- Primary Vinyl Ethers as Acetylene Surrogate: A Flexible Tool for Deuterium-Labeled Pyrazole Synthesis
-
A novel synthetic path to 1,3-disubstituted pyrazoles and their deuterated derivatives was developed. It is based on the reaction of vinyl ethers with hydrazonoyl chlorides in the presence of triethylamine. The reaction mechanism, clarified by the joint experimental and computational study, involves 1,3-dipolar cycloaddition of the in situ generated nitrile imines to vinyl ethers and subsequent cleavage of alcohol from the formed alkoxypyrazoline. The results highlight the possibility of using vinyl ethers as acetylene surrogate and provide a novel access to pyrazoles, 4,5-dideuteropyrazoles and their regioselectively labeled derivatives, 5-deuteropyrazoles.
- Ananikov, Valentine P.,Lebedev, Andrey N.,Ledovskaya, Maria S.,Polynski, Mikhail V.,Voronin, Vladimir V.
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- Copper-Promoted Coupling of Propiophenones and Arylhydrazines for the Synthesis of 1,3-Diarylpyrazoles
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Synthesis of 1,3-diarylpyrazoles from commercial substrates and/or simple transformations is still underrated. In this report, we have developed a method for copper-promoted coupling of propiophenones and arylhydrazines. The reactions afforded substituted pyrazoles in the presence of TEMPO oxidant, acetic acid additive, and DMF solvent. A number of functionalities were compatible with reaction conditions, including halogens, methoxy, trifluoromethyl, and nitro groups. An indazole could be obtained if an electron-poor propiophenone was used.
- Dang, Ha V.,Le, Ha V.,Nguyen, Tien M.,Nguyen, Tung T.,Pham, Thuyet L. D.,Phan, Nam T. S.,Tran, Khuong A.
-
supporting information
p. 801 - 804
(2020/05/19)
-
- Ruthenium-catalyzed formation of pyrazoles or 3-hydroxynitriles from propargyl alcohols and hydrazines
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Functionalized pyrazoles are generated from secondary propragyl alcohols and hydrazines in a ruthenium-catalyzed cascade process, consisting of redox isomerization, Michael addition, cyclocondensation and dehydrogenation steps. The same bifunctional catalyst mediates the conversion of tertiary propargyl alcohols with hydrazine to 3-hydroxynitriles via anti-Markovnikov hydroamination followed by elimination of ammonia.
- Kaufmann, Julia,J?ckel, Elisabeth,Haak, Edgar
-
supporting information
p. 91 - 101
(2019/07/09)
-
- COMPOUNDS AND METHODS FOR HEMATOPOIETIC REGENERATION
-
The invention relates to compounds that promote hematopoietic regeneration. The invention further relates to methods of promoting hematopoietic regeneration using the novel compounds of the invention.
- -
-
Page/Page column 39-40
(2019/06/17)
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- [3+2]-cycloaddition of in situ generated nitrile imines and acetylene for assembling of 1,3-disubstituted pyrazoles with quantitative deuterium labeling
-
A novel synthetic methodology for the preparation of 1,3-disubstituted pyrazoles from in situ generated nitrile imines and acetylene is reported. The reactions are performed in a simple two-chamber reactor. One part of the reactor is loaded with hydrazonoyl chloride precursors of active nitrile imine species and a base. The other part is used to generate acetylene from CaC2 and water. Partitioning of the reactants improves the yields of desired pyrazoles up to 99% and simplifies their isolation to a simple procedure of solvent evaporation. The approach requires no complex equipment and utilizes inexpensive, safe, and easy to handle calcium carbide as a starting material. A model deuterium incorporation is carried out according to the developed methodology, producing a series of novel 4,5-dideuteropyrazoles with excellent deuterium enrichment. Theoretical calculations on reaction mechanism and characterization of possible intermediate structures were performed.
- Voronin, Vladimir V.,Ledovskaya, Maria S.,Gordeev, Evgeniy G.,Rodygin, Konstantin S.,Ananikov, Valentine P.
