4636-73-1Relevant articles and documents
Molecular palladium precursors for Pd0 nanoparticle preparation by microwave irradiation: Synthesis, structural characterization and catalytic activity
Heinrich, Frank,Kebler, Michael T.,Dohmen, Stephan,Singh, Mrityunjay,Prechtl, Martin H. G.,Mathur, Sanjay
, p. 6027 - 6033 (2012)
Two new palladium complexes [Pd(MEA)2Cl2] (1) and [Pd(MEA)2Br2] (2) [MEA = (2-methoxyethyl)amine] were synthesized by the reaction of 2 equiv. of MEA with PdCl2 or [(cod)PdBr2] (cod = cyclo
Cyclic amidine hydroiodide for the synthesis of cyclic carbonates and cyclic dithiocarbonates from carbon dioxide or carbon disulfide under mild conditions
Aoyagi, Naoto,Furusho, Yoshio,Endo, Takeshi
supporting information, (2019/12/09)
Hydroiodides of amidines can catalyze the reaction of carbon dioxide and epoxides under mild conditions such as ordinary pressure and ambient temperature, and the corresponding five-membered cyclic carbonates were obtained in high yields. The reaction of epoxide with carbon disulfide was also examined under the same conditions. Detailed investigation showed that the catalytic activity was highly affected by the counter anions of the amidine salts; the iodides were effective catalysts for both of the reaction of epoxide with carbon dioxide and carbon disulfide, whereas the bromide, chloride and fluoride counterparts exhibited almost no catalysis.
Palladium-Catalyzed Hydride Addition/C-H Bond Activation Cascade: Cycloisomerization of 1,6-Diynes
Rodríguez, José F.,Burton, Katherine I.,Franzoni, Ivan,Petrone, David A.,Scheipers, Ina,Lautens, Mark
supporting information, p. 6915 - 6919 (2018/11/21)
The use of ammonium halide salts as metal hydride precursors in a new Pd-catalyzed cycloisomerization of 1,6-diynes, which affords unexplored silylated 2-azafluorenes, is reported. This cascade process includes the addition of a Pd-hydride species to a π-system, intramolecular carbopalladation, and C(sp2)-H bond activation. A variety of functional groups are tolerated, and the synthetic utility of the resulting products has been demonstrated by a series of derivatizations.
Deciphering a 20-Year-Old Conundrum: The Mechanisms of Reduction by the Water/Amine/SmI2 Mixture
Maity, Sandeepan,Hoz, Shmaryahu
, p. 18394 - 18400 (2015/12/24)
The reaction of SmI2 with the substrates 3-methyl-2-butanone, benzyl chloride, p-cyanobenzyl chloride, and anthracene were studied in the presence of water and an amine. In all cases, the water content versus rate profile shows a maximum at around 0.2 M H2O. The rate versus amine content profile shows in all cases, except for benzyl chloride, saturation behavior, which is typical of a change in the identity of the rate-determining step. The mechanism that is in agreement with the observed data is that electron transfer occurs in the first step. With substrates that are not very electrophilic, the intermediate radical anions lose the added electron back to samarium(III) relatively quickly and the reaction cannot progress efficiently. However, in a mixture of water/amine, the amine deprotonates a molecule of water coordinated to samarium(III). The negatively charged hydroxide, which is coordinated to samarium(III), reduces its electrophilicity, and therefore, lowers the rate of back electron transfer, which allows the reaction to progress. In the case of benzyl chloride, in which electron transfer is rate determining, deprotonation by the amine is coupled to the electron-transfer step.
Synthesis and properties of arsenic(III)-reactive coumarin-appended benzothiazolines: A new approach for inorganic arsenic detection
Ezeh, Vivian C.,Harrop, Todd C.
