Researches on structural peculiarities and chemical reactions of carbazole and some of its derivatives

Dipropargyl esters of 9-ethyl, 9-n-butyl, and 9-isoamylcarbazole-3, 6-dicarboxylic acids, not hitherto described in the literature, are synthesized. It is shown that, in the presence of tert-butyl peroxide, these esters can polymerize to infusible and insoluble products.For Part XIII see [1].     

Palladium catalyzed Suzuki C-C couplings in an ionic liquid: nanoparticles responsible for the catalytic activity

A new family of functionalized ligands derived from norborn-5-ene-2,3-dicarboxylic anhydride has been used in Suzuki C-C cross-couplings between aryl boronic acids and aryl bromide derivatives in [BMI][PF(6)] (BMI=1-n-butyl-3-methyl-imidazolium), using palladium acetate as catalytic precursor. High conversions and yields are obtained when amine ligands containing hydroxy groups are involved. TEM analyses after catalysis show the formation of small nanoparticles, in contrast to the agglomerates observed when nanoparticles are intentionally preformed, with a consequent decrease in the catalytic activity in the latter case. Some tests, including the correlation effect between solvent and ligand, are carried out to try to identify the true nature of the catalyst. All the results obtained suggest that formation of nanoparticles is required to lead to a catalytically active system.     

Reduction and hydrolysis of substituted 5-oxa-6-azaspiro[2.4]heptane-1,2-dicarboxylic acid esters

Substituted 5-oxa-6-azaspiro[2.4]heptane-1,2-dicarboxylic acid esters synthesized by reaction of nitrones with dimethyl 3-methylidenecyclopropane-1,2-dicarboxylate were reduced with lithium tetrahydridoaluminate to the corresponding bis(hydroxymethyl)cyclopropanes. Alkaline hydrolysis of the title compounds gave substituted cyclopropane-1,2-dicarboxylic acids. In both cases, the 5-oxa-6-azaspiro[2.4]heptane fragment remained intact.     

3,3-Dialkyltriazencarbonsäure-Derivate durch oxydative Hydro-Acyl-Elimination von 3,3-Dialkyltriazan-1,2-dicarbonsäure-Derivaten

3,3-Dialkyltriazenecarboxylic Derivatives by Oxidative Hydro-Acyl-Elimination from 3,3-Dialkyltriazane-1,2-dicarboxylic Derivatives The preparation and some properties of esters and amides of 3,3-dialkyltriazenecarboxylic acids ( 6 ) are described. These novel triazenes 6 were obtained by treatment of diesters, diamides and ester-amides of 3,3-dialkyltriazane-1,2-dicarboxylic acids ( 3 ) with lead tetraacetate, when an elimination of the COOR- or the CONHR-group at N(2) together with the H-atom at N(1) took place. The precursor triazanes 3 were readily available from the addition of secondary amines 2 to diesters, diamides or ester-amides of diazenedicarboxylic acid ( 1 ). The spectral properties of the triazanes 6 , including the ¹⁵N-NMR signals of one example, are compared with those of the triazanes 3 . They express the structural features due to conjugation in 3,3-dialkyltriazenecarboxylic derivatives, including the resistance to rotation around the N(2), N(3)-bond.     

Synthesis of 3 or 4-Substituted Pyridine-2, 6-Dicarboxylic Acid

Time-resolvedcircularlypolarizedluminescence(CPL)studieshavebeenparticularlysuccessfulatmeasuringdifferencesinquenchingrateconstantsincertaindiastereomericdonor-acceptorsystems'ItisanticipatedthatthesetypesofexperimentsmaybeappliedtomorecomplexsystemsinvolvingracemiclanthanideemittercomplexesinasolutioncontainingtransitionmetalcomplexesenantioselectivelyboundtoDNA2.However,theluminophoreswereonlyconfinedtoLn(DPA),'-andLn(CDA),'(Ln=Eu' ,Tb' ,DPA=dipicolinatedianion,CDA=chelidamate).Eff…     

A new synthesis of some indolecarboxylic acids

1-Substituted isatins are transformed into indole derivatives by means of ethyl chloroacetate. In fact, under the conditions of the Darzens reaction they give two glycidic ester isomers 4 and 5 which, by hydrolysis in alkaline medium, undergo a transposition to indole-2,3-dicarboxylic acids 2 together with minor amounts of indole-3-carboxylic acids 3 . From isatin itself, 2,3-dicarboxyindole-1-acetic acid ( 6 ) was obtained.     

Regio- and stereoselectivity of cycloaddition of C-amidonitrones to esters of methylenecyclopropanedicarboxylic acids

C-Amidonitrones add regio- and stereoselectively to esters of 3-methylenecyclopropane-1,2-dicarboxylic, 2-(diphenylmethylene)cyclopropane-1,1-dicarboxylic, and 2-(1-phenylethylidene)cyclopropane-1,1-dicarboxylic acids to form a single diastereomer of 4-spirocyclopropaneisoxazolidines.     

