- Transition Metal-Catalyzed N-Alkylation of NH Groups of Azoles with Alcohols
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Azoles containing acidic NH-group react with various alcohols in the presence of catalytic amount of ruthenium-, rhodium-, and iridium- trialkylphosphite complexes to give the corresponding N-alkylated azoles in good to excellent yields.
- Tanaka, Norio,Hatanaka, Masataka,Watanabe, Yoshihisa
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- Simple, efficient and convenient synthesis of pyrroles and pyrazoles using zeolites
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A convenient heterogeneous catalytic methodology for the synthesis of Pyrroles and Pyrazoles by an intermolecular reaction of γ or β-diketones with primary amines or hydrazine derivatives over zeolites are described.
- Sreekumar,Padmakumar, Raghavakaimal
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- Pyrazolium- versus imidazolium-based ionic liquids: Structure, dynamics and physicochemical properties
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Ionic liquids (ILs) composed of two different pyrazolium cations with dicyanamide and bis(trifluoromethanesulfonyl)imide anions have been synthesized and characterized by NMR, Kamlet-Taft solvatochromic parameters, conductivity and rheological measurements, as well as ab initio calculations. Density functional calculations for the two pyrazolium cations, 1-butyl-2- methylpyrazolium [bmpz] and 1-butyl-2,3,5-trimethylpyrazolium [bm 3pz], provide a full picture of their conformational states. Homo- and heteronuclear NOE show aggregation motives sensitive to steric hindrance and the anions' nature. Self-diffusion coefficients D for the anion and the cation have been measured by pulsed field gradient spin-echo NMR (PGSE-NMR). The ionic diffusivity is influenced by their chemical structure and steric hindrance, giving the order Dcation > Danion for all of the examined compounds. The measured ion diffusion coefficients, viscosities, and ionic conductivity follow the Vogel-Fulcher-Tammann (VFT) equation for the temperature dependencies, and the best-fit parameters have been determined. Solvatochromic parameters indicate an increased ion association upon going from bis(trifluoromethanesulfonyl)imide to dicyanamide-based pyrazolium salts, as well as specific hydrogen bond donor capability of H atoms on the pyrazolium ring. All of these physical properties are compared to those of an analogous series of imidazolium-based ILs.
- Chiappe, Cinzia,Sanzone, Angelo,Mendola, Daniele,Castiglione, Franca,Famulari, Antonino,Raos, Guido,Mele, Andrea
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- Synthesis and reactivity of (pyrazol-1-yl)acyl iron complexes
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Abstract Treatment of 1-methyl-3,5-dialkylpyrazoles with n-BuLi, and subsequently with iron carbonyl and iodine yielded (pyrazol-1-yl)acyl iron complexes CH2(CO) (3,5-R2Pz)Fe(CO)3I (R = Me or Pri, Pz = pyrazol-1-yl). Reaction of CH2(CO) (3,5-Me2Pz)Fe(CO)3I with PhSNa gave a dimeric complex [CH2(CO) (3,5-Me2Pz)Fe(CO)2(SPh)]2, while similar reactions of CH2(CO) (3,5-R2Pz)Fe(CO)3I with PySNa (Py = 2-pyridyl) gave mononuclear complexes CH2(CO) (3,5-R2Pz)Fe(CO)2(SPy), which exhibited an isomerization in solution. Treatment of the dimeric complex with PPh3 at room temperature resulted in the decomposition of the starting material. Furthermore, this dimeric complex readily underwent reductive elimination to generate CH2(COSPh) (3,5-Me2Pz) when heated at relatively low temperature, and thermal decomposition reaction to give PhSSPh in refluxing toluene solution. Reaction of mononuclear complexes with PPh3 caused one carbonyl to be replaced by phosphine ligand to give complexes CH2(CO) (3,5-R2Pz)Fe(CO) (PPh3) (SPy). All these acyl iron complexes were fully characterized by IR and NMR spectroscopy, and their structures were unambiguously determined by X-ray crystallography.
- Zhao, Da-Wei,Xu, Yi,Guo, Yao-Wei,Song, Hai-Bin,Tang, Liang-Fu
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- C- and N-amidotrichloroethylation of azoles
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1H-Pyrazoles, triazoles, and imidazoles in reaction with ethoxycarbonylimine and arylsulfonylimines of chloral yield addition products, corresponding 1-(1-amidotrichloroethyl)azoles. Derivatives of 1-alkylpyrazoles and pyrazolones react with chloral 4-chl
- Evstafyeva,Bozhenkov,Aizina,Rozenzveig,Ermakova,Levkovskaya,Mirskova
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- PRODUCING METHOD OF NITROGEN-CONTAINING ORGANIC COMPOUND
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A hydrazine-carbon dioxide-binding compound or hydrazine derivatives 2 carbonyl group react with a compound having one or more nitrogen-containing organic for preparing the compounds of relates to method.
