cas 1628-89-3, 2-Methoxypyridine | Articles data

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Murmann,Basolo
p. 3484
(1955)
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A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
García-Domínguez, Andrés,Gonzalez, Jorge A.,Leach, Andrew G.,Lloyd-Jones, Guy C.,Nichol, Gary S.,Taylor, Nicholas P.
supporting information

(2022/01/04)

Preparation method of ortho-alkoxy substituted pyridine compound
The invention provides a preparation method of an ortho-alkoxy substituted pyridine compound, the preparation method comprises the following step: reacting an ortho-amino substituted pyridine compound with an ortho-formate compound in the presence of a nitrite compound to generate the ortho-alkoxy substituted pyridine compound. The method has the advantages of high efficiency, low cost, environmental protection and the like.
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Paragraph 0052-0056

(2021/09/08)

Catalytic Reductions Without External Hydrogen Gas: Broad Scope Hydrogenations with Tetrahydroxydiboron and a Tertiary Amine
Facile reduction of aryl halides with a combination of 5% Pd/C, B2(OH)4, and 4-methylmorpholine is reported. Aryl bromides, iodides, and chlorides were efficiently reduced. Aryl dihalides containing two different halogen atoms underwent selective reduction: I over Br and Cl, and Br over Cl. Beyond these, aryl triflates were efficiently reduced. This combination was broadly general, effectuating reductions of benzylic halides and ethers, alkenes, alkynes, aldehydes, and azides, as well as for N-Cbz deprotection. A cyano group was unaffected, but a nitro group and a ketone underwent reduction to a low extent. When B2(OD)4 was used for aryl halide reduction, a significant amount of deuteriation occurred. However, H atom incorporation competed and increased in slower reactions. 4-Methylmorpholine was identified as a possible source of H atoms in this, but a combination of only 4-methylmorpholine and Pd/C did not result in reduction. Hydrogen gas has been observed to form with this reagent combination. Experiments aimed at understanding the chemistry led to the proposal of a plausible mechanism and to the identification of N,N-bis(methyl-d3)pyridin-4-amine (DMAP-d6) and B2(OD)4 as an effective combination for full aromatic deuteriation. (Figure presented.).
Korvinson, Kirill A.,Akula, Hari K.,Malinchak, Casina T.,Sebastian, Dellamol,Wei, Wei,Khandaker, Tashrique A.,Andrzejewska, Magdalena R.,Zajc, Barbara,Lakshman, Mahesh K.
supporting information
p. 166 - 176
(2020/01/02)

Discovery and characterization of an acridine radical photoreductant
Photoinduced electron transfer (PET) is a phenomenon whereby the absorption of light by a chemical species provides an energetic driving force for an electron-transfer reaction1–4. This mechanism is relevant in many areas of chemistry, including the study of natural and artificial photosynthesis, photovoltaics and photosensitive materials. In recent years, research in the area of photoredox catalysis has enabled the use of PET for the catalytic generation of both neutral and charged organic free-radical species. These technologies have enabled previously inaccessible chemical transformations and have been widely used in both academic and industrial settings. Such reactions are often catalysed by visible-light-absorbing organic molecules or transition-metal complexes of ruthenium, iridium, chromium or copper5,6. Although various closed-shell organic molecules have been shown to behave as competent electron-transfer catalysts in photoredox reactions, there are only limited reports of PET reactions involving neutral organic radicals as excited-state donors or acceptors. This is unsurprising because the lifetimes of doublet excited states of neutral organic radicals are typically several orders of magnitude shorter than the singlet lifetimes of known transition-metal photoredox catalysts7–11. Here we document the discovery, characterization and reactivity of a neutral acridine radical with a maximum excited-state oxidation potential of ?3.36 volts versus a saturated calomel electrode, which is similarly reducing to elemental lithium, making this radical one of the most potent chemical reductants reported12. Spectroscopic, computational and chemical studies indicate that the formation of a twisted intramolecular charge-transfer species enables the population of higher-energy doublet excited states, leading to the observed potent photoreducing behaviour. We demonstrate that this catalytically generated PET catalyst facilitates several chemical reactions that typically require alkali metal reductants and can be used in other organic transformations that require dissolving metal reductants.
MacKenzie, Ian A.,Wang, Leifeng,Onuska, Nicholas P. R.,Williams, Olivia F.,Begam, Khadiza,Moran, Andrew M.,Dunietz, Barry D.,Nicewicz, David A.
p. 76 - 80
(2020/04/17)

