15898-47-2Relevant academic research and scientific papers
Isolation of the Metalated Ylides [Ph3P?C?CN]M (M=Li, Na, K): Influence of the Metal Ion on the Structure and Bonding Situation
Schwarz, Christopher,Scharf, Lennart T.,Scherpf, Thorsten,Weismann, Julia,Gessner, Viktoria H.
, p. 2793 - 2802 (2019)
The isolation and structural characterization of the cyanido-substituted metalated ylides [Ph3P?C?CN]M (1-M; M=Li, Na, K) are reported with lithium, sodium, and potassium as metal cations. In the solid-state, most different aggregates could be determined depending on the metal and additional Lewis bases. The crown-ether complexes of sodium (1-Na) and potassium (1-K) exhibited different structures, with sodium preferring coordination to the nitrogen end, whereas potassium binds in an unusual η2-coordination mode to the two central carbon atoms. The formation of the yldiide was accompanied by structural changes leading to shorter C?C and longer C?N bonds. This could be attributed to the delocalization of the free electron pairs at the carbon atom into the antibonding orbitals of the CN moiety, which was confirmed by IR spectroscopy and computational studies. Detailed density functional theory calculations show that the changes in the structure and the bonding situation were most pronounced in the lithium compounds due to the higher covalency.
Rational design of a highly reactive ratiometric fluorescent probe for cyanide
Yuan, Lin,Lin, Weiying,Yang, Yueting,Song, Jizeng,Wang, Jiaoliang
, p. 3730 - 3733 (2011)
A novel highly reactive ratiometric fluorescent cyanide probe was judiciously designed based on 2-formylacrylonitrile moiety as a new cyanide reaction site. A DFT study was conducted to rationalize the extremely high reactivity nature of the ratiometric f
Generation and Rearrangement of N,O-Dialkenylhydroxylamines for the Synthesis of 2-Aminotetrahydrofurans
Son, Jongwoo,Reidl, Tyler W.,Kim, Ki Hwan,Wink, Donald J.,Anderson, Laura L.
, p. 6597 - 6600 (2018)
A new diastereoselective route to 2-aminotetrahydrofurans has been developed from N,O-dialkenylhydroxylamines. These intermediates undergo a spontaneous C?C bond-forming [3,3]-sigmatropic rearrangement followed by a C?O bond-forming cyclization. A copper-catalyzed N-alkenylation of an N-Boc-hydroxylamine with alkenyl iodides, and a base-promoted addition of the resulting N-hydroxyenamines to an electron-deficient allene, provide modular access to these novel rearrangement precursors. The scope of this de novo synthesis of simple nucleoside analogues has been explored to reveal trends in diastereoselectivity and reactivity. In addition, a base-promoted ring-opening and Mannich reaction has been discovered to covert 2-aminotetrahydrofurans to cyclopentyl β-aminoacid derivatives or cyclopentenones.
Selective Construction of C?C and C=C Bonds by Manganese Catalyzed Coupling of Alcohols with Phosphorus Ylides
Liu, Xin,Werner, Thomas
supporting information, p. 1096 - 1104 (2020/12/31)
Herein, we report the manganese catalyzed coupling of alcohols with phosphorus ylides. The selectivity in the coupling of primary alcohols with phosphorus ylides to form carbon-carbon single (C?C) and carbon-carbon double (C=C) bonds can be controlled by the ligands. In the conversion of more challenging secondary alcohols with phosphorus ylides the selectivity towards the formation of C?C vs. C=C bonds can be controlled by the reaction conditions, namely the amount of base. The scope and limitations of the coupling reactions were thoroughly evaluated by the conversion of 21 alcohols and 15 ylides. Notably, compared to existing methods, which are based on precious metal complexes as catalysts, the present catalytic system is based on earth abundant manganese catalysts. The reaction can also be performed in a sequential one-pot reaction generating the phosphorus ylide in situ followed manganese catalyzed C?C and C=C bond formation. Mechanistic studies suggest that the C?C bond was generated via a borrowing hydrogen pathway and the C=C bond formation followed an acceptorless dehydrogenative coupling pathway. (Figure presented.).
Enantioselective Rauhut–Currier Reaction with β-Substituted Acrylamides Catalyzed by N-Heterocyclic Carbenes
Pitchumani, Venkatachalam,Breugst, Martin,Lupton, David W.
supporting information, p. 9413 - 9418 (2021/12/09)
β-Substituted acrylamides have low electrophilicity and are yet to be exploited in the enantioselective Rauhut–Currier reaction. By exploiting electron-withdrawing protection of the amide and moderate nucleophilicity N-heterocyclic carbenes, such substrates have been converted to enantioenriched quinolones. The reaction proceeds with complete diastereoselectivity, good yield, and modest enantioselectivity. Derivatizations are reported, as are computational studies, supporting decreased amide bond character with electron-withdrawing protection of the nitrogen.
