7073-99-6Relevant academic research and scientific papers
Synthesis of Amides and Esters by Palladium(0)-Catalyzed Carbonylative C(sp3)?H Activation
?arny, Tomá?,Baudoin, Olivier,Clemenceau, Antonin,Rocaboy, Ronan
supporting information, p. 18980 - 18984 (2020/09/01)
The 1,4-palladium shift strategy allows the functionalization of remote C?H bonds that are difficult to reach directly. Reported here is a domino reaction proceeding by C(sp3)?H activation, 1,4-palladium shift, and amino- or alkoxycarbonylation, which generates a variety of amides and esters bearing a quaternary β-carbon atom. Mechanistic studies showed that the aminocarbonylation of the σ-alkylpalladium intermediate arising from the palladium shift is fast using PPh3 as the ligand, and leads to the amide rather than the previously reported indanone product.
An Improved PIII/PV=O-Catalyzed Reductive C-N Coupling of Nitroaromatics and Boronic Acids by Mechanistic Differentiation of Rate- And Product-Determining Steps
Li, Gen,Nykaza, Trevor V.,Cooper, Julian C.,Ramirez, Antonio,Luzung, Michael R.,Radosevich, Alexander T.
supporting information, p. 6786 - 6799 (2020/04/30)
Experimental, spectroscopic, and computational studies are reported that provide an evidence-based mechanistic description of an intermolecular reductive C-N coupling of nitroarenes and arylboronic acids catalyzed by a redox-active main-group catalyst (1,2,2,3,4,4-hexamethylphosphetane P-oxide, i.e., 1·[O]). The central observations include the following: (1) catalytic reduction of 1·[O] to PIII phosphetane 1 is kinetically fast under conditions of catalysis; (2) phosphetane 1 represents the catalytic resting state as observed by 31P NMR spectroscopy; (3) there are no long-lived nitroarene partial-reduction intermediates observable by 15N NMR spectroscopy; (4) the reaction is sensitive to solvent dielectric, performing best in moderately polar solvents (viz. cyclopentylmethyl ether); and (5) the reaction is largely insensitive with respect to common hydrosilane reductants. On the basis of the foregoing studies, new modified catalytic conditions are described that expand the reaction scope and provide for mild temperatures (T ≥ 60 °C), low catalyst loadings (≥2 mol%), and innocuous terminal reductants (polymethylhydrosiloxane). DFT calculations define a two-stage deoxygenation sequence for the reductive C-N coupling. The initial deoxygenation involves a rate-determining step that consists of a (3+1) cheletropic addition between the nitroarene substrate and phosphetane 1; energy decomposition techniques highlight the biphilic character of the phosphetane in this step. Although kinetically invisible, the second deoxygenation stage is implicated as the critical C-N product-forming event, in which a postulated oxazaphosphirane intermediate is diverted from arylnitrene dissociation toward heterolytic ring opening with the arylboronic acid; the resulting dipolar intermediate evolves by antiperiplanar 1,2-migration of the organoboron residue to nitrogen, resulting in displacement of 1·[O] and formation of the target C-N coupling product upon in situ hydrolysis. The method thus described constitutes a mechanistically well-defined and operationally robust main-group complement to the current workhorse transition-metal-based methods for catalytic intermolecular C-N coupling.
Atropisomerism in Diarylamines: Structural Requirements and Mechanisms of Conformational Interconversion
Clayden, Jonathan,Costil, Romain,Duarte, Fernanda,Sterling, Alistair J.
supporting information, p. 18670 - 18678 (2020/08/25)
In common with other hindered structures containing two aromatic rings linked by a short tether, diarylamines may exhibit atropisomerism (chirality due to restricted rotation). Previous examples have principally been tertiary amines, especially those with
Palladium-Catalyzed Alkylation with Alkyl Halides by C(sp3)?H Activation
Wu, Zhuo,Ma, Ding,Zhou, Bo,Ji, Xiaoming,Ma, Xiaotian,Wang, Xiaoling,Zhang, Yanghui
supporting information, p. 12288 - 12291 (2017/09/06)
Utilizing halogens as traceless directing goups represents an attractive strategy for C?H functionalization. A two C?H alkylation system, initiated by the oxidative addition of organohalides to Pd0, has been developed. The first reaction involves an intermolecular alkylation of palladacycles to form C(sp3)?C(sp2) bonds followed by C(sp2)?H activation/cyclization to deliver alkylated benzocyclobutenes as the final products. In the second reaction, two C?C bonds are formed by the reaction of palladacycles with CH2Br2, and provides a facile and efficient method for the synthesis of indanes. The alkylated benzocyclobutene products can be transformed into tricyclic hyrocarbons, and the indane derivatives are essential structural motifs in bioactive and odorant molecules.