Room temperature dehalogenation of (hetero)aryl halides with magnesium/methanol
Magnesium in methanol was found to be an effective and inexpensive reagent for the dehalogenation of (hetero)aryl chlorides, bromides and iodides under mild conditions. The halogen/hydrogen exchange proceeded at room temperature and tolerated functional groups such as esters, nitriles, alcohols, and alkenes.
Jouha, Jabrane,Khouili, Mostafa,Hiebel, Marie-Aude,Guillaumet, Gérald,Suzenet, Franck
supporting information
p. 3108 - 3111
(2018/07/13)

NITROGEN-CONTAINING BIOPOLYMER-BASED CATALYSTS, THEIR PREPARATION AND USES IN HYDROGENATION PROCESSES, REDUCTIVE DEHALOGENATION AND OXIDATION
The present invention relates to a process for the preparation of a nitrogen containing biopolymer-based catalyst by pyrolysis of a metal complex with a nitrogen-containing biopolymer and to the nitrogen containing biopolymer-based catalysts obtainable by this process. In particular, the invention relates to a nitrogen containing biopolymer-based catalyst comprising metal particles and at least one nitrogen containing carbon layer. The invention also relates to the use of a nitrogen containing biopolymer-based catalyst in a hydrogenation process, preferably in a process for hydrogenation of nitroarenes, nitriles or imines; in a reductive dehalogenation process of C-X bonds, wherein X is CI, Br or I, preferably in a process for dehalogenation of organohalides or in a process for deuterium labelling of arenes via dehalogenation of organohalides; or in an oxidation process. Further, the invention relates to a metal complex with the nitrogen containing biopolymer, wherein the metal is a transition metal selected from the group consisting of manganese, ruthenium, cobalt, rhodium, nickel, palladium and platinum, preferably cobalt or nickel, and wherein the nitrogen containing biopolymer is selected from chitosan, chitin and a polyamino acid, preferably chitosan or chitin.
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Page/Page column 19

(2018/07/29)

Application of Silicon-Initiated Water Splitting for the Reduction of Organic Substrates
The use of water as a donor for hydrogen suitable for the reduction of several important classes of organic compounds is described. It is found that the reductive water splitting can be promoted by several metalloids among which silicon shows the best efficiency. The developed methodologies were applied for the reduction of nitro compounds, N-oxides, sulfoxides, alkenes, alkynes, hydrodehalogenation as well as for the gram-scale synthesis of several substrates of industrial importance.
Gevorgyan, Ashot,Mkrtchyan, Satenik,Grigoryan, Tatevik,Iaroshenko, Viktor O.
p. 375 - 382
(2018/06/04)

Novel synthesis method for ortho-alkane superseded pyridine
The invention relates to a novel synthesis method for ortho-alkane superseded pyridine. According to the method, ortho halogenated pyridine serves as raw materials, the ortho halogenated pyridine and corresponding alcohol react to obtain the ortho-alkane superseded pyridine under the action of sodium hydroxide. The reaction has universality for the ortho halogenated pyridine, and the method is simple and practical. Influence of consumption of the sodium hydroxide on mono-substitution and di-substitution in the reaction is inspected, alkoxy mono-substitution products and alkoxy di-substitution production are acquired, and a novel simply-operated, economical and favorable process for synthesis ortho-alkane superseded pyridine is provided.
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Paragraph 0018; 0019; 0020; 0021

(2017/07/19)

