Synthesis of chiral crown ethers and complexation with chiral protonated amine compounds: X-ray crystal and nuclear magnetic resonance studies of perchlorate salt of chiral benzo-monoaza-15-crown-5 and chiral monoaza-15-crown-5

The X-ray crystal structure of IX, perchlorate salt of R-(?-2-ethyl-N-benzyl-4,7,19,13-tetraoxa-8,9-benzo-1-azacyclopentadec-8-ene has been determined. In the molecule, the protonated nitrogen atom participates in two N-H?O hydrogen bonds. The unusually high proton affinity of aza crown ether leads to the formation of diastreomer instead of complex formation with chiral R-(+)-1-phenyl ethyl ammonium perchlorate and S-(?)-1-phenyl ethyl ammonium perchlorate. The complex ability of host ethers was evaluated in terms of structural modification.     

Reactions of N- and C-alkenylanilines: VI. Synthesis of 6-methyl-2-[(E or Z)-1-propenyl]anilines and the corresponding anilides and their reaction with bromine

Isomerization of 2-allyl-6-methylaniline by the action of potassium hydroxide at 300°C afforded cis and trans isomers of 2-methyl-6-(1-propenyl)aniline which were converted into the corresponding carbamates by treatment with ethyl chloroformate. Ethyl 2-methyl-6-(1-propenyl)phenylcarbamates reacted with bromine to give mixtures of 4-(1-bromoethyl)-8-methyl-1,4-dihydro-2H-3,1-benzoxazin-2-one and ethyl 2- methyl-6-(1,2-dibromopropyl)phenylcarbamates. Treatment of the same compounds with N-bromosuccinimide resulted in formation of 2-ethoxy-4H-3,1-benzoxazine derivatives. The reaction of N-{6-methyl-2-[(Z)- 1-propenyl]-phenyl}methanesulfonamide gave a mixture of stereoisomeric N-[6-methyl-2- (1,2-dibromopropyl)-phenyl]-methanesulfonamides.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 12, 2004, pp. 1815–1818.Original Russian Text Copyright © 2004 by Afonkin, Sotnikov, Gataullin, Spirikhin, Abdrakhmanov.For communication V, see [1].     

Synthesis,molecular structure,and absolute configuration of 1-α-pheitylethyl-3-(2-cyanoethyl)-4-piperidone

The Michael addition of acrylonitrile to the pyrrolidine enamine of 1-(S--phenyl-ethyl)-4-piperidone proceeds with the formation of. a 1:1 mixture of l-(S--phenyl ethyl)-3-(2-cyanoethyl)-4-piperidone diastereomers. A diastereomer isolated in pure form was shown by x-ray diffraction structural analysis to have S-configuration of the new chiral center at C₍₃₎ of the piperidone ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp, 1656–1662, December, 1985.     

Spectral properties and structures of supramolecular complexes of naphthylpyridine with β-cyclodextrin

The electronic absorption and fluorescence spectra of 4-(2-naphthyl)pyridine (1) and N-methyl-4-(2-naphthyl)pyridinium perchlorate (2 ⁺·ClO₄ ^–) were studied in aqueous solutions in the absence and presence of -cyclodextrin (-CD). In aqueous solutions and organic solvents in the presence of water or H⁺ ions, compound 1 exhibits intense fluorescence with a maximum at 21 270 cm^–1, and its quantum yield in an aqueous solution is 0.9±0.09. The same fluorescence spectrum was detected for an aqueous solution of 2 ⁺·ClO₄ ^–. In an aqueous solution, compound 1 and -CD form stable fluorescing supramolecular 2:2 complexes, whose structure was calculated by the quantum-chemical MNDO/PM3 method. The formation of these complexes induces a hypsochromic shift of the fluorescence maximum of 1 by 5000 cm^–1. The stability constant of the complex is 2·10³ L mol^–1. A decrease in the pH results in the formation of a protonated form of 1(1·H⁺) and destruction of the complex, thus favoring the escape of the substrate from the -CD cavity. The quantum-chemical calculations showed that the insertion of 1 into the -CD cavity is thermodynamically more favorable than hydration; on the contrary, the formation of 1·H⁺ increases dramatically the hydration energy, which promotes the escape of 1·H⁺ from the -CD cavity; cation 2 ⁺ does not form a complex with -CD; in the thermodynamically most favorable 2:2 complex, the naphthalene fragments of two molecules 1 are parallel to each other in a broad section of the -CD dimer constructed according to the head-to-head type.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2420–2425, November, 2004.     

