- Accelerated hydrolysis of α-halo and α-cyano pyridinium relative to uracil derivatives: A model for ODCase-catalyzed hydrolysis of 6-cyanoUMP
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α-Halo and α-cyano pyridiniums were found to undergo facile hydrolysis, in contrast to the sluggish reactions of corresponding uracils. The greatly enhanced rates found with pyridinium compounds have indicated a possible source of the rate acceleration seen in the hydrolysis of 6-cyanouridine 5′-monophosphate catalyzed by orotidine 5′-monophosphate decarboxylase.
- Huang, Sha,Wong, Freeman M.,Gassner, George T.,Wu, Weiming
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Read Online
- Micellar Effects upon the Reaction of Hydroxide Ion with N-Alkyl-2-bromopyridinium Ion
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The reactivity of N-alkyl-2-bromopyridinium ions (alkyl = Me, Et, n-C12H25, n-C14H29, n-C16H33) toward OH(-) is affected by cationic micelles of alkyltrimethylammonium chloride or bromide (alkyl = n-C14H29, n-C16H33) which inhibit reactions of the methyl
- Al-Lohedan, Hamad A.,Bunton, Clifford A.,Romsted, Laurence S.
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Read Online
- PhICl2/NH4SCN-Mediated Oxidative Regioselective Thiocyanation of Pyridin-2(1H)-ones
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The reaction of pyridin-2(1H)-ones with PhICl2 and NH4SCN enables an efficient regioselective thiocyanation, leading to the synthesis of the biologically interesting C5 thiocyanated 2-pyridones in good to high yields. The mechanistic pathway of this metal-free approach is postulated to involve the formation of the reactive thiocyanogen chloride from the reaction of PhICl2 and NH4SCN followed with the regioselective electrophilic thiocyanation of the pyridin-2(1H)-one ring.
- Tao, Shanqing,Xiao, Jiaxi,Li, Yadong,Sun, Fengxia,Du, Yunfei
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p. 2536 - 2546
(2021/07/31)
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- Manganese-Promoted Regioselective Direct C3-Phosphinoylation of 2-Pyridones
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A highly efficient and regioselective manganese-induced radical oxidative direct C?P bond formation between 2-pyridones and secondary phosphine oxides was developed. The C3-selective phosphinoylation was conveniently achieved through a combination of substoichiometric manganese and persulfate oxidant under mild conditions. Various 3-phosphinoylated pyridone products can be obtained in moderate to high yields. Preliminary mechanistic studies suggest that the reaction is likely to involve a radical pathway induced by catalytically active Mn3+ species.
- Chantarojsiri, Teera,Kittikool, Tanakorn,Phakdeeyothin, Kunita,Yotphan, Sirilata
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supporting information
p. 3071 - 3078
(2021/07/22)
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- Decarboxylation of orotic acid analogues: Comparison of solution and gas-phase reactivity
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The decarboxylation of orotic acid and analogues have been investigated as a model for enzymatic decarboxylation catalyzed by orotidine-5′-monophosphate decarboxylase (ODCase). The rate of decarboxylation of 1-methyl-4-pyridone-2-carboxylic acid in solution has been reported to be three orders of magnitude greater than those of 1,3-dimethylorotic acid and 1-methyl-2-pyridone-6-carboxylic acid in solution. Here, the gas-phase decarboxylation of the three corresponding carboxylates were investigated. The carboxylate of 1,3-dimethylorotic acid decarboxylates at a faster rate and thus the relative rates of decarboxylation are different from those observed in solution. The relative rates of decarboxylation correlate well with the stability of the corresponding carbanions and the calculated activation energies for gas-phase decarboxylation. Therefore, the reactions in the gas phase seem to go through the direct decarboxylation mechanism whereas the reactions in solution likely go through zwitterionic intermediates as previously proposed.
- Wong, Amy,Vikse, Krista,Wu, Weiming
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supporting information
(2020/08/06)
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- Iron-Catalyzed Reactions of 2-Pyridone Derivatives: 1,6-Addition and Formal Ring Opening/Cross Coupling
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In the presence of simple iron salts, 2-pyridone derivatives react with Grignard reagents under mild conditions to give the corresponding 1,6-addition products; if the reaction medium is supplemented with an aprotic dipolar cosolvent after the actual addition step, the intermediates primarily formed succumb to ring opening, giving rise to non-thermodynamic Z,E-configured dienoic acid amide derivatives which are difficult to make otherwise. Control experiments as well as the isolation and crystallographic characterization of a (tricarbonyl)iron pyridone complex suggest that the active iron catalyst generated in situ exhibits high affinity to the polarized diene system embedded into the heterocyclic ring system of the substrates, which likely serves as the actual recognition element.
