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1.
Reactions of N-aryl-3-oxobutanethioamides with 1H-1,2,4-triazole-5-amine give mixtures of 7-arylamino-5-methyl[1,2,4]triazolo[1,5-a]pyrimidines, 5-methyl-4,7-dihydro[1,2,4]triazolo[1,5-a]pyrimidine-7-thione, 7-methyl-4,5-dihydro[1,2,4]triazolo[1,5-a]pyrimidine-5-thione, and 5-arylamino-7-methyl[1,2,4]triazolo[ 1,5-a]pyrimidines whose ratio depends on the substituent in the aryl group of initial N-aryl-3-oxobutanethioamide and solvent nature (the presence of a proton-donor solvent).  相似文献   

2.
Diazafulvenium methides generated from the solution pyrolysis of pyrazolo[1,5-c][1,3]thiazole-2,2-dioxides participate in [8π+2π] cycloadditions giving pyrazolo[1,5-a]pyridine derivatives. 1-Methyl-diazafulvenium, generated under flash vacuum pyrolysis reaction conditions, undergoes an intramolecular sigmatropic [1,8]H shift giving 1-vinyl-1H-pyrazoles.  相似文献   

3.
《Mendeleev Communications》2022,32(5):637-639
The cascade heterocyclization of 1,2-diamino-4-phenyl-imidazole with ethyl 2-arylidene-2-cyanoacetates affords 1,2,3,4-tetrahydroimidazo[1,5-b]pyridazine-3-carbonitrile derivatives as mixtures of diastereomers. The experimental data and quantum chemical calculations were used to propose processes. The three-component processing with above-mentioned diamine, ethyl cyanoacetate and aromatic aldehydes leads to the same products in generally lower yields.  相似文献   

4.
Excess enthalpies and excess volumes at 298.15 K and atmospheric pressure have been measured for mixtures of n-hexane + (an equimolar mixture of n-tridecane + n-nonadecane). The agreement of the results with the corresponding results for mixtures of n-hexane + n-hexadecane is interpreted as confirmation of the applicability of the principle of congruence to multicomponent mixtures.  相似文献   

5.
Quinalizarin and anions derived therefrom exist as equilibrium mixtures of different tautomers and conformers, whose structure depends on the conditions. Quinalizarin was shown to have 9,10-, 1,10-, 1,4-, 1,5-, 1,7-, and 2,9-quinoid structures, but not 1,2-quinoid structure; and its anions in ethanol media were identified as 9,10-, 1,10-, 2,9-, and 1,5-quinoid tautomers. Interactions with solvents and ionization could give rise to displacement of tautomeric and conformational equilibria, leading to considerable change in the number and position of π l ,π* bands in the electronic absorption spectra, which are responsible for the color.  相似文献   

6.
Surface tensions of mixtures of 1,2-dibromoethane+cyclohexane, benzene, +toluene, +o-xylene, +m-xylene, and +p-xylene have been measured as a function of composition at 298.15, 303.15 and 308.15 K. Interchange energies and surface heats of mixing in these mixtures were computed.  相似文献   

7.
N-Benzyl aldimines react with arylacetylenes in the presence of ButOK/DMSO superbase system to afford 2,3,5-triaryl-1-pyrrolines as two tautomers with 1,2- and 1,5-location of the double bond, both being the trans-diastereomers. This version of the C=N bond ethynylation differs from the previous one with N-benzyl ketimines. The oxidation of the pyrroline tautomeric mixtures without their isolation gives 2,3,5-triaryl-1H-pyrroles.  相似文献   

8.
《Fluid Phase Equilibria》1999,155(2):261-276
The excess isentropic compressibilities, KsE for seven binary mixtures of methyl methacrylate+benzene, +o-xylene, +m-xylene, +p-xylene, +toluene, +ethylbenzene and +cyclohexane were estimated from the measured densities and speeds of sound at 298.15 and 308.15 K. The KsE values were large and positive for MMA+cyclohexane and +m-xylene, while they were negative for other mixtures. A qualitative analysis of KsE values was made in terms of molecular interactions. The speeds of sound of all the mixtures were also predicted from the free length theory (FLT) and collision factor theory (CFT).  相似文献   

9.
Solid+liquid equilibrium, NMR and colorimetric measurements have been made for the mixtures of o-phenylenediamine+phenol, p-phenylenediamine+hydroquinone, m-phenylenediamine+phenol, m-phenylenediamine+hydroquinone, p-phenylenediamine+phenol, and p-phenylenediamine+hydroquinone. The types and melting temperatures of the complexes formed in these mixtures were ascertained from phase diagrams. The nature of the complexes was ascertained from colorimetric and NMR data.  相似文献   