Asymmetric halogenation and hydrohalogenation of ethyltrans-cinnamate in crystalline cyclodextrin complexes

The gas-solid halogenation and hydrohalogenation using microcrystalline cyclodextrin complexes are found to be efficient for production of the optical active halides of ethyltrans-cinnamate in moderate optical yields: On exposure to HBr at 20°C for 15–20 hr, the cinnamate in solid - and -cyclodextrin complexes yields ethyl R-(+)-3-bromo-3-phenylpropanoate in 46% e.e., and S-(–)-enantiomer in 31% e.e., respectively. No addition nor substitution products are obtained with HC1 vapor at 0–50°C for 15–65 hr. Bromination of the -cyclodextrin complex results in the formation of optical active ethylerythro-2,3-dibromo-3-phenylpropanoate, while chlorination gives the optical active mixture oftrans andcis addition products, ethylerythro- andthreo-2,3-dichloro-3-phenylpropanoates in 60–80% yields. Mechanism of chiral induction in the present gas-solid reaction has been proposed on the basis of the crystal structure of the complex.     

Extraction and spectrophotometric determination of titanium(iv) with 3-hydroxy-2-methyl-1-(4-tolyl)-4-pyridone

Titanium(IV) in sulphuric, perchloric and hydrochloric acid media reacts with 3-hydroxy-2-methyl-1-(4-tolyl)-4-pyridone (HY) to give a complex which is extractable into chloroform. The composition of the extractable complex depends on the acidity of the aqueous phase and on which mineral acid is used. The mixed titanium-perchlorate-HY complex which is formed in the presence of excess of perchlorate is the most suitable for the spectrophotometric determination of titanium. The molar absorptivity of the complex is 1.6×10⁴1·mole^–1·cm^–1 at 355 nm. The optimum titanium concentration range is 0.5–6,g/ml. The method has been successfully applied to the determination of titanium in samples of bauxite and alumina refractory.     

Photochemical properties and the structure of 6-methyl-2,4-diphenyl-1-(p-tolyl)pyrimidinium perchlorate and the product of its photocyclization

The structure and photochemical properties of 6-methyl-2,4-diphenyl-1-(p-tolyl)pyrimidinium perchlorate (1) and 4,8-dimethyl-2-phenylpyrimido[1,2-f]phenanthridinium (2) formed as a result of photocyclization of1 have been studied. The crystal structure of compound1 has been studied at –140 °C and 25 °C. In cation1, theN-tolyl substituent and -Ph ring are noncoplanar with the pyrimidinium fragment (the angles are 67.9° and 41.1°, respectively), while the angle between the -Ph ring and the pyrimidinium moiety is only 7.1° (–140 °C). The photocyclization product2 has a flattened structure.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1731–1735, September, 1995.This work was partly (studies performed at Scientific Research Institute of Physical and Organic Chemistry at Rostov State University) supported by the Science Foundation Russian Universities.     

Crystal Structure of (2.2.2-Cryptand)lithium Perchlorate

(2.2.2-Cryptand)lithium perchlorate [Li(2.2.2-Crypt)]⁺ClO^– ₄ (I) is prepared and characterized by X-ray structural analysis. Structure I (space group P2₁2₁2, a = 10.149 Å, b = 13.475 Å, c = 8.580 Å, Z = 2) is solved by the direct method and refined anisotropically by the full-matrix least-squares method to R = 0.056 for 2312 reflections (CAD4 automated diffractometer, MoK ). Crystal of complex I is built of [Li(2.2.2-Crypt)]⁺ complex cations of the host–guest type and randomly disordered ClO^– ₄ anions. Both ions are located on the twofold crystallographic axes. The Li⁺ cation, which is also randomly disordered about the 2 axis, is coordinated by the N atom and five O atoms from eight heteroatoms (2N + 6O) of the cryptand. Two Li–O and one Li–N bonds are noticeably elongated. The Li⁺ cation forms irregular six-vertex coordination polyhedron.     

