- Anomalous Products from 1,2,5-Triaza- and 1,5-Diaza-pentadiene Thermolyses: Formation of Amidines and Pyrroles, respectively
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Gas-phase thermolysis of the dimethylaminoazoalkene (1) gives the formamidine (2) by loss of HCN: in contrast, the related 1,5-diazapentadiene (4) under more forcing conditions gives aniline (30percent) and N-methylpyrrole (43percent).
- McNab, Hamish,Murray, Elizabeth-Ann
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- Acylation of tertiary amides. Formation of 1-acyloxyiminium salts and 1-acyloxyenamines
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Tertiary carboxamides are acylated at the oxygen atom by benzoyl or acetyl chloride in the presence of silver trifluoromethanesulphonate; if the resulting 1-acyloxyiminium salts contain hydrogen atoms at positions 2 or 4 they can be deprotonated to yield unstable 1-acyloxy-enamines or -dienamines, which have been trapped by reaction with 4-phenyl-1,2,4-triazoline-3,5-dione.
- Bottomley, William E.,Boyd, Gerhard V.
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- 3-Aminothieno[2,3-b]pyridine-2-carboxylate: Effective precursor for microwave-assisted three components synthesis of new pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(3H)-one hybrids
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In this study, ethyl 3-aminothieno[2,3-b]pyridine-2-carboxylate was taken as a versatile precursor for the one-pot three-component synthesis of related fused pyrimidine hybrids. The tandem protocol involved the reaction of 3-aminothieno[2,3-b]pyridine, di
- Mohamed Teleb, Mohamed A.,Mekky, Ahmed E. M.,Sanad, Sherif M. H.
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Read Online
- Novel synthesis of 1-substituted-4-imidazolecarboxylates via solvent-free cycloaddition reaction between formamidines and isocyanides
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A simple and efficient protocol for cyclization between formamidines and ethyl isocyanoacetate has been described in the absence of metal catalyst and solvent. A series of 1-substituted-4-imidazolecarboxylates were synthesized in moderate to good yields with DABCO as base additive.
- Cao, Han,Bie, Fu-sheng,Liu, Xue-jing,Han, Ying,Ma, Jie,Shi, Yi-jun,Yan, Peng,Sun, Chao-yue,Wang, Hai-meng
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- Direct synthesis of 2-oxo-acetamidines from methyl ketones, aromatic amines and DMF: Via copper-catalyzed C(sp3)-H amidination
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A convenient method for the synthesis of 2-oxo-acetamidines from methyl ketones using aromatic amines and DMF as nitrogen sources is reported via copper-catalyzed C(sp3)-H amidination. Various methyl ketones react readily with aromatic amines a
- Xie, Dianke,He, Wei,Xiao, Jiang,Wu, Yao,Guo, Yongjia,Liu, Qiang,Guo, Cancheng
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p. 7203 - 7209
(2019/03/19)
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- C–N cross-coupling on supported copper catalysts: The effect of the support, oxidation state, base and solvent
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A series of supported copper catalysts at two different loadings (1 and 2?wt%) have been prepared by deposition precipitation on various supports including TiO2, ZnO, Al2O3 and active carbon and submitted or not to reductive treatments to favor the increase in population of Cu(I). The samples have been characterized by textural measurements, electron microscopy and spectroscopic techniques including EPR and XPS, concluding the presence of dispersed copper oxides on the support with small particle size and contrasting prevalence of Cu(II) or Cu(I). The catalytic activity of all these catalysts for the C–N coupling of aniline and bromobenzene has been evaluated. A strong influence of the support, copper oxidation state, solvent, nature of the base was observed, the optimal conditions being the use of ZnO or TiO2 as supports and toluene/dioxane as solvent and EtOK as base. t-C5H11OK as base in either THF or toluene give rise to the formation of t-C5H11 phenyl ether in some extent. The catalyst undergoes deactivation during the reaction, but about 88% of the activity of the fresh sample could be regained by dioxane washings before reuse. XPS indicates that the most likely origin of catalyst deactivation is adsorption on the copper catalyst surface of KBr and inorganic salts formed as byproducts during the reaction.
- Tirsoaga, Alina,Cojocaru, Bogdan,Teodorescu, Cristian,Vasiliu, Florin,Grecu, Maria Nicoleta,Ghica, Daniela,Parvulescu, Vasile I.,Garcia, Hermenegildo
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p. 205 - 220
(2016/08/04)
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- Method For Preparing Formamidines
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A method for preparing formamidines of formula (I) in a single step by reducing ureas of formula (II) using silanes of formula (III), according to reaction (II)+(III)+(I) is provided. The present invention also provides a method for preparing insecticides
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Paragraph 0109; 0110; 0114
(2015/11/09)
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- Chromatographic and chromato-mass spectral characterization of amino acids derivatives formed via the interaction with dimethyl acetal of dimethylformamide
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A series of amino acids have been converted into the derivatives via interaction with dimethylformamide dimethyl acetal for gas chromatography identification. The derivatives have been for the first time characterized with mass spectra and retention indices corresponding to the standard nonpolar polydimethylsiloxane stationary phases. Basic features of mass spectroscopic fragmentation of the derivatives have been stated; the rules for interpretation of their gas chromatography retention indices have been figured out, including the additive scheme elements.
