89-21-4Relevant academic research and scientific papers
Experimental and Computational Studies towards Chemoselective C?F over C?Cl Functionalisation: Reversible Oxidative Addition is the Key
Jacobs, Emily,Keaveney, Sinead T.
, p. 637 - 645 (2020/12/07)
Catalytic cross-coupling is a valuable tool for forming new carbon-carbon and carbon-heteroatom bonds, allowing access to a variety of structurally diverse compounds. However, for this methodology to reach its full potential, precise control over all competing cross-coupling sites in poly-functionalised building blocks is required. Carbon-fluorine bonds are one of the most stable bonds in organic chemistry, with oxidative addition at C?F being much more difficult than at other C-halide bonds. As such, the development of methods to chemoselectively functionalise the C?F position in poly-halogenated arenes would be very challenging if selectivity was to be induced at the oxidative addition step. However, metal-halide complexes exhibit different trends in reactivity to the parent haloarenes, with metal-fluoride complexes known to be very reactive towards transmetalation. In this current work we sought to exploit the divergent reactivity of Ni?Cl and Ni?F intermediates to develop a chemoselective C?F functionalisation protocol, where selectivity is controlled by the transmetalation step. Our experimental studies highlight that such an approach is feasible, with a number of nickel catalysts shown to facilitate Hiyama cross-coupling of 1-fluoronapthalene under base free conditions, while no cross-coupling with 1-chloronapthalene occurred. Computational and experimental studies revealed the importance of reversible C?Cl oxidative addition for the development of selective C?F functionalisation, with ligand effects on the potential for reversibility also presented.
3-(5-CHLORO-2-OXOBENZO[D]OXAZOL-3(2H)-YL)PROPANOIC ACID DERIVATIVES AS KMO INHIBITORS
-
Page/Page column 41; 49, (2015/07/07)
A compound of formula (I) or a salt thereof are provided wherein R1, X and R3 are defined in the specification, useful in the treatment of disorders mediated by KMO such as acute pancreatitis, chronic kidney disease, other conditions associated with systemic inflammatory response syndrome (SIRS), Huntington's disease, Alzheimer's disease, spinocerebellar ataxias, Parkinson's disease, AIDS-dementia complex, amylotrophic lateral sclerosis (ALS), depression, schizophrenia, sepsis, cardiovascular shock, severe trauma, acute lung injury, acute respiratory distress syndrome, acute cholecystitis, severe burns, pneumonia, extensive surgical procedures, ischemic bowel, severe acute hepatic disease, severe acute hepatic encephalopathy or acute renal failure.
Ligand-free, palladium-catalyzed dihydrogen generation from TMDS: Dehalogenation of aryl halides on water
Bhattacharjya, Anish,Klumphu, Piyatida,Lipshutz, Bruce H.
supporting information, p. 1122 - 1125 (2015/03/14)
A mild and environmentally attractive dehalogenation of functionalized aryl halides has been developed using nanoparticles formed from PdCl2 in the presence of tetramethyldisiloxane (TMDS) on water. The active catalyst and reaction medium can be recycled. This method can also be applied to cascade reactions in a one-pot sequence.
Triton B-mediated efficient and convenient alkoxylation of activated aryl and heteroaryl halides
Meshram,Goud, P. Ramesh,Reddy, B. Chennakesava,Kumar, D. Aravind
experimental part, p. 2122 - 2129 (2010/08/13)
A simple and convenient one-pot synthesis of aryl alkyl ethers by the alkoxylation of aryl halides with alcohol in the presence of Triton B as a base is described. The procedure is applicable for a variety of aryl and heteroaryl halides, and yields are very good. The use of a nonmetallic base and solvent-free conditions are important features of the reaction. Copyright Taylor & Francis Group, LLC.
KINASE INHIBITORS AND METHODS OF USE
-
Page/Page column 83-84, (2010/04/03)
The present invention provides chemical entities or compounds and pharmaceutical compositions thereof that are capable of modulating certain protein kinases such as mTor, tyrosine kinases, and/or lipid kinases such as PI3 kinase. Also provided in the present invention are methods of using these compositions to modulate activities of one or more of these kinases, especially for therapeutic applications.
