12/16)
A new protocol for the alkoxycarbonylation of α-olefins to the corresponding unsaturated esters has been developed. Differently substituted styrenes were selectively converted to cinnamate derivatives, via C[sbnd]H bond functionalization. Various palladium sources, including heterogeneous ones, in combination with CuI exhibited a high catalytic efficiency using oxygen as the most cheap oxidant. Monocarbonylated products were obtained in good yields and high chemoselectivity working with a low CO pressure (2 atm) and an excess of air (35 atm) avoiding in this way explosion risks. Commercial cinnamate derivatives were prepared in good to excellent yields by this very simple one-pot procedure.
Facile synthesis of 2-aryl or β,γ-unsaturated esters via 1,2-Migration from aryl or α,β-unsaturated ketones using thallium(III) p-tosylate
Lee, Jae In
, p. 125 - 128 (2017/06/07)
The experiment reports that 2-aryl esters can be efficiently synthesized via 1,2-aryl migration from aryl ketones using thallium(III) p-tosylate in high yields. To determine optimum conditions for conversion of aryl ketones to 2-aryl esters, the effects of solvents were examined. An initial reaction of 4'-methoxypropiophenone and perchloric acid using thallium(III) p-tosylate in ethanol afforded ethyl 2-(4-methoxyphenyl)propanoate in only 10% yield after 24 h at room temperature. However, the corresponding reaction in ethanol/triethyl orthoformate (4/1) was completed in 1 h between 0 °C and room temperature to give ethyl 2-(4-methoxyphenyl)propanoate in 94% yield. The presence of triethyl orthoformate induced rapid ketalization of enol intermediate and facilitated 1,2-migration of the 4-methoxyphenyl group. The relative effectiveness of several metal salts was also examined for conversion of 2',4'-dimethoxypropiophenone to ethyl 2-(2,4-dimethoxyphenyl)propanoate. The solvents were evaporated off under reduced pressure, and the residue was dissolved in methylene chloride. The white precipitate was filtered off, and the resulting yellow solution was poured into saturated NaHCO3 solution and extracted with methylene chloride. The combined organic layers were dried over anhydrous MgSO4, filtered, and concentrated in vacuo. The residue was purified by vacuum distillation using a Kugelrohr apparatus to give 4g as a colorless liquid.