- Zenkevich,Pushkareva
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p. 1920 - 1928
(2015/10/12)
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- Pushing back the limits of hydrosilylation: Unprecedented catalytic reduction of organic ureas to formamidines
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Pushing back the limits: A novel catalytic transformation has been designed to prepare formamidine derivatives by reduction of substituted ureas with hydrosilanes. Simple iron catalysts based on commercially available iron salts and phosphine ligands prov
- Pouessel, Jacky,Jacquet, Olivier,Cantat, Thibault
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p. 3552 - 3556
(2014/01/06)
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- Synthetic potentiality of α-amino nitrones as oxidizing reagent in the conversion of alkyl halides to aldehydes
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α-Amino nitrones have been used successfully as an oxidizing reagent for the synthesis of aldehydes from various alkyl halides with an excellent yield. In addition, hydrolysis of the side product (imines) furnishes starting material amides which are recyclable along with corresponding amines.
- Chakraborty, Bhaskar,Chhetri, Manjit Singh,Kafley, Saurav,Sharma, Prawin,Rai, Neelam
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experimental part
p. 1399 - 1402
(2011/09/20)
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- Iron-catalyzed epoxidation of aromatic olefins and 1,3-dienes
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The combination of iron(III) chloride, pyridine-2,6-dicarboxylic acid and formamidine ligands allows for the epoxidation of styrenes and conjugated dienes in excellent chemoselectivity and yields.
- Schroeder, Kristin,Enthaler, Stephan,Join, Benoit,Junge, Kathrin,Beller, Matthias
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experimental part
p. 1771 - 1778
(2010/09/11)
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- Change of the favored routes of EI MS fragmentation when proceeding from N1, N1-dimethyl-N2-arylformamidines to 1,1,3,3-tetraalkyl-2-arylguanidines: Substituent effects
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Although series of N1, N1-dimethyl-N 2-arylformamidines and of 1,1,3,3-tetraalkyl-2-arylguanidines are structurally analogous and similar electron-ionization mass spectral fragmentationmay be expected, they display important differences in the favored routes of fragmentation andconsequently in substituent effectsonion abundances. In the caseof formamidines, the cyclizationelimination process (initiated by nucleophilic attack of the N-amino atom on the 2-position of the phenyl ring) and formation of the cyclic benzimidazolium [M-H]+ ions dominates, whereas the loss of the NR2 group ismore favored for guanidines. In order to gain information on the most probable structures of the principal fragments, quantum-chemical calculations were performed on a selected set. A good linear relation between log{I[M-H]+I [M]+?} and σR+ constants of substituent at para position in the phenyl ring occurs solely for formamidines (r = 0.989). In the case of guanidines, this relation is not significant (r = 0.659). A good linear relation is found between log{I[M-NMe2]+/I [M]+?} and σp+ constants (r = 0.993). Copyright
- Raczynska, Ewa D.,Makowski, Mariusz,Gal, Jean-Francois,Maria, Pierre-Charles
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body text
p. 762 - 771
(2011/09/12)
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- Reductive monoalkylation of aromatic amines via amidine intermediates
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The convenience and efficiency of using amidines as intermediates in the reductive monoalkylation of aromatic amines has been demonstrated. This monoalkylation can be performed as either a two-step synthesis or a one-pot procedure. Several examples are presented which clearly demonstrate the utility of this new method for the methylation or ethylation of aromatic amines, including unprotected nucleosides.
- Zhang, Jianxing,Chang, Hui-Min,Kane, Robert R.
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p. 643 - 645
(2007/10/03)
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- Amidines. Part 39.1 Formation of N1,N1-dialkylamidines in the reaction between amide acetals and substituted anilines in pyridine. Reaction mechanisms
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The reaction rates of six N,N-dialkylformamide acetals (R1)2N-CH(OR2)2, with a series of anilines substituted on the phenyl ring have been measured in pyridine. The reaction is found to be irreversible and obeys second-order kinetics. Reaction rates are correlated with Hammett σ constants. Based on the plots and a comparison of reaction rate constants it is shown that the reaction proceeds via two mechanisms which differ from that for the reaction in neutral solvents. It is shown that for compounds with weakly basic NH2 groups the reaction rates in pyridine are markedly higher than in neutral solvents.