Synthesis and catalytic reactivity of mononuclear substituted tetramethylcyclopentadienyl molybdenum carbonyl complexes
Ma, Zhi-Hong,Lv, Lin-Qian,Wang, Hong,Han, Zhan-Gang,Zheng, Xue-Zhong,Lin, Jin
, p. 225 - 233 (2016/02/20)
The reactions of five dinuclear carbonyl complexes [(η 5-C5Me4R)Mo(CO)3]2 [R = allyl, n Bu, t Bu, Ph, Bz] with I2 in chloroform solution gave the corresponding mononuclear substituted tetramethylcyclopentadienyl molybdenum carbonyl complexes [(η 5-C5Me4R)MoI(CO)3] [R = allyl (1), n Bu (2), t Bu (3), Ph (4), Bz (5)]. The molecular structures of complexes 2, 3 and 5 were determined by X-ray diffraction analysis. The results show that the substituent in the ring can directly affect the Mo-I bond distances; the more sterically hindered the substituent, the longer the Mo-I bond. Friedel-Crafts reactions of aromatic compounds with a variety of alkylation reagents catalyzed by the complexes showed that all of these mononuclear molybdenum carbonyl complexes have catalytic activity in Friedel-Crafts alkylation reactions. Indeed, compared with traditional catalysts, these mononuclear metal carbonyl complexes have obvious advantages such as higher activities, mild reaction conditions, high selectivity, simple post-processing, and environmentally friendly chemistry.
METHODS AND COMPOSITIONS FOR TREATING INFECTION
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Paragraph 0291, (2015/09/28)
Provided herein are compositions and methods for treating or preventing infection.
LUMINESCENT DIAZABENZIMIDAZOLE CARBENE METAL COMPLEXES
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Page/Page column 171, (2015/02/25)
The present invention relates to metal-carbene complexes of the general formula (I), where variable M is Ir or Pt and that are characterized by variable R being a group of formula (a). The complexes are used in organic electronic devices, especially OLEDs (Organic Light-Emitting Diodes), illuminating elements, stationary visual display units and in material layers as emitter, charge transport material and/or charge or exiton blocker.
Nucleotides and nucleosides and methods for their use in DNA sequencing
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Page/Page column 137; 138, (2015/12/18)
The present invention relates generally to labeled and unlabled cleavable terminating groups and methods for DNA sequencing and other types of DNA analysis. More particularly, the invention relates in part to nucleotides and nucleosides with chemically cleavable, photocleavable, enzymatically cleavable, or non-photocleavable groups and methods for their use in DNA sequencing and its application in biomedical research.
Repurposing the antihistamine terfenadine for antimicrobial activity against staphylococcus aureus
Perlmutter, Jessamyn I.,Forbes, Lauren T.,Krysan, Damian J.,Ebsworth-Mojica, Katherine,Colquhoun, Jennifer M.,Wang, Jenna L.,Dunman, Paul M.,Flaherty, Daniel P.
supporting information, p. 8540 - 8562 (2014/12/11)
Staphylococcus aureus is a rapidly growing health threat in the U.S., with resistance to several commonly prescribed treatments. A high-throughput screen identified the antihistamine terfenadine to possess, previously unreported, antimicrobial activity against S. aureus and other Gram-positive bacteria. In an effort to repurpose this drug, structure-activity relationship studies yielded 84 terfenadine-based analogues with several modifications providing increased activity versus S. aureus and other bacterial pathogens, including Mycobacterium tuberculosis. Mechanism of action studies revealed these compounds to exert their antibacterial effects, at least in part, through inhibition of the bacterial type II topoisomerases. This scaffold suffers from hERG liabilities which were not remedied through this round of optimization; however, given the overall improvement in activity of the set, terfenadine-based analogues provide a novel structural class of antimicrobial compounds with potential for further characterization as part of the continuing process to meet the current need for new antibiotics.
Cucurbit[8]uril recognition of rapidly interconverting diastereomers
Joseph, Roymon,Masson, Eric
, p. 632 - 641 (2015/10/19)
The diastereoselectivity of Cucurbit[8]uril (CB[8]) binding was probed towards a series of rapidly interconverting diastereomers containing a Caryl-Caryl chiral axis and at least one other stereocenter. Relative binding affinities of up to 4.9 were determined when CB[8] interacted with ortho, meta, ortho′-substituted biphenyls bearing a chiral dialkylsulfonium substituent at their meta-position. Diastereoselectivities of up to 2.4-fold were obtained for ortho′-substituted 2-phenylpyridinium derivatives that bear a chiral myrtenyl N-substituent prone to CB[8] binding.
