- Synthesis, characterization and electrochemical investigations of mixed-ligand copper(II)-organic supramolecular frameworks
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Two mixed-ligand copper(II)-organic coordination compounds with 5,5′-dimethyl-2,2′-bipyridine (5,5′-Me2bpy) as a primary ligand while aliphatic malonate (Hmal) and aromatic 2-hydroxynicotinate (2-OHNA) as secondary ligands, were synthesized. These complexes are formulated as: [Cu(Hmal)(5,5′-Me2bpy)(H2O)](ClO4) 1 and [Cu2(2-OHNA)2(5,5′-Me2bpy)2(NO3)](NO3) 2. These two complexes were structurally characterized by single crystal X-ray diffraction analysis. Characterization was further supported by powder X-ray diffraction analysis, elemental analyses, FT-IR, FAB-MASS and TGA, DSC studies. Cyclic voltammetric and UV-visible spectral studies of these two complexes have also been done. The electrochemical studies of complex 1 in DMSO and DMF have shown that this complex undergoes quasi-reversible diffusion-controlled one-electron transfer reaction without any chemical complication while complex 2 in DMSO undergoes quasi-reversible diffusion-controlled one electron transfer reaction, following EC mechanism. The electrochemical behaviour of complex 2 in DMF is complicated probably due to presence of more than one species in solution phase.
- Singh, Sandeep K.,Srivastava, Ashish Kumar,Srivastava, Krishna,Banerjee, Rahul,Prasad, Jagdish
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Read Online
- Solid-state identity of 2-hydroxynicotinic acid and its polymorphism
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2-Hydroxynicotinic acid (2-HNA), a derivative of nicotinic acid, was found to exist in four polymorphs. In the solid state, 2-HNA is actually present as its tautomer, 2-oxo-1,2-dihydro-3-pyridinecarboxylic acid (2-ODHPCA). The polymorphism stems from distinctive packing arrangements of the molecules, and the formation of the distinct polymorphs can be affected by using various acidic additives. The thermal behaviors of the four polymorphs indicate that form I is the most stable at elevated temperature, form II converts into form I during heating, and forms III and IV transform into form II when heated. Theoretical studies showed that 2-ODHPCA is more energetically favored than 2-HNA. Condensed Fukui functions and the dual descriptor were used jointly to examine the local preference of hydrogen bonding in the crystal. Lattice energy calculations were conducted to further evaluate energetic properties of the system.
- Long, Sihui,Zhou, Panpan,Theiss, Kathryn L.,Siegler, Maxime A.,Li, Tonglei
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Read Online
- Preparation method of 2-chloronicotinic acid
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The invention relates to a preparation method of 2-chloronicotinic acid. 2-chloronicotinic acid as a product is obtained by two steps of reactions of carboxylation and chlorination of 2-hydroxypyridine in an organic solvent at a certain temperature. The method provided by the invention has the advantages of more raw material sources, obvious cost advantage, safer and more convenient preparation method, high total yield and less three wastes, especially can avoid the use of phosphine oxychloride or triphosgene, and is beneficial to industrialization.
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Paragraph 0023-0028
(2021/06/26)
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- A tautomeric ligand enables directed C-H hydroxylation with molecular oxygen
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Hydroxylation of aryl carbon-hydrogen bonds with transition metal catalysts has proven challenging when oxygen is used as the oxidant. Here, we report a palladium complex bearing a bidentate pyridine/ pyridone ligand that efficiently catalyzes this reaction at ring positions adjacent to carboxylic acids. Infrared, x-ray, and computational analysis support a possible role of ligand tautomerization from monoanionic (L,X) to neutral (L,L) coordination in the catalytic cycle of aerobic carbon-hydrogen hydroxylation reaction. The conventional site selectivity dictated by heterocycles is overturned by this catalyst, thus allowing late-stage modification of compounds of pharmaceutical interest at previously inaccessible sites.
- Li, Zhen,Wang, Zhen,Chekshin, Nikita,Qian, Shaoqun,Qiao, Jennifer X.,Cheng, Peter T.,Yeung, Kap-Sun,Ewing, William R.,Yu, Jin-Quan
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p. 1452 - 1457
(2021/06/30)
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- Halogen–metal exchange on bromoheterocyclics with substituents containing an acidic proton via formation of a magnesium intermediate
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A selective and practical bromine–metal exchange on bromoheterocyclics bearing substituents with an acidic proton under non-cryogenic conditions was developed by a simple modification of an existing protocol. Our protocol of using a combination of i-PrMgCl and n-BuLi has not only solved the problem of intermolecular quenching that often occurred when using alkyl lithium alone as the reagent for halogen–lithium exchange, but also offered a highly selective method for performing bromo–metal exchange on dibrominated arene compounds through chelation effect.