- Huang, Lin,Gu, Yiting,Fürstner, Alois
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supporting information
p. 4017 - 4023
(2019/08/07)
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- Metal-free regioselective direct thiolation of 2-pyridones
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A highly regioselective metal-free direct C-H thiolation of 2-pyridones with disulfides or thiols has been developed. A combination of persulfate and a commercially available halide source such as LiCl, NCS or I2 enables the successful direct incorporation of a sulfide moiety into the 5-position of pyridone under mild conditions, providing a useful and convenient approach for the preparation of a diverse array of 5-thio-substituted pyridones in moderate to excellent yields.
- Phakdeeyothin, Kunita,Yotphan, Sirilata
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supporting information
p. 6432 - 6440
(2019/07/09)
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- Catalytic O- to N-Alkyl Migratory Rearrangement: Transition Metal-Free Direct and Tandem Routes to N-Alkylated Pyridones and Benzothiazolones
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The present study reports the synthesis of N-alkylated pyridones and benzothiazolones via O- to N-alkyl group migration under transition metal-free TfOH-catalyzed reaction conditions for the first time, to the best of our knowledge. Primary as well as secondary alkyl groups smoothly migrate under the present reaction conditions. Moreover, a minor modification of the protocol used in this study is found to be applicable for an entirely new tandem synthesis of 2-alkoxy-N-heterocycles from the simplest starting materials in a solvent-free reaction conditions. Density Functional Theory (DFT) calculation identifies the energy species associated with the rearrangement, whereas, mechanistic experiments explore the role of the catalyst as the alkyl group transfer mediator. (Figure presented.).
- Mishra, Abhishek Kumar,Morgon, Nelson Henrique,Sanyal, Suparna,Robinson de Souza, Aguinaldo,Biswas, Srijit
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p. 3930 - 3939
(2018/09/14)
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- Synthetic method for drug intermediate N-methylpyridin-2-one
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The invention discloses a synthetic method for the drug intermediate N-methylpyridin-2-one. The synthetic method comprises the following steps: adding 6-methoxypyridine, a potassium chloride solutionand a heptane solution into a reaction vessel, controlling a solution temperature, adding an aqueous solution and aluminum isopropoxide, controlling a stirring speed and continuing a reaction; and adding osmium trichloride powder, controlling the temperature, continuing the reaction, then lowering the temperature, carrying out stand so as to realize layering of the obtained solution, separating anoil layer, carrying out washing with a sodium sulfate solution a plurality of times, then carrying out washing with a xylene solution a plurality of times, carrying out recrystallization in a cyclohexene solution, and then carrying out dehydration with a dehydrating agent to obtain the finished N-methylpyridin-2-one.
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Paragraph 0012; 0014-0025
(2018/07/30)
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- Direct Pd(II)-Catalyzed Site-Selective C5-Arylation of 2-Pyridone Using Aryl Iodides
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A straightforward Pd(II)-catalyzed general strategy was developed for the C5-selective arylation of the 2-pyridone core with easily available aryl iodides. The transformation was highly regioselective and accomplished with a wide scope and functional group tolerance. Silver nitrate played a crucial role in this direct site-selective arylation. The method was extended to synthesize biologically active molecules.
- Maity, Saurabh,Das, Debapratim,Sarkar, Souradip,Samanta, Rajarshi
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supporting information
p. 5167 - 5171
(2018/09/13)
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- Compositions for Treatment of Cystic Fibrosis and Other Chronic Diseases
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The present invention relates to pharmaceutical compositions comprising an inhibitor of epithelial sodium channel activity in combination with at least one ABC Transporter modulator compound of Formula A, Formula B, Formula C, or Formula D. The invention also relates to pharmaceutical formulations thereof, and to methods of using such compositions in the treatment of CFTR mediated diseases, particularly cystic fibrosis using the pharmaceutical combination compositions.