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p. 3819 - 3828
(2018/04/14)
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- Facile synthesis of pyrazoles by iron-catalyzed regioselective cyclization of hydrazone and 1,2-diol under ligand-free conditions
-
A facile synthesis of pyrazoles by the cyclization of hydrazones and 1,2-diols was described. In the presence of ferric nitrate, the reaction occurs under neat conditions and makes the use of potassium persulfate to oxidize the diol to α-hydroxy carbaldehyde for the reaction with hydrazones to produce 1,3- and 1,3,5-substituted pyrazoles selectively. The overall regioselective transformation occurs in one-pot under ligand-free, mild conditions even in the presence of air.
- Panda, Niranjan,Ojha, Subhadra
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p. 244 - 251
(2018/03/13)
-
- COMPOUNDS AND METHODS FOR HEMATOPOIETIC REGENERATION
-
The invention relates to compounds that promote hematopoietic regeneration. The invention further relates to methods of promoting hematopoietic regeneration using the novel compounds of the invention.
- -
-
Page/Page column 36-37
(2017/12/29)
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- Solvent-dependent copper-catalyzed synthesis of pyrazoles under aerobic conditions
-
We present a copper-catalyzed oxidative cyclization of β,γ-unsaturated hydrazones, utilizing molecular oxygen as a stoichiometric oxidant. The methodology provides distinct classes of pyrazoles simply by changing the reaction solvent. Tris-substituted pyr
- Pünner, Florian,Sohtome, Yoshihiro,Sodeoka, Mikiko
-
p. 14093 - 14096
(2016/12/09)
-
- Catalytic Chan-Lam coupling using a 'tube-in-tube' reactor to deliver molecular oxygen as an oxidant
-
A flow system to perform Chan-Lam coupling reactions of various amines and arylboronic acids has been realised employing molecular oxygen as an oxidant for the re-oxidation of the copper catalyst enabling a catalytic process. A tube-in-tube gas reactor has been used to simplify the delivery of the oxygen accelerating the optimisation phase and allowing easy access to elevated pressures. A small exemplification library of heteroaromatic products has been prepared and the process has been shown to be robust over extended reaction times.
- Mallia, Carl J.,Burton, Paul M.,Smith, Alexander M. R.,Walter, Gary C.,Baxendale, Ian R.
-
supporting information
p. 1598 - 1607
(2016/08/02)
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- Cu-promoted sydnone cycloadditions of alkynes: Scope and mechanism studies
-
Cu salts have been found to promote the cycloaddition reaction of sydnones and terminal alkynes, providing significant reduction in reaction times. Specifically, the use of Cu(OTf)2 is found to provide 1,3-disubstituted pyrazoles, whereas simpl
- Comas-Barcel?3, Jffllia,Foster, Robert S.,Fiser, B??la,Gomez-Bengoa, Enrique,Harrity, Joseph P. A.
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p. 3257 - 3263
(2015/03/05)
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- Practical synthesis of pyrazoles via a copper-catalyzed relay oxidation strategy
-
Various 1,3- and 1,3,4-substituted pyrazoles are smoothly formed via copper-catalyzed cascade reactions of oxime acetates, amines and aldehydes. This relay oxidative process involves copper-promoted N-O bond cleavage and C-C/C-N/N-N bond formations to furnish pyrazolines, and sequential Cu-O2 system-involved oxidative dehydrogenation of pyrazolines to afford pyrazoles. This transformation provides a novel and versatile approach for the synthesis of pyrazoles, with an inexpensive copper catalyst and green oxidants. It is atom- and step-economical, and possesses a good functional group tolerance, as well as operational simplicity. This journal is
- Tang, Xiaodong,Huang, Liangbin,Yang, Jidan,Xu, Yanli,Wu, Wanqing,Jiang, Huanfeng
-
supporting information
p. 14793 - 14796
(2014/12/11)
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- One-pot oxidation and rearrangement of propargylamines and in situ pyrazole synthesis
-
Reported here are procedures for a one-pot oxidation and rearrangement of propargylamines to synthesize enaminones, with supporting mechanistic studies. Also reported are the extended one-pot syntheses of pyrazoles, including celecoxib and various heterocyclic compounds.
- Chen, Jinshan,Properzi, Roberta,Uccello, Daniel P.,Young, Jennifer A.,Dushin, Russell G.,Starr, Jeremy T.