A Bifunctional Reagent Designed for the Mild, Nucleophilic Functionalization of Pyridines
Herein is reported the design and application of a reagent for the direct functionalization of pyridines. These reactions occur under mild conditions and exhibit broad functional group tolerance, enabling the late-stage functionalization of drug-like molecules. The reagent can be easily prepared on large scale from inexpensive reagents, and reacts in the title reaction with acetonitrile, sodium chloride, and sodium methanesulfonate as the sole byproducts. Although this Communication focuses primarily on reactions with cyanide as nucleophile, preliminary experiments with other nucleophiles foreshadow the broad reaching synthetic utility of this approach.
Fier, Patrick S.
supporting information
p. 9499 - 9502
(2017/07/24)

A Biomass-Derived Non-Noble Cobalt Catalyst for Selective Hydrodehalogenation of Alkyl and (Hetero)Aryl Halides
Hydrodehalogenation is a straightforward approach for detoxifications of harmful anthropogenic organohalide-based pollutants, as well as removal of halide protecting groups used in multistep syntheses. A novel sustainable catalytic material was prepared from biowaste (chitosan) in combination with an earth-abundant cobalt salt. The heterogeneous catalyst was fully characterized by transmission electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy measurements, and successfully applied to hydrodehalogenation of alkyl and (hetero)aryl halides with broad scope (>40 examples) and excellent chemoselectivity using molecular hydrogen as a reductant. The general usefulness of this method is demonstrated by successful detoxification of non-degradable pesticides and fire retardants. Moreover, the potential of the catalyst as a deprotection tool is demonstrated in a multistep synthesis of (±)-peronatin B (alkaloid).
Sahoo, Basudev,Surkus, Annette-Enrica,Pohl, Marga-Martina,Radnik, J?rg,Schneider, Matthias,Bachmann, Stephan,Scalone, Michelangelo,Junge, Kathrin,Beller, Matthias
supporting information
p. 11242 - 11247
(2017/09/02)

The effects of intramolecular hydrogen bonding on the reactivity of phenoxyl radicals in model systems
The effects of hydrogen bonding and spin density at the oxygen atom on the gas-phase reactivity of phenoxyl radicals were investigated experimentally and theoretically in model systems and the dipeptide LysTyr. Gas-phase ion-molecule reactions were carried out between radical cations of several aromatic nitrogen bases with the neutrals nitric oxide and n-propyl thiol. Reactivity of radical cations 4-6 correlated with the spin density. The possibility of hydrogen bonding was explored in compounds which allowed four-, five-, and six-membered rings to be formed between the protonated nitrogen and the phenoxyl oxygen, while possessing similar spin density at the oxygen atom. The N+-H?O? bond length was calculated to decrease in the series (1-3), consistent with the theoretical calculations finding weak hydrogen bonding in 2 and strong hydrogen bonding in 3. This coincided with the decrease in reaction rates of 1-3 with both nitric oxide and n-propyl thiol. DFT calculations found that the lowest energy structure of the distonic radical cation of the dipeptide [LysTyr(O)?]+ has a short hydrogen bond between the protonated Lys side chain and the phenoxyl oxygen, 1.70 ?, which is consistent with its low reactivity.
Lesslie, Michael,Piatkivskyi, Andrii,Lawler, John,Helgren, Travis R.,Osburn, Sandra,O'Hair, Richard A.J.,Ryzhov, Victor
p. 124 - 131
(2015/10/20)

A Magnesium-Based Diastereoselective Preparation of Pyridylic 1,3-Amino Alcohols Using the tert -Butyl Sulfinamide Auxiliary
1,3-Amino alcohols were prepared by using a two-step approach and an interesting reversal in diastereoselectivity is discussed.
Fjelbye, Kasper,Svenstrup, Niels,Püschl, Ask
p. 3231 - 3240
(2015/10/19)