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Paragraph 0697
(2015/09/22)
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- Kinetic assessment of N-methyl-2-methoxypyridinium species as phosphonate anion methylating agents
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Organophosphate nerve agents and pesticides are potent inhibitors of acetylcholinesterase (AChE). Although oxime nucleophiles can reactivate the AChE-phosphyl adduct, the adduct undergoes a reaction called aging. No compounds have been described that reactivate the aged-AChE adduct. A family of 2-methoxypyridinium species which reverse aging in a model system is presented. A kinetic study of this system, which includes an SAR analysis, demonstrates that the reaction is highly tunable based on the ring substituents.
- Topczewski, Joseph J.,Quinn, Daniel M.
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p. 1084 - 1087
(2013/04/10)
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- Ir(I)-catalyzed synthesis of N-substituted pyridones from 2-alkoxypyridines via C-O bond cleavage
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A cationic Ir(I) complex-catalyzed O-to-N-alkyl migration in 2-alkoxypyridines bearing a secondary alkyl group on the oxygen atom by C-O bond cleavage is described. The present transformation gave various N-alkylpyridones in moderate to good yields. The addition of sodium acetate played a key role in suppressing β-hydrogen elimination.
- Pan, Shiguang,Ryu, Naoto,Shibata, Takanori
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supporting information
p. 1902 - 1905
(2013/06/04)
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- MODULATORS OF ATP-BINDING CASSETTE TRANSPORTERS
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The present invention relates to modulators of ATP-Binding Cassette (“ABC”) transporters or fragments thereof, including Cystic Fibrosis Transmembrane Conductance Regulator, compositions thereof, and methods therewith. The present invention also relates to methods of treating ABC transporter mediated diseases using such modulators.
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- On the reactivity of imidazole carbamates and ureas and their use as esterification and amidation reagents
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The optimization, substrate scope, and mechanism of esterification and amidation of carboxylic acids mediated by imidazole-based reagents are discussed. The innate reactivity of carbonylimidazole reagents with a range of nucleophiles is also explored. New reagents developed for the synthesis of α,β-unsaturated esters are described, as are reagents for the preparation of tertiary amides directly from carboxylic acids.
- Heller, Stephen T.,Sarpong, Richmond
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scheme or table
p. 8851 - 8859
(2011/12/02)
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- COMPOSITIONS FOR TREATMENT OF CYSTIC FIBROSIS AND OTHER CHRONIC DISEASES
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The present invention relates to pharmaceutical compositions comprising an inhibitor of epithelial sodium channel activity in combination with at least one ABC Transporter modulator compound of Formula A, Formula B, Formula C, or Formula D. The invention also relates to pharmaceutical formulations thereof, and to methods of using such compositions in the treatment of CFTR mediated diseases, particularly cystic fibrosis using the pharmaceutical combination compositions.
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- Microwave assisted rapid preparation of N-alkyl-2-pyridones under neutral conditions by Hilbert-Johnson reaction
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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
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experimental part
p. 2057 - 2062
(2011/04/12)
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- Synthesis and rearrangement of quinone-embedded epoxycyclopentenones: A new avenue to pyranonaphthoquinones and indenopyranones
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The epoxyquinones (e.g., 24), readily assembled in one step from the quinols (e.g., 27) by a simplified version of the Dowd oxidation, are shown to undergo rearrangement to pyranonaphthoquinones (e.g., 28) and their ring contracted homologues (e.g., 29) on flash vacuum pyrolysis at 450 °C and 0.01 Torr. The rearrangement has been demonstrated to be useful for a regiospecific synthesis of lambertellin (3). Similarly, the masked aziridinocyclopentanone 9 rearranges to 2-pyridone (37).
- De Saroj,Ghorai, Sujit K.,Mal, Dipakranjan
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body text
p. 1598 - 1604
(2009/07/17)
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- Carbanions from decarboxylation of orotate analogs: Stability and mechanistic implications
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The pKa's of the 6-CH groups of 1,3-dimethyluracil, N-methyl-2-pyridone, and N-methyl-4-pyridone were determined through their reactions with bases derived from carbon acids with known pKa and the reactions of their corresponding carbanions with the carbon acids. No correlation between the stability of the carbanions and the rate of decarboxylation of corresponding carboxylic acids was found.
- Yeoh, Fong Ying,Cuasito, Roxanne R.,Capule, Christina C.,Wong, Freeman M.,Wu, Weiming
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p. 338 - 343
(2008/09/19)
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- Accelerated decarboxylation of 1,3-dimethylorotic acid in ionic liquid
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The solvent effect of ionic liquids on the decarboxylation of 1,3-dimethylorotic acid and its analogue in ionic was investigated. The rate acceleration observed was proposed to be a result of the stabilization of the zwitterionic intermediates by the charged groups available in these special solvents.
