- Bidentate NHC pyrozolate ligands in luminescent platinum(ii) complexes
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A bidentate C^N donor set derived from an N-heterocyclic carbene (NHC) precursor linked to a trifluoromethyl (CF3) functionalized pyrazole ring is described for the first time. The ligands have been employed to prepare four new phosphorescent complexes by the coordination of platinum(ii) centres bearing cyclometalated phenyl-pyridine/triazole-pyridine chelates. The electronic and steric environments of these complexes were tuned through the incorporation of suitable substituents in the phenyl-pyridine/triazole-pyridine ligands, wherein the position of the phenyl-ring substituent (a CF3 group) also directs the selective adoption of either a trans or a cis configuration between the CNHC and the Cphenyl donor atoms. Molecular structures obtained by X-ray diffraction for three of the complexes confirm a distorted square-planar configuration around the platinum centre, and DFT calculations show that the substituents have a significant influence on the energies of the frontier orbitals. Moreover, a platinum(ii) complex featuring the new bidentate NHC^pyrazolate ligand and a bulky adamantyl functionalized pyridine-triazole luminophore was observed to be highly emissive and exhibiting a sky-blue luminescence (λEm = 470 nm) with photoluminescence quantum yields as high as 50% in doped PMMA matrices. A complete photophysical investigation of all of the complexes in solution as well as in the solid state is herein reported.
- Naziruddin, Abbas Raja,Galstyan, Anzhela,Iordache, Adriana,Daniliuc, Constantin G.,Strassert, Cristian A.,De Cola, Luisa
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- Trifluoromethylated 3-(Pyrazol-1-yl)propanamide (PPA) Ligands
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The new PPA ligands 3-[5-methyl-3-(trifluoromethyl)-1H-pyrazol-1-yl]propanamide (CF3MePPA; 3) and 3-[3,5-bis(trifluoromethyl)-1H-pyrazol-1-yl]propanamide ((CF3)2PPA; 4) were synthesized by Aza-Michael addition of the specific pyrazole derivatives to acrylamide. Both products were characterized by elemental analyses, IR and NMR spectroscopy, and mass spectrometry. X-Ray structure determination of 3 revealed the presence of a one-dimensional hydrogen-bonded structure in the solid state. The ligating ability of the new ligands towards PdCl2 was studied, showing that 3 behaves similar to Me2PPA and reacts cleanly with PdCl2 to afford the sparingly soluble complex PdCl2(CF3MePPA-κN)2. By contrast, the donor ability of pyrazolyl group in 4 was found to be considerably reduced, thus resulting in the formation of the unusual complex PdCl2{(CF3)2PPA-κN}{(CF3)2PPA-κO}.
- Liebing, Phil,Edelmann, Frank T.
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- A modified and practical synthetic route to indazoles and pyrazoles using tungstate sulfuric acid
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Tungstate sulfuric acid-catalyzed Knorr reaction have been used as a simple, rapid, atom economic and green method for the synthesis of indazole and pyrazole derivatives based on the condensation of hydrazine derivatives and ss-dicarbonyl compounds under solvent-free conditions. It was found that the catalyst could be recovered and reused without significant loss of its activity. The use of this method provides a novel and improved modification of Knorr synthesis in terms of clean reaction profile, use of a safe catalyst and solvent-free conditions. A green method for the synthesis of indazole and pyrazole derivatives from the condensation of hydrazine derivatives with dicarbonyl compounds has been described. Tungstate sulfuric acid (TSA) catalyzed efficiently the reactions to give good yields.
- Rahmatzadeh, S. Setareh,Karami, Bahador,Khodabakhshi, Saeed
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- 3-Substituted pyrazoles and 4-substituted triazoles as inhibitors of human 15-lipoxygenase-1
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Investigation of 1N-substituted pyrazole-3-carboxanilides as 15-lipoxygenase-1 (15-LOX-1) inhibitors demonstrated that the 1N-substituent was not essential for activity or selectivity. Additional halogen substituents on the pyrazole ring, however, increased activity. Further development led to triazole-4-carboxanilides and 2-(3-pyrazolyl) benzoxazoles, which are potent and selective 15-LOX-1 inhibitors.