A convenient and practical synthesis of anisoles and deuterated anisoles by palladium-catalyzed coupling reactions of aryl bromides and chlorides
Synthesis of anisole: Aryl and heteroaryl halides undergo selective C-O cross-coupling reactions with methanol in the presence of a Pd(OAc) 2/L3 catalyst system. The corresponding ethers were obtained under mild conditions in good yields. The catalytic methodology was also used for the synthesis of labeled deuterated anisoles in good yields (see scheme). Copyright
Gowrisankar, Saravanan,Neumann, Helfried,Beller, Matthias
supporting information; experimental part
p. 2498 - 2502
(2012/03/27)

Synthesis of unsymmetrical arylheteroarylmethanes by direct "on water" cross-coupling between benzylic and heteroaromatic halides
Walking on water: Pharmacologically important unsymmetrical arylheteroarylmethanes are prepared by simple palladium-catalyzed zinc-mediated Negishi-like cross-couplings in good yields. This reaction tolerates various benzylic chlorides and heteroaromatic bromides "on water" and at room temperature.
Krasovskaya, Valeria,Krasovskiy, Arkady,Lipshutz, Bruce H.
scheme or table
p. 1974 - 1976
(2011/10/31)

Microwave assisted rapid preparation of N-alkyl-2-pyridones under neutral conditions by Hilbert-Johnson reaction
The reactions of 2-methoxypyridine with haloalkanes without solvent and catalyst under microwave irradiation (100-200 °C, 5 min) yielded the corresponding N-alkyl-2(1H)-pyridones in good to moderate yields. However, the reactions were sensitive to length of haloalkanes. In contrast, the reactions of 2-alkoxypyridines with corresponding iodoalkanes under microwave irradiation (150 °C) proceeded rapidly without catalyst and solvent, and were complete within 5 min to afford N-alkyl-2(1H)-pyridones in good to excellent yields. The Japan Institute of Heterocyclic Chemistry.
Iida, Hirokazu,Suda, Machiko,Nakajima, Etsuko,Hakamatsuka, Hiroko,Nagashima, Yuka,Joho, Kouta,Amemiya, Kenta,Moromizato, Tatsuya,Matsumoto, Kiyoshi,Murakami, Yasuoki,Hamana, Hiroshi
scheme or table
p. 2057 - 2062
(2011/04/12)

Mechanism of the triplet-sensitized photolysis of 1-[1-(1-naphthyl)ethoxy]-2-pyridone and related derivatives
On irradiation at 366 nm in the presence of benzophenone, the title 2-pyridone derivatives (1) in nitrogen-saturated acetonitrile underwent sensitized decomposition to give arylaldehyde and 2-methoxypyridine in addition to the expected N-O bond cleavage p
Watanabe, Asako,Matsushita, Maya,Masuda, Aya,Igarashi, Tetsutaro,Sakurai, Tadamitsu
experimental part
p. 2431 - 2437
(2010/04/25)

Rhodium-catalyzed asymmetric 1,4-addition of heteroaryl cyclic triolborate to α,β-unsaturated carbonyl compounds
Rhodium-catalyzed asymmetric 1,4-additions of electron-deficient heteroaryl groups to α,β-unsaturated carbonyl compounds were established. The reaction resulted in very low yields due to competitive C-B bond cleavage when arylboronic acids, their pinacol
Yu, Xiao-Qiang,Yamamoto, Yasunori,Miyaura, Norio
scheme or table
p. 994 - 998
(2009/10/10)

Microwave-assisted silver(I)-mediated selective O-alkylation of aromatic imidate systems
A novel microwave-assisted protocol has been developed for the selective O-alkylation of aromatic imidate systems with various halides under microwave irradiation using silver carbonate as the base. Products were obtained in short reaction time and in excellent yields. Georg Thieme Verlag Stuttgart.
Singh, Brajendra K.,Cavalluzzo, Claudia,De Maeyer, Marc,Debyser, Zeger,Parmar, Virinder S.,Van Der Eycken, Erik
experimental part
p. 2725 - 2728
(2010/01/21)