- Wong, Freeman M.,Wu, Weiming
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- Mix-and-heat benzylation of alcohols using a bench-stable pyridinium salt
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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.
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p. 3923 - 3927
(2007/10/03)
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- On the thermally induced rearrangement of 2-alkoxypyridines to N-alkylpyridones
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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.
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p. 913 - 916
(2007/10/03)
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- Methyl orthocarboxylates as methylating agents of heterocycles
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Methylation reactions occurring between trimethyl orthocarboxylates or N,N-dimethylcarboxamide dimethyl acetals and various hydroxylated heterocycles, involving a lactam-lactim tautomeric equilibrium, were investigated as an alternative to classic methyla
- Janin, Yves L.,Huel, Christiane,Flad, Genevieve,Thirot, Sylvie
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p. 1763 - 1769
(2007/10/03)
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- Quinolinecarboxamides as antiviral agents
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The present invention provides a compound of formula I which is useful as antiviral agents, in particular, as agents against viruses of the herpes family.
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- Chemoselective methylation of amides and heterocycles using chloromethyldimethylsilyl chloride
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The reaction of chloromethyldimethylsilyl chloride with an amide generates a pentacoordinate N-(amidomethyl)-halosilane that can be desilylated with cesium fluoride to give the N-methyl amide. This provides a selective method for the monoalkylation of amides in the presence of other, more nucleophilic groups. (C) 2000 Elsevier Science Ltd.
- Bassindale, Alan R.,Parker, David J.,Patel, Pravin,Taylor, Peter G.
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p. 4933 - 4936
(2007/10/03)
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- The chemistry of the N-methyl-3-dehydropyridinium ylid
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The reaction of atomic carbon with N-methylpyrrole, 5b, at 77 K generates the N-methyl-3-dehydropyridinium ylid, 6b, which can be trapped with added hydrogen halides or CO2. The addition of CO2 is strong evidence for the ylid 6b rather than cumulene 7. Deuterium and 13C labeling studies demonstrate that 6b rapidly rearranges to the N-methyl-2-dehydropyridinium ylid, 13, by an intermolecular mechanism. Ylid 13 can be trapped with added acids or with O2 to form 1-methyl-2-pyridone.
- Pan, Weitao,Shevlin, Philip B.
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p. 5091 - 5094
(2007/10/03)
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- Effect of Cationic and Anionic Micelles Upon the Reactions of Alkylamines with N-Alkyl-2-chloropyridinium Salts. Base-catalyzed Reactions.
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The reactivities of the N-alkyl-2-chloropyridinium ions (alkyl = Me, n-C10H21, n-C14H25) (1a-c respectively) toward alkylamines, namely methylamine, dimethylamine and trimethylamine, are affected by cationic micelles of alkyltrimethylammonium chloride (alkyl = n-C16H33), which slightly catalyze reactions of the methyl substrate (1a) and greatly increase the reaction rates of the more hydrophobic derivatives (1b and 1c).These results are understandable in terms of the distribution of both reactants between the aqueous and miceller pseudophases.Anionic micelles of sodium alkyl sulphate (alkyl = n-C12H25) also catalyze the reactions of methylamine and dimethylamines with substrates (1a-c) but inhibit the reactions of these substrates with trimethylamine.The catalysis by both cationic and anionic micelles increases with increasing length of the alkyl group of the substrate.The reaction is first order with respect to all the amines and the overall reaction is considered to be a base catalyzed reaction.
- Al-Lohedan, Hamad A.,Al-Sulaim, Adel M.,Al-Ayed, Abdullah S.,Issa, Zuhair A.
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p. 3101 - 3127
(2007/10/02)
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- An alternative efficient method for transformation of thiocarbonyl to carbonyl group using trifluoroacetic anhydride
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A simple and efficient procedure for the rapid and mild conversion of thiocarbonyls to carbonyls in high yields is described.