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Paragraph 0410
(2016/12/01)
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- N-methylation of nitrogen-containing heterocycles with dimethyl carbonate
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Reactivity of dimethyl carbonate, the environmentally friendly reagent, as methylating agent for nitrogen-containing heterocyclic compounds has been studied. Reactions of imidazole, pyrazole, pyrrole, morpholine, and piperazine with dimethyl carbonate to afford N-methylated products were reported. The reactions were carried out with neither catalyst nor solvent at a temperature range of 110-170°C under atmospheric pressure. Copyright Taylor & Francis, Inc.
- Ouk, Samedy,Thiebaud, Sophie,Borredon, Elisabeth,Chabaud, Bernard
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p. 3021 - 3026
(2007/10/03)
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- Monomethylation of nitrogeneous heterocycles
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A process for the monomethylation of nitrogenous heterocycles having at least one nitrogen atom bonded to a hydrogen atom by reacting the nitrogenous heterocycle with dimethyl carbonate at a temperature of between 100° and 200° C. and a pressure of between 0.93×105 Pa and 1.07×105 Pa while methanol produced during the reaction is distilled off as it is formed.
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- Heterocyclic-substituted alkylamide acat inhibitors
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Pharmaceutically useful compounds having ACAT inhibitory activity of the formula wherein n is 0, 1, or 2, for X other than tetrazole and n = 2 then R2 = R3 = H; R1 is phenyl, substituted phenyl, naphthyl, substituted naphthyl, a heteroaromatic group or a hydrocarbon group having from one to 18 carbon atoms; R2 and R3 are hydrogen, halo, hydroxy, alkyl, alkenyl, cycloalkyl, phenyl, substituted phenyl, a heteroaryl, or form a spiroalkyl group; x is a 5-membered heteromonocyclic group containing at least one to four heteroatoms selected from the group consisting of isothiazole, oxazole, thiazole, imidazole, furan, thiophene, pyrrole, tetrazole, 1,2,3-triazole, 1,2,4-oxadiazole, 1,3,4-oxadiazole, 1,3,4-thiadiazole, 1,2,4-triazole, and 1,2,4-oxadiazole said heteromonocyclic group being unsubstituted or substituted at any available position along the ring,
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- Study of the reactivity of α-acylenaminoketones. Synthesis of pyrazoles
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The reactions of 4-(methylamino)-3-penten-2-one with diazoketones yielded the α-acylenaminoketones 1-3 in good yields. Preparation of the α-acylenaminoketone 4 was carried out by treatment of 4-(t-butylamino)-3-penten-2-one with benzoyl chloride being followed by reaction of transamination with methylamine. The reactions were carried out in five different solvents and were submitted to gas chromatography/mass spectrometry analysis, with the goal of obtaining substituted pyrazoles and determining which of the carbonyls would preferentially be attacked by the nucleophile. The reactions of compounds 1-4 with hydrazine reagents led to the formation of the pyrazoles 5-7a-q. Small amounts of 4-methylamino-2-pentenones 10a-q, amides 11a-q and pyrazoles 12a-q were also obtained in these reactions. The unexpected formation of pyrazoles 15d,h,q was detected when methanol and N,N-dimethylformamide were used as solvents in the reactions of α-acylenaminoketone 4 with hydrazine reagents.
- Negri,Kascheres
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p. 109 - 123
(2007/10/03)
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- Scope and limitations in the regioselective synthesis of 1,3,5-trisubstituted pyrazoles from β-amino enones and hydrazine derivatives. 13C-chemical shift prediction rules for 1,3,5-trisubstituted pyrazoles
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β-amino enones react with hydrazine derivatives to give regioselectively 1,3,5-trisubstituted pyrazoles. The synthetic method only presents limitations when the β-substituent of the enone and the hydrazine substituent are bulky or possess an electron withdrawing character. Comparison of the 13C-NMR spectra of the seventy pyrazoles allowed us to estimate a 13C-chemical shift prediction rule for 1,3,5-trisubstituted pyrazoles, with deviations of less than ± 1 ppm.