Streamlined synthesis of the bippyphos family of ligands and cross-coupling applications
We describe the efficient preparation of Bippyphos, 1. The key precursor to Bippyphos, 5, was prepared via a one-pot bromination of diketone 2 followed by alkylation with pyrazole and condensation with phenylhydrazine. Lithiation of 5 and trapping with ditert-butylchlorophosphine afforded Bippyphos, 1. Using this approach we have prepared several derivatives of Bippyphos to probe the structure and activity relationships of this family of phosphine ligands. We also demonstrate the utility of these ligands in Pdcatalyzed amination reactions and other cross-coupling reactions.
Withbroe, Gregory J.,Singer, Robert A.,Sieser, Janice E.
p. 480 - 489
(2013/01/03)

ANTIBACTERIAL COMPOSITIONS
Compounds of formula (I) have antibacterial activity: wherein: m is 0 or 1 ; Q is hydrogen or cyclopropyl; AIk is an optionally substituted, divalent C1-C6 alkylene, alkenylene or alkynylene radical which may contain an ether (-O-), thioether (-S-) or amino (-NR)- link, wherein R is hydrogen, -CN or C1-C3 alkyl; X is -C(=O)NR6-, -S(O)NR6-, -C(=O)O- or -S(=O)O- wherein R6 is hydrogen, optionally substituted C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, -Cyc, or -( C1-C3 alkyl)-Cyc wherein Cyc is optionally substituted monocyclic carbocyclic or heterocyclic having 3-7 ring atoms; Z is N or CH, or CF; R2 and R3 are as defined in the description.
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Page/Page column 67

(2008/06/13)

Mix-and-heat benzylation of alcohols using a bench-stable pyridinium salt
2-Benzyloxy-1-methylpyridinium inflate (1) is a stable, neutral organic salt that converts alcohols into benzyl ethers upon warming. The synthesis and reactivity of 1 are described herein. Benzylation of a wide range of alcohols occurs in good to excellent yield.
Poon, Kevin W. C.,Dudley, Gregory B.
p. 3923 - 3927
(2007/10/03)

Lithiation of 2-chloro- and 2-methoxypyridine with lithium dialkylamides: Initial ortho-direction or subsequent lithium ortho-stabilization?
The lithiation pathway of 2-chloro and 2-methoxypyridine with LDA and LTMP has been investigated using deuterated probes. The availability of both H-6 and H-3 protons on the pyridine nucleus was found to be critical to ensure complete C-3 lithiation. We thus concluded that the C-3 lithiation was not a straightforward process. A mechanism involving precomplexation of lithium dialkylamides near the H-6 proton and formation of a 3,6-dilithio pyridine intermediate is proposed.
Gros, Philippe,Choppin, Sabine,Fort, Yves
p. 2243 - 2247
(2007/10/03)

On the thermally induced rearrangement of 2-alkoxypyridines to N-alkylpyridones
Analogues of 2-methoxypyridine undergo rearrangement to N-methylpyridones under flash vacuum pyrolysis (FVP) conditions. Ethoxy derivatives undergo competitive ethyl migration and elimination of ethylene. Analogues of 4-methoxypyridine do not undergo rearrangement under FVP conditions, but demethylation on silica may occur. The ease of rearrangement follows the basicity of the alkoxyhetarene to some extent. The vapour-phase rearrangements have been contrasted to condensed-phase pyrolyses. and a four-centre transition state for the former is supported by computation. The rearrangement allows structural assignment to the two products from the reaction of 2,4-dichloroquinoline with pyrrolidine.
Lister, Troy,Prager, Rolf H.,Tsaconas, Michael,Wilkinson, Kerry L.
p. 913 - 916
(2007/10/03)