- Oszczapowicz, Janusz,Osek, Jerzy
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p. 1919 - 1923
(2007/10/03)
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- Reactivity of 1-aryl-4-dimethylamino-2-phenyl-1,3diaza-1,3-butadienes towards dienopheles, 1,3-dipoles and carbanions
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The reactivity of 1-aryl-4-dimethylamino-2-phenyl-1,3-diaza-1,3-butadienes (1) towards dienophiles, 1,3-dipoles and C-nucleophiles was investigated. N-Phenylmethylene-benzenesulfonamide (2), phenylisocyanate (6), C,N-diphenylnitrone (9) and acylacetates (10) reacted with 1 giving quinazoline or pyrimidine derivatives. The possible mechanisms involved in products formation are discussed.
- Croce, Piero Dalla,Ferraccioli, Raffaella,Rosa, Concetta La
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p. 1309 - 1318
(2007/10/03)
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- Amidines. Part 31. pKa Values of N1,N1-Dialkyl-N2-phenylformamidines in Water-Ethanol Solutions
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The pKa values of three series (30 compounds in all) of N1,N1-dialkyl-N2-phenylformamidines (XC6H4N=CHNRR) have been measured in water-ethanol mixtures.The obtained pKa values of the amidines have been correlated with Hammett-type substituent constants and the pKa values of the corresponding primary amines determined in the same solvent.The applicability of various ? values is discussed and it is shown that, in each case, for substituents on the phenyl ring at the amino nitrogen atom ?0 values should be used.It is found that the slopes of regression lines for correlations with Hammett-type constants depend on the substituents at the amino nitrogen atom, as well as on the solvent.
- Oszczapowicz, Janusz,Jaroszewska-Manaj, Jolanta
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p. 1677 - 1680
(2007/10/02)
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- REACTION OF PHENYL AZIDE WITH N,N-DIMETHYL-AMINOMETHYLENEPHENYLPHOSPHINES
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Phenyl azide reacts with N,N-dimethylamino-P-phenylmethylenephosphines with cleavage of the phosphorus-carbon double bond and formation of the dimer of diiminophosphorane and amidines.
- Arbuzov, B. A.,Ionkin, A. S.,Ignat'eva, S. N.,Efremov, Yu. Ya.,Nekhoroshkov, V. M.
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p. 2191 - 2192
(2007/10/02)
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- α-AMINO CARBANIONS. A COMPETITION STUDY TO ASSESS RELATIVE ACIDITIES IN VARIOUS FORMAMIDINES
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Various N-groups on formamidines have been examined to see which enhance proton removal adjacent to nitrogen.
- Gonzales, Michael A.,Meyers, A. I.
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- Thermolysis of polyazapentadienes. Part 10. Flash vacuum pyrolysis of azoalkenes and some azocarbonyl compounds
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Thermolysis of the azoalkenes (1) and (6) - (8) takes place by 4π-electron electrocyclisation, followed by elimination of HCN to give imines. Decomposition of the related compounds (9)-(12) is less well defined, though the indole (22) has been identified from the thermolysis of (10) at high temperature. Alternatively, the azo ketones (15) - (18) undergo homolysis of the central C-N bond at 750 °C, and low yields of biaryls, formed by intermolecular radical coupling are generally found. Decarbonylation of intermediate aroyl radicals is extremely rapid under these conditions.
- McNab, Hamish,Murray, M. Elizabeth-Ann
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p. 583 - 587
(2007/10/02)
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- The Synthesis of Some Compounds Containing the Selenocarbonyl Group by Using Viehe's Salt/Sodium Hydrogen Selenide: an Approach to Cyclic Selenocarbonates in the Monosaccharide Series
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The treatment of various thiols, phenols and amines with Viehe's salt (Me2N+=CCl2Cl-, followed by addition to sodium hydrogen selenide in ethanol, can lead to useful syntheses of compounds containing the selenocarbonyl group, namely selenothiocarbamates, selenodithiocarbonates, selenothiocarbonates and selenoureas.As well, the combination of Viehe's salt/sodium hydrogen selenide allows the conversion of some carbohydrate cis vicinal diols into novel cyclic selenocarbonates, and a single-crystal X-ray diffraction structure determination of one of these selenocarbonates is reported.The treatment of these selenocarbonates with methyl iodide and various phosphorus reagents is reported, as well as some unsuccessful attempts towards tellurocarbonates and telluroureas.
- Copeland, Christopher M.,Ghosh, Jaya,McAdam, David P.,Skelton, Brian W.,Stick, Robert V.,White, Allan H.