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p. 4146 - 4149
(2014/09/29)
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- An efficient regioselective copper catalyzed multi-component synthesis of 1,3-disubstituted pyrazoles
-
An efficient synthesis of unsymmetrically substituted 1,3-pyrazole derivatives has been developed via three-component coupling reaction involving 3-(dimethylamino)-1-phenylprop-2-en-1-one, hydrazine, and aryl halides in one pot process exhibiting high regioselectivity. The pyrazole synthesis proceeds via a sequential series of reactions such as Michael addition, heterocyclization, dehydration, and Ullmann cross-coupling.
- Raghunadh, Akula,Meruva, Suresh Babu,Mekala, Ramamohan,Raghavendra Rao,Krishna, Thalishetti,Gangadhara Chary,Vaikunta Rao,Syam Kumar
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p. 2986 - 2990
(2014/05/06)
-
- N-arylation of indoles with aryl halides using copper/glycerol as a mild and highly efficient recyclable catalytic system
-
A simple, efficient, and inexpensive copper catalyzed protocol has been developed for cross-coupling of indoles with aryl halides by using glycerol as a green recyclable solvent and DMSO as an additive. The reaction was carried out at low catalyst loading furnishing various N-aryl indoles in good to excellent yield. This copper/glycerol mixture was recycled up to four runs without any loss in its catalytic activity.
- Yadav, Dilip Kumar T.,Rajak, Sanil S.,Bhanage, Bhalchandra M.
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p. 931 - 935
(2014/02/14)
-
- N-arylation of indoles with aryl halides using copper/glycerol as a mild and highly efficient recyclable catalytic system
-
A simple, efficient, and inexpensive copper catalyzed protocol has been developed for cross-coupling of indoles with aryl halides by using glycerol as a green recyclable solvent and DMSO as an additive. The reaction was carried out at low catalyst loading furnishing various N-aryl indoles in good to excellent yield. This copper/glycerol mixture was recycled up to four runs without any loss in its catalytic activity.
- Yadav, Dilip Kumar T.,Rajak, Sanil S.,Bhanage, Bhalchandra M.
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p. 931 - 935
(2015/02/19)
-
- Nickel-catalyzed decyanation of inert carbon-cyano bonds
-
Nickel catalyzed decyanation of aryl and aliphatic cyanides with hydrosilane as the hydride source has been developed. This method is easy to handle, scalable and can be carried out without a glove box. The method has been applied in the cyanide directed functionalization reaction and α-substitution of benzyl cyanide.
- Patra, Tuhin,Agasti, Soumitra,Akanksha,Maiti, Debabrata
-
-
- Nickel-catalyzed hydrogenolysis of unactivated carbon-cyano bonds
-
Selective hydrogenolysis of C-CN bonds can allow chemists to take advantage of ortho-directing ability, α-C-H acidity and electron withdrawing ability of the cyano group for synthetic manipulations. We have discovered hydrogenolysis of aryl and aliphatic cyanides under just 1 bar of hydrogen by using a nickel catalyst. This protocol was applied in the aryl cyanide directed functionalization reaction and α-substitution of benzyl cyanides.
- Patra, Tuhin,Agasti, Soumitra,Modak, Atanu,Maiti, Debabrata
-
supporting information
p. 8362 - 8364
(2013/09/23)
-
- Fe-catalyzed one-pot synthesis of 1,3-Di- and 1,3,5-trisubstituted pyrazoles from hydrazones and vicinal diols
-
An iron-catalyzed route for the regioselective synthesis of 1,3- and 1,3,5-substituted pyrazoles from the reaction of diarylhydrazones and vicinal diols has been developed. This method was found to be practical with wide substrate scope.
- Panda, Niranjan,Jena, Ashis Kumar
-
p. 9401 - 9406,6
(2012/12/11)
-
- Fe-catalyzed one-pot synthesis of 1,3-Di- and 1,3,5-trisubstituted pyrazoles from hydrazones and vicinal diols
-
An iron-catalyzed route for the regioselective synthesis of 1,3- and 1,3,5-substituted pyrazoles from the reaction of diarylhydrazones and vicinal diols has been developed. This method was found to be practical with wide substrate scope.