Non-peptide bombesin receptor antagonists
The compounds of the instant invention are novel compounds of Formula I or a pharmaceutically acceptable salt thereof wherein Ar is phenyl or pyridyl unsubstituted or substituted. Ar1can be independently selected from Ar and can also include pyridyl-N-oxide, indolyl, imidazole, and pyridyl; R3can be independently selected from Ar or is hydrogen, hydroxy, NMe2, N-methyl-pyrrole, imidazole, tetrazole, thiazole (a), (b), (c), or (d), wherein Ar2is phenyl or pyridyl. The instant compounds antagonize the bombesin receptors in mammals and are therefore effective in treating and/or preventing depression, psychoses, seasonal affective disorders, cancer, feeding disorders, gastrointestinal disorders, inflammatory bowel disease, sleep disorders, and memory impairment.
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(2008/06/13)

Improved synthesis of aryltriethoxysilanes via palladium(O)-catalyzed silylation of aryl iodides and bromides with triethoxysilane
The scope of the palladium-catalyzed silylation of aryl halides with triethoxysilane has been expanded to include aryl bromides. A more general Pd(0) catalyst/ligand system has been developed that activates bromides and iodides: palladium(O) dibenzylideneacetone (Pd(dba)2) is activated with 2-(di-tert-butylphosphino)biphenyl (Buchwald's ligand) (1:2 mol ratio of Pd/phosphine). Electronrich para- and meta-substituted aryl halides (including unprotected aniline and phenol derivatives) undergo silylation to form the corresponding aryltriethoxysilane in fair to excellent yield; however, ortho-substituted aryl halides failed to be silylated.
Manoso,DeShong
p. 7449 - 7455
(2007/10/03)

Thrombin inhibitors
Compounds of the invention, useful as thrombin inhibitors and having therapeutic value in for example, preventing coronary artery disease, have the following structure: or a pharmaceutically acceptable salt thereof, wherein A is
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(2008/06/13)

Elemental fluorine. Part 10.1 Selective fluorination of pyridine, quinoline and quinoxaline derivatives with fluorine-iodine mixtures
Selective fluorination of a range of pyridine and quinoline substrates to give corresponding 2-fluoro-derivatives can be readily achieved in high yield at room temperature using elemental fluorine-iodine mixtures. Reaction of fluorine with iodine forms, in situ, systems that function like sources of both iodonium and fluoride ions and fluorination of heterocyclic derivatives is suggested to proceed by fluoride ion attack on intermediate W-iodo-heterocyclic species. Quinoxaline derivatives react under similar conditions to give either the 2-fluoro- or 2,3-difluoro-quinoxaline derivatives depending on the ratio of fluorine passed through the solution. In related processes, pyridine can be alkoxylated upon reaction of an appropriate alcohol and fluorine.
Chambers, Richard D.,Parsons, Mandy,Sandford, Graham,Skinner, Christopher J.,Atherton, Malcolm J.,Moilliet, John S.
p. 803 - 810
(2007/10/03)

Novel base-initiated reactions of N-substituted pyridinium salts
Reaction of N-fluoropyridinium triflate with a base in dichloromethane gave 2-chloropyridine as the major product along with 2-pyridyl triflate and 2-fluoropyridine, regardless of the nature of the base. This base-initiated reaction was also shown to take place similarly in other halogenated alkanes, ethers, a nitrile, aromatics, a ketone, vinyl ethers, alcohols and trimethylsilyl acetate as solvents to give pyridine derivatives substituted with a solvent molecule (s) at the 2-position. N-(Trifluoromethanesulfonyloxy)-and (benzenesulfonyloxy) pyridinium salts were found to undergo the same base-initiated reaction. These reactions may be explained by a postulated singlet carbene (canonical formula 11b) produced through proton abstraction of N-substituted pyridinium salts. A similar carbene reaction may thus likely occur in the thermal decomposition of thiatriazole 10. Ab initio MO calculations revealed the structure and properties of the labile deprotonated N-fluoropyridinium cation and supported the carbene intermediate reaction mechanism rather than a pyridynium or pyridyl cation mechanism. Quarroz's reports on the reactions of picolinic acid N-oxide and the reported reactions of pyridines with F2, CH3COOF or CsSO4F in solvents may be explained by this carbene mechanism.
Umemoto, Teruo,Tomizawa, Ginjiro,Hachisuka, Hitoharu,Kitano, Masakatsu
p. 161 - 168
(2007/10/03)