1-Aryl-6-azauracile, 8. Mitt.: Herstellung von p-Carboxy-, p-Acetyl- und p-Sulfamoylphenylderivaten

Zusammenfassung In Fortsetzung unserer Synthesen wurden aus p-Amino-benzoesäure, ihrem Äthylester, p-aminoacetophenon und Sulfanilamid die entsprechenden Arylhydrazono-cyanacetylcarbamid-säureäthylester (1 a–1 d), 1-Aryl-6-azauracil-5-carbonsäure-nitrile (2 a–2 d), 1-Aryl-6-azauracil-5-carbonsäure (3 a–3 d) und die Thioamide (4 a–4 d) dieser Säuren hergestellt. Durch Decarboxylierung der Säure3 a wurde 1-(p-Carboxyphenyl)-6-azauracil (5 a) gewonnen.

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From p-aminobenzoic acid, its ethyl ester, p-aminoaceto-phenone and sulfanilamide the corresponding ethyl arylhydrazonocyanoacetylcarbamidates (1a–1 d), 1-aryl-6-azauracil-5-carboxylic acid nitriles (2 a–2 d), carboxylic acids (3 a–3 d) and thioamides (4 a–4 d) have been prepared. Decarboxylation of3 a yielded 1-(p-carboxyphenyl)-6-azauracil (5 a).

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7. Mitt.:J. Slouka undP. Pe, Mh. Chem.98, 1201 (1967).     

Diborane as a reducing agent IX: Reduction of aTris(trifluoroacetyl)enaminospiroindoline

Summary Reduction of the title compound (2) with diborane furnishes 1-trifluoroethyl-3-(2-(trifluoroethylamino)ethyl)-3-vinylindoline (4), 1-hydroxy-trifluoroethyl-3-(2-(trifluoroethylamino)ethyl)indole (5), and 1-methyl-2-trifluoroethyl-1,2,3,4-tetrahydro--carboline (6). However, treatment of2 with lithium aluminum hydride, H₂/Pd on charcoal, and sodium borohydride affords hydroxyspiroindolenine8, hydroxy-bis(trifluoroacetyl)enaminospiroindoline9, andN-ethyltryptamine7, respectively. The results are discussed and the mechanisms of the reactions leading to4–8 are presented.

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Diboran als Reduktionsmittel, 9. Mitt.: Reduktion einesTris(trifluoroacetyl)enaminospiroindolins

Zusammenfassung Reduktion der Titelverbindung (2) mit Diboran ergibt 1-Trifluoroethyl-3-(2-(trifluoroethylamino)ethyl)-3-vinylindolin (4), 1-Hydroxy-trifluoroethyl-3-(2-(trifluoroethylamino)ethyl)indol (5) und 1-Methyl-2-trifluoroethyl-1,2,3,4-tetrahydro--carbolin (6). Behandlung von2 mit Lithiumaluminiumhydrid, H₂/Pd auf Aktivkohle und Natriumborhydrid führt jedoch zu Hydroxyspiroindolenin8, Hydroxy-bis(trifluoroacetyl)enaminospiroindolin9 und N-Ethyltryptamin (7). Die Ergebnisse werden diskutiert und die Mechanismen der zu den Produkten4–8 führenden Reaktionen werden vorgestellt.

     

Crystal Structure of Diaqua(1,2-bis(2-(o-hydroxyphenoxy)ethyloxy)ethane)(perchlorato-O)strontium Perchlorate Hydrate

The aqua complex of podand 1,2-bis(2-(o-hydroxyphenoxy)ethyloxy)ethane (L) with strontium perchlorate of the composition [Sr(ClO₄)L(H₂O)₂]⁺ · ClO₄ ^– · H₂O (I) was synthesized and studied using X-ray diffraction analysis: space group P2₁/c, a = 16.195 Å, b = 11.382 Å, c = 16.646 Å, = 117.01°, Z = 4. The structure was solved by direct method and anisotropically refined by the full-matrix least-squares method to R = 0.069 for 4278 independent reflections (CAD4 autodiffractometer, MoK ). Structure I contains complex cation [Sr(ClO₄)L(H₂O)₂]⁺ of the host–guest type. The Sr²⁺ cation (coordination number 9) is coordinated to all six O atoms of the L podand, O atom of a disordered ClO₄ ^– ligand, and two O atoms of two water molecules. The coordination polyhedron of Sr²⁺ is irregular; in a rough approximation, it can be described as a face-centered cube. The crystal structure of I contains an infinite three-dimensional network of the O–H···O hydrogen bonds joining the complex cations, ClO₄ ^– anions, and molecules of crystallization water.     