- Tian, Qingqiang,Shang, Suqin,Wang, Huajun,Shi, Guoqiang,Li, Zhiyao,Yuan, Jianyong
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supporting information
(2017/12/05)
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- PHARMACEUTICAL COMPOSITION COMPRISING PYRIDONE DERIVATIVES
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A pyridone derivative compound and a pharmaceutically acceptable salt, isomer, solvate or hydrate thereof, and a preventive or therapeutic pharmaceutical composition for cognitive disorders that includes the pyridone derivative compound or a pharmaceutically acceptable salt, isomer, solvate or hydrate thereof.
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Paragraph 0403
(2013/12/04)
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- PHARMACEUTICAL COMPOSITION COMPRISING PYRIDONE DERIVATIVES
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A pyridone derivative compound and a pharmaceutically acceptable salt, isomer, solvate or hydrate thereof, and a preventive or therapeutic pharmaceutical composition for cognitive disorders that includes the pyridone derivative compound or a pharmaceutically acceptable salt, isomer, solvate or hydrate thereof.
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Page/Page column 72
(2012/08/08)
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- Kinetics of oxidation of heterocyclic compounds by quinolinium dichromate
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Quinolinium dichromate in sulfuric acid oxidized heterocyclic aldehydes (to the corresponding acids) and heterocyclic carboxylic acids (to the corresponding hydroxy-substituted acids) in acetic acidwater medium (vol. ratio, v(water)/v(acetic acid) = 50:50). The kinetic results supported a mechanistic pathway proceeding via a rate-determining decomposition of the chromate ester.
- Saunte, Hauzachin,Chaubey, Girija S.,Mahanti, Mahendra K.
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experimental part
p. 291 - 298
(2012/04/10)
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- A simple and practical copper-catalyzed approach to substituted phenols from aryl halides by using water as the solvent
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Water surprise! A simple and practical copper-catalyzed approach to substituted phenols by hydroxylation of aryl halides has been developed by using environmentally benign water as the solvent (see scheme). The method proceeds under mild conditions and is tolerant towards various functional groups in the substrates.
- Yang, Daoshan,Fu, Hua
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supporting information; experimental part
p. 2366 - 2370
(2010/06/15)
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- AMINO NICOTINIC AND ISONICOTINIC ACID DERIVATIVES AS DHODH INHIBITORS
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A compound of formula (I) wherein : - one of the groups G1represents a nitrogen atom or a group CRc and the other represents a group CRc; - G2 represents a nitrogen atom or a group CRd; - R1 represents a group selected from hydrogen atoms, halogen atoms, C1-4 alkyl groups which may be optionally substituted by 1, 2 or 3 substituents selected from halogen atoms and hydroxy groups, and C3-8 cycloalkyl groups which may be optionally substituted by 1, 2 or 3 substituents selected from halogen atoms and hydroxy groups; - R2 represents a group selected from hydrogen atoms, halogen atoms, hydroxyl groups, C1-4 alkyl groups which may be optionally substituted by 1, 2 or 3 substituents selected from halogen atoms and hydroxy groups, C1-4 alkoxy groups which may be optionally substituted by 1, 2 or 3 substituents selected from halogen atoms and hydroxy groups, and C3-8 cycloalkyl groups which may be optionally substituted by 1, 2 or 3 substituents selected from halogen atoms and hydroxy groups; - Ra, Rb and Rc independently represent groups selected from hydrogen atoms, halogen atoms, C1-4 alkyl groups which may be optionally substituted by 1, 2 or 3 substituents selected from halogen atoms and hydroxy groups, and C1-4alkoxy groups which may be optionally substituted by 1, 2 or 3 substituents selected from halogen atoms and hydroxy groups; - Rd represents a group selected from hydrogen atoms, halogen atoms, hydroxyl groups, C1-4 alkyl groups which may be optionally substituted by 1, 2 or 3 substituents selected from halogen atoms and hydroxy groups, and C1-4 alkoxy groups which may be optionally substituted by 1, 2 or 3 substituents selected from halogen atoms and hydroxy groups, and C3-8 cycloalkoxy groups which may be optionally substituted by 1, 2 or 3 substituents selected from halogen atoms and hydroxy groups; - one of the groups G3 and G4 is a nitrogen atom and the other is a CH group; - M is a hydrogen atom or an pharmaceutically acceptable cation with the proviso that, when at least one of the groups Ra and Rb represent a hydrogen atom and G2 is a group CRd, then Rd represents a groups selected from C1-4 alkoxy groups which may be optionally substituted by 1, 2 or 3 substituents selected from halogen atoms and hydroxy groups, C3-8 cycloalkoxy groups which may be optionally substituted by 1, 2 or 3 substituents selected from halogen atoms and hydroxy groups; and the pharmaceutically acceptable salts and N-oxides thereof.
