- More than steric effects: Unlocking the coordination chemistry of barium pyrazolates
-
To further our understanding of the coordination chemistry of the heavy alkaline earth metals, we here report on a family of barium pyrazolates bearing various substitution patterns that illustrate the delicate balance between ligand bulk, donor size, sto
- O'Brien, Anna Y.,Hitzbleck, Julia,Torvisco, Ana,Deacon, Glen B.,Ruhlandt-Senge, Karin
-
-
Read Online
- COMPOUNDS WITH COPPER- OR ZINC-ACTIVATED TOXICITY AGAINST MICROBIAL INFECTION
-
Heterocyclic compounds with a novel pyrazole thioamide-based NNSN structural motif, having highly effective zinc- or copper-activated toxicity against microbial infections at micromolar or nanomolar minimum inhibitory concentrations (MIC), and methods of making and using same.
- -
-
-
- Fragmenlt Recombination Design, Synthesis, and Safener Activity of Novel Ester-Substituted Pyrazole Derivatives
-
Fenoxaprop-p-ethyl (FE), a type of acetyl-CoA carboxylase (ACCase) inhibitor, has been extensively applied to a variety of crop plants. It can cause damage to wheat (Triticum aestivum) even resulting in the death of the crop. On the prerequisite of not reducing herbicidal efficiency on target weed species, herbicide safeners selectively protect crops from herbicide injury. Based on fragment splicing, a series of novel substituted pyrazole derivatives was designed to ultimately address the phytotoxicity to wheat caused by FE. The title compounds were synthesized in a one-pot way and characterized via infrared spectroscopy, 1H nuclear magnetic resonance, 13C nuclear magnetic resonance, and high-resolution mass spectrometry. The bioactivity assay proved that the FE phytotoxicity to wheat could be reduced by most of the title compounds. The molecular docking model indicated that compound IV-21 prevented fenoxaprop acid (FA) from reaching or acting with ACCase. The absorption, distribution, metabolism, excretion, and toxicity predictions demonstrated that compound IV-21 exhibited superior pharmacokinetic properties to the commercialized safener mefenpyr-diethyl. The current work revealed that a series of newly substituted pyrazole derivatives presented strong herbicide safener activity in wheat. This may serve as a potential candidate structure to contribute to the further protection of wheat from herbicide injury.
- Fu, Ying,Gao, Shuang,Jia, Ling,Ye, Fei,Zhang, Yuan-Yuan,Zhao, Li-Xia
-
p. 8366 - 8379
(2021/08/20)
-
- Green, homogeneous oxidation of alcohols by dimeric copper(II) complexes
-
Three pyrazole derivatives, 3,5-dimethyl-1H-pyrazole (DMPz) (I), 3-methyl-5-phenyl-1H-pyrazole (MPPz) (II), and 3,5-diphenyl-1H-pyrazole (DPPz) (III), were prepared via reacting semicarbazide hydrochloride with the acetylacetone, 1-phenylbutane-1,3-dione, and 1,3-diphenylpropane-1,3-dione, respectively. Complexes 1–3 were isolated by reacting CuCl2·2H2O with I–III, respectively, and characterized by CHNS elemental analyses, FT-IR, UV-Vis, 1H and 13C NMR, EPR spectra, and TGA/DTA. Molecular structures of the pyrazole derivatives I–III and copper(II) complexes 2 and 3 were studied through single-crystal XRD analysis to confirm their molecular structures. Overlapping of hyperfine splitting in the EPR spectra of the dimeric copper(II) complexes 1–3 indicates that both copper centers do not possess the same electronic environment in solution. The copper(II) complexes are dimeric in solid state as well as in solution and catalyze the oxidation of various primary and secondary alcohols selectively. Catalysts 1–3 show more than 92% product selectivity toward ketones during the oxidation of secondary alcohols. Surprisingly primary alcohols, which are relatively difficult to oxidize, produce carboxylic acid as a major product (48%–90% selectivity) irrespective of catalytic systems. The selectivity for carboxylic acid rises with decreasing the carbon chain length of the alcohols. An eco-friendly and affordable catalytic system for oxidation of alcohols is developed by the utilization of H2O2, a green oxidant, and water, a clean and greener solvent, which is a notable aspect of the study.