Vibrational analysis and FTIR spectra of seven isotopic congeners of ethyl benzoate including18O carbonyl and ether labelled esters

FTIR spectra of seven isotopic congeners of ethyl benzoate are fitted to a force field with a standard deviation of less than 7 cm^–1. The field has been transferred to ethyl anisate and an equimolar titanium tetrachloride-ethyl benzoate complex with encouraging success. The band at 1280cm^–1 is definitely assigned as mainly an-C-O stretch.     

Thermochemical study of some cubane derivatives

The thermochemical study of cubane-1,4-dicarboxylic acid (1), diethyl cubane-1,4-dicarboxylate (2), diisopropyl cubane-1,4-dicarboxylate (3), and bis(2-fluoro-2,2-dinitro)ethyl cubane-1,4-dicarboxylate (4) was performed. The standard enthalpies of combustion (_c H°) and formation (_f H°) of these compounds were estimated using the method of combustion in a calorimetric bomb in an oxygen atmosphere. Using the additive group method, calculated values for _f H° of these substances which agreed satisfactorily with the experimental ones were obtained. The strain energies (E _s) of the cubic structure of derivatives1–4 were calculated. It was concluded thatE _s did not change on substitution of hydrogen atoms in cubane for various functional groups and was equal toE _s of the structure of cubane itself. The reliability of the single published value of _f H° in the cubane crystal state, 541.8 kJ mol^–1 (129.5 kcal mol^–1), was confirmed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2471–2473, October, 1996.     

The reaction of ethyl 2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate with fullerene C60

Heating (100 °C, toluene) or photolysis (Nd³⁺ : YAG laser, = 532 mil, benzonitrile) of a mixture of ethyl 2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (Hantsch ester) (1) and fullerene C₆₀ under anaerobic conditions results in the formation of fullerene hydrogenation products and ethyl 2,6-dimethylpyridine-3,5-dicarboxylate, which is the product of dehydrogenation of1, identified by IR spectroscopy and mass spectrometry. The triplet state of C₆₀ is quenched by the Hantsch ester.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2531–2534, October, 1996.     

The reaction of Se(IV) with 2-aminodiphenylamine and its application to spectrophotometric determination of selenium in a strongly acidic medium

Se(IV) reacts with 2-aminodiphenylamine in perchloric, sulphuric or hydrochloric acid media to give the phenylbenzoselen-adiazolium cation. The optimum hydrogen-ion concentration ranges from about 0.1 to 5M. The molar absorptivity at =352 nm is 1.81×10⁴ 1 · mole^–1 · cm^–1. The product is extracted as an ion-association complex with perchlorate into a mixture of hexanol and chlorobenzene. The kinetics of the reaction was investigated.     

Novel Immobilized Hydrosilylation Catalysts Based on Rhodium 1,3-Bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidenes

Summary. The reactivity of a well defined Rh (I) complex, i.e. Rh(CF₃COO)(NHC)(COD) (1, NHC=1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene, COD=⁴-cycloocta-1,5-diene) in the hydrosilylation of 1-alkenes, alkynes, and ,-unsaturated carbonyl compounds, respectively, is described. With this complex, excellent reactivity was observed and turn-over numbers (TONs) up to 1000 were reached. A supported version of 1 was realized by reaction of RhCl(NHC)(COD) with PS-DVB–CH₂–O–CO–CF₂–CF₂–CF₂–COOAg (PS-DVB=poly(styrene-co-divinylbenzene) to yield PS-DVB–CH₂–O–CO–CF₂–CF₂–CF₂–COORh(NHC)(COD). This supported version of 1 exhibited at least comparable, in some cases increased reactivity compared to 1 and allowed the rapid removal of the catalyst from the reaction mixture. Due to reduced catalyst bleeding, the synthesis of target compounds with a Rh-content of less than 130ppm was accomplished.This revised version was published online in February 2005. In the previous version the issue was not marked as a special issue, and the issue title and the editor was missing     