One-Pot Synthesis of 2,5-Disubstituted Furans through In Situ Formation of Allenes and Enolization Cascade
Bernhard, Yann,Gilbert, Joachim,Bousquet, Till,Favrelle-Huret, Audrey,Zinck, Philippe,Pellegrini, Sylvain,Pelinski, Lydie
supporting information, p. 7870 - 7873 (2019/12/24)
A one-pot synthesis of 2,5-disubstituted furans from γ-ketoacids is reported. In situ formation of allenoates by action of chloroformate on carboxylic acid following by enolization of ketone affords furan derivatives by cyclization. The reaction was extended to a wide scope of ketoacids and phosphonium salts. This methodology was applied on levulinic acid and derivatives, one of the biosourced platform chemicals.
METALLO-BETA-LACTAMASE INHIBITORS AND METHODS OF USE THEREOF
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Page/Page column 47, (2019/02/06)
The present invention relates to metallo-β-lactamase inhibitor compounds of Formula (I) and pharmaceutically acceptable salts thereof, wherein Z, RA, X1, X2 and R1 are as defined herein. The present invention also relates to compositions which comprise a metallo-β-lactamase inhibitor compound of the invention or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier, optionally in combination with a beta lactam antibiotic and/or a beta-lactamase inhibitor. The invention further relates to methods for treating a bacterial infection comprising administering to a patient a therapeutically effective amount of a compound of the invention, in combination with a therapeutically effective amount of one or more β-lactam antibiotics and optionally in combination with one or more beta-lactamase inhibitor compounds. The compounds of the invention are useful in the methods described herein for overcoming antibiotic resistance.
Titania-promoted carboxylic acid alkylations of alkenes and cascade addition-cyclizations
Manley, David W.,McBurney, Roy T.,Miller, Phillip,Walton, John C.,Mills, Andrew,O'Rourke, Christopher
, p. 1386 - 1398 (2014/03/21)
Photochemical reactions employing TiO2 and carboxylic acids under dry anaerobic conditions led to several types of C-C bond-forming processes with electron-deficient alkenes. The efficiency of alkylation varied appreciably with substituents in the carboxylic acids. The reactions of aryloxyacetic acids with maleimides resulted in a cascade process in which a pyrrolochromene derivative accompanied the alkylated succinimide. The selectivity for one or other of these products could be tuned to some extent by employing the photoredox catalyst under different conditions. Aryloxyacetic acids adapted for intramolecular ring closures by inclusion of 2-alkenyl, 2-aryl, or 2-oximinyl functionality reacted rather poorly. Profiles of reactant consumption and product formation for these systems were obtained by an in situ NMR monitoring technique. An array of different catalyst forms were tested for efficiency and ease of use. The proposed mechanism, involving hole capture at the TiO2 surface by the carboxylates followed by CO2 loss, was supported by EPR spectroscopic evidence of the intermediates. Deuterium labeling indicated that the titania likely donates protons from surface hydroxyl groups as well as supplying electrons and holes, thus acting as both a catalyst and a reaction partner.
Phosphine-catalyzed β′-umpolung addition of nucleophiles to activated α-alkyl allenes
Martin, Tioga J.,Vakhshori, Venus G.,Tran, Yang S.,Kwon, Ohyun
supporting information; scheme or table, p. 2586 - 2589 (2011/06/25)
Highly functionalized alkenes can be prepared through phosphine-catalyzed β′-umpolung additions of nucleophiles (carbon-, oxygen-, nitrogen-, and sulfur-centered) to activated α-disubstituted allenes, providing many potentially useful synthetic intermediates in good to excellent yields, often with high levels of stereoselectivity for the product olefin geometry. Various substitution patterns around the allene are compatible with the process, showcasing the synthetic utility of allenes under the conditions of nucleophilic phosphine catalysis.
C-H activation reactions of ruthenium N-heterocyclic carbene complexes: Application in a catalytic tandem reaction involving C-C bond formation from alcohols
Burling, Suzanne,Paine, Belinda M.,Nama, Devendrababu,Brown, Victoria S.,Mahon, Mary F.,Prior, Timothy J.,Pregosin, Paul S.,Whittlesey, Michael K.,Williams, Jonathan M. J.
, p. 1987 - 1995 (2007/10/03)
A series of ruthenium hydride N-alkyl heterocyclic carbene complexes has been investigated as catalysts for a tandem oxidation/Wittig/reduction reaction to give C-C bonds from alcohols. The C-H-activated carbene complex Ru(I iPr2Me2)′(PPh3) 2(CO)H (9) proves to be the most active precursor catalyzing the reaction of PhCH2OH and Ph3P=CHCN in 3 h at 70 °C. These results provide (a) a rare case in which N-alkyl carbenes afford higher catalytic activity than their N-aryl counterparts and (b) a novel example of the importance of NHC C-H activation in a catalytic cycle.
