403-19-0Relevant articles and documents
Synthesis of 2 - fluoro phenol compounds
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, (2017/04/21)
The present invention provides a method for synthetizing a 2-fluoro phenol compound shown in a formula IV. The phenol compound shown in the formula I is prepared into a 2-pyridine oxygroup arene compound shown in a formula II through an Ullmann reaction, the 2-pyridine oxygroup arene compound shown in the formula II is mixed with a palladium catalyst, a fluorinating reagent, an additive and an organic solvent, the mixture is stirred under the temperature of 30-160 DEG C to perform a fluorination reaction to obtain an ortho-position fluoridated 2-pyridine oxygroup arene compound shown in a formula III, and the ortho-position fluoridated 2-pyridine oxygroup arene compound shown in the formula III is prepared into the 2-fluoro phenol compound shown in the formula IV through the action of alkali. The method provided by the present invention has the advantages of mild reaction conditions, simplicity in operations, good substrate adaptability, high fluorination selectivity and the like. The 2-fluoro phenol compound is shown in the figure below.
Design of chemical shift-switching 19F magnetic resonance imaging probe for specific detection of human monoamine oxidase A
Yamaguchi, Koya,Ueki, Ryosuke,Nonaka, Hiroshi,Sugihara, Fuminori,Matsuda, Tetsuya,Sando, Shinsuke
supporting information; experimental part, p. 14208 - 14211 (2011/10/31)
Monoamine oxidase (MAO) A is a flavoenzyme that catalyzes the oxidation of biologically important monoamines and is thought to be associated with psychiatric disorders. Here, we report a strategy for rationally designing a 19F magnetic resonanc
The element effect and nucleophilicity in nucleophilic aromatic photosubstitution (SNAR*). Local atom effects as mechanistic probes of very fast reactions
Wubbels, Gene G.,Brown, Toby R.,Babcock, Travis A.,Johnson, Kandra M.
, p. 1925 - 1934 (2008/09/19)
(Chemical Equation Presented) Photoreactions of 4-nitroanisole and the 2-halo-4-nitroanisoles (halogen = F, Cl, Br, and I) with the nucleophiles hydroxide ion and pyridine have been investigated quantitatively to extend the findings recently communicated for cyanide ion. The halonitroanisoles on excitation form triplet π,π* states, which undergo substitution of the halogen by nucleophiles. Chemical yields of photoproducts, Stern-Volmer kinetic plots, triplet lifetimes, and triplet yields are reported for the five compounds with the three nucleophiles. Following a standard kinetic treatment, 73 rate constants are determined for elementary reactions of the triplets including quenching and various nucleophilic addition processes. The photoadditions are roughly 14 orders of magnitude faster than thermal counterparts. Rate constants for attack at the fluorine-bearing carbon of triplet 2-fluoro-4-nitroanisole are 2.9 × 109, 1.3 × 109, and 6.3 × 108 M-1 s-1 for cyanide ion, hydroxide ion, and pyridine, respectively. The relative rates for attack at the halogen-bearing carbons for F/Cl/Br/I are 27:1.9:1.9:1 (cyanide ion), 29:2.6:2.4:1 (hydroxide ion), and 39:3.9: 3.5:1 (pyridine), respectively. The relative nucleophilicities vary somewhat with the attack site; they are about 5:2:1 for cyanide ion, hydroxide ion, and pyridine for attack at the halogen-bearing carbons. The trend of the element effect opposes that of aliphatic substitution and elimination but is similar in size and parallel to that of thermal nucleophilic aromatic substitution. Relative nucleophilicities in the photoreactions are also similar to those of comparable but vastly slower thermal reactions. The findings imply that the efficiency-determining step of the halogen photosubstitution is simple formation of a σ-complex through electron-paired bonding within the triplet manifold.
Elemental fluorine. Part 20. Direct fluorination of deactivated aromatic systems using microreactor techniques
Chambers, Richard D.,Fox, Mark A.,Sandford, Graham,Trmcic, Jelena,Goeta, Andres
, p. 29 - 33 (2008/03/13)
Continuous flow microreactor technology has been used for the direct fluorination of a range of deactivated di- and tri-substituted aromatic systems.