- Maurya, Abhishek,Haldar, Chanchal
-
p. 885 - 904
(2020/12/18)
-
- Pyrazole derivative compound, and preparation method and application thereof
-
The invention belongs to the technical field of medicine synthesis, and particularly relates to a pyrazole derivative compound, and a preparation method and an application thereof. The polysubstitutedpyrazole compound disclosed by the invention has a structure represented by a formula (I), wherein R1, R2 and R3 in the formula are respectively defined in the specification. The invention also relates to an agricultural composition containing the compound or the pharmaceutically acceptable salt thereof. The prepared compound has good safener activity, can well relieve the toxicity of herbicidesto crops after being used, and is beneficial to the growth of crops. Compared with similar compounds, the compound provided by the invention shows good detoxification effect and safety.
- -
-
Paragraph 0035-0036; 0055-0056
(2020/04/06)
-
- Monohydrochloride Assisted Synthesis of Functionalized Isoxazoles and Pyrazoles from Allenic Ketones: First Synthesis of (Z)-2-Methyl-7H-benzo[b]pyrazolo[5,1-d][1,5]oxazocines
-
A facile hydrochloride promoted regioselective synthesis of isoxazoles and pyrazoles from 1,2-allenic ketones is reported. The reaction has been scaled up to gram scale. A direct 8-endo dig ring annulations towards the first synthesis of (Z)-2-methyl-7H-b
- Sarkar, Debayan,Sahoo, Sushree Ranjan
-
p. 2035 - 2049
(2019/03/07)
-
- Pyrazole compound containing N-aryl sulfonate and synthesis and application thereof
-
The invention discloses a pyrazole compound containing N-aryl sulfonate. A structural formula of the pyrazole compound is shown in the description. Proofed by pharmacological study, the pyrazole compound has the advantages that the activity of cyclooxygenase 2 is inhibited; the high-efficiency inhibition function on the generation of cyclooxygenase 2 due to inflammation mediums is realized, so that the pyrazole compound can be used as an active matter, and the prepared anti-inflammation medicine can be used for treating the inflammations, such as rheumatic arthritis and rheumatalgia, and the diseases and symptoms, such as fevers.
- -
-
Paragraph 0038
(2018/07/10)
-
- 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.
- -
-
Page/Page column 19
(2018/07/29)
-
- 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)
-
- Direct synthesis of pyrazoles from esters using tert-butoxide-assisted C-(C=O) coupling
-
This paper describes the direct synthesis of pyrazoles from esters that comprises two sequential reactions: tert-butoxide-assisted C-C(=O) coupling reaction to yield β-ketonitrile or α,β-alkynone intermediates, and condensation by hydrazine addition. The method reported allows for easy control of the regioselectivity and structure of substituents at N-1, C-3, C-4 and/or C-5 positions.
- Kim, Bo Ram,Sung, Gi Hyeon,Ryu, Ki Eun,Lee, Sang-Gyeong,Yoon, Hyo Jae,Shin, Dong-Soo,Yoon, Yong-Jin
-
supporting information
p. 9201 - 9204
(2015/06/08)
-
- Clean and efficient synthesis of pyrazole derivatives in aqueous media
-
A series of 5-aryl-1H-pyrazole derivatives were synthesized via the reaction of 3-(dimethylamino)-1-arylprop-2-en-1-one with hydrazine in aqueous media without using any catalyst. This method has the advantages of easier work-up, mild reaction condition, high yields, and an environmentally benign procedure.
- Xu, Pan,Xi, Yu-Kun,Chen, Hui,Shi, Da-Qing
-
p. 611 - 613
(2015/03/30)
-
- 'Unconventional' coordination chemistry by metal chelating fragments in a metalloprotein active site
-
The binding of three closely related chelators: 5-hydroxy-2-methyl-4H- pyran-4-thione (allothiomaltol, ATM), 3-hydroxy-2-methyl-4H-pyran-4-thione (thiomaltol, TM), and 3-hydroxy-4H-pyran-4-thione (thiopyromeconic acid, TPMA) to the active site of human ca
- Martin, David P.,Blachly, Patrick G.,Marts, Amy R.,Woodruff, Tessa M.,De Oliveira, César A. F.,McCammon, J. Andrew,Tierney, David L.,Cohen, Seth M.
-
supporting information
p. 5400 - 5406
(2014/05/06)
-
- An efficient synthesis of isoxazoles and pyrazoles under ultrasound irradiation
-
A series of 5-arylisoxazole and 5-aryl-1H-pyrazole derivatives was synthesized by the reaction of 3-(dimethylamino)-1-arylprop-2-en-1-one with hydroxylamine hydrochloride or hydrazine hydrate under ultrasound irradiation without using any catalyst. This m
- Huang, Zhi-Bin,Li, Li-Li,Zhao, Yan-Wei,Wang, Hui-Yuan,Shi, Da-Qing
-
p. E309-E313
(2014/11/07)
-
- Solid-state and solvent-free synthesis of azines, pyrazoles, and pyridazinones using solid hydrazine
-
Azines, pyrazoles, and pyridazinones were isolated as the sole products in high yields (>97%) by grinding solid hydrazine (H3N +NHCO2-) with di-carbonyl compounds or by their reaction in the absence of solvent. Neither catalysts nor additives were needed to promote the reactions. The solid-state and solvent-free reactions proceeded under ambient conditions and did not produce any wastes other than water and carbon dioxide. They are operationally easy, environmentally safe, and readily scalable, allowing for highly selective synthesis of compounds containing the hydrazine motif. Copyright
- Lee, Byeongno,Kang, Philjun,Lee, Kyu Hyung,Cho, Jaeheung,Nam, Wonwoo,Lee, Won Koo,Hur, Nam Hwi
-
supporting information
p. 1384 - 1388
(2013/04/23)
-
- One-pot formation of aza-enolates from secondary amines and condensation to esters and alkyl bromides
-
Starting from commercial secondary amines, a one-pot procedure allows a direct access to enaminones through a one-pot deprotonation/oxidation/in situ re-deprotonation/acylation sequence without intermediate isolation of the intermediate Schiff base or its corresponding enamine tautomer. An alternative one-pot sequence involving a similar oxidation step followed by one or two alkylation steps yields, after acidic work-up, functionalized ketones directly from the parent amine. This process has been applied to an expeditious synthesis of the male aggregation pheromone of the cereal leaf beetle Oulema melanopus.
- Chevalley, Alice,Férézou, Jean-Pierre
-
experimental part
p. 5882 - 5889
(2012/09/11)
-
- A novel synthesis of fluorinated pyrazoles via gold(I)-catalyzed tandem aminofluorination of alkynes in the presence of Selectfluor
-
A mild and efficient protocol for the synthesis of fluorinated pyrazoles has been developed via gold(I)-catalyzed tandem aminofluorination of alkynes in the presence of Selectfluor. This method offers a broad substrate scope.
- Qian, Jianqiang,Liu, Yunkui,Zhu, Jie,Jiang, Bo,Xu, Zhenyuan
-
supporting information; experimental part
p. 4220 - 4223
(2011/10/04)
-
- Nitrogen-containing heterocycles from metal β-diketonates
-
Factors determining the reaction of metal β-diketonates with hydrazine, in particular the nature of central metal ion and structure of β-diketonate ligand, are discussed. The possibility for the preparation of other heterocyclic compounds via reaction of metal acetylacetonates with phenylhydrazine, o-phenylenediamine, urea, and thiourea was studied.
- Svistunova,Shapkin,Nikolaeva,Apanasenko
-
experimental part
p. 756 - 761
(2011/08/06)
-
- A regioselective synthesis of some new pyrazol-1′-ylpyrazolo[1,5-a] pyrimidines in aqueous medium and their evaluation as antimicrobial agents
-
An efficient and environmental benign regioselective synthesis of some new pyrazol-1′-ylpyrazolo[1,5-a]pyrimidines (7b-h) has been accomplished via treatment of 3(5)-amino-5(3)-hydrazinopyrazole dihydrochloride (5) with several unsymmetrical 1,3-diketones (6b-h) using water as a solvent without any catalysts or additives. The structure of 7b-h was established on the basis of rigorous analysis of 1H, 13C NMR, IR spectral data and MS. Eight compounds (7a-h) were screened for their antibacterial activity against two gram-positive and two gram-negative bacteria and compounds (7a, b, d and e) for antifungal activity against four phytopathogenic fungi. Compounds 7c and 7e manifest rather broad antibacterial activity than standard antibiotics. One lead compound, 7a (10 mg/ml and 200 mg/ml) exhibited equipotent or more potent antifungal activity against all tested microorganisms than standard drug.
- Aggarwal, Ranjana,Sumran, Garima,Garg, Neelam,Aggarwal, Ashok
-
experimental part
p. 3038 - 3046
(2011/07/08)
-
- Synthesis and structural characterization of pyrazol-1′-ylpyrazolo[1,5-a]pyrimidines by multinuclear NMR spectroscopy
-
3(5)-Amino-5(3)-hydrazinopyrazole dihydrochloride (8) reacts with pentane-2,4-dione (9a) to afford 2-(3′,5′-dimethylpyrazol-1′-yl)-5,7-dimethylpyrazolo[1 ,5-a]pyrimidine (10a) instead of the 3-(3′,5′-dimethylpyrazol-1′-yl)-4,6-dimethyl-1H-pyrazo lo[3,4-b]
- Aggarwal, Ranjana,Sumran, Garima,Claramunt, Rosa M.,Sanz, Dionisia,Elguero
-
experimental part
p. 96 - 102
(2010/02/15)
-
- β-Acetyl-β-nitrostyrenes: Structure and use for synthesis of heteryl-containing structures
-
1H, IR, and electronic absorption spectroscopy and X-ray diffraction analysis were used to establish that 1-acetyl-1-nitro-2-phenyl-and 2-(p-methoxyphenyl)ethenes have Z configuration, and their 2-(p-N, Ndimethylaminophenyl)-substituted analog exists in chloroform-d 3 as a mixture of Z and E isomers. The reactions of gem-acetylnitroethenes with N-methylpyrrole were shown to involve alkylation at the C2-reaction center of the heterocycle. The reactions of these nitroalkenes with hydrazine form pyrazoles and azines, with acetylhydrazine, the corresponding hydrazones (via transalkenylation), and with sodium azide, acetylsubstituted 1,2,3-triazoles.
- Aboskalova,Smirnova,Kataeva,Baichurin,Fel'gendler,Berkova,Berestovitskaya
-
experimental part
p. 1711 - 1718
(2009/02/06)
-
- A ceric ammonium nitrate N-dearylation of N-p-anisylazoles applied to pyrazole, triazole, tetrazole, and pentazole rings: Release of parent azoles. Generation of unstable pentazole, HN5/N5-, in solution
-
(Chemical Equation Presented) The reaction of cerium(IV) ammonium nitrate (CAN) with a range of N-(p-anisyl)azoles in acetonitrile or methanol solvents leads to N-dearylation releasing the parent NH-azole and p-benzoquinone in comparable yields. The scope and limitations of the reaction are explored. It was successful with 1-(p-anisyl)pyrazoles, 2-(p-anisyl)-1,2,3-triazoles, 2-(p-anisyl)-2H-tetrazoles, and 1-(p-anisyl)pentazole. The dearylation renders the p-anisyl group as a potentially useful N-protecting group in azole chemistry. The azole released in solution from 1-(p-anisyl)pentazole is unstable HN5, the long-sought parent pentazolic acid. p-Anisylpentazole samples were synthesized with combinations of one, two, and three 15N atoms at all positions of the pentazole ring. The unstable HN 5/N5- produced at -40°C did not build up in the solution but degraded to azide ion and nitrogen gas with a short lifetime. The 15N-labeling of the N3- ion obtained from all samples proved unequivocally that it came from the degradation of HN 5 (tautomeric forms) and/or its anion N5- in the solution.
- Butler, Richard N.,Hanniffy, John M.,Stephens, John C.,Burke, Luke A.
-
p. 1354 - 1364
(2008/04/12)
-
- New "green" approaches to the synthesis of pyrazole derivatives
-
A novel approach to the synthesis of pyrazole derivatives from tosylhydrazones of α,β-unsaturated carbonyl compounds possessing a β-hydrogen is proposed, exploiting microwave (MW) activation coupled with solvent free reaction conditions. The cycloaddition was studied on three ketones (trans-4-phenyl-3-buten-2-one, β-ionone and trans-chalcone). The corresponding 3,5-disubstitued-1H-pyrazoles were obtained in high yields and after short reaction times. In order to simplify and point out the green chemistry features of the method, a further improvement was achieved under the same catalytic conditions with a "one pot" synthesis of these heterocyclic compounds, starting directly from their carbonyl precursors via tosylhydrazones generated in situ. For an exhaustive study, the dielectric properties of the solid reaction mixtures were also measured, in order to obtain input data for the numerical simulation of their heating behaviour in the single mode MW cavity which was used for experimental work. In order to supply a valid methodology and tool for measuring the environmental impact, a comparative study between the synthetic route proposed and the classical synthetic route has been carried out.
- Corradi, Anna,Leonelli, Cristina,Rizzuti, Antonino,Rosa, Roberto,Veronesi, Paolo,Grandi, Romano,Baldassari, Sara,Villa, Carla
-
p. 1482 - 1495
(2007/12/27)
-
- Facile preparation of allyl amines and pyrazoles by hydrazinolysis of 2-ketoaziridines
-
Allyl amines and pyrazoles can be obtained by hydrazinolysis of 2-ketoaziridines. A variety of aziridines, including N-unprotected, N-substituted, as well as bicyclic enamine and aminal type, can be transformed into diversely substituted linear or cyclic products. The hydrazinolysis of homochiral aziridines proceeds without racemization.
- Chen, Gang,Sasaki, Mikio,Yudin, Andrei K.
-
p. 255 - 259
(2007/10/03)
-
- Palladium-catalyzed coupling of pyrazole triflates with arylboronic acids
-
A general protocol for the palladium-mediated Suzuki coupling reaction of pyrazole inflates and aryl boronic acids has been developed. The use of additional dppf ligand was determined to increase product yields allowing for the use of a broad range of rea
- Dvorak, Curt A.,Rudolph, Dale A.,Ma, Sandy,Carruthers, Nicholas I.
-
p. 4188 - 4190
(2007/10/03)
-
- First generation of pentazole (HN5, pentazolic acid), the final azole, and a zinc pentazolate salt in solution: A new N-dearylation of 1-(p-methoxyphenyl) pyrazoles, a 2-(p-methoxyphenyl) tetrazole and application of the methodology to 1-(p-methoxyphenyl) pentazole
-
Ceric ammonium nitrate (CAN) in methanol-water gave a new N-dearylation of a series of substituted 1-(p-methoxyphenyl) pyrazoles and a 2-(p-methoxyphenyl)tetrazole producing p-benzoquinone and the parent azole in a mole for mole ratio. Application of this reaction to 1-(p-methoxyphenyl) pentazole at -40°C produced p-benzoquinone. 15N NMR spectra suggest that pentazole, HN5, was also produced and held in solution as N5- with Zn2+ ion. The 15N signal from N5- was -10.0 ± 2.0 ppm in agreement with calculated values.
- Butler,Stephens, John C.,Burke, Luke A.
-
p. 1016 - 1017
(2007/10/03)
-
- 5-Hydroxy-2-pyrazolines and some of their 1-substituted analogs
-
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
-
p. 668 - 676
(2007/10/03)
-
- Inverse electron demand Diels-Alder reaction - A facile synthetic route to pyrazoles from conjugated oximes utilizing diimides as dipolarophile
-
Conjugated oximes are convened into pyrazoles in a one-pot reaction by refluxing with hydrazine and iodine in ethanol. The reaction proceeds via an inverse electron demand Diels-Alder reaction involving electron deficient heterodienes and diimide species as dipolarophile.
- Ahmed, Shahadat,Longchar, Moanochet,Boruah, Romesh C.
-
p. 125 - 127
(2007/10/03)
-
- Reactions of β-aminoenones with acetylhydrazine, semicarbazide and methoxycarbonylhydrazine. Synthesis of 1-acetyl-, 1-carboxamide- or methyl 1- carboxylated pyrazole derivatives
-
Acetylhydrazine, semicarbazide and methoxycarbonylhydrazine react with β-aminoenones to give regioselectively the corresponding N-acetyl- or N- carboxypyrazole derivatives. The reaction are highly regioselective and occurs via 5-hydroxypyrazolines which in several case can be isolated and characterized.