Synthesis and reactions of 3-(N-arylcarbamoyl)-2-methylcinchoninic acid

The Pfitzinger reaction between acetoacetic acid arylamides and the potassium salt of isatinic acid leads in good yield to 3-(N-arylcarbamoyl)-2-methylcinchoninic acids. Refluxing the latter in 2-propanol produced N-substituted imides of 2-methylquinoline-3,4-dicarboxylic acids and, with benzaldehyde in p-xylene in the presence of piperidine, to N-phenylimides of 2-styrylquinoline-3,4-dicarboxylic acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 652–653, May, 1988.     

Synthesis of Derivatives of Pyrazolin-1H-3-ones from 2′-N-Substituted Monohydrazides of Cyclohexenedicarboxylic Acids

2-(6-Aryl-4-methylcyclohex-3-enecarbonyl)-4-ethoxycarbonylpyrazolin-1H-3-ones have been synthesized from 2′-N-(2,2-diethoxycarbonylvinyl)monohydrazides of 6-aryl-4-methylcyclohex-3-ene-1,1-dicarboxylic acids by boiling in DMF, pyridine, or toluene in the presence of potassium carbonate. Under analogous conditions, but without potassium carbonate, 2′-N-substituted hydrazides of cyclohexenecarboxylic acids are obtained. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1007–1011, July, 2005.     

Effect of water and organic solvents on the ionic dissociation of ionic liquids

The effect of water and several organic solvents on the density, viscosity, and conductivity of ionic liquids (ILs) 1-n-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), 1-n-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), and 1-n-butyl-3-methylimidazolium trifluoroacetate ([bmim][CF3CO2]) was studied at 298.15 K in wide composition ranges. The density, viscosity, and conductivity of the three neat ILs were also determined at various temperatures. Upon the basis of the molar conductivity of the mixtures and that of the neat ILs of the same viscosity, the degree of dissociation of ILs in the solutions was investigated. It can be deduced that the organic solvents enhance the ionic association of the ILs, the effect depending on the solvent dielectric constant, while water promotes dissociation significantly due to its high dielectric constant and its ability to form strong hydrogen bonds with the anions of the ILs.     

Synthesis and structure of new 6-substituted 5-methyl-5,6-dihydrocyclohepta[<Emphasis Type="Italic">b</Emphasis>]indole-9,10-dicarboxylic anhydrides

Reactions of (2-chloro-1-methyl-1H-indol-3-yl)-2-oxoacetyl chloride with alk-3-enoic acids gave the corresponding 6-substituted 5-methyl-5,6-dihydrocyclohepta[b]indole-9,10-dicarboxylic anhydrides which showed fluorescent properties.     

Synthesis and reduction of derivatives of aziridinemono- and-dicarboxylic acids

Amides and esters of aziridine-2-carboxylic acid were synthesized by the reaction of 1,1,1-trimethyl-2-(2-carboxyethyl)hydrazinium derivatives with an anion-exchange resin or with sodium hydride. Enamines were obtained from 1,1,1-trimethyl-2-[1,2-bis(alkoxycarbonyl)ethyl]hydrazinium salts and basic agents. Methods for the synthesis of amides of aziridine-2,2- and aziridine-2,3-dicarboxylic acids were developed. The stereochemistry of the esters and amides of aziridine-2,3-dicarboxylic acids was established. Dialkylcarbamoylaziridines were reduced with lithium aluminum hydride to 2-(N,N-dialkylaminomethyl)aziridines. The reduction of esters of aziridine-2-carboxylic acid and their functionally substituted derivatives leads to the formation of 2-hydroxymethylaziridines. An O-silylation product was obtained by silylation of 2-hydroxymethylaziridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1227–1235, September, 1983.     

The mass spectra of carboxylic acids—V: Carboxyl-carboxyl interaction in the fragmentation of some cycloalkene-1,2-dicarboxylic acids

The fragmentation mechanisms of the six isomeric cyclohexene-1,2-dicarboxylic acids are discussed. Only the 1-cyclohexene acid, by virtue of the major sequential losses of H₂O and CO₂ from the molecular ion, is readily distinguishable from its isomers, all of whose mass spectra are closely similar. In contrast to cis and trans cyclohexane-1,2-dicarboxylic acids, whose mass spectra were markedly different, the cis and trans cyclohexene-1,2-dicarboxylic acids fragment in a similar fashion. The mass spectra of 1-cyclopentene-1,2-dicarboxylic acid and 1-cyclobutene-1,2-dicarboxylic acid also exhibit a strong carboxyl-carboxyl interaction; the fragmentation behaviour of the 1-cyclopenteneacid is, however, more complex than that of the 1-cyclohexene and 1-cyclobutene acids.     

