Recyclization of 1-acyl(thioacyl)-5-hydroxy-2-pyrazolines to 1,3,4-oxa(thia)diazol-2-ine derivatives on acetylation

The acetylation of 1-acyl(thioacyl)-5-hydroxy-2-pyrazoline produces recyclization to the corresponding acyl-5-(2-oxoalkyl)-1,3,4-oxa(thia)diazol-2-ine.Military Medical Academy, St. Petersburg 194175, Russia.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 90–96, January, 1999.     

Synthesis of substituted 2,5-diazabicyclo[2.2.1]heptanes

A new method is proposed for the synthesis of substitituted 2,5-diazabicyclo[2.2.1]heptanes from 1-(tert-butoxycarbonyl)-4-tosyloxy-2-(tosyloxymethyl)pyrrolidine.¹H NMR spectroscopy indicated multiple conformations of 2-(tert-butoxycarbonyl)-2,5-diazabicyclo[2.2.1]heptanes in solution.St. Petersburg State University, 198904 St. Petersburg, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 501–503, April, 2000.     

Synthesis of substituted cyclohexenyl-, cyclohexadienylarylamines

Reaction of 3-R-5-hydroxy-5-methyl-2,4-diethoxycarbonylcyclohexanones with aromatic amines afforded cyclohexenyl- and cyclohexadienylarylamines with electron-donor and electron-acceptor groups attached to aryl substituents. The structure of the reaction products was proved by IR,¹H and¹³C NMR spectroscopy. The study was carried out under financial support of the Competition Center of Fundamental Natural Sciences at St. Petersburg State University (grant no. 97-9.4-322).     

Synthesis of 2-Methacryloyl-5-hydroxy-3,3,5-trimethylisoxazolidine and Copolymers Thereof

Previously unknown 2-methacryloyl-5-hydroxy-3,3,5-trimethylisoxazolidine was prepared by the reaction of 5-hydroxy-3,3,5-trimethylisoxazolidine with methacryloyl chloride. Homopolymers of this compound and its copolymers with N-vinylformamide and N-vinylpyrrolidone were obtained by radical polymerization.     

Synthesis and properties of carbamoyl derivatives of 5-hydroxy-3,3,5-trimethylisoxazolidine

The reaction of 5-hydroxy-3,3,5-trimethylisoxazolidine with alkyl (or aryl) isocyanates gives N-alkyl(aryl)-carbamoyl-5-hydroxy-3,3,5-trimethylisoxazolidines, which react with methanol in the presence of p-toluenesulfonic acid to give 5-methoxy-1-carbamoyl derivatives of isoxazolidine. When arylcarbamoyl-5-hydroxy-3,3,5-trimethylisoxazolidines are heated in carbon tetrachloride, they are converted to O-arylcarbamoyl-N-(2-methyl-4-oxo-2-pentyl)hydroxylamines, the treatment of which with hydrogen chloride in benzene made it possible to isolate 1,2,6-oxadiazepin-7-ones along with the hydrochloride of the given compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 746–750, June, 1979.     

Basicity of 3,6-diphenyl-1,2,4,5-tetrazine

We have determined the basicity of 3,6-diphenyl-1,2,4,5-tetrazine in aqueous solutions of sulfuric acid (pK_BH+ is –4.8). According to quantum chemical calculations done by the MNDO method and theab initio method in a 6-31G++ basis, the tetrazine ring is a nonpolar, highly aromatic system similar to benzene. The aromaticity of the tetrazine hererocycle decreases significantly upon protonation, which considerably destabilizes the protonated form.St. Petersburg State Technological Institute, St. Petersburg 198013, Russia, Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 34, No. 1, pp. 120–123, January, 1998.     

Ring-Ring Tautomerism in the Series of Isoxazolidine and Δ2-Isoxazoline Derivatives

We have studied the reaction of 5-hydroxy-3,3,5-trimethylisoxazolidine and 5-hydroxy-3,5-dimethyl-²-isoxazoline with derivatives of thiosemicarbazide and also thiocarbonohydrazine. Both reactions serve as a method for synthesis of the previously unknown 5-thiosemicarbazido(thiocarbonohydrazino)isoxazolidines and -²-isoxazolines. ¹H and ¹³C NMR spectroscopy revealed a tendency of the indicated compounds toward ring-chain and ring-ring tautomeric conversions in solutions involving the 1,2,4-triazolidine, ²-pyrazoline, and 1,2,4,5-tetrazine rings.     

Synthesis of isoxazolidine derivatives from N-substituted hydroxylamines and α,Β-unsaturated ketones

The reaction of methyl vinyl ketone with N-Phenyl-hydroxylamine leads to a tautomeric mixture of 5-hydroxy-2-phenyl-5-methylisoxazolidine and its linear form, while the reaction with benzohydroxamic acid leads to linear products of addition to the oxygen or nitrogen atoms, depending on the reaction conditions. The first representatives of 5-hydroxyisoxazolidines with the residue of an aliphatic carboxylic acid attached to the nitrogen atom were obtained by acylation of 5-hydroxy-3,3,5-trimethylisoxazolidine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 823–826, June, 1989.     

Adsorption properties of low-silica zeolite ZK-5

Water vapor, methanol, and argon adsorption isotherms, as well as the heat of adsorption of ammonia, methanol, and carbon dioxide have been determined on zeolite types A, ZK-4, and ZK-5. The results are explained by the distribution and the bond lengths of cations in the zeolite crystal lattice. It was shown that the exchange of 10–15% of the Na⁺ ions with Li⁺ in zeolite ZK-5 leads to a deformation of the 8-membered ring impeding the diffusion of adsorbed molecules. Cations contained in the 8-membered ZK-5 zeolite ring are bound more strongly to the framework, than in zeolite NaA, resulting in their smaller adsorption capacity.I. V. Grebenshchikov Institute of Silicate Chemistry, Russian Academy of Sciences, 199164 St. Petersburg, Russia. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2494–2500, November, 1992.     

Synthesen von Heterocyclen, 133. Mitt.: Zur Chlorierung von 4-Hydroxy-2-pyridonen

Zusammenfassung Die Chlorierung des 5-Äthoxycarbonyl-4-hydroxy-6-methyl-2-pyridons (1) mit SO₂Cl₂ gibt bei unterschiedlichen Reaktionsbedingungen die chlorierten Derivate2,3 bzw.4. Bei der Reaktion des 4-Hydroxy-6-phenyl-2-pyridons (5) mit SO₂Cl₂ erhält man das 3,3,5-Trichlor-pyridin-2,4-dion (6), das mittels Zn/Eisessig zum Dichlorderivat7 reduziert wird. Durch Hydrolyse von6 und Decarboxylierung entsteht das Enaminketon8.

---

Syntheses of heterocycles, CXXXIII: Concerning the chlorination of 4-hydroxy-2-pyridones

Chlorination of ethyl 4-hydroxy-6-methyl-2-pyridone-5-carboxylate (1) with SO₂Cl₂ gives, depending on the reaction conditions, the chlorinated derivatives2,3 and4. The reaction of 4-hydroxy-6-phenyl-2-pyridone5 with SO₂Cl₂ yields 3,3,5-trichloro-pyridin-2,4-dione (6), which can be reduced with Zn/AcOH to give 3,5-dichloro-4-hydroxy-2-pyridone (7). Hydrolysis of6 and decarboxylation leads to the enaminoketone8.

     

17O NMR spectra of equatorial and axial hydroxycyclohexanes and 5-hydroxy-1,3-dioxