- Vinyldiazo Compounds as 3-Carbon Radical Acceptors: Synthesis of 4-Fluoroacridines via Visible-Light-Promoted Cascade Radical Cyclization
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Vinyldiazo reagents were developed as the radical acceptors in a visible-light-promoted sequential radical cyclization reaction, providing a mechanistically distinct pathway to achieve (3 + 3) cyclization. Using N-aryl chlorodifluoromethyl alkynyl ketoimines as the radical precursors, the reaction allows the introduction of a fluorine atom to the acridine skeleton during the construction of both the pyridine and benzene motifs from acyclic building blocks. The resulting 4-fluoroacridines exhibited pronounced fluorescent properties in the solid state.
- Li, Weiyu,Zhou, Lei
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Read Online
- Two new palladium and platinum complexes with a bidentate pyrazole-based ligand: Crystal structure, fluorescence and Hirshfeld surface analysis
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Two new precious metal coordination complexes [Pd(HL)2] (1) and [PtL2] (2) (where H2L is 1-(carboxymethyl)-1H-pyrazole-3-carboxylic acid) were synthesized by one-pot in situ hydrolysis. The complexes are assembled into a 3D structure by hydrogen bonding interactions and intermolecular contacts. The structures have been established by single-crystal X-ray diffraction, and characterized by FT-IR and liquid state fluorescent spectroscopy. Hirshfeld surface analysis reveals that the OH contacts outnumber the other contacts in both structures (49.4 % of the total interactions for 1 and 41.6 % for 2).
- Feng, Chao,Li, Xue-Jing,Zhang, Duo,Qu, Zhi-Rong,Zhao, Hong
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Read Online
- 1-vinyl-3- and 1-vinyl-5-pyrazolecarboxylic acids. synthesis and anti-burn activity of their chitosan salts
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The synthesis of 1-vinyl-3- and 1-vinyl-5-pyrazolcarboxylic acids is developed and the anti burn activity of the chitosan salts of 1-vinyl-3(5)-carboxylic acids is studied.
- Rstakyan,Akopyan,Saakyan,Attaryan,Asratyan
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Read Online
- COMPOUNDS WITH COPPER- OR ZINC-ACTIVATED TOXICITY AGAINST MICROBIAL INFECTION
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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.
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- Design, synthesis and biological evaluation of ring-fused pyrazoloamino pyridine/pyrimidine derivatives as potential FAK inhibitors
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We report herein the synthesis of novel ring-fused pyrazoloamino pyridine/pyrimidine derivatives as potential FAK inhibitors and the evaluation of pharmaceutical activity against five cancer cell lines (MDA-MB-231, BXPC-3, NCI-H1975, DU145 and 786O). Generally, the majority of compounds displayed strong anti-FAK enzymatic potencies (IC50 1 nM) and could effectively inhibit several class of cancer cell lines within the concentration of 3 μM in comparison with GSK2256098 as a reference. Among them, compound 4o is considered to be the most effective due to high sensitivity in antiproliferation. In culture, 4o could not only inhibit FAK Y397 phosphorylation in MDA-MB-231 cell line, but also trigger apoptosis in a dose-dependent manner. Furthermore, computational docking analysis also suggested that 4o and TAE-226 displayed the similar interaction with FAK kinase domain.
- Xie, Hongming,Lin, Xinglong,Zhang, Yingjun,Tan, Fuxing,Chi, Bo,Peng, Zhihong,Dong, Wanrong,An, Delie
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supporting information
(2020/10/06)
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- Structure-activity relationship studies for the development of inhibitors of murine adipose triglyceride lipase (ATGL)
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High serum fatty acid (FA) levels are causally linked to the development of insulin resistance, which eventually progresses to type 2 diabetes and non-alcoholic fatty liver disease (NAFLD) generalized in the term metabolic syndrome. Adipose triglyceride lipase (ATGL) is the initial enzyme in the hydrolysis of intracellular triacylglycerol (TG) stores, liberating fatty acids that are released from adipocytes into the circulation. Hence, ATGL-specific inhibitors have the potential to lower circulating FA concentrations, and counteract the development of insulin resistance and NAFLD. In this article, we report about structure–activity relationship (SAR) studies of small molecule inhibitors of murine ATGL which led to the development of Atglistatin. Atglistatin is a specific inhibitor of murine ATGL, which has proven useful for the validation of ATGL as a potential drug target.
- Breinbauer, Rolf,Doler, Carina,Fuchs, Elisabeth,Grabner, Gernot F.,Mayer, Nicole,Melcher, Michaela-Christina,Migglautsch, Anna K.,Romauch, Matthias,Schweiger, Martina,Zechner, Rudolf,Zimmermann, Robert
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supporting information
(2020/07/13)
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- Structure Kinetics Relationships and Molecular Dynamics Show Crucial Role for Heterocycle Leaving Group in Irreversible Diacylglycerol Lipase Inhibitors
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Drug discovery programs of covalent irreversible, mechanism-based enzyme inhibitors often focus on optimization of potency as determined by IC50-values in biochemical assays. These assays do not allow the characterization of the binding activity (Ki) and reactivity (kinact) as individual kinetic parameters of the covalent inhibitors. Here, we report the development of a kinetic substrate assay to study the influence of the acidity (pKa) of heterocyclic leaving group of triazole urea derivatives as diacylglycerol lipase (DAGL)-α inhibitors. Surprisingly, we found that the reactivity of the inhibitors did not correlate with the pKa of the leaving group, whereas the position of the nitrogen atoms in the heterocyclic core determined to a large extent the binding activity of the inhibitor. This finding was confirmed and clarified by molecular dynamics simulations on the covalently bound Michaelis-Menten complex. A deeper understanding of the binding properties of covalent serine hydrolase inhibitors is expected to aid in the discovery and development of more selective covalent inhibitors.
- Janssen, Antonius P.A.,Van Hengst, Jacob M.A.,Béquignon, Olivier J.M.,Deng, Hui,Van Westen, Gerard J.P.,Van Der Stelt, Mario
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p. 7910 - 7922
(2019/10/11)
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- Batch and Continuous-Flow One-Pot Processes using Amine Diazotization to Produce Silylated Diazo Reagents
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A novel synthesis of trimethylsilyldiazomethane (TMSCHN2) by diazotization of trimethylsilylmethylamine (TMSCH2NH2) is reported using batch and continuous flow synthesis. The latter affords a daily production of 275 g (2.4 mol) of TMSCHN2. Other silylated methylamines were also successfully reacted under the developed reaction conditions to furnish various silicon-bearing diazomethane reagents. The applicability of the process is highlighted by disclosure of batch and continuous flow one-pot esterification and 1,3-dipolar cycloaddition processes. Furthermore, the high-yielding esterification of carboxylic acids with silylated and substituted methylamines in continuous flow is disclosed. Finally, work-up and purification procedures are reported for the preparation of a 2-MeTHF solution of TMSCHN2, which can be used in rhodium-catalyzed methylenation and homologation reactions.
- Audubert, Clément,Gamboa Marin, Oscar Javier,Lebel, Hélène
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supporting information
p. 6294 - 6297
(2017/05/19)
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- PYRROLOPYRIMIDINE COMPOUND
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The present application relates to the field of pharmaceutical chemistry, and in particular, to a pyrrolopyrimidine compound represented by general formula (I), a stereoisomer thereof, or a pharmaceutically acceptable salt thereof. The present invention further relates to a method for preparing the pyrrolopyrimidine compound represented by general formula (I), pharmaceutical compositions and an application of the pyrrolopyrimidine compound in treating diseases mediated by Janus Kinase.
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Paragraph 0264; 0265
(2017/11/11)
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- Laboratory-Scale Membrane Reactor for the Generation of Anhydrous Diazomethane
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A configurationally simple and robust semibatch apparatus for the in situ on-demand generation of anhydrous solutions of diazomethane (CH2N2) avoiding distillation methods is presented. Diazomethane is produced by base-mediated decomposition of commercially available Diazald within a semipermeable Teflon AF-2400 tubing and subsequently selectively separated from the tubing into a solvent- and substrate-filled flask (tube-in-flask reactor). Reactions with CH2N2 can therefore be performed directly in the flask without dangerous and labor-intensive purification operations or exposure of the operator to CH2N2. The reactor has been employed for the methylation of carboxylic acids, the synthesis of α-chloro ketones and pyrazoles, and palladium-catalyzed cyclopropanation reactions on laboratory scale. The implementation of in-line FTIR technology allowed monitoring of the CH2N2 generation and its consumption. In addition, larger scales (1.8 g diazomethane per hour) could be obtained via parallelization (numbering up) by simply wrapping several membrane tubings into the flask.
- Dallinger, Doris,Pinho, Vagner D.,Gutmann, Bernhard,Kappe, C. Oliver
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p. 5814 - 5823
(2016/07/26)
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- ATGListatin and pharmaceutical composition comprising the same
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A compound of formula (I) as defined herein is useful in the treatment and prevention of a disorder such as cachexia, stroke, atherosclerosis, coronary artery disease, and diabetes and pharmaceutical compositions of the same. Also, a method of screening f
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Page/Page column 25-26
(2015/12/26)
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- KINASE INHIBITORS
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Compounds of formula (I) described herein are p38 MAPK inhibitors and are useful as anti-inflammatory agents in the treatment of, inter alia, diseases of the respiratory tract
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Paragraph 0729; 0730
(2015/01/06)
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- KINASE INHIBITORS
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This invention relates to compounds and compositions that are p38 MAPK inhibitors, useful as anti-inflammatory agents in the treatment of, inter alia, diseases of the respiratory tract.
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Page/Page column 232
(2015/01/06)
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- A new pyrrole synthesis via silver(I)-catalyzed cycloaddition of vinylogous diazoester and nitrile
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A new synthesis of di- and trisubstituted pyrroles was achieved by treating in situ generated vinylogous diazoesters and readily available nitriles with a catalytic amount of silver(I) antimony hexafluoride at room temperature. This method showcased the potential of utilizing silver(I) carbenoids in preparing heterocyclic compounds.
- Billedeau, Roland J.,Klein, Klara R.,Kaplan, Daniel,Lou, Yan
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p. 1421 - 1423
(2013/06/26)
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- CHEMOKING RECEPTOR ANTAGONISTS
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Disclosed herein are chemokine receptor antagonists of formula (I) wherein G1, X1, X2, and X3 are as defined in the specification. Compositions comprising such compounds; and methods for treating conditions and disorders using such compounds and compositions are also described.
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Page/Page column 106
(2013/03/26)
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- TRICYCLIC COMPOUNDS AS ALLOSTERIC MODULATORS OF METABOTROPIC GLUTAMATE RECEPTORS
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The present invention describes and claims compounds of the Structural Formula (I), Structural Formula (II), or Structural Formula (III). In Formula (I), R1, R2, R3 and R3' are -H or methyl, or R3 and R3' taken together form a double bond, or R3' is -H and R2 and R3 taken together form a spiro-cyclopropyl substituent, R4 is -H or -F, and R5 is -H, methyl, -Cl or -Br. In Formula (II), R1 is -H, ethyl-, isopropyl-, cyclopropyl-, methyl- or methoxy-, R4 is -H or -F, and "Y" is: (a) -CH2-; (b) -CR6H-O-CR7R8-, wherein R6, R7, and R8 are independently -H or methyl; (c) -CR6H-N(R9)-CR7R8-, wherein R6, R7, and R8 are independently -H or methyl; (d) -CH2-C(R9)(R10)-C(R7)(R8)-, wherein R7, R8, R9 and R10 are independently -H or -methyl, or both R7 and R8 are -F, R9 and R10 are independently -H or -methyl, or both R9 and R10 are -F, or R9 and R10 taken together are (O=), which together with the carbon to which they are attached forms a carbonyl group.
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Page/Page column 47
(2012/02/02)
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- TRICYCLIC COMPOUNDS AS ALLOSTERIC MODULATORS OF METABOTROPIC GLUTAMATE RECEPTORS
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The present invention describes and claims compounds of the Structural Formula I, Structural Formula II, or Structural Formula III: wherein R1, R2, R3 and R3' are -H or methyl, or R3 and R3 taken together form a double bond, or R3' is -H and R2 and R3 taken together form a spiro-cyclopropyl substituent, R4 is -H or -F, and R5 is -H, methyl, -CI or -Br, Formula II wherein R1 is -H, ethyl-, isopropyl-, cyclopropyl-, methyl- or methoxy-, R4 is -H or -F, and "Y" is: (a) -CH2-; (b) -CR6H-0-CR7R8-, wherein R6, R7, and R8 are independently - H or methyl; (c) -CR6H-N(R9)-CR7R8-, wherein R6, R7, and R8 are independently -H or methyl; (d) -CH2-C(R9)(R10)-C(R7)(R8)-, wherein R7, R8, R9 and R10 are independently - H or -methyl, or both R7 and R8 are -F, R9 and R10 are independently -H or -methyl, or both R9 and R10 are -F, or R9 and R10 taken together are (0=), which together with the carbon to which they are attached forms a carbonyl group.
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Page/Page column 47
(2012/02/02)
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- PYRAZOLE DERIVATIVES AS S1P1 AGONISTS
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The present invention relates to a compound of formula (I), to the process for preparing such compounds and to their use in the treatment of a pathological condition or disease susceptible to amelioration by sphingosine-1-phosphate receptors (S1P1) agonists.
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Page/Page column 94-95
(2011/12/04)
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- New pyrazole derivatives
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The present invention relates to a compound of formula (I), to the process for preparing such compounds and to their use in the treatment of a pathological condition or disease susceptible to amelioration by sphingosine-1-phosphate receptors (S1P1) agonists.
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Paragraph 0351; 0352; 0461; 0462
(2013/03/26)
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- N-Benzylimidazole carboxamides as potent, orally active stearoylCoA desaturase-1 inhibitors
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A potent, small molecule inhibitor with a favorable pharmacokinetic profile to allow for sustained SCD inhibition in vivo was identified. Starting from a low MW acyl guanidine (5a), identified with a RapidFire High-Throughput Mass Spectrometry (RF-MS) assay, iterative library design was used to rapidly probe the amide and tail regions of the molecule. Singleton synthesis was used to probe core changes. Biological evaluation of a SCD inhibitor (5b) included in vitro potency at SCD-1 and in vivo modulation of the plasma desaturation index (DI) in rats on a low essential fatty acid (LEFA) diet. In addition to dose-dependent decrease in DI, effects on rodent ocular tissue were noted. Therefore, in rat, these SCD inhibitors only recapitulate a portion of phenotype exhibited by the SCD-1 knockout mouse.
- Atkinson, Karen A.,Beretta, Elena E.,Brown, Janice A.,Castrodad, Mayda,Chen, Yue,Cosgrove, Judith M.,Du, Ping,Litchfield, John,Makowski, Michael,Martin, Kelly,McLellan, Thomas J.,Neagu, Constantin,Perry, David A.,Piotrowski, David W.,Steppan, Claire M.,Trilles, Richard
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scheme or table
p. 1621 - 1625
(2011/05/05)
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- Method for the Production of N-Substituted (3-Dihalomethyl-1-Methyl-Pyrazole-4-yl) Carboxamides
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The present invention relates to a process for preparing N-substituted (3-dihalomethylpyrazol-4-yl)carboxamides of the formula (I) in which R1 is optionally substituted phenyl or C3-C7-cycloalkyl, R1a is hydrogen or fluorine, or R1a together with R1 is optionally substituted C3-C5-alkanediyl or C5-C7-cycloalkanediyl, R2 is C1-C6-alkyl, C2-C6-alkenyl, C2-C6-alkynyl or C1-C4-alkoxy-C1-C2-alkyl, X is F or Cl and n is 0, 1, 2 or 3; which comprises A) providing a compound of the formula (II) in which X is F or Cl, Y is Cl or Br and R2 has one of the meanings given above and B) reacting a compound of the formula (II) with carbon monoxide and a compound of the formula (III) in which R1, R1a and n have one of the meanings given above; in the presence of a palladium catalyst; to intermediates used for the preparation according to the process according to the invention, and also to processes for their preparation.
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Page/Page column 15-16
(2010/07/10)
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- MODULATORS OF CXCR7
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Compounds having formula (I) or pharmaceutically acceptable salts, hydrates or N-oxides thereof are provided and are useful for binding to CXCR7, and treating diseases that are dependent, at least in part, on CXCR7 activity. Accordingly, the present inven
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Page/Page column 59
(2010/06/11)
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- PROCESSES FOR THE PREPARATION OF PYRAZOLE DERIVATIVES USEFUL AS MODULATORS OF THE 5-HT2A SEROTONIN RECEPTOR
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The present invention relates to processes for preparing pyrazole derivatives of Formula (I) and salts and pharmaceutical compositions of the salts thereof, useful as modulators of 5-HT2A serotonin receptor activity. The present invention also relates to intermediates used in the processes, and their preparation. The present invention also relates to salts of compounds of Formula (I) and pharmaceutical compositions thereof
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Page/Page column 52
(2009/10/30)
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- Synthesis of pyrazoles through catalyst-free cycloaddition of diazo compounds to alkynes
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The synthesis of pyrazoles via 1,3-dipolar cycloaddition of diazo compounds to alkynes proceeds easily by heating. With α-diazocarbonyl substrates the reactions are conducted under solvent-free conditions affording the pyrazole products in high yields wit
- Vuluga, Daniela,Legros, Julien,Crousse, Benoit,Bonnet-Delpon, Daniele
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scheme or table
p. 156 - 159
(2010/04/22)
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- PYRIDINYL-PYRAZOLE DERIVATIVES AND THEIR USE AS POTASSIUM CHANNEL MODULATORS
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This invention relates to novel pyridinyl-pyrazole derivatives and their use as potassium channel modulating agents. Moreover the invention is directed to pharmaceutical compositions useful for the treatment or alleviation of diseases or disorders associa
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Page/Page column 20
(2008/12/07)
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- OXADIAZOLE DERIVATIVES AS S1P1 RECEPTOR AGONISTS
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The present invention relates to novel oxadiazole compounds of formula (I) having pharmacological activity, processes for their preparation, pharmaceutical compositions containing them and their use in the treatment of various disorders.
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Page/Page column 20
(2008/12/06)
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- Fluorinated pyrazole acids are agonists of the high affinity niacin receptor GPR109a
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A series of 5-alkyl pyrazole-3-carboxylic acids were prepared and found to act as potent and selective agonists of the human GPCR, GPR109a, the high affinity nicotinic acid receptor. No activity was observed at the highly homologous low affinity niacin receptor, GPR109b. A further series of 4-fluoro-5-alkyl pyrazole-3-carboxylic acids were shown to display similar potency. One example from the series was shown to have improved properties in vivo compared to niacin.
- Skinner, Philip J.,Cherrier, Martin C.,Webb, Peter J.,Shin, Young-Jun,Gharbaoui, Tawfik,Lindstrom, Andrew,Hong, Vu,Tamura, Susan Y.,Dang, Huong T.,Pride, Cameron C.,Chen, Ruoping,Richman, Jeremy G.,Connolly, Daniel T.,Semple, Graeme
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p. 5620 - 5623
(2008/04/02)
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- NOVEL FUSED HETEROCYCLES AND USES THEREOF
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This invention relates to novel compounds having the Formula (I) and to their pharmaceutical compositions and to their methods of use. These novel compounds provide a treatment or prophylaxis of H. pylori infection.
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Page/Page column 104
(2010/02/14)
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- The reaction of 2-(tetrazol-5-yl)alkyl ketones and of 2-(tetrazol-5-yl)alkanoic acid derivatives with lead tetraacetate. A novel method of preparation of alk-2-ynyl ketones and alk-2-ynoic acid derivatives
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The majority of tetrazolylacetyl derivatives 2 and 7, when treated with lead tetraacetate in dry 1,4-dioxane at room or lower temperature, are oxidized with elimination of molecular nitrogen mainly to the corresponding alkynoyl derivatives 4 and 8, respectively. Vinylidenes (25) have been shown to be the intermediates of the reaction. The reaction does not take place when either the tetrazolyl group is N-substituted or the carbon atom separating the tetrazolyl and the carbonyl groups is disubstituted or these two groups are separated by two carbon atoms as in compound 17. The reaction offers a convenient method for the conversion of 2-cyanoacetyl derivatives into alk-2-ynoyl derivatives via intermediate tetrazolylacetyl derivatives. The 4-methoxyanilide 7o reacts differently, affording the fused heterocyclic compounds 19o and 20o.
- Fetter,Nagy,Giang,Kajtar-Peredy,Rockenbauer,Korecz,Czira
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p. 1131 - 1139
(2007/10/03)
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- Lanthanide podates with programmed intermolecular interactions: Luminescence enhancement through association with cyclodextrins and unusually large relaxivity of the gadolinium self-aggregates
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The synthesis of the phenyl anchored podand H4L1 fitted with four 3-carboxylate pyrazole arms and programmed for intermolecular interactions is reported, and its protonation constants are determined. Interaction with Ln3+ ions (Ln = La, Eu, Lu) in dilute aqueous solutions leads to complexes with 1:1 and 1:2 metal-ligand stoichiometry. The stability constants are in the range log β110 = 12.7-13.5 and log β120 = 22.5-23.8 (pLn values in the range 9-10). The podates display a fair sensitization of the metal-centered luminescence with an absolute quantum yield of 5% in case of TbIII. The average numbers of water molecules coordinated to the LnIII ion amount to 3.8 and 4.9 for the 1:1 Eu and Tb podates, respectively, as determined by lifetime measurements. The addition of β- and γ-cyclodextrins to the 1:1 podates results in a strong association with the host, mainly through the phenyl anchor (Ln = Tb, log K11 = 5-6 depending on the cyclodextrin) and, for the Tb complex, to a large increase in luminescence intensity at physiological pH. Self-aggregation of the podates occurs at concentration larger than 3 x 10-5 M. This process is characterized by luminescence, using a pyrene probe, light-scattering measurements, and transmission electron microscopy. The novelty of the reported systems is their ability to self-aggregate into nanometric, rigid, and spherical particles in a controlled way (mean diameter: 10, 60, and ~300 nm), opening large perspectives for various applications. In particular, a record-high relaxivity (r1 = 53 mM-1 s-1 at 20 MHz, T = 25°C) is observed for the aggregates of 1:2 Gd podate, which is not modified upon addition of an equimolar quantity of ZnII.
- Fatin-Rouge, Nicolas,Toth, Eva,Perret, Didier,Backer, Robin H.,Merbach, Andre E.,Buenzli, Jean-Claude G.
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p. 10810 - 10820
(2007/10/03)
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- The synthesis and antiviral activity of 4-fluoro-1-β-D-ribofuranosyl- 1h-pyrazole-3-carboxamide
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A novel fluoropyrazole ribonucleoside has been shown to have significant antiinfluenza activity in vitro. The compound is compared and contrasted with the structurally-related compound ribavirin in attempts to identify factors having significant bearing on the mode of action of both compounds.
- Storer, Richard,Ashton, Claire J.,Baxter, Anthony D.,Hann, Michael M.,Marr, Clara L. P.,Mason, Andrew M.,Mo, Chi-Leung,Myers, Peter L.,Noble, Stewart A.,Penn, Charles R.,Weir, Niall G.,Woods, Jacqueline M.,Coe, Paul L.
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p. 203 - 216
(2007/10/03)
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- Effect of Electron-withdrawing Groups on the Thermal Ring Opening of 3H-Pyrazoles to Diazoalkenes
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3-Cyano-3H-pyrazoles, bearing a cyano, a p-chlorophenyl, or a p-chlorobenzyl group at C-3, generated from elimination reaction of the corresponding dihydropyrazoles with a leaving group such as a chlorine or p-chlorobenzoyloxy group, gave diazolkene derivatives, resulting from the ring-opening of the 3H-pyrazoles.However, 3-methoxycarbonyl-3H-pyrazoles bearing a methoxycarbonyl, a p-chlorophenyl, or p-chlorobenzyl group at C-3, prepared in a similar manner, gave mainly 1-methoxycarbonyl-1H-pyrazole derivatives, resulting from migration of the 3-methoxycarbonyl group to the adjacent nitrogen within the generated 3H-pyrazoles.Treatment of 3H-pyrazoles (8a and 29b) and 5-substituted 1-methoxycarbonyl-1H-pyrazoles (10a and 31b) with triethylamine gave 3-substituted 1-methoxycarbonyl-1H-pyrazoles, resulting from migration of the methoxycarbonyl group to the remote nitrogen.
- Nakano, Yoshihiko,Ilamaguchi, Masashi,Nagai, Toshikazu
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p. 1701 - 1757
(2007/10/02)
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- REACTIONS OF TETRAFLUOROETHENE OLIGOMERS. PART XII. CYCLOADDITION REACTIONS OF 3,3,4,4,4-PENTAFLUORO-2-PENTAFLUOROETHYL-2-TRIFLUOROMETHYLDIAZOBUTANE. A NOVEL SYNTHESIS OF PYRAZOLES
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The title diazoalkane (1) reacts smoothly with a variety of electron deficient alkenes to give, unexpectedly, the corresponding pyrazole derivatives.Thus, reaction with methyl or ethyl propenoate affords the methyl and ethyl esters of pyrazole-3-carboxylic acid (2) and (3).Reaction with diethyl maleate yields 3,4-bis-(ethoxycarbonyl)pyrazole (4), and dimethyl maleate gives the corresponding dimethyl ester (5).Treatment of (1) with propenonitrile afforded 3-cyanopyrazole (6), and with propenoic acid the corresponding pyrazole-3-carboxylic acid (7) was obtained.In all of these reactions two side products were isolated, namely perfluoro-(3-methylpent-2-ene) (8) and 3H-3-trifluoromethyldecafluoropentane (9).A mechanistic rationale for these unusual and potentially useful reactions is given.
- Coe, Paul L.,Cook, Michael I.
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p. 323 - 330
(2007/10/02)
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- Effective Methods for the Syntheses of 2-Pyrazolines and Pyrazoles from Diazocarbonyl Compounds
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Dipolar addition of diazocarbonyl compounds to α,β-unsaturated esters and nitriles in the presence of pyridine results in the production 2-pyrazolines in nearly quantitative yields.In one case, reaction of α-diazoacetophenone with acrylonitrile, Michael addition of the 2-pyrazoline to the conjugated olefin is observed, but this process is minimized by limiting the amount of pyridine employed. 5-Cyano-2-pyrazolines are converted to derivative pyrazoles through alkoxide promoted hydrogen cyanide elimination.With vinyl sulfone, α-diazoacetophenone undergoes sequential dipolar addition, Michael addition, and vinyl sulfite elimination under exceptionally mild conditions to form the derivative β-(1-pyrazolyl)ethyl vinyl sulfone in good yield.
- Doyle, Michael P.,Colsman, Mark R.,Dorow, Roberta L.
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p. 943 - 946
(2007/10/02)
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- Mass Spectrometry of Nitroazoles. 3-Ortho Effects: The loss of OH. and H2O from Methyl Substituted Nitrodiazoles
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Methyl substituted nitrodiazoles which have the substituents at adjacent positions in the ring are subject to several ortho effects.Deuterium labelling of the methyl group and the mobile N-bonded hydrogen show that the loss of OH. originates from the substituents.In some cases the N-bonded hydrogen atom participates also in the loss of OH. and of H2O.
- Luijten, W. C. M. M.,Thuijl, J. van
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p. 299 - 303
(2007/10/02)
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