A highly regioselective reaction of N-fluoropyridinium salts with stabilized sulfur, oxygen, and nitrogen nucleophiles: A convenient route to 2-substituted pyridines
2-Substituted pyridines are efficiently obtained by the reactions of N- fluoropyridinium tetrafluoroborate or triflate with anions derived from benzenethiols, phenols, azoles, cyanamide, and with azide anion. The results are consistent with a nucleophile addition at the position 2 of the N- fluoropyridinium cation as the major reaction pathway.
Kiselyov,Strekowski
p. 1361 - 1364
(2007/10/02)

Cyclisation reactions of 2-substituted biphenyl-2'-yldiazonium salts leading to O-alkyldibenzofuranium and S-alkyldibenzothiophenium salts: Modified Meerwein reagents
The preparation of 2-amino-2'-methoxybiphenyl and 2-amino-2'-thiomethoxybiphenyl and analogues and their transformation into diazonium salts and hence into dibenzofuranium and dibenzothiophenium salts is described together with their use as alkylating agents.
Downie,Heaney,Kemp,King,Wosley
p. 4005 - 4016
(2007/10/02)

Copper(I) Halide Catalysed Synthesis of Alkyl Aryl and Alkyl Heteroaryl Ethers
A number of alkyl aryl and alkyl heteroaryl ethers have been prepared from (hetero) aryl halides (mainly bromides) and sodium alkoxides, using copper(I)bromide as a catalyst.The influence of the main solvent, the halogen atom, reaction temperature and the presence of oxygen upon the rate and selectivity has been studied.Furthermore the decomposition of the catalyst and the reduction of the aryl halide are studied.
Keegstra, Menno A.,Peters, Theo H. A.,Brandsma, Lambert
p. 3633 - 3652
(2007/10/02)

Utilizing Acetyl Hypofluorite for Chlorination, Bromination, and Etherification of the Pyridine System
Acetyl hypofluorite, which is easily made from F2, possesses a strong electrophilic fluorine.This electrophile is able to attach itself to the nitrogen atom of pyridine and activate the ring toward nucleophilic attacks.The ultimate elimination of HF results in an overall easy nucleophilic displacement of the hydrogen of the important 2-position .The nucleophiles used: Clδ-, Brδ-, ROδ-, originate from solvents such as CH2Cl2, CH2Br2, and various primary alcohols.Thus, 2-halo- or 2-alkoxypyridines were formed.The reaction conditions (room temperature, very short reaction times, and good yields) transform the task of direct substitution of the pyridine ring from an extremely difficult to a very easy procedure.
Hebel, David,Rozen, Shlomo
p. 6298 - 6301
(2007/10/02)

Direct photolysis of halopyridines in solutions; generation of the 2-pyridyl cation
Direct photolyses of 2-halopyridine in various solvents afforded the corresponding ionic products, as well as the radical product pyridine, while 3- and 4-halopyridines produced pyridine exclusively. The formation of the ionic products may occur via the 2-pyridyl cation generated through the initial photo-induced homolytic cleavage of the C-X bond followed by electron transfer within the resulting radical pair. The participation of the unshared pair of electrons adjacent to the radical carbon is suggested to be important for releasing the unpaired electron.
Ohkura,Seki,Terashima,Kanaoka
p. 3168 - 3169
(2007/10/02)

Method for the synthesis of huperzine A and analogs thereof and compounds useful therein
The present invention relates to a method for the synthesis of certain bridged fused ring pyridines. Such bridged fused ring pyridines can be converted to huperzine A and analogs of huperzine A. The present invention also covers such bridged fused ring pyridines, compounds utilized for the preparation of the bridged fused ring pyridines and analogs of huperzine A.
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(2008/06/13)