- Alberola, Angel,Calvo, Luis,Ortega, Alfonso Gonzalez,Sadaba, M. Luisa,Sanudo, M. Carmen,Granda, Santiago Garcia,Rodriguez, Elena Garcia
-
p. 2675 - 2686
(2007/10/03)
-
- 5-Hydroxy-4,5-Dihydropyrazoles
-
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.
-
p. 11251 - 11256
(2007/10/02)
-
- Synthesis of Pyrazole, 1,2,4,5-Tetrazine, and 1,2,4-Triazole Derivatives from Thiocarbonohydrazides and β-Dicarbonyl Compounds
-
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.
-
p. 868 - 873
(2007/10/03)
-
- Nitrosation of Methyl and Phenyl Styryl Ketoximes Under Oxygen. Formation of 4-Nitro-1-hydroxypyrazole 2-Oxides and 3,5-Diphenyl-4-nitrato-4,5-dihydroisoxazole
-
The nitrosation of the oximes of 4-phenyl-3-buten-2-one and 1,3-diphenyl-2-propen-1-one under oxygen has been reinvestigated.In addition to 4-oxo- and 4-oximino-4H-pyrazole 1,2-dioxides previously reported, the reactions give 4-nitro-1-hydroxypyrazole 2-oxides.In the case of 1,3-diphenyl-2-propen-1-one oxime the nitrosation reaction also gives 3,5-diphenyl-4-nitrato-4,5-dihydroisoxazole.Evidence is presented suggesting that the nitrate ester is formed through the rearrangement of a peroxynitrite intermediate.
- Hansen, John F.,Georgiou, Paul J.
-
p. 1487 - 1492
(2007/10/02)
-
- THERMOLYSIS OF 1,2,3-TRIAZINES
-
Thermal reactions of 1,2,3-triazines were investigated using neat thermolysis and flash vacuum thermolysis (FVT).Neat thermolysis afforded the products which were derived from intermolecular reaction, whereas unimolecular degradation occurred by FVT to give alkyne, nitrile and nitrogen.The selectivity of the reaction was considered using molecular orbital calculation.
- Itoh, Takashi,Okada, Mamiko,Nagata, Kazuhiro,Ohsawa, Akio
-
p. 1183 - 1190
(2007/10/02)
-
- SYNTHESIS AND REARRANGEMENT OF 5-ISOTHIOCYANATOPYRAZOLINES
-
1-(3-Iminoprop-1-enyl)-5-isothiocyanato-2-pyrazolines have been synthesized by reaction of hydrazine derivatives with carbon disulfide.These pyrazoline derivatives are precursors of pyrimidinylpyrazoles.
- Gotor, Vicente,Brieva, Rosario,Foces-Foces, Concepcion,Cano, Felix Hernandez
-
p. 1783 - 1792
(2007/10/02)
-
- INVESTIGATION OF THE MECHANISMS OF FORMATION OF HETEROCYCLES BY NMR SPECTROSCOPY. III. THE EFFECT OF ELECTRONIC FACTORS ON THE KINETICS OF THE DEHYDRATION OF DIHYDROXYPYRAZOLIDINES AND HYDROXYPYRAZOLINES- THE INTERMEDIATES IN THE REACTION OF HYDRAZINE WITH 1,3-DIKETONES
-
The rate constants for the dehydration of the dihydroxypyrazolidine and hydroxypyrazoline intermediates in the reaction of hydrazine with substituted benzoylacetones p-XC6H4COCH2COCH3 (X= CH3O, CH3, H, Cl, NO2) in methanol were determined by NMR spectroscopy using the stopped-flow technique.Increase in the electronegativity of the substituent leads, on the one hand, to an increase in the contribution from the reaction path involving the formation of the tautomeric pyrazoles with the participation of 3-methyl-5-(p-XC6H4)-5-hydroxypyrazoline and, on the other hand, to an increase in the rate of its conversion into the corresponding pyrazole.Analysis of the relationships between the dehydration rates and the Hammett ? constants confirms a reaction mechanism with the participation of the cyclic dihydroxypyrazolidine intermediate.
- Selivanov, S. I.,Golodova, K. G.,Abbasov, Ya. A.,Ershov, B. A.
-
p. 1361 - 1364
(2007/10/02)
-