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Page/Page column 23
(2008/12/06)
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- Synthesis and biological evaluation of 2,4,6-functionalized derivatives of pyrido[2,3-d]pyrimidines as cytotoxic agents and apoptosis inducers
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In the search for new derivatives with anticancer activity that are able to induce a selective proapoptotic mechanism in cancer cells, we have designed, synthesized, and evaluated a series of new 2-(alkylsulfanyl)-N-alkylpyrido[2,3- d]pyrimidine-4-amine derivatives as cytotoxic and apoptosis inducers. The potential antitumor activity of the compounds was evaluated in vitro by examining their cytotoxic effects against human breast, colon, and bladder cancer-cell lines. The IC50 values of the compounds that showed cytotoxic activity were calculated. The cytotoxic compounds were then tested for their ability to induce caspase-3 activation and nuclear-chromatin degradation. Some compounds, such as 6c, 6d, 6e, 6j, 6o, and 6p, show significant in-vitro cytotoxicity in at least two of the three tested cell lines, induced apoptosis, and also produced a rapid dose-dependent increase in the caspase-3 level in some of the cell lines tested. In order to test the selectivity of the compounds, two non-tumoral human cell lines were used. Several compounds of the did not show cytotoxicity in these cell lines.
- Sanmartin, Carmen,Dominguez, Maria Victoria,Cordeu, Lucia,Cubedo, Elena,Garcia-Foncillas, Jesus,Font, Maria,Palop, Juan Antonio
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- Kinetic studies on the quinolinium dichromate oxidation of heteroacids
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Heterocyclic carboxylic acids reacted with quinolinium dichromate, in sulfuric acid, to yield the corresponding hydroxy-substituted acids. The kinetic results supported a mechanistic pathway proceeding via the rate-determining formation of the cyclic chromate ester.
- Suante,Mahanti
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p. 1813 - 1819
(2007/10/03)
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- Photochemistry of the three carboxypyridines in water: A pH dependent reaction
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The photochemistry of ortho, meta and para-carboxypyridines (pK a1 = 1.0-2.1 and pKa1 = 4.7-5.3) in aqueous medium was studied by laser-flash photolysis and product studies. At pH a1, hydroxylated compounds are produced with low quantum yields. Within the pH range 4-7, ortho and meta isomers undergo dimerization together with decarboxylation with a quantum yield showing a very sharp maximum around pKa2 (φmax = 0.09 and 0.01, respectively) while the para isomer is photostable. End-of-pulse transients assigned to triplet states were detected by laser-flash photolysis at pH a1 and pH > 4. Additionally, the carboxypyridinyl radicals were detected as secondary intermediates at pH a1 and 4 a1. This is in favour of an electron transfer reaction between triplet and starting compound producing a charge transfer species. The radical anion would escape as carboxypyridinyl radical while the radical cation may add water at pH a1 yielding the OH-adduct radical or may undergo decarboxylation at pH > 4. The high quantum yield of phototransformation of the ortho isomer at pH > 4 is due to an easy decarboxylation process. A reaction scheme is proposed accounting for the dependences of φ on both the pH and the carboxypyridines concentration. This study points out the distinct pattern of reactivity of carboxypyridines depending on the ionisation state of starting compounds and isomeric substitution.
- Rollet, Florence,Richard, Claire,Pilichowski, Jean-Francois,Aboab, Bettina
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p. 2253 - 2261
(2007/10/03)
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- Quinolinium dichromate oxidation of heterocyclic carboxylic acids
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Heterocyclic carboxylic acids were oxidized to the corresponding hydroxy-substituted acids by quinolinium dichromate in sulfuric acid, in 50% (v/v) acetic acid-water as solvent. The kinetic results supported a mechanistic pathway proceeding via a rate-determining decomposition of the chromate ester.
- Suante, Hauzachin,Mahanti, Mahendra K.