- Pelcman, Benjamin,Sanin, Andrei,Nilsson, Peter,No, Kiyo,Schaal, Wesley,?hrman, Sara,Krog-Jensen, Christian,Forsell, Pontus,Hallberg, Anders,Larhed, Mats,Boesen, Thomas,Kromann, Hasse,Vogensen, Stine Byskov,Groth, Thomas,Claesson, Hans-Erik
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p. 3024 - 3029
(2015/06/22)
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- The effect of pressurized carbon dioxide on the cyclocondensation reaction between 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones and hydrazines
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The synthesis of 1-unsubstituted and 1-phenyl-5-trifluoromethylpyrazoles from the reaction of 4- alkoxy-1,1,1-trifluoro-3-alken-2-ones [CF 3C(O)CH=C(R1)OR, where R = Me, Et and R1 = H, Me, Ph] with hydrazines [NH2NHR2, where R2 = H, Ph] in pressurized carbon dioxide is reported for the first time. Reaction conditions such as pressure, temperature and time were evaluated. The methodology developed herein was suitable to synthesize products in moderate to excellent yields (60 % - 96 %) and short reaction times (15 - 45 min).
- Rossatto, Marcelo,Casanova, Caroline,Lima, Ana P.,Emmerich, Daniel J.,Oliveira, Vladimir,Dallago, Rogerio M.,Frizzo, Clarissa P.,Moreira, Dayse N.,Buriol, Lilian,Brondani, Sergio,Zanatta, Nilo,Bonacorso, Helio G.,Martins, Marcos A. P.
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p. 224 - 232
(2014/03/21)
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- Ionic liquid and Lewis acid combination in the synthesis of novel (E)-1-(benzylideneamino)-3-cyano-6-(trifluoromethyl)-1H-2-pyridones
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In this work, a new catalytic system to synthesize a series of new (E)-1-(benzylideneamino)-3-cyano-6-(trifluoromethyl)-1H-2-pyridones from the cyclo-condensation reaction of benzylidene cyanoacetohydrazide with 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones [CF3C(O)C (R2) = C(R1)(OR), where R = Me, Et; R1 = H, Me, Pr, Bu, Ph, 4-Me-Ph, 4-F-Ph, 4-Cl-Ph, 4-Br-Ph; R2 = H, Me and R 1,R2 = -(CH2)4-] is presented. The products were obtained at room temperature in moderate to good yields (42-87%). Comparison of the catalytic system with a conventional method was not possible, because the products were obtained only when the new catalyst system - consisting of triethylamine and Lewis acid in ionic liquid [BMIM][BF 4] - was used. Springer-Verlag 2011.
- Moreira, Dayse N.,Frizzo, Clarissa P.,Longhi, Kelvis,Soares, Aline B.,Marzari, Mara R.B.,Buriol, Lilian,Brondani, Sergio,Zanatta, Nilo,Bonacorso, Helio G.,Martins, Marcos A.P.
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experimental part
p. 1265 - 1270
(2012/06/04)
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- Trifluoromethylation of various aromatic compounds by CF3I in the presence of Fe(II) compound, H2O2 and dimethylsulfoxide
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Trifluoromethylation of aromatic and hetero-aromatic compounds by CF3I in the presence of Fe(II) compound, H2O2 and dimethylsulfoxide was investigated. Various trifluoromethylated benzene derivatives, six-membered nitrogen-containing aromatic compounds and five-membered hetero-aromatic compounds were obtained under mild conditions. General orientation of electrophilic substitution of aromatic compounds was observed similarly as reported in other radical trifluoromethylation previously.