Reactions of Caesium Fluoroxysulphate with Pyridine
Pyridine readily reacts with CsSO4F in various solvents at room temperature producing a mixture of up to three products (2-fluoropyridine, 2-pyridyl fluorosulfonate and 2-chloro or 2-alkoxypyridine), their distribution strongly depending on the solvent used.Reaction of 3-chloropyridine with CsSO4F in methanol leads regioselectively to 2-methoxy-3-chloropyridine, while 3-methylpyridine was converted into 2-methoxy-3-methyl and 2-methoxy-5-methylpyridine in a 2:1 relative ratio.
Stavber, Stojan,Zupan, Marko
p. 775 - 776
(2007/10/02)

THE PYRIDYL CATION AS A REACTIVE INTERMEDIATE IN THE PHOTOREACTION OF IODOPYRIDINES WITH BENZENES
The electrophilic behavior of the reactive entity in the photosubstitution of benzenes with 2-iodopyridine was found to be ascribable to the intermediary 2-pyridyl cation, rather than the electrophilic 2-pyridyl radical.
Ohkura, Kazue,Seki, Koh-ichi,Terashima, Masanao,Kanaoka, Yuichi
p. 3433 - 3436
(2007/10/02)

Chlorination, Bromination, and Oxygenation of the Pyridine Ring Using AcOF Made from F2
Acetyl hypofluorite reacts with pyridines in halogenated solvents or alcohols to give the corresponding 2-halo- or 2-alkoxypyridines.
Hebel, David,Rozen, Shlomo
p. 1123 - 1125
(2007/10/02)

BASE-INITIATED REACTIONS OF N-FLUOROPYRIDINIUM SALTS; A NOVEL CYCLIC CARBENE PROPOSED AS A REACTIVE SPECIES
A new type of base-initiated reactions of pyridinium salts was found and a novel cyclic carbene was proposed as the reactive species.
Unemoto, Teruo,Tomizawa, Ginjiro
p. 2705 - 2708
(2007/10/02)

ACTIVATION OF REDUCING AGENTS. SODIUM HYDRIDE CONTAINING COMPLEX REDUCING AGENTS 23. SYMMETRICAL COUPLING OF NITROGEN-CONTAINING HETEROCYCLIC HALIDES
The preparation of NiCRA (NaH-tBuONa-Ni(OAc)2) in the presence of PPh3 leads to a reagent (termed NiCRA-PPh3) which is shown to be one of the most efficient Ni containing reagents reported so far for the homocoupling of heteroaromatic halides.
Vanderesse, R.,Lourak, M.,Fort, Y.,Caubere, P.
p. 5483 - 5486
(2007/10/02)

A convenient synthesis of bipyridines by nickel-phosphine complex-mediated homo coupling of halopyridines
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Tiecco,Testaferri,Tingoli,et al.
p. 736 - 738
(2007/10/02)

DEILS-ALDER ADDUCTS FROM N-SUBSTTITUED TAUTOMERIC 2(1H)-PYRIDONE-2-HYDROXYPYRIDINES; 5,6-BENZO-AZABARRELENONES AND 5,6-BENZO-AZABARRELENES
Diels-Alder reactions of several N-unsubstitued tautomeric 2(1H)-pyridone-2-hydroxypyridines with benzyne were examined and found to afford 5,6-azabarrelenones, wich were converted to hitherto unknown 5,6-benzo-azabarrelenes.
Kuzuya, Masayuki,Mano, Ei-ichi,Adachi, Michihiro,Noguchi, Akihiro,Okuda, Takachiyo
p. 475 - 478
(2007/10/02)

A NEW METHOD FOR DEOXYGENATION OF HETEROAROMATIC N-OXIDES WITH CHLOROTRIMETHYLSILANE/SODIUM IODIDE/ZINC
Heteroaromatic N-oxides are easily deoxygenated with chlorotrimethylsilane/sodium iodide/zinc in acetonitrile to give the corresponding parent bases in good yields.
Morita, Tsuyoshi,Kuroda, Koji,Okamoto, Yoshiki,Sakurai, Hiroshi
p. 921 - 924
(2007/10/02)