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p. 489 - 492
(2007/10/03)
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- Degradation of quinoline by wet oxidation - Kinetic aspects and reaction mechanisms
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The high temperature, high pressure wet oxidation reaction of quinoline has been studied as a function of initial concentration, pH and temperature. At neutral to acidic pH, it is effective in the oxidation of quinoline at 240°C and above, whereas under alkaline conditions the reaction is markedly slowed down. The results indicate that the reaction is an auto-catalysed, free radical chain reaction transforming 99% of quinoline to other substances. Of the quinoline, 30-50% was oxidised to CO2 and H2O depending on the initial concentration. Wet oxidation of deuterium-labelled quinoline was used as a method for verifying and quantifying the reaction products. Fifteen reaction products were identified and quantitatively determined, accounting for 70% of the carbon present after treatment. Nicotinic acid was a main product, accounting for up to 35% of the parent substance. The formation of succinic acid is suggested to be a result of a coupling reaction of the acetic acid radical. A reaction mechanism is suggested for the degradation of quinoline; it involves hydroxyl radicals and the possible interaction with autoclave walls is discussed. The high temperature, high pressure wet oxidation reaction of quinoline has been studied as a function of initial concentration, pH and temperature. At neutral to acidic pH, it is effective in the oxidation of quinoline at 240°C and above, whereas under alkaline conditions the reaction is markedly slowed down. The results indicate that the reaction is an auto-catalysed, free radical chain reaction transforming 99% of quinoline to other substances. Of the quinoline, 30-50% was oxidised to CO2 and H2O depending on the initial concentration. Wet oxidation of deuterium-labelled quinoline was used as a method for verifying and quantifying the reaction products. Fifteen reaction products were identified and quantitatively determined, accounting for 70% of the carbon present after treatment. Nicotinic acid was a main product, accounting for up to 35% of the parent substance. The formation of succinic acid is suggested to be a result of a coupling reaction of the acetic acid radical. A reaction mechanism is suggested for the degradation of quinoline; it involves hydroxyl radicals and the possible interaction with autoclave walls is discussed.
- Thomsen, Anne Belinda
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p. 136 - 146
(2007/10/03)
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- COMPOSITIONS AND METHODS FOR THE TREATMENT OF IMMUNOMEDIATED INFLAMMATORY DISORDERS
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Compositions and methods for the prevention and treatment of immunomediated inflammatory disorders, especially for those disorders associated with the respiratory tract, are provided. More particularly, a tryptase inhibitor, typically a hydroxyaroyl or hydroxyheteroaroyl substituted dipeptide, is administered. Also provided by this invention are pharmaceutical compositions, typically aerosol or topical, as well as aerosol devices for administering these compositions intranasally.
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- Facile desulfurization of cyclic thioureas by hydrogen peroxide in acetic acid.
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A simple, mild and synthetically useful method for the desulfurization of cyclic thioureas and related compounds, existing as thiol-thione tautomeric mixtures, by hydrogen peroxide in acetic acid is proposed. The effect of substituting different solvents for the acetic acid was investigated.
- Grivas,Ronne
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p. 225 - 229
(2007/10/02)
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- SELECTIVE CLEAVAGE OF THE ETHER AND AMIDE BONDS IN N-(2,4-DIFLUOROPHENYL)-2--3-PYRIDINECARBOXAMIDE (DIFLUFENICAN)
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Heated to reflux in water containing 8 gpercent KOH, the herbicide diflufenican -3-pyridinecarboxamide, 1> was selectively transformed into 2--3-pyridinecarboxylic acid (2) plus 2,4-difluoroaniline (5); after 60 hr of heating, 27percent of the initial diflufenican was transformed, yielding 21percent (molepercent relative to initial diflufenican) of compound 2.Heated to reflux in a mixture of acetic acid + concentrate hydrochloric acid, diflufenican was transformed into a mixture of N-(2,4-difluorophenyl)-2-hydroxy-3-pyridinecarboxamide (3) and 2-hydroxy-3-carboxypyridine (4) plus 2,4-difluoroaniline (5) and 3-trifluoromethylphenol (6); after 48 hr of heating, diflufenican was completely transformed, yielding 28percent (molepercent relative to initial diflufenican) of compound 3, and 57percent of compound 4.The base catalyzed hydrolysis thus selectively yielded compound 2; the acid catalyzed one yielded compounds 3 + 4: diflufenican first was transformed into compound 3, which thereafter was transformed into compound 4.