- Masuda, Ryoichi,Hojo, Masaru,Ichi, Tadaaki,Sasano, Shigetoshi,Kobayashi, Tatsuya,Kuroda, Chihiro
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p. 1195 - 1198
(2007/10/02)
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- 2-CHLORO-2-CYCLOPROPYLIDENACETATE IN SYNTHESIS ll: FACILE CONSTRUCTION OF VARIOUS SPIROCYCLOPROPANE ANELLATED HETEROCYCLES
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Methyl 2-chloro-2-cyclopropylidenacetate (1a) reacts with 1,2- and 1,3-bidentate nucleophiles in a heterogeneous system of solid base and dichloromethane under phase transfer catalysis.Spirocyclopropane anellated heterocyclic carboxylates 7, 9, 14, 10, 11 were obtained with KOH from 2-aminothiophenol, 1,2-dihydroxybenzene, 1,3-propanedithiol and with K2CO3 from 2-aminophenol and 2-aminoethanethiol respectively.With KOH the latter gave the seven-membered lactam 13, and 2-aminophenol led to methyl 4-benzoxazolylbutyrate 12.The adduct of benzylamine to the t-butyl ester 1b in a three-step sequence yielded the β-lactame 24 and an isomericcompound , probably the imido-β-lactone E/Z-25.Following a similar strategy, i.e. a sequence of Mukaiyama type alkylation, substitution, functional group interconversion and cyclization, 1a was converted to the cyclic imine 29a which served as a precursor to the carbapenam derivative 31.Finally, a few examples of 1,3-dipolar cycloaddition onto 1a are reported.Diazomethane added regioselectively in the "normal", diphenyl-diazomethane in the opposite mode to yield pyrazolines 33a and 34a respectively; 2-diazopropane gave both regioisomeric pyrazolines.The primary cycloadduct of nitrilylid 35 and 1a could not be isolated but rather the pyrrole derivative 38 derived by ring-opening rearrangement.
- Meijere, Armin de,Teichmann, Stefan,Yu, Dahai,Kopf, Juergen,Oly, Mathias,Thienen, Norbert von
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p. 2957 - 2968
(2007/10/02)
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- THE FISCHER INDOLIZATION OF 4-ACETONYL-2,6-PIPERIDINEDIONES
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The PPA induced Fischer indolization of 4-acetonyl-2,6-piperidinediones 4 takes place both at the methylene and the methyl carbons, although the latter regioisomer (3) undergoes a further cyclization of the imide moiety upon the indole 3-position followed by ring-opening of the resulting intermediate 9 to give tetrahydrocarbazolone 8.Fragmentation of two possible regioisomers 3 and 7 to 2-methylindole occurs at higher temperatures.This process is more pronounced when using 4-acetonyl-3,4-dihydro-2(1H)-pyridone 13 as the substrate for the indolization.The use of N-acetylphenylhydrazone derivatives leads to similar results as a consequence of the deacylation of the initially formed indole derivatives.In this case, an additional C-acylation of the indole ring also occurs.
- Amat, Mercedes,Sanfeliu, Enric,Bosch, Joan
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p. 7939 - 7946
(2007/10/02)
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- A Convenient Preparation of Bis(phosphorothioyl) Sulfides
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The reaction of piperidinium and potassium phosphorodithioates with 2-chloro-1-methyl-pyridinium salts afforded the corresponding bis(phosphorothioyl) sulfides in good yields.The similar reaction with potassium diphenylphosphorothioate gave exclusively bis(diphenylphosphorothioyl) oxide. - Keywords: Bis(phosphorothioyl) Sulfides, Piperidinium Phosphorodithioates, Bis(phosphorothioyl) Oxides
- Min, Shi,Ishihara, Hideharu,Murai, Toshiaki,Kato, Shinzi
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p. 153 - 157
(2007/10/02)
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- PREPARATION OF LACTAMS VIA OXIDATION OF CYCLIC, TERTIARY AND SECONDARY AMINES WITH Hg(II)-EDTA COMPLEX IN ALKALINE MEDIUM
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Oxidation of N-alkylpiperidines and other cyclic, tertiary amines with Hg(II)-EDTA complex in basic solution yields lactams, similar oxidation of N-hydroxypiperidines gives hydroxamic acids (presumably via nitrones) and oxidation of N-unsubstituted piperidines affords lactams, probably via 1-piperidine trimers.