- Kino, Tatsuhito,Nagase, Yu,Ohtsuka, Yuhki,Yamamoto, Kyoko,Uraguchi, Daisuke,Tokuhisa, Kenji,Yamakawa, Tetsu
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experimental part
p. 98 - 105
(2010/03/03)
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- Pyrazole synthesis under microwave irradiation and solvent-free condition
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This paper presents a study of solvent-free reaction conditions using microwave irradiation (MW) to obtain 4,5-dihydro-1H-pyrazoles and dehydrated pyrazoles by the cyclocondensation reaction of 4-alkoxy-1,1,1-trifuoro-3-alken- 2-ones [CF3C(O)CH=C(R1)OR, where R/R1 = Et/H, Me/Me and Me/Ph] with hydrazines [NH2NH-R2, where R2 = CO2Me, Ph, CH2CH2OH]. Some reactions were performed under the same reaction conditions using methanol as solvent. The results obtained using MW equipment for synthesis under solvent-free conditions were also compared with those described in literature for conventional thermal heating and heating with a domestic MW oven. In general, the products furnished by reaction in MW equipment for synthesis presented better yields and shorter reaction times. In addition, it was demonstrated that the reaction temperature altered the formation of products for each hydrazine showing that MW equipment for synthesis is effcient for reacting hydrazines and 4-alkoxy-1,1,1-trifuoro-3- alken-2-ones to procedure the products 4,5-dihydro-1H-pyrazoles and dehydrated pyrazoles.
- Buriol, Lilian,Frizzo, Clarissa P.,Marzari, Mara R. B.,Moreira, Dayse N.,Prola, Lizie? D. T.,Zanatta, Nilo,Bonacorso, Helio G.,Martins, Marcos A. P.
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experimental part
p. 1037 - 1044
(2010/10/21)
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- Straightforward microwave-assisted synthesis of 1-carboxymethyl-5- trifluoromethyl-5-hydroxy-4,5-dihydro-1H-pyrazoles under solvent-free conditions
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(Chemical Equation Presented) An efficient microwave-assisted synthesis of 1-carboxymethyl-5-trifluoromethyl-5-hydroxy-4,5-dihydro-1H-pyrazoles from the cyclocondensation reaction between enones [CF3C(O)C(R2) = C(R1)(OR), where R2 = H, Me; R1 = H, Me, Et, Pr, i-Pr, t-Bu, i-Bu, Ph, 4-NO2-Ph, 4-Cl-Ph, 4-Br-Ph, 4-F-Ph and R = Me, Et] and methyl hydrazinocarboxylate under solvent-free conditions is reported. This process is an efficient alternative to the traditional thermal heating and furnishes the heterocyclic compounds in good to excellent yields in a short reaction time. To show the versatility of 1-carboxymethyl-5- trifluoromethyl-5-hydroxy-4,5-dihydro-1H-pyrazoles, dehydration reactions of these compounds are also demonstrated.
- Martins, Marcos A. P.,Beck, Paulo H.,Moreira, Dayse N.,Buriol, Lilian,Frizzo, Clarissa P.,Zanatta, Nilo,Bonacorso, Helio G.
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experimental part
p. 301 - 308
(2010/06/13)
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- An efficient synthesis of 1-cyanoacetyl-5-halomethyl-4,5-dihydro-1H- pyrazoles in ionic liquid
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The synthesis of eleven 1-cyanoacetyl-5-hydroxy-5-halomethyl-4,5-dihydro- 1H-pyrazoles from the reaction of 4-alkoxy-3-alken-2-ones f(R 3C(O)C(R2) = C(R1)OR, where R 3 = CF3, CCl3, CHClsub
- Moreira, Dayse N.,Frizzo, Clarissa P.,Longhi, Kelvis,Zanatta, Nilo,Bonacorso, Helio G.,Martins, Marcos A. P.