- Alberola, Angel,Calvo Bleye, Luis,Gonza?lez-Ortega, Alfonso,Sa?daba, M.Luisa,San?udo, M.Carme
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p. 331 - 352
(2007/10/03)
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- β-Aminoenones in the regioselective synthesis of 1,3,5-trialkyl-pyrazoles. The influence of the substituents in the mechanism and the regioselectivity of the reaction
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β-Aminoenones react with monoalkyl hydrazines to give regioselectively 1,3,5-trisubstituted pyrazoles. The mechanism and level of regioselectivity depend on both the substitution pattern of the substrates and the reaction conditions. When the least bulky
- Alberola, Angel,Gonzalez-Ortega, Alfonso,Sadaba, M. Luisa,Sanudo, M. Carmen
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p. 4061 - 4065
(2007/10/03)
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- Isoxazolyl-substituted alkyl amide ACAT inhibitors
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Pharmaceutically useful compounds having ACAT inhibitory activity of the formula STR1 wherein n is 0, 1, or 2, for X other than tetrazole and n=2 then R2 =R3 =H; R1 is phenyl, substituted phenyl, naphthyl, substituted naphthyl, a heteroaromatic group or a hydrocarbon group having from one to 18 carbon atoms; R2 and R3 are hydrogen, halo, hydroxy, alkyl, alkenyl, cycloalkyl, phenyl, substituted phenyl, a heteroaryl, or form a spiroalkyl group; X is a heteromonocyclic 5-membered ring containing one to four heteroatoms, said heteroatoms being nitrogen, oxygen or sulfur, and combination thereof; and R4 is a hydrocarbon group having from one to 20 carbon atoms are described as well as methods of their manufacture.
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- N-alkylation of heterocyclic, aromatic amines
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A process for producing a heterocyclic tertiary amine of the formula (III): STR1 wherein A is a nitrogen atom or C-R5, B is a nitrogen atom or C-R6, is a single bond or a double bond, and each of R1, R2, R3, R4, R5 and R6 which may be the same or different, is a hydrogen atom, an acyl group, a halogen atom, a cyano group, etc., provided that two of R1, R2, R3 and R4 may together form a 3-membered, 4-membered, 5-membered or 6-membered aliphatic ring, a heterocyclic rig or aromatic ring, and R7 is a C1-6 alkyl group which may be substituted, etc., which process comprises reacting a heterocyclic secondary amine of the formula (I): STR2 wherein A, B, , R1, R2, R3 and R4 are as defined above, with an alkylating agent of the formula (II): wherein R7 is as defined above, and X is a hydroxyl group, a halogen atom, a OSO3 R7 group, a OSO2 R7 group, a OCO2 R7 group, a OCOR7 group, a OP(O)(OR7) group, a OP(O)O(R7)2 group or an amino group, in the presence of a catalyst of Group VIII of the Periodic Table.
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- Phase transfer catalyzed reductive acylation of nitrogen-containing heteroaromatics with acetylcobalt tetracarbonyl
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Phase transfer catalyzed reductive ring-cleavage acylation of isoxazoles or isothiazoles with acetylcobalt tetracarbonyl gives N-acylated 1-amino-2-alkene-3-ones or thiones.Under the same conditions phthalazine, quinoline and isoquinoline react with acetylcobalt tetracarbonyl to give N-acylated dimers.The reactivity of several other nitrogen-containing heterocycles was also investigated.
- Wang, Ming de,Alper, Howard
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p. 169 - 173
(2007/10/02)
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- An N.M.R. Investigation of Ground-State Polarization of Some Substituted Aromatic Systems
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The previously established n.m.r. method for estimating mobile bond orders was applied to the investigation of ground-state polarization of benzene derivatives with ortho or para pairs of +R/-R substituents, naphthalene and five heteroaromatic systems (furan, thiophen, pyrrole, quinoline and pyrazole).Evidence for significant ground-state polarization which is solvent-independent was found in a number of these systems, especially benzene, pyrrole and pyrazole.
- Collins, Michael J.,Hatton, Paul M.,Sternhell, Sever
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p. 1119 - 1134
(2007/10/02)
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- THE REACTIVITY OF MONOCYCLIC 1,2,3-TRIAZINE
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The reactivity of unsubstituted 1,2,3-triazine was investigated using various nucleophilic and electrophilic reagents, molecular orbital calculations, and low temperature nmr measurements.
- Itoh, Takashi,Nagata, Kazuhiro,Kaihoh, Terumitsu,Okada, Mamiko,Kawabata, Chikako,et al.
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p. 631 - 639
(2007/10/02)
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- SYNTHESIS OF PYRAZOLE, 1,3,4-THIADIAZOLE, AND 1,2,4-TRIAZOLE DERIVATIVES BY CONDENSATION OF 1,3-DIOXO COMPOUNDS WITH THIOSEMICARBAZIDE DERIVATIVES
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The reaction of β-diketones with 2-unsubstituted thiosemicarbazides leads to the formation of the corresponding 1-thiocarbamoyl-5-hydroxy-2-pyrazolines, which readily undergo aromatization to give pyrazoles, while the reaction of benzoylacetaldehyde leads to the formation of the corresponding hydrazone.Acetylacetone 2-methyl- and 2,4-dimethylthiosemicarbazones are inclined to undergo tautomerization and, depending on the conditions, can exist in enehydrazine, hydrazone, 1,2,4-triazoline, and 1,3,4-thiadiazoline forms or mixtures of these forms.Upon heating these substances are converted to mixtures of the 1,3,5-trimethylpyrazole and the corresponding 1,2,4-triazoline-5-thione.The structures of the compounds were studied by means of IR and 1H, 13C, and 15N NMR spectroscopy and mass spectrometry.