- Wenkert, Ernest,Angell, E. Charles
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p. 1331 - 1338
(2007/10/02)
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- Hydrolyses of 2- and 4-Fluoro N-Heterocycles. 2. Nucleophilic Catalysis by Buffer Bases in the Hydrolysis of 2-Fluoro-1-methylpyridinium Iodide
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Pseudo-first-order rate constants are reported for hydrolysis of 2-fluoro-1-methylpyridinium iodide (1) in carboxylate buffers.The reaction is catalyzed by the carboxylase bases, with a Brensted slope of 0.66.Hydrolyses in 99percent 18O-labeled water with 0.04 M unlabeled acetate and complementary hydrolyses in unlabeled water with 90percent 18O-labeled acetate indicate that 85-95percent of the oxygen in product 2 is derived from the acetate rather than from water.The results are consistent with nucleophilic catalysis by acetate (and presumably by the other carboxylate bases) rather than general base catalysis.
- Muscio, Olivier J.,Rutheford, Denise R.
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p. 5194 - 5198
(2007/10/02)
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- SYNTHESE DE DILACTONES MACROCYCLIQUES ASSISTEE PAR LES ORGANOSTANNIQUES APPLICATION AUX MACROCYCLES SOUFRES (SULFURES, SULFOXYDES, DISULFURES) COMPLEXATION SELECTIVE DE L'ION Ca(2+)
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Tin "template driven" condensation of diacid fluorides with triphenyltin derivatives of diols affords macrocyclic dilactones in good yields.The reaction proceeds at moderate dilution conditions from diacids and diols without isolation of the intermediate activated species.The dilution, temperature and ring-size effects on this reaction are detailed.This method is applied to the praparation of sulfur-, disulfide- and sulfoxide-containing macrocyclic dilactones, as well as to the preparation of chiral macrocycles derived from α-aminoacids.The binding abilities of these twelve new ligands (12- to 21-membered rings) are estimated by picra te extraction from water to chloroform.Selective complexation for calcium is found in some cases.
- Picard, C.,Cazaux, L.,Tisnes, P.
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p. 3503 - 3520
(2007/10/02)
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- Oxidative Cleavage of Pseudobases from 2-α-Alkylated 2,3-Cycloalkenopyridinium Salts
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In contrast to former assumptions pyridinium salts with a tertiary 2-α-C-atom like 2a and 16 are not oxidized to pyridinium-carbinol intermediates during alkaline hexacyanoferrate(III) oxidation because 10 yields the pyridones 11 and 12, both missing after oxidation of 2a.The title compounds 2 show the same reactivity against alkaline hexacyanoferrate(III).The pseudobases 14 suffer ring fission simultaneously forming the pyridones 6-8. 4 and 5 were characterized as further oxidation products of 2. - Key words: Cycloalkapyridinium Salts, Hexacyanoferrate(II) Oxidation , Pyridinones
- Weber, Horst,Lippe, Gotelind von der,Matyja, Magdalena
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p. 655 - 662
(2007/10/02)
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- Relative Reactivities of Heteroaromatic Cations toward Ferricyanide Ion Oxidation
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The kinetics of the ferricyanide ion oxidation of the N-methyl cations of pyridine (also N-ethyl cation), quinoline, 5,6-benzoquinoline, 7,8-benzoquinoline, 1,10-phenanthroline, and phenanthridine have been investigated in 20percent acetonitrile- 80percent water over the range pH 12-14 (25 deg C, ionic strength 1.0).The initial rates of oxidation of all of these cations are first order in each of ferricyanide ion and heterocyclic cation.All cations, with the exception of the pyridinium cations, display inhibition by the ferrocyanide ion reaction product, in an analogous manner to that previously analyzed in detail for the oxidation of isoquinolinium cations (accompanying paper).The pH dependences of these oxidations are all consistent with rate-determining attack of ferricyanide ion upon the alkoxide ion of the pseudobase derived from each cation.The relative reactivities of these pseudobase alkoxide ions (of the N-methyl cations) toward ferricyanide ion attack are shown to be isoquinolinium > pyridinium > quinolinium ca. 5,6-benzoquinolinium ca. 7,8-benzoquinolinium > 1,10-phenanthrolinium > phenanthridinium > acridinium.
- Bunting, John W.,Stefanidis, Dimitrios
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p. 2068 - 2071
(2007/10/02)
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- THIOCARBONYL TO CARBONYL GROUP TRANSFORMATION USING CuCl AND NaOH
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A simple and efficient procedure for the rapid and mild conversion of thiocarbonyls to carbonyls is described.
- Narasimhamurthy, N.,Samuelson, A. G.