, p. 2323 - 2334 (2013/04/10)
The EPA has established a maximum contaminant level (MCL) of 10 ppb for arsenic (As) in drinking water requiring sensitive and selective detection methodologies. To tackle this challenge, we have been active in constructing small molecules that react specifically with As3+ to furnish a new fluorescent species (termed a chemodosimeter). We report in this contribution, the synthesis and spectroscopy of two small-molecule fluorescent probes that we term ArsenoFluors (or AFs) as As-specific chemodosimeters. The AFs (AF1 and AF2) incorporate a coumarin fluorescent reporter coupled with an As-reactive benzothiazoline functional group. AFs react with As3+ to yield the highly fluorescent coumarin-6 dye (C6) resulting in a 20-25-fold fluorescence enhancement at λem ~ 500 nm with detection limits of 0.14-0.23 ppb in tetrahydrofuran (THF) at 298 K. The AFs also react with common environmental As3+ sources such as sodium arsenite in a THF/CHES (N-cyclohexyl-2-aminoethanesulfonic acid) (1:1, pH 9, 298 K) mixture resulting in a modest fluorescence turn-ON (1.5- to 3-fold) due to the quenched nature of coumarin-6 derivatives in high polarity solvents. Bulk analysis of the reaction of the AFs with As3+ revealed that the C6 derivatives and the Schiff-base disulfide of the AFs (SB1 and SB2) are the ultimate end-products of this chemistry with the formation of C6 being the principle photoproduct responsible for the As3+-specific turn-ON. It appears that a likely species that is traversed in the reaction path is an As-hydride-ligand complex that is a putative intermediate in the proposed reaction path.
Pd-catalysed oxidative carbonylation of amino alcohols to N,N′-bis(hydroxyalkyl)ureas under mild conditions using molecular oxygen as the oxidant
Giannoccaro, Potenzo,Ferragina, Carla,Gargano, Michele,Quaranta, Eugenio
experimental part, p. 78 - 84 (2010/09/06)
A very simple method has been developed for the selective synthesis of symmetrical N,N′-bis(hydroxyalkyl)ureas, OC[NH-(CH2)x-OH]2 (x = 3-6), by oxidative carbonylation of α,ω-amino alcohols [3-aminopropanol (3-AP), 4-aminobutanol (4-AB), 5-aminopentanol (5-APe), 6-aminohexanol (6-AH)] with CO/O2 mixtures (O2 = 5 mol%) in the presence of Pd(II)/ligand/NEt3·HI catalytic systems. The catalytic process takes place under very mild conditions (p(CO/O2) = 0.1 MPa; 303-333 K). The target products can be isolated in high yield through a very simple and straightforward procedure. The catalytic system can be easily recovered and recycled for several times. The influence of a few reaction parameters (nature of ancillary ligand and iodide co-catalyst, I/Pd molar ratio, etc.) on the catalytic activity has also been investigated and the main mechanistic features of the catalytic process fully elucidated.
Preparation of mono- and di-arylphosphines
-
, (2008/06/13)
Mono- and di-arylphosphines are prepared by reacting an aryl compound that has a leaving group attached to a carbon atom of the aromatic ring with phosphine in the presence of a Group VIII metal catalyst.
Reaction of N-alkylpyredinium salts with phosphorus trichloride
Bansal, Raj K.,Gupta, Neelima,Gupta, Rakhi,Pandey, Garima,Agarwal, Mamta
, p. 121 - 130 (2007/10/03)
1-Alkylpyridinium bromides 1 having activated N-methylene group react with phosphorus trichloride to give N-(dichlorophosphinomethylene)pyridinium ylides 2. The site of the reaction in 1,2-dialkylpyridinium halides 3 under these conditions is determined by the relative activation of 1- and 2-methylene groups; in the absence of sufficient activation of N-methylene group, reaction occurs at the 2-methylene group to give dichlorophosphinylated anhydrobases 5 and 11. 1,4-Dialkylpyridinium bromide 13 behaves analogously to give the corresponding dichlorophosphinylated anhydrobase 14.
AMINOLYSIS OF VINYLAMMONIUM SALTS. EFFECTS OF STRUCTURE AND MEDIUM
Kravchenko, V. V.,Popov, A. F.,Kotenko, A. A.
, p. 1332 - 1336 (2007/10/02)
The kinetics of the aminolysis of a series of vinylammonium salts ZCH=CHN+R3*X- were investigated in polar solvents and in water at 25 deg C.A quantitative assessment was made of the effect of the nature of the medium and the structure of activating group Z on the rate of the investigated processes.The aminolysis rate of the salts increases with increase in the donating characteristics of the solvent on account of the greater stabilization of the transition state compared with the initial state.Increase in the accepting characteristics of the medium leads to retardation of the process as a result of increase in the electrophilic solvation of the amine in the initial state.
Ethynylthiophenoxy derivatives of diphenylhexafluoropropane
-
, (2008/06/13)
Ethynylphenyl derivatives of diphenylhexafluoropropane having the formula: STR1 where X is oxygen or sulfur and each of R, R1, or R2 is hydrogen or ethynyl. The compounds are useful in forming polymer structures, either homopolymers or copolymers.