- Panda, Niranjan,Jena, Ashis Kumar
-
p. 9401 - 9406
(2013/01/15)
-
- Palladium-catalyzed carbonylative heck reaction of aryl bromides with vinyl ethers to 3-alkoxy alkenones and pyrazoles
-
Three COming together: The first carbonylative Heck coupling reaction of aryl bromides and vinyl ethers leading to 1-aryl-3-alkoxy-2-propen-1-ones has been established (see scheme). Based on this coupling methodology, a novel one-pot synthesis of aryl-substituted pyrazoles was also realized. Copyright
- Schranck, Johannes,Wu, Xiao-Feng,Neumann, Helfried,Beller, Matthias
-
supporting information; experimental part
p. 4827 - 4831
(2012/05/20)
-
- Palladium-catalyzed dehalogenation of 5-halopyrazoles
-
A new and efficient method for the dehalogenation of 5-halopyrazoles was developed by using the catalytic amount of palladium (II) chloride and triphenylphosphine as a ligand at reflux under constant flow of hydrogen gas. The reaction gave the correspondi
- Chen, Chun-Yen,Huang, Yu-Ying,Su, Wei-Nien,Kaneko, Kimiyoshi,Kimura, Masayuki,Takayama, Hiroyuki,Wong, Fung Fuh
-
p. 183 - 189
(2012/05/05)
-
- Single-step synthesis of pyrazoles using titanium catalysis
-
A simple titanium complex catalyzes the coupling of alkynes, isonitriles, and monosubstituted hydrazines to generate substituted pyrazoles in a single step.
- Dissanayake, Amila A.,Odom, Aaron L.
-
supporting information; experimental part
p. 440 - 442
(2012/01/05)
-
- Cu(OAc)2·H2O-catalyzed N-arylation of nitrogen-containing heterocycles
-
In the absence of any additional ligands, the efficient N-arylation of nitrogen-containing heterocycles with aryl iodides catalyzed by relative low catalyst amount of Cu(OAc)2·H2O was developed. This simple catalytic system is involved in the C-N cross-coupling reaction and works for a variety of pyrazole, pyrrole, imidazole, triazole, indole, benzoimidazole, benzotriazole, carbazole, and anilines as well as aryl iodides with different electronic properties. Highly efficient copper(II)-catalyzed N-arylation protocol was established.
- Xu, Zhong-Lin,Li, Hong-Xi,Ren, Zhi-Gang,Du, Wei-Yuan,Xu, Wei-Chang,Lang, Jian-Ping
-
supporting information; experimental part
p. 5282 - 5288
(2011/08/04)
-
- Regioselectivity studies of sydnone cycloaddition reactions of azine-substituted alkynes
-
The synthesis of azine-substituted pyrazoles by a sydnone cycloaddition strategy is described. Incorporation of a 3-pyridyl moiety at the sydnone N-atom has little effect on either reactivity or regioselectivity, however, 2-ethynyl-pyridine and -pyrimidin
- Foster, Robert S.,Jakobi, Harald,Harrity, Joseph P.A.
-
experimental part
p. 1506 - 1508
(2011/05/16)
-
- Alkyne [3 + 2] cycloadditions of iodosydnones toward functionalized 1,3,5-trisubstituted pyrazoles
-
(Chemical Equation Presented) The cycloaddition of 4-iodosydnones with terminal alkynes proceeds with excellent regiocontrol to provide 5-iodo pyrazoles. These products participate smoothly in subsequent C-C and C-heteroatom bond forming processes.
- Browne, Duncan L.,Taylor, John B.,Plant, Andrew,Harrity, Joseph P. A.