- Rouchaud, Jean,Gustin, Fabrice,Moulart, Claude,Herin, Marc
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p. 339 - 344
(2007/10/02)
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- CONTROLLED, REGIOSPECIFIC OXIDATION OF PYRIDINE CARBOXYLIC ACIDS AND ESTERS WITH ELEMENTAL FLUORINE
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Pyridine carboxylic acid salts or esters in water or water-acetonitrile mixtures were treated with elemental fluorine to give the corresponding 2-pyridones.
- Puy, Michael Van Der,Nalewajek, David,Wicks, Gene E.
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p. 4389 - 4392
(2007/10/02)
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- REINVESTIGATION OF THE REACTION OF NICOTINIC ACID 1-OXIDE WITH ACETIC ANHYDRIDE
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Reinvestigation of the reaction of nicotinic acid 1-oxide (1) with boiling acetic anhydride has revealed that the primary product is not 2-acetylnicotinic acid 1-oxide (3) but 3-acetoxy-4-aza-3-methyl-1(3H)-isobenzofuranone 4-oxide (2), the acetate of the ring tautomer of 3.Reactions of 2 and 3 with phosphorus trichloride and some related reactions are reported.
- Nagano, Hiroyuki,Hamana, Masatomo,Nawata, Yoshiharu,Prachayasittikul, Supaluk,Abdel-Sayed, Ashraf N.,Bauer, Ludwig
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p. 1263 - 1270
(2007/10/02)
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- Reactions of Nicotinic Acid 1-Oxide with Propionic, Phenylacetic and Benzoic Anhydrides
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Nicotinic acid 1-oxide (1) reacts with hot propionic anhydride to give 4-aza-3-ethyl-3-propionyloxy-1(3H)-isobenzofuranone 4-oxide (2), 5-aza-3-methyl-4-propionyloxyisocoumarin (3), 4-aza-3-ethyl-3-propionyloxy-1(3H)-isobenzofuranone (4), 4-aza-3-ethyl-3,5-dipropionyloxy-1(3H)-isobenzofuranone (5) and a mixture of 2- and 6-hydroxynicotinic acids (6 and 7).Product 2 is a 2-propionylation product of 1, and 3, 4 and 5 arise from further action of the anhydride on 2.Phenylacetic anhydride undergoes oxidative decarboxylation with 1 to give benzaldehyde and nicotinic acid.The reaction of 1 with benzoic anhydride affords a 2-benzoylation product 4-aza-3-benzoyloxy-3-phenyl-1(3H)-isobenzofuranone 4-oxide (12).Keywords - nicotinic acid 1-oxide; 4-aza-1(3H)-isobenzofuranone 4-oxide; 5-azaisocoumarin; propionic anhydride; phenylacetic anhydride; benzoic anhydride; 2-propionylation; 2-benzoylation; deoxygenative β-propionyloxylation; oxidative decarboxylation
- Nagano, Hiroyuki,Nawata, Yoshiharu,Hamana, Masatomo
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p. 4093 - 4100
(2007/10/02)
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- 5-Diaza-aryl-3-substituted pyridone compounds
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5-Diaza-aryl-3-substituted-2-pyridone compounds useful for increasing cardiac contractility, pharmaceutical compositions and a method for the treatment of congestive heart failure comprising the use of said compounds.
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- On derivatives of 4-oxo-3,4-dihydropyrido[2,3-d]pyrimidine (author's transl)
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A typical representative of the hypnotic and anticonvulsive 4-quinazoline group is methaqualone (1). A number of new derivatives of 4-oxo-3,4-dihydropyrido[2,3-d]pyrimidine (10) were synthetized by substituting the benzene ring in the quinazolone molecule by the pyridine ring. The synthesis was achieved by the condensation of 2-acetaminonicotinic acid (9) and a primary amine or by the reaction of 2-aminonicotinic acid (8) with acetic acid and a primary amine. These new compounds were tested on animals for antiphlogistic, analgetic and antipyretic activities and for effects on the central nervous system as well. It was tried to establish, on the basis of the results obtained, relations between the chemical constitution and the pharmacological efficacy. It was found that, depending on the nature of the substituents in the position 3; either the antiphlogistic, analgetic and antipyretic effects or the anticonvulsive action will prevail.
- Kretzschmar
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p. 253 - 256
(2007/10/02)
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- Process for preparing 2-halogeno nicotinic acids
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This invention relates to a novel process for preparing 2-halogeno-nicotinic acids. The compounds, especially 2-chloro-nicotinic acid, are intermediates in the preparation of anilino nicotinic acid derivatives. The latter compounds are useful as analgesic anti-diarrheal and anti-inflammatory agents.
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