- Zelenin, K. N.,Solod, O. V.,Alekseev, V. V.,Pekhk, T. I.,Kuznetsova, O. B.,et al.
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p. 1051 - 1060
(2007/10/02)
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- REACTIONS OF HETEROCYCLIC CATIONS WITH N-CONTANINING NUCLEOPHILES. 16. STUDY OF THE INTERACTION OF 2,6-DIPHENYLPYRYLIUM PERCHLORATE WITH DIAZOLES
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The direct interaction of 2,6-diphenylpyrylium perchlorate with pyrazoles and pyrazolones led to the synthesis of 4-azolylpyrylium salts, which readily cleave a molecule of perchloric acid in the case of the N-unsubstituted pyrazolones, being converted to
- Zhdanov, Yu. A.,Zvezdina, E. A.,Statsenko, S. M.,Maksimova, A. N.
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p. 149 - 154
(2007/10/02)
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- Pyrrole and Pyrazole Ring Closure in Heterogeneous Media
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Pyrroles and pyrazoles may be conveniently prepared by dispersing primary amines or hydrazines and 1,4- or 1,3-diketones, respectively, on alumina or clay (montmorillonite K 10) without solvent, keeping the mixture at 20 deg C or higher temperatures for 1-26 h, and then eluting the product with dichloromethane.
- Texier-Boullet, F.,Klein, B.,Hamelin, J.
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p. 409 - 411
(2007/10/02)
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- The Reaction of 1,2,3-Triazines with Grignard Reagents
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Monocyclic 1,2,3-triazines reacted with Grignard reagents to form adducts due to N-2 and C-5 attack together with β-substituted acrylaldehydes and N-substituted pyrazoles; the results show that the N-2, C-4, and C-5 positions are reactive towards Grignard reagents.
- Ohsawa, Akio,Kaihoh, Terumitsu,Igeta, Hiroshi
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p. 1370 - 1371
(2007/10/02)
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- Enehydrazines, 34. The Addition of Methylhydrazine to Dimethyl Acetylenedicarboxylate is Reversible
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The cyclisation of the enehydrazine 1 to the pyrazolone 5 proceeds by cleavage of 1 to its educts 2 and 3 followed by their recombination to 4.Addition of 2 or 3 supresses the dissociation of 1, furthermore 2 and 3 could be separately captured from 1.
- Sucrow, Wolfgang,Bredthauer, Gerhard
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p. 1520 - 1524
(2007/10/02)
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- INVESTIGATIO OF THE MECHANISMS OF FORMATION OF HETEROCYCLES BY NMR SPECTROSCOPY. INTERMEDIATES IN THE PRODUCTION OF PYRAZOLES FROM 1,3-DIKETONES AND HYDRAZINES
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The structure of the intermediates formed in the reaction of 1,3-diketones RCOCH2COCH3 (R = Me, Et, t-Bu, Ph, CF3) with hydrazines NH2NHR' (R'= H, Me) in methanol and chloroform was determined by NMR spectroscopy in the normal and flow techniques.When R' = H, the reaction takes place through the formation of dihydroxypyrazolidine and 5-hydroxy-2-pyrazolines; for R'= Me, in addition, intermediate products with ketohydroxyazine and ketoenehydrazone structures were detected.A scheme with their participation is proposed for the formation of the isomeric pyrazoles.A pre-equilibrium between the 1,3-diketone, its hydrazinium salt in the Z,Z configuration, and the anion in the E,Z configuration was detected.The reaction rate of the ketone form of the 1,3-diketone is significantly higher than the reaction rate of the enol.
- Selivanov, S. I.,Bogatkin, R. A.,Ershov, B. A.
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p. 788 - 795
(2007/10/02)
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- Recherches en serie triazepine XVI. Condensation des composes β-dicarbonyles avec les thiosemicarbazides
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Condensations of β-dicarbonyl compounds with thiosemicarbazide and 1- and 2-methylthiosemicarbazide give three types of heterocyclic compounds.Depending upon the reagents and experimental conditions, triazepinones, triazepines, 1,2,4-triazolines or pyrazoles are formed.Mechanisms explaining these cyclisations are proposed.
- Hasnaoui, A.,Lavergne, J.-P.,Viallefont, Ph.
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p. 301 - 306
(2007/10/02)
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