10.
《Fluid Phase Equilibria》2004,216(2):293-299
Excess molar enthalpies, measured at 298.15 K in a flow microcalorimeter, are reported for the ternary mixtures (tetrahydrofuran + diisopropyl ether + n-heptane) and (tetrahydrofuran + 2-methyltetrahydrofuran + n-heptane). Smooth representations of the results are described and used to construct constant excess molar enthalpy contours on Roozeboom diagrams. The latter are compared with diagrams obtained when the model of Liebermann and Fried is used to estimate the excess enthalpies of the ternary mixtures from the physical properties of the components and their binary mixtures.  相似文献   

11.
《Fluid Phase Equilibria》1988,41(3):277-285
The results of measurements of molar excess volumes VE at 303.15 K over the whole mole fraction range for eight mixtures: n-octylacetate + n-hexane; +n--heptane; + n-octane; +nn-nonane; + n-decane; +nn-dodecane; + n-tetradecane and + n-hexadecane are presented. The experimental values of VE show a regular pattern of behaviour for the eight sets of binary mixtures. The magnitude of VE for this class of mixtures decreases as the n-alkane chain-length decreases. In order to explain the observed behaviour, the Prigogine-Flory-Patterson theory is used to predict the total VE and the three different contributions to VE. Agreement between the theoretical and experimental VE is reasonable for the eight systems  相似文献   

12.
The possibility of controlling the association of tetraviologen calix[4]resorcinol (MVCA-C5 8+) with 3,7-di(l-menthyl)-1,5-di(p-sulfonatophenyl)-1,5-diaza-3,7-diphosphacyclooctane (APCO-22?) in the electrochemical cycle of reduction-reoxidation of viologen units was shown. Reduction to tetra(radical cation) MVCA-C5 4+· transforms monomeric MVCA-C5 8+ and APCO-22- into the associate (π-polymer) (xAPCO-22?·yMVCA-C5 4+·) n , which is completely returned by reoxidation to the initial state.  相似文献   

13.
1,5-Diaza-cis-decalin populates two conformations in which the nitrogen atoms are either gauche (N-in) or anti (N-out) to one another. The equilibrium mixture of the two conformers depends on the substituents at the nitrogen atom, as well as the reaction conditions. Ab initio (HF/6-31G, B3LYP/6-31+G) and molecular mechanics (Amber) calculations have been performed to examine the possible role of stereoelectronics and steric effects in controlling the equilibrium of substituted 1,5-diaza-cis-decalins. In the present study, N,N'-diethyl- and N,N'-bistrifluoroethyl-1,5-diaza-cis-decalins have been synthesized, and the equilibrium mixtures have been measured using 1H and 13C NMR experiments. Steric effects appear to control the equilibria between the two conformational isomers of 1,5-diaza-cis-decalin while torsional effects appear to dominate the equilibria for the N,N'-dialkyl derivatives.  相似文献   

14.
Methods were developed of the synthesis of alkyl 2-hydroxy-2-fluoroalkyl-4-phenyl-1,2,3,4—tetrahydroimidazo-[1,5-a]pyrimidine-3-carboxylates and alkyl-5-hydroxy-2,7-diphenyl-5-fluoroalkyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidine-6-carboxylates by regioselective [3+3]-cycloaddition of 5-aminoimidazole or 5-aminopyrazole to alkyl 2-benzylidene-3-oxo-3-fluoroalkylpropionates at the fluoroacylvinyl fragment.  相似文献   

15.
An equation free of fitting parameters is proposed for calculating the standard heats of solution for compounds in nonaqueous binary mixtures. The parameters of the equation are the standard heats of solution of a compound in the components of the mixed solvent. Nonlinear ΔH 0(x) trends are reconstructed for solutions of water in i-PrOH + MeOH and MeCN + MeOH, t-BuOH in MeCN + MeOH, squalane in CHCl3 + CCl4 and C6H6 + CHCl3, and hexadecane in MeOH + i-Pr2O and in mixtures of butyl acetate, ethyl acetate, and 1,4-dioxane with 1-octanol. The standard heats of solutions are calculated for water in alcohol + alcohol, alcohol + aprotic solvent, and aprotic solvent + aprotic solvent mixtures  相似文献   