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p. 549 - 561
(2007/10/02)
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- A New, Convenient Synthesis of N2-Aryl-N1-alkylformamidines and N2-Aryl-N1,N1-dialkylformamidines
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N2-Aryl-N1-alkylformamidines are conveniently and rapidly prepared by the reaction of an aromatic amine with ethyl N-cyanoformamidate to give the N2-aryl-N1-cyanoformamidine.Addition of this intermediate to an e
- Cereda, Enzo,Bellora, Elio,Donetti, Arturo
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p. 288 - 291
(2007/10/02)
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- Amidines. Part 20. Rate of Reaction of N,N-Dialkylformamide Acetals with Substituted Anilines
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Rate of reaction of seven N,N-dialkylformamide acetals R2N-CH(OR2)2 with a series of anilines substituted on the phenyl ring have been measured in benzene, methanol, chloroform, and tetrahydrofuran by use of a g.l.c. method.In each case studied reaction is irreversible and obeys a second-order kinetic equation.Reaction rates correlate with Hammett ? constants for substituents on the phenyl ring of the aniline molecule.On the basis of the kinetic data, the mechanism of reaction is discussed.
- Osek, Jerzy,Oszczapowicz, Janusz,Drzewinski, Witold
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p. 1961 - 1964
(2007/10/02)
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- AMIDINES.PART XI. BASICITY OF N1,N1-DIMETHYLFORMAMIDINES
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The pKa values of twenty four N1,N1-dimethyl-N2-phenyl- and N1,N1-dimethyl-N2-alkyl-formamidines in 95.6percent ethanol (azeotrope) at 25+/-0.2 degC have been measured by the potentiometric method.The pKa values of N2-phenyl derivatives obey Hammett equation and obtained ρ value is ca. 2/3 of that for symmetrically disubstituted N,N'-diphenylformamidines.It is shown that there is a good correlation, common for both N2-alkyl as well as for N2-aryl formamidines between pKa values of dimethylformamidines and pKa of corresponding primary amines.The slope of this correlation line is also ca. 2/3 of that for symmetricall y disubstituted N,N'-dialkyl- and N,N'-diarylformamidines.Experimental conditions securing reliable results of pKa determinations by potentiometric method in ethanol are discussed.
- Oszczapowicz, Janusz,Raczynska, Ewa
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p. 419 - 428
(2007/10/02)
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- A Versatile New Synthesis of Quinolines and Related Fused Pyridines. Part 5. The Synthesis of 2-Chloroquinoline-3-carbaldehydes
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Acetanilides are converted into 2-chloroquinoline-3-carbaldehydes in good yield by the action of Vilsmeier's reagent in phosphoryl chloride solution.The reaction is shown to involve successive conversion of the acetanilide into an imidoyl chloride and then an N-(α-chlorovinyl)aniline.The latter enamine is diformylated at its β-position and subsequently cyclised to the chloroquinolinecarbaldehyde.The diformylated intermediates may be isolated in several cases and separately cyclised with polyphosphoric acid.
- Meth-Cohn, Otto,Narine, Bramha,Tarnowski, Brian
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p. 1520 - 1530
(2007/10/02)
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- Formation of Cycloadducts from Heterocyclic Formamidines and Phenyl Isocyanate
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Heterocyclic formamidines react with phenyl isocyanate at room temperature to give a cycloadduct which decomposes at elevated temperatures in two different ways; phenyl isocyanate reacts with the heterocyclic isocyanate formed in situ to form a new cycloadduct, a fused 1,3,5-triazine-2,4-dione derivative.
- Tisler, Miha,Stanovnik, Branko
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p. 313 - 314
(2007/10/02)
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- Orthoamides, XXXII. - Reactions of tert-Butoxy-N,N,N',N'-tetramethylmethanediamine with NH- and CH-acidic Compounds
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tert-Butoxy-N,N,N',N'-tetramethylmethanediamine (1) reacts with N-formylglycine ethyl ester (2) and with N-formyl-β-alanine ethyl ester (9) to form the aminomethylene compounds 3 and 10, respectively.Glycine ester is aminomethylenated by 1 at the acidic NH2 group to give the amidine 6.Dimethylaminoformaldehyde dimethyl acetal (5) is also suitable for this reaction.On reaction with 1 the compounds 3 as well as 6 yield the amidine 4.N-Monosubstituted formamides are transformed by 1 into formamidines 13.Reaction of isocyanoacetate 17 and 1 affords the enamine 18, whereas reaction of benzyl isonitrile with 1 gives the amidine 19. 2-Alkyl-Δ2-oxazolines 21, carboximidates 23, 25, and amidines 27 are aminomethylenated by 1 to yield the products 22, 24, 26, and 28, respectively.The vinylogous guanidinium salt 34 is obtained by reaction of 1 with N,N,N',N'-tetramethylacetamidinium tetrafluoroborate (31a).Phosphonates 36 react with 1 to afford the enamines 37.The reaction of 1 on ethyl trimethylsilylacetate (39) gives rise to formation of ethyl 3-dimethylaminoacrylate (11).
- Kantlehner, Willi,Wagner, Fritz,Bredereck, Hellmut
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p. 344 - 357
(2007/10/02)
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