-
supporting information; experimental part
p. 984 - 987
(2010/05/18)
-
- Pd-catalyzed cross-coupling reactions of halogenated 1-phenylpyrazol-3-ols and related triflates
-
1-Phenyl-1H-pyrazol-3-ol was used as a versatile synthon for the preparation of various 1-phenyl-1H-pyrazole derivatives substituted at C-3 and C-4 of the pyrazole nucleus and at the phenyl ring para-position. Treatment of 1-phenyl-1H-pyrazol-3-ol with tr
- Arba?iauskiene, Egle,Vilkauskaite, Gyte,Eller, Gernot A.,Holzer, Wolfgang,?a?kus, Algirdas
-
experimental part
p. 7817 - 7824
(2009/12/26)
-
- Regioselective microwave-assisted synthesis of substituted pyrazoles from ethynyl ketones
-
Reaction of α,β-ethynyl ketones and hydrazine derivatives gives 1,3- and 1,5-disubstituted pyrazoles in good yield. Microwave irradiation in concentrated hydrochloric acid-methanol (1.5% v/v), with concurrent cooling at sub-ambient temperatures or at 120°
- Bagley, Mark C.,Lubinu, M. Caterina,Mason, Christopher
-
p. 704 - 708
(2007/12/27)
-
- Conversion of 3-benzoyl-1-methyl-4-phenyl-γ-piperidol by arylamines and arylhydrazines. Synthesis of 3-arylamino-1-oxo-1-phenylpropanes and 1,3-diarylpyrazoles and their fragmentation under electron impact
-
It has been established that on heating, 3-benzoyl-4-hydroxy-1-methyl-4- phenylpiperidine is ring-opened in the presence of arylamines by a type of retroaldol reaction, with subsequent transamination of the intermediate Mannich base and the formation of 3-arylamino-1-oxo-1-phenylpropanes. When using arylhydrazines this γ-piperidol is recyclized with the formation of 1,3-diarylpyrazoles and their 4,5-dihydro derivatives. The mass spectral behavior of a series of 3-arylamino-substituted 1-phenylpropanones has been studied.
- Volkov,Kutyakov,Levov,Polyakova,An, Le Tuan,Soldatova,Terentiev,Soldatenkov
-
p. 1260 - 1268
(2008/09/19)
-
- Reaction of 3-benzoyl-1-methyl-4-phenyl-γ-piperidol with arylamines and arylhydrazines. Synthesis of 3-arylamino-1-oxo-1-phenylpropanes and 1,3 diarylpyrazoles and their fragmentation under electron impact
-
Upon heating in the presence of arylamines 3-benzoyl-4-hydroxy-1-methyl-4- phenylpiperidine decyclizes via a retroaldol type reaction with subsequent transamination of the intermediate Mannich base to give 3-arylamino-1-oxo-1- phenylpropanes. In the case of the use of arylhydrazines this γ-piperidol recyclizes to give 1,3-diarylpyrazoles and their 4,5-dihydro derivatives. The mass spectroscopic behavior of a series of 3-arylamino-substituted 1-phenylpropanones has been studied.
- Volkov,Kutyakov,Levov,Polyakova,Anh, Le Tuan,Soldatova,Terentiev,Soldatenkov
-
p. 445 - 453
(2008/12/20)
-
- Regioselective synthesis of 1-aryl-3,4-substituted/annulated-5-(methylthio) pyrazoles and 1-aryl-3-(methylthio)-4,5-substituted/annulated pyrazoles
-
Highly efficient and regioselective synthesis of 1-aryl-3,4-substituted/ annulated-5-(methylthio)-pyrazoles and 1-aryl-3-(methylthio)-4,5-substituted/ annulated pyrazoles has been reported via cyclocondensation of arylhydrazines with either α-oxoketene dithioacetals or β-oxodithioesters.
- Peruncheralathan,Khan,Ila,Junjappa
-
p. 10030 - 10035
(2007/10/03)
-
- Transition metal catalyzed ring opening reactions of 2-phenyl-3-vinyl substituted 2H-azirines
-
Treatment of 2-phenyl-3-vinyl-substituted 2H-azirines with Grubbs' catalyst induces a clean rearrangement and affords products derived from carbon-nitrogen bond cleavage of the 2H-azirine ring. However, when the reaction was carried out using Wilkinson's catalyst in an alcoholic solvent, the only product obtained in high yield corresponded to an α,β-unsaturated oxime.
- Padwa, Albert,Stengel, Thomas
-
p. 5991 - 5993
(2007/10/03)
-
- Phenylselenenyl sulfate induced cyclization of allylhydrazines. Synthesis of pyrazole derivatives
-
Allylhydrazines react with phenylselenenyl sulfate, produced by diphenyl diselenide and ammonium persulfate in the presence of trifluoromethanesulfonic acid, to afford phenylseleno substituted pyrazolidines. Under the reaction conditions employed, these suffer dehydrogenation and oxidative deselenenylation to eventually give pyrazole derivatives.