16.
Molar excess enthalpies, HE, for pyridine (i) + α-picoline (j), + β-picoline (j), + γ-picoline (j); pyridine (i) + cyclohexane (j); β-picoline (i) + cyclohexane (j); methylenebromide (i) + pyridine (j), + β-picoline (j) mixtures have been measured calorimetrically as a function of temperature and composition. The HE data at 298.15 and 308.15 K have been analysed in terms of the Sanchez and Lacombe theory and the “graph theoretical approach”. The graph theoretical approach describes the HE data well for all these mixtures. This approach has been critically examined and it is found to provide an insight into the nature of molecular interactions between the components of these mixtures. NMR studies on methylene bromide (i) + β-picoline (j) andβ-picoline (i) + pyridine (j) further support these conclusions.  相似文献   

17.
Cyclocondensations of diethyl benzylidenemalonate with 3-amino-5-methylpyrazole, 3,5-diamino-1,2,4-triazole, 3,4,5-triamino-1,2,4-triazole, and 2-amino-benzimidazole in alcohols take a single route and lead to the formation of functionally substituted partially hydrogenated pyrazolo-, triazolo[1,5-a]-pyrimidin-5-ones and pyrimido[1,2-a]benzimidazol-2-one respectively. From reaction mixtures involving 3-amino-1,2,4-triazole and its 5-methylsulfanyl analog in methanol the intermediate products of heterocyclization were isolated forming as a result of alkylation with the β-carbon of the unsaturated ester the endocyclic nucleophilic sites of aminoazoles. The structure of one among the products obtained, diethyl(3-amino-5-methylsulfanyl-1,2,4-triazol-2-yl)benzylmalonate was proved by X-ray crystallography. In DMF the same reagents yielded mixtures of partially hydrogenated triazolo[1,5-a]pyrimidin-5-ones.  相似文献   

18.
The dissolution enthalpies of NaI in the mixtures of methanol with 1,2-alkanediols (1,2-propanediol, 1,2-butanediol, 1,2-pentanediol) and with ??,??-alkanediols (1,3-propanediol, 1,4-butanediol, 1,5-pentanediol), as well NaI in the mixtures of water with 1,3-propanediol and 1,2-pentanediol, were determined at 298.15?K. The energetic effect of interactions between the investigated alkanediols and NaI in methanol and in water was calculated using the enthalpic pair interaction coefficients (h xy ) model. These results along with the other data concerning the NaI?Cnon-electrolyte pairs taken from our earlier reports and from the literature were analyzed with respect to the effect of the non-electrolyte properties on the variations of the h xy values. The group contributions illustrating the interactions of NaI with selected functional groups in non-electrolyte (alkanediol and alkanol) molecules, namely: CH2 and OH groups were calculated and discussed.  相似文献   

19.
Thermally induced opening of the diaziridine ring in 6-aryl-2-methyl-1,5-diazabicyclo[3.1.0]-hexanes at the carbon-nitrogen bond is characterized by low regioselectivity; isomerization of unstable intermediate azomethine imines leads to mixtures of the corresponding 1-arylmethyl-5-methyl-4,5-dihydro-1H-pyrazoles and 1-arylmethyl-3-methyl-4,5-dihydro-1H-pyrazoles at a ratio of ~6:5. Analogous regioselectivity in opening of the three-membered ring is observed in the presence of phenyl isocyanate. In this case, adducts with cis arrangement of the aryl and methyl groups are formed as the major products (cis/trans ratio ~3:1).  相似文献   

20.
《Fluid Phase Equilibria》1996,118(2):227-240
Densities, ϱ, and speeds of sound, u, have been measured for the ternary mixture {benzene + cyclohexane + hexane} and the corresponding binary mixtures {benzene + cyclohexane}, {benzene + hexane} and {cyclohexane + hexane}, at the temperature 298.15 K. Using these results, the isentropic compressibilities, κs, the excess isentropic compressibilities, κsE, and the speeds of sound deviations, Δu, have been calculated for both the binary mixtures and the ternary system. Excess isentropic compressibilities, κsE, and the speeds of sound deviations, Δu, have been fitted to the Redlich-Kister equation in the case of binary mixtures, while the equation of Cibulka was used to fit the values relating to the ternary system. The empiric equations of Redlich-Kister, Tsao-Smith, Kohler and Colinet have been applied in order to predict the κsE and Δu of ternary mixtures from the binary contributions.  相似文献   

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