Anomalous behavior of the amides of benzo-and dibenzocrown thiocarboxylic acids under the conditions of methylation

During the reaction of the amides of benzo-and dibenzocrown thiocarboxylic acids with methyl iodide in the presence of potassium hydroxide they exhibit anomalous behavior leading to the nitriles of benzo-and dibenzocrown carboxylic acids. The nitriles of benzo-15-crown-5-, benzo-12-crown-4-, and dibenzo-18-crown-6-4′-carboxylic acids and the dinitriles of dibenzo-18-crown-6-and dibenzo-24-8-4′,4″(5″)-dicarboxylic acids were obtained. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 357–360, March, 2007.     

Investigation of furan compounds L. Synthesis of N-alkyl- and N-aryl-substituted diureides of tetrahydrofuran-2,5- and tetrahydrothiophene-2,5-dicarboxylic acids

The corresponding diureides of tetrahydrofuran-2,5- and tetrahydrothiophene-2,5-dicarboxylic acids and the dithioureide of tetrahydrothiophene-2,5-dicarboxylic acid were obtained by the acylation of thiourea, urea, and its N-methyl-, N-tert-butyl- and N-phenyl derivatives with the acid dichlorides of tetrahydrofuran-2,5- and tetrahydrothiophene-2,5-dicarboxylic acids.See [1] for communication XLIX.DeceasedTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1587–1589, December, 1971.     

Synthesis of Derivatives of 3,5-Dioxopyrazolidine

The reaction of monohydrazides of 2-R-4-methylcyclohex-4-ene-1,1-dicarboxylic acids with ethoxymethylenemalonic acid diethyl ester leads to N-(2,2-diethoxycarbonylethylenyl)hydrazides of 2-R-4-methylcyclohex-4-ene-1,1-dicarboxylic acids, which are acylated by the anhydrides of trifluoroacetic and acetic acids with the formation of derivatives of 3,5-dioxopyrazolidine and 5-oxopyrazoline respectively.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 216–220, February, 2005.     

Reactions of cyclononatetraenyl dianion with electrophiles: geometry and conformation of 1,3,6-cyclononatrienes

Carbonation of the parent cyclononatetraene dianion gives a mixture of (a) the minor products, 1,3,6-cyclononatriene-5,9- and 5,8-dicarboxylic acids, and (b) the major product, bis(5-carboxy-1,3,6-cyclononatrien-9-yl). In contrast, the 9,9-dimethyl dianion affords almost entirely a mixture of the two monocyclic diacids. Similar results are obtained on trimethylsilylation. Conformations of the products are discussed.     

The synthesis of 7-hydroxy-3, 9-diazabicyclo[3.3.1]nonane

7-Hydroxy-3, 9-diazabicyclo[3.3.1]nonane is synthesized, starting from the dimethyl ester of the 4-hydroxypiperidine-2, 6-dicarboxylic acid, by preparing the N-benzyl derivative and cyclizing the latter with benzylamine to the benzylimide of the 1-benzyl-4-hydroxypiperidine-2, 6-dicarboxylic acid. On reduction of the given imide with lithium aluminum hydride and catalytic hydrogenolysis of the benzyl groups, the final 7-hydroxy-3,9-diazabicyclo[3.3.1]nonane is obtained, the three-dimensional structure of which (chair-chair type) is proved by comparison of its methyl derivative with a known compound of demonstrated three-dimensional structure.     

The effect of C2 substitution on melting point and liquid phase dynamics of imidazolium based-ionic liquids: insights from molecular dynamics simulations

Using molecular dynamics simulations, the melting points and liquid phase dynamic properties were studied for four alkyl-imidazolium-based ionic liquids, 1-n-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), 1-n-butyl-2,3-dimethylimidazolium hexafluorophosphate ([BMMIM][PF6]), 1-ethyl-3-methylimidazolium hexafluorophosphate ([EMIM][PF6]), and 1-ethyl-2,3-dimethylimidazolium hexafluorophosphate ([EMMIM][PF6]), respectively. Experimentally it has been observed that the substitution of a methyl group for a hydrogen at the C2 position of the cation ring leads to an increase in both the melting point and liquid phase viscosity, contrary to arguments that had been made regarding associations between the ions. The melting points of the four ionic liquids were accurately predicted using simulations, as were the trends in viscosity. The simulation results show that the origin of the effect is mainly entropic, although enthalpy also plays an important role.     

An improved synthesis and some reactions of diethyl 4-oxo-4H-pyran-2,5-dicarboxylate

The reaction of ethyl 2-(dimethylamino)methylene-3-oxobutanoate with diethyl oxalate in the presence of sodium hydride in THF gave diethyl 4-oxo-4H-pyran-2,5-dicarboxylate, from which 4-oxo-4H-pyran-2,5-dicarboxylic and 4-oxo-1-phenyl-1,4-dihydropyridine-2,5-dicarboxylic acids and their derivatives were obtained in good yields.