- Tieco, Marcello,Testaferri, Lorenzo,Marini, Francesca,Bagnoli, Luana,Santi, Claudio,Temperini, Andrea
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p. 4441 - 4446
(2007/10/03)
-
- Intramolecular Reaction of the Hydrazonyl Group with Formyl and Oxo Groups: Preparation of Pyrazoloindoles and Related Pyrazolo Compounds
-
Lewis acid-catalysed intramolecular nucleophilic attack of a hydrazonyl group onto aldehyde and ketone groups gives pyrazoles and dihydropyrazoles.Pyrazoloindoles and related pyrazolo compounds have also been prepared.
- Shen, Jing-Kang,Katayama, Hajime,Takatsu, Noriyuki,Shiro, Itsuo
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p. 2087 - 2098
(2007/10/02)
-
- SYNTHESIS AND REACTION OF TRIBUTYLSTANNYLPYRAZOLES
-
1,3-Dipolar cycloaddition reaction of diazomethane and ethyl diazoacetate with tributylstannylacetylenes occurred regioselectively to afford the corresponding 3(5)-tributylstannylpyrazoles.The cycloaddition reaction of 3-phenylsydnone with the stannylacetylenes proceeded also regioselectively, and 3-tributylstannyl-1-phenylpyrazoles were isolated. 4-Tributylstannyl- and 5-tributylstannyl-1-phenylpyrazole were prepared by the stannylation of 4-lithio- and 5-lithio-1-phenylpyrazoles with tributylstannyl chloride.Iodination, benzoylation, and phenylation of the stannylpyrazoles were examined.
- Sakamoto, Takao,Shiga, Futoshi,Uchiyama, Daishi,Kondo, Yoshinori,Yamanaka, Hiroshi
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p. 813 - 818
(2007/10/02)
-
- (13)C Chemical Shifts and (1)H - (13)C Coupling Constants of N-Phenyl-, N-p-Fluorophenyl- and N-o-Nitrophenylpyrazoles
-
The (13)C chemical shifts and some (1)H - (13)C coupling constants of twelve N-arylpyrazoles are reported.The assignments were made by using the effects of a fluorine substituent and two-dimensional techniques. Key words: (13)C chemical shifts, (1)H - (13
- Begtrup, Mikael,Vedso, Per,Cabildo, Pilar,Claramunt, Rosa Maria,Elguero, Jose,Meutermans, Wim
-
p. 455 - 459
(2007/10/02)
-
- Preparation of Pyrazole and Pyrazoline Derivatives by Intramolecular Reaction of Hydrazones
-
Pyrazole and pyrazoline derivatives are prepared by the intramolecular cyclization reaction of a hydrazonyl group with formyl or keto groups in the presence of a Lewis acid.
- Shen, Jing-Kang,Katayama, Hajime
-
p. 451 - 452
(2007/10/02)
-
- CHIRAL ACETYLENES AS SYNTHETIC INTERMEDIATES. V. A REINVESTIGATION ON THE SYNTHESIS OF OPTICALLY ACTIVE ISOXAZOLES
-
The synthesis of 3- or 5-alkyl isoxazoles and pyrazoles has been achieved starting from alkyl-substituted acetylenic ketones: the influence of the structure of the carbonyl compound on the isomeric composition of the heterocyclic compound has been studied.Some optically active monoalkyl-substituted isoxazoles have also been prepared: in this context, an investigation on the stereochemistry of the cyclization process has been carried out.
- Falorni, Massimo,Lardicci, Luciano,Giacomelli, Giampaolo
-
-
- SITE SELECTIVITY IN THE REACTIONS OF 1,3-DIPOLES AND DIENES WITH TETRACYCLO2,10.03,6>DODECA-4,8,11-TRIENE
-
1,3-Dipoles and dienes reacted smoothly with excess tetracyclo2,10.03,6>dodeca-4,8,11-triene (1) to give good yields of monoadducts in a highly selective reaction.The attack by 1,3-dipoles and dienes to 1 occurred only at the
- Burdisso, M.,Gamba, A.,Gandolfi, R.,Pevarello, P.
-
p. 4355 - 4360
(2007/10/02)
-
- THE REACTIONS OF ISOTHIAZOLIUM SALTS WITH NITROGEN NUCLEOPHILIC REAGENTS
-
Isothiazolium salts were allowed to react with a number of nitrogen nucleophiles including ammonia, hydrazine, phenylhydrazine, hydroxylamine, and benzylamine.The products obtained suggest that the position of initial nucleophilic attack is at the sulphur
- Hassan, Mohamed E.,Magraby, M. A.,Aziz, Magda A.