Elemental fluorine Part 12. Fluorination of 1,4-disubstituted aromatic compounds
Chambers, Richard D.,Hutchinson, John,Sparrowhawk, Matthew E.,Sandford, Graham,Moilliet, John S.,Thomson, Julie
, p. 169 - 173 (2007/10/03)
Direct fluorination of a series of 1,4-disubstituted benzene derivatives in acid reaction media at convenient temperature leads, in many cases, to selectively fluorinated aromatic products in preparatively useful conversions and yields.
Hydroxylation of Nitroarenes with Alkyl Hydroperoxide Anions via Vicarious Nucleophilic Substitution of Hydrogen
Makosza, Mieczyslaw,Sienkiewicz, Krzysztof
, p. 4199 - 4208 (2007/10/03)
Rhone-Poulenc Polska Ltd., ul. Grzybowska 80/82, 00-844 Warszawa, Poland Garbo- and heterocyclic nitroarenes react with anions of tert-butyl and cumyl hydroperoxides in the presence of strong bases to form substituted o- and p-nitrophenols. The reaction usually proceeds in high yields and is of practical value as a method of synthesis and manufacturing of nitrophenols. Orientation of the hydroxylation can be controlled to a substantial extent by selection of the proper conditions. Basic mechanistic features of this process were clarified.
Electrophilic Fluorination Using Elemental Fluorine
Chambers, Richard D.,Skinner, Christopher J.,Thomson, Julie,Hutchinson, John
, p. 17 - 18 (2007/10/02)
Electrophilic fluorination by elemental fluorine is promoted by the use of protonic acids; formic and sulfuric acids are especially effective.
Power and structure-variable fluorinating agents. The N-fluoropyridinium salt system
Umemoto, Teruo,Fukami, Shinji,Tomizawa, Ginjiro,Harasawa, Kikuko,Kawada, Kosuke,Tomita, Kyoichi
, p. 8563 - 8575 (2007/10/02)
The usefulness of the N-fluoropyridinium salt system as a source of fluorinating agents was examined by using substituted or unsubstituted N-fluoropyridinium triflates 1-11, N-fluoropyridinium salts possessing other counteranions 1a-d and 3a, and the counteranion-bound salts, N-fluoropyridinium-2-sulfonates 12 and 13. Electrophilic fluorinating power was found to vary remarkably according to the electronic nature of the ring substituents. This power increased as the electron density of positive nitrogen sites decreased, and this was correlated to the pKa values of the corresponding pyridines. By virtue of this variation, it was possible to fluorinate a wide range of nucleophilic substrates differing in reactivity. It is thus possible to fluorinate aromatics, carbanions, active methylene compounds, enol alkyl or silyl ethers, vinyl acetates, ketene silyl acetals, and olefins through the proper use of salts pentachloro 6 through 2,4,6-trimethyl 2, their power decreasing in this order. All the reactions could be explained on the basis of a one-electron-transfer mechanism. N-Fluoropyridinium salts showed high chemoselectivity in fluorination, the extent depending on the reactive moiety. In consideration of these Findings, selective 9α-fluorination of steroids was carried out by reacting 1 with tris(trimethylsilyl ether) 73 of a triketo steroid. Regio- or stereoselectivity in fluorination was determined by a N-fluoropyridinium salt structure. Steric bulkiness of the N-F surroundings hindered the ortho fluorination of phenols and aniline derivatives, while the capacity for hydrogen bonding on the part of the counteranions prompted this process, and the counteranion-bound salts 12 and 13 underwent this fluorination exclusively or almost so. Both bulky N-fluoropyridinium triflates 2 and 7 preferentially attacked the 6-position of the conjugated vinyl ester of a steroid from the unhindered β-direction to give a thermally unstable 6β-fluoro isomer. On the basis of these results, N-fluoropyridinium salts may be concluded to constitute a system that can serve as a source of the most ideal fluorinating agents for conducting desired selective fluorination through fluorinating capacity or structural alteration.
Hydroxylation of Nitroarenes with Alkyl Hydroperoxide Anions via Vicarious Nucleophilic Substitution of Hydrogen
Makosza, Mieczyslaw,Sienkiewicz, Krzysztof
, p. 4979 - 4981 (2007/10/02)
tert-Butyl and cumyl hydroperoxides in strongly basic media react with a variety of nitroarenes to produce o- and/or p-nitrophenols.The reaction proceeds via an addition-base-induced β-elimination pathway analogous to that of vicarious nucleophilic substitution.