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p. 3911 - 3912
(2007/10/02)
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- Convenient Preparations of 3,5-Disubstituted 1,2,4-Thiadiazoles by Oxidative Dimerization of Thioamides
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3,5-Disubstituted 1,2,4-thiadiazoles 2 were prepared by reaction of thioamides 1 with DMSO in the presence of such an electrophilic reagent as 1-methyl-2-chloropyridinium iodide, benzoyl chloride, acetyl chloride, hydrochloric acid, or trimethylsilyl chloride in organic solvents at room temperature in high yields.Thiadiazoles 2 were also obtained by reaction of 1 with NBS at room temperature in high yields.Thioamide S-oxides reacted with electrophilic reagents at room temperature to give the corresponding thiadiazoles 2 in high yields.
- Takikawa, Yuji,Shimada, Kazuaki,Sato, Katsuyuki,Sato, Shinichi,Takizawa, Saburo
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p. 995 - 999
(2007/10/02)
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- A CONVENIENT METHOD FOR THE CONSTRUCTION OF β-LACTAM COMPOUNDS FROM β-AMINO ACIDS USING 2-CHLORO-1-METHYLPYRIDINIUM IODIDE AS CONDENSING REAGENT
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Various β-lactams are prepared from the corresponding β-amino acids under mild reaction conditions in high yields by employing 2-chloro-1-methylpyridinium iodide as a condensing reagent.
- Huang, Huamin,Iwasawa, Nobuharu,Mukaiyama, Teruaki
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p. 1465 - 1466
(2007/10/02)
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- AN ANOMALOUS DEALKYLATION-ACYLATION OF N,N-DIALKYLANILINES
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N,N-Dialkylaniline undergoes a thermal N-dealkylation and acylation in the presence of 2-acetoxypyridines.
- Newkome, George R.,Yuanjiao, Xia
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p. 981 - 982
(2007/10/02)
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- Quaternary Heterocyclylamino β-Lactams: A Generic Alternative to the Classical Acylamino Side Chain
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6β-penam-3-carboxylates and 7β-ceph-3-em-4-carboxylates have been found to be interesting new classes of antibacterial β-lactams, readily available by SN2 Ar coupling of fluoro-substituted quaternized pyridines and appropriate amino lactam carboxylic acids.Compared to penicillin G, the penam 12c exhibited a spectrum extended to Gram-negative species, such as Escherichia, Shigella, Klebsiella and Enterobacter, offset by a loss of potency against Gram-positive spacies.Excluding Pseudomonas, many examples of the cephems showed excellent activity against the above Gram-negative organisms, and in some cases, such as 15i, the spectrum included good performance against the staphylococci and streptococci.With Serratia and many Proteus species, there was an adverse inoculum and medium effect which was not observed in the good Gram-positive reach of the cephem series.
- Hannah, John,Johnson, Charles R.,Wagner, Arthur F.,Walton, Edward
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p. 457 - 469
(2007/10/02)
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- Kinetics and Mechanism of Osmium Tetroxide Catalysed Oxidation of Pyridinium and Quinolinium Methiodides by Hexacyanoferrate(III) in Aqueous Alkaline Medium
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The rates of the title reactions at constant ionic strength are found to be first order in , and but zero order in .The rates of reactions decrease with the decrease in the dielectric constant and increase with the increase in ionic strength of the medium.The entropy of activation is found to be negative.A suitable mechanism has been proposed in the light of results and product (1-methyl-2-pyridone), in the case of pyridinium salt, isolated.
- Mohapatra, R. C.,Khandual, N. C.
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p. 517 - 519
(2007/10/02)
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- DEILS-ALDER ADDUCTS FROM N-SUBSTTITUED TAUTOMERIC 2(1H)-PYRIDONE-2-HYDROXYPYRIDINES; 5,6-BENZO-AZABARRELENONES AND 5,6-BENZO-AZABARRELENES
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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
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p. 475 - 478
(2007/10/02)
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- 2- and 4-Pyridones by Oxidative Demethylation of 2- and 4-Methylpyridinium Cations
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1-Substituted-2- and -4-methylpyridinium cations are converted by pentyl or ethyl nitrite and sodium methoxide into 1-substituted-2- and -4-pyridones respectively.
- Katritzky, Alan R.,Patel, Ranjan C.,Shanta, Mohammed
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p. 1888 - 1889
(2007/10/02)
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