-
p. 1885 - 1892
(2007/10/02)
-
- PREPARATION OF SOME trans-BIS (2H-AZIRINE)PALLADIUM DICHLORIDE COMPLEXES AND THE OPENING OF THEIR AZIRINE RINGS IN BENZENE
-
The trans-bis(2H-azirine)palladium dichloride complexes 2f, 2g, 2h and 2i are formed in the reaction of (C6H5CN)2PdCl2 with 3-phenyl- (1f), 2-phenyl-3-styryl-(1g), 2(formyl-N-phenylimine)-3-phenyl- (1h) and 2-styryl-3-phenyl-2H-azirine (1i).The cleavage o
- Filho, Pedro Faria Dos Santos,Schuchardt, Ulf
-
p. 385 - 394
(2007/10/02)
-
- 1,3-Dipolar Cycloadditions, 89. New Contributions to the Chemistry of Diphenylnitrilimine
-
Methyl propiolate, tetrolate, and phenylpropiolate combine with diphenylnitrilimine (1) to afford regioisomeric cycloadducts; the preferential orientation shifts in the sequence given from the pyrazole-5-carboxylic ester to the 4-carboxylic ester.Correspo
- Clovis, James S.,Fliege, Werner,Huisgen, Rolf
-
p. 3062 - 3070
(2007/10/02)
-
- The Cycloaddition of N,N-Diethyl-1,3-butadienylamine with Some Diarylnitrilimines
-
The cycloaddition of N,N-diethyl-1,3-butadienylamine with some diarylnitrilimines was investigated. 1,3-diaryl-4-vinylpyrazoles, (1,3-diaryl-2-pyrazolin-5-yl)acetaldehydes, 1,3-diaryl-4-(1,3-diaryl-2-pyrazolin-5-yl)pyrazoles, and 1,3-diarylpyrazoles were obtained.
- Oido, Tatsuo,Tanimoto, Shigeo,Ikehira, Hideyuki,Okano, Masaya
-
p. 1203 - 1205
(2007/10/02)
-
- SITE SELECTIVITY IN THE REACTIONS OF 1,3-DIPOLES WITH NORBORNADIENE DERIVATIVES
-
The cycloadditions of arylazides, benzonitrile oxides and diphenylnitrile imine to norbornadiene derivatives 1a-c showed varying degree of site- and stereo-selectivity.With dipolarophile 1a arylazides and benzonitrile oxides attack, preferentially, the electron-poor tetrasubstituted double bond, while in the case of 1b and 1c is the substituted double bond which enters the cycloaddition.By contrast, 2-diazopropane and C-phenyl-N-methylnitrone react with the sole tetrasubstituted double bond of 1a-c in stereo- and site-specific cycloadditions.The quantitative evaluation of the two possible reaction paths was performed by glc analysis.The compounds detected were those arising from Diels-Alder cycloreversions of the thermally labile intermediate adducts 2 and 3 (Scheme 1).The results were rationalized on the basis of a qualitative perturbation treatment which considers frontier orbital interactions only.
- Cristina, D.,Amici, M. De,Micheli, C. De,Gandolfi, R.
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p. 1349 - 1357
(2007/10/02)
-
- Neue thermische Reaktionen von 3 Amino- und 4-(Phenylthio)sydnonen mit Alkinen und Alkenen
-
As cyclic azomethine imines, the 3-aminosydnones 1a - c, e - h react at 80 - 160 deg C with dimethyl acetylenedicarboxylate via non-isolable primary adducts 3 with evolution of carbon dioxide to produce the 1-aminopyrazoles 2a, c, d, e - h (yield 70 - 2percent) of table 1.Surprisingly, the analogous reactions of 1a, e proceed also with formation of the 1,2-oxazin-6-one derivative 4 as a result of an amino nitrene elimination from the primary adduct 3 which competes with the carbon dioxide elimination.In some cases, the 1-methylpyrazole 13, the pyridinetetracarboxylic ester18, as well as the benzothiophene derivative 19 are also isolable.Furthermore, the reactions of 1 with diphenylacetylene, styrene and dimethyl fumarate are described.
- Gotthardt, Hans,Reiter, Friedemann
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p. 2450 - 2464
(2007/10/02)
-