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scheme or table
p. 1049 - 1054
(2009/12/01)
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- Synthesis of novel 1,4,5-trisubstituted 3-trifluoromethylpyrazoles via microwave-assisted Stille coupling reactions
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1,5-Disubstituted 3-trifluoromethylpyrazoles were reacted with N-bromosuccinimide in DMF at room temperature or 70-80 °C for 1-2 h to afford the corresponding 4-bromo-substituted pyrazoles 2 in 95-99% yields. The microwave-assisted Stille coupling reactio
- Jeon, Sung Lan,Choi, Ji Hoon,Kim, Bum Tae,Jeong, In Howa
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p. 1191 - 1197
(2008/02/10)
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- PYRAZOLES USEFUL IN THE TREATMENT OF INFLAMMATION
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There is provided compounds of formula (I), wherein R1, R2, X1, X2 and n have meanings given in the description, and pharmaceutically-acceptable salts thereof, which compounds are useful in the treatment of diseases in which inhibition of the activity of a lipoxygenase (e.g. 15-lipoxygenase) is desired and/or required, and particularly in the treatment of inflammation.
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Page/Page column 56
(2008/06/13)
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- PYRAZOLE COMPOUNDS USEFUL IN THE TREATMENT OF INFLAMMATION
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There is provided compounds of formula (I), wherein R1, R2, Ra and Rb have meanings given in the description, and pharmaceutically-acceptable salts thereof, which compounds are useful in the treatment of diseases in which inhibition of the activity of a lipoxygenase (e.g. 15-lipoxygenase) is desired and/or required, and particularly in the treatment of inflammation.
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Page/Page column 43
(2010/10/20)
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- 5-Hydroxy-2-pyrazolines and some of their 1-substituted analogs
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The use of 1,3-dicarbonyl compounds containing strong electron-withdrawing substituents (perfluoroalkyl, 4-nitrophenyl) at one of the carbonyl groups in reaction with hydrazine or its monosubstituted derivatives (4-nitro- and 2,4-dinitrophenylhydrazines) leads to the formation of stable intermediates for the synthesis of pyrazoles (5-hydroxy-2-pyrazolines) or their linear tautomers (hydrazones).
- Zelenin,Tugusheva,Yakimovich,Alekseev,Zerova
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p. 668 - 676
(2007/10/03)
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- Selective cleavage of Cbz-protected amines
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(MatrixPresented) Under conditions of catalytic Ni(0) and in most cases just over 1 equiv of Me2NH·Br3/K2CO3 or Cs2CO3, a Cbz-protected nitrogen, which is part of a heteroaromatic ring, can
- Lipshutz, Bruce H.,Pfeiffer, Steven S.,Reed, Anthony B.
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p. 4145 - 4148
(2007/10/03)
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- Haloacetylated enol ethers 10. Condensation of β-alkoxyvinyl trifluoromethyl ketones with thiosemicarbazide. Synthesis of new trifluoromethyl 4,5-dihydro-1H-1-pyrazolethiocarboxyamides
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The synthesis of 3-aryl[alkyl]-5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1- pyrazolethiocarboxyamides (2a-g) from the direct cyclo-condensation reaction of β-alkoxyvinyl trifluoromethyl ketones (1a-g) with thiosemicarbazide in methanol, under mild conditions, is reported. Similarly, the 1H-1-pyrazolethiocarboxyamide derivatives (2a-g) were easily dehydrated and the thiocarboxyamide group hydrolyzed in a one-step reaction by stirring with concentrated sulfuric acid to give the 3-aryl[alkyl]-5-trifluoromethyl-1H-pyrazoles (3a-g) in good yields. Specific syntheses and physical properties of 3-aryl[alkyl]-5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1- pyrazolethiocarboxyamides are reported here for the first time.