Novel Immobilized Hydrosilylation Catalysts Based on Rhodium 1,3-Bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidenes

The reactivity of a well defined Rh (I) complex, i.e. Rh(CF₃COO)(NHC)(COD) (1, NHC=1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene, COD=⁴-cycloocta-1,5-diene) in the hydrosilylation of 1-alkenes, alkynes, and ,-unsaturated carbonyl compounds, respectively, is described. With this complex, excellent reactivity was observed and turn-over numbers (TONs) up to 1000 were reached. A supported version of 1 was realized by reaction of RhCl(NHC)(COD) with PS-DVB–CH₂–O–CO–CF₂–CF₂–CF₂–COOAg (PS-DVB=poly(styrene-co-divinylbenzene) to yield PS-DVB–CH₂–O–CO–CF₂–CF₂–CF₂–COORh(NHC)(COD). This supported version of 1 exhibited at least comparable, in some cases increased reactivity compared to 1 and allowed the rapid removal of the catalyst from the reaction mixture. Due to reduced catalyst bleeding, the synthesis of target compounds with a Rh-content of less than 130ppm was accomplished.     

Temperature deactivation of excited Tb3+ in the presence of 1,2-dioxetane in acetonitrile

Quenching the fluorescence (FL) of terbium perchlorate by 2,2-adamantane-2,2-dioxide (1) was shown to have a chemical character and was caused by the formation of the [1...Tb³⁺] complex. The dependence of the lifetime () of FL of Tb^*3+ in acetonitrile on the temperature and concentration of1 has been studied. The temperature dependence of is caused by a rearrangement of the inner sphere of the aquasolvate complexes of Tb³⁺, which leads to the replacement of H₂O with MeCN and1. The energy of replacing the H₂O molecule in the inner sphere of complexes with a solvent molecule has been calculated.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1762–1766, October, 1994.     

Synthesis, Spectral and Structural Study of N-[1-(N,N,N′,N′-Tetramethylphosphoramidoyl)- 1H-Benzimidazol-2-yl]-Propionimidic Ethyl Ether

The preparation of N-[1-(N,N,N,N-tetramethylphosphoramidoyl)-1H-benzimidazol-2-yl]-proponimidic ethyl ester 2 has been achieved by the reaction of N-(1H-benzimidazol-2-yl)-proponimidic acid ethyl ester 1 with N,N,N,N-tetramethylchlorophosphoramide. The structure of compound 2 has been determined by X-ray diffraction. The results of (¹H, ¹³C, ³¹P) NMR, IR, EI-MS spectral data are consistent with those obtained from the X-ray diffraction. The compound crystallizes in the triclinic system, following the EsZ conformation. In the crystal, there are two weak C3–H3s1 and C15–H15sO1 intermolecular hydrogen bonds.     

A rapid and sensitive GC–MS method for determination of 1,3-dichloro-2-propanol in water

A rapid analytical method for sensitive determination of 1,3-dichloro-2-propanol (1,3-DCP) in river water has been developed. 1,3-DCP is extracted from water with ethyl acetate. After filtration through sodium sulfate the ethyl acetate phase is analyzed by gas chromatography–mass spectrometry. The method uses 1,3-DCP-d₅ as internal standard. Different extraction solvents, concentrations of ammonium sulfate in the water samples, and the effect of humic acid were tested and their influence on the recovery of DCP has been evaluated. The method quantification limit was 0.1 g L^–1. For spiked water samples (0–5.2 g L^–1, n=21) a repeatability coefficient of variation of 5.4% was obtained. The average recovery rate of 1,3-DCP was 105±3% (n=21). Stability tests, which were carried out with Danube river water, led to an estimated 1,3-DCP degradation rate of 0.008±0.0008 day^–1 at 6°C.