Catalytic process for regiospecific chlorination of alkanes, alkenes and arenes
-
Page column 6, (2008/06/13)
The present invention provides a process for regiospecific chlorination of an aromatic or aliphatic compound with a chlorine source comprising a metal chloride and other than Cl2and SO2Cl2in presence of hypervalent iodine catalyst and in acidic medium.
NaIO4-Mediated Selective Oxidative Halogenation of Alkenes and Aromatics Using Alkali Metal Halides
Dewkar, Gajanan K.,Narina, Srinivasarao V.,Sudalai, Arumugam
, p. 4501 - 4504 (2007/10/03)
(Equation presented) NaIO4 oxidizes alkali metal halides efficiently in aqueous medium to halogenate alkenes and aromatics and produce the corresponding halo derivatives in excellent regio and stereoselectivity. The system also demonstrates the asymmetric version of bromo hydroxylation using β-cyclodextrin complexes, resulting in moderate ee.
Kinetic studies of the reactions of some phenols and alkyl aryl ethers with dinitrogen pentoxide in perfluorocarbon solvents
Crampton,Gibbons,Millar
, p. 1662 - 1665 (2007/10/03)
The reaction of dinitrogen pentoxide in perfluorocarbon solvents with phenols and alkyl aryl ethers carrying halogeno ring-substituents results in nitrodehydrogenation. Rate measurements show that the preferred orientation of nitration is ortho > para > meta to the hydroxy group; the kinetic isotope effect, kH/kD, has a value close to unity. Phenols show considerably higher reactivity than similarly substituted alkyl phenyl ethers, and a mechanism is suggested involving initial interaction of N2O5 with the hydroxy function followed by reaction via cyclic transition states.
Chemoselective O-methylation of phenols under non-aqueous condition
Basak, Anindita,Nayak, Mrinal K.,Chakraborti, Asit K.
, p. 4883 - 4886 (2007/10/03)
Chemoselective O-methylation of substituted phenols takes place in dry. tetrahydrofuran (THF) in the presence of LiOH.H2O and dimethylsulfate (DMS). Quantitative methyl transfer from DMS preserves the atom economy.
Photochemical Nitration by Tetranitromethane. X. A Possible Addition/Elimination Pathway to Trinitromethylaromatic Compounds
Eberson, Lennart,Hartshorn, Michael P.,Svensson, Jan Olof
, p. 925 - 934 (2007/10/02)
The photolysis of tetranitromethane and 4-chloroanisole in dichloromethane at +20, -20 and -50 deg C led to the formation of mainly 4-chloro-2-trinitromethylanisole (40-50percent yield) and a pair of adducts (ca. 30percent yield) in which nitrito/trinitromethyl addition had taken place across the 2,5-positions of 4-chloroanisole.Small amounts of a pair of labile adducts (2-3percent yield), assigned the structure of the analogous hydroxy/trinitromethyl adducts were formed in the beginning of the runs.In acetonitrile, the major product from the same reaction was 4-chloro-2-nitroanisole at all three temperatures.Only at -50 deg C were the nitrito/trinitromethyl adducts detectable in low yield (1-2percent).The pair of nitrito/trinitromethyl adducts spontaneously decomposed in acetonitrile to give 4-chloro-2-trinitromethylanisole with rate constants of 7*10-4 min-1 at 0 deg C and 0.020 min-1 at 20 deg C, implying that they should be stable in this solvent at -20 and -50 deg C, if formed.The adducts also decomposed to 4-chloro-2-trinitromethylanisole under photochemical conditions accounting for the formation of this compound in low yield also in acetonitrile.The nitration process predominantly observed in acetonitrile presumably occurs via coupling of 4-chloroanisole radical cation and NO2, both formed in the initial photochemical step.The nitrito/trinitromethyl adducts were thermally and photochemically stable in dichloromethane under the reaction periods employed for photolysis.The conversion into labile hydroxy/trinitromethyl adducts was assumed to occur via acid-catalysed hydrolysis, eventually leading to 4-chloro-2-trinitromethylanisole via acid-promoted elimination of water from the latter adducts.However, only a minor part of this compound can be accounted for in this way.