- Bonacorso,Wastowski,Zanatta,Martins,Naue
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- Reactions of regioisomeric fluoroalkyl-containing β-aminovinyl ketones with hydrazines
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Fluoroalkyl β-alkyl-β-aminovinyl ketones react with hydrazine hydrate to give the respective pyrazoles, and with phenylhydrazine they form a mixture of pyrazoles and 5-hydroxy-Δ2-pyrazolines. Alkyl(aryl) β-fluoroalkyl-β-aminovinylketones do not react with the hydrazines mentioned above. With 2,4-dinitrophenylhydrazine, both types of fluoroalkyl-containing β-aminovinyl ketones give only hydrazones of the corresponding methyl alkyl(aryl) ketones.
- Pashkevich,Filyakova,Kuznetsova
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p. 2868 - 2870
(2007/10/03)
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- 5-Hydroxy-4,5-Dihydropyrazoles
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The use of β-diketones with strong electron-withdrawing substituents in reaction with hydrazine and its monosubstituted derivatives leads to the stable intermediates of pyrazole synthesis - 5-hydroxy-4,5-dihydropyrazoles or their open chain isomers.
- Zelenin, Kirill N.,Alekseyev, Valery V.,Tygysheva, Alja R.,Yakimovitch, Stanislav I.
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p. 11251 - 11256
(2007/10/02)
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- Synthesis of Pyrazole, 1,2,4,5-Tetrazine, and 1,2,4-Triazole Derivatives from Thiocarbonohydrazides and β-Dicarbonyl Compounds
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Reactions of acetylacetone, α-methylacetylacetone, and benzoyl- and 4-methoxybenzoylacetone with thiocarbonohydrazide yield corresponding pyrazoles with no substituent at N1.Reactions of 1-substituted thiocarbonohydrazides with acetylacetone, as well as of trifluoromethyl-substituted β-diketones and aroylacetones containing acceptor substituents with unsubstituted thiocarbonohydrazide, result in formation of corresponding 1-(N-aminothiocarbamoyl)-5-hydroxy-Δ5-pyrazolines which in some cases are converted into respective 1-(N-aminothiocarbamoyl)pyrazoles and further into 1-unsubstituted pyrazoles.Reaction of thiocarbonohydrazide with aroylacetaldehyde leads to 1,2,4,5-tetrazine-3-thiones.The product of reactions of 1,1,4-trimethylthiocarbonohydrazide with acetylacetone is a 1,2,4-triazole derivative.
- Alekseev, V. V.,Zelenin, K. N.,Yakimovich, S. I.
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p. 868 - 873
(2007/10/03)
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- Haloacetylated Enol Ethers. 2. Synthesis of 5-Trifluoromethylpyrazoles
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1-Methyl-5-(trifluoromethyl)-1H-pyrazoles 2,3 and 4,5-dihydro-1-phenyl-5-(trifluoromethyl)-1H-pyrazol-5-ol 4 were prepared by reaction of 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones 1 and hydrazine, methylhydrazine, and phenylhydrazine, respectively, in good yields.Compound 1 proved to be a versatile building block for the regiospecific construction of pyrazole rings having an 5-trifluoromethyl substituent.
- Braibante, Mara E. F.,Clar, Gunter,Martins, Marcos A. P.
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p. 1159 - 1160
(2007/10/02)
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- REACTIONS OF COPPER(II) POLYFLUORINATED β-DIKETONATES AND β-KETOESTERATES WITH HYDRAZINES
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It has been shown that pyrazoles (hydroxypyrazoles) are formed upon reaction of fluorine-containing copper β-diketonates (β-ketoesterates) with hydrazines and their hydrochlorides.A preparative method has been developed for the synthesis of fluorinated pyrazoles and hydroxypyrazoles via treatment of fluorine-containing β-diketonate and β-ketoesterate copper compounds with hydrazines.The molecular structure of 1-phenyl-3-octafluorobutyl-5-hydroxypyrazole has been established based on x-ray structural analysis.
- Kondrat'ev, P. N.,Skryabina, Z. E.,Saloutin, V. I.,Pashkevich, K. I.,Klyuev, N. A.,Aleksandrov, G. G.
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p. 561 - 565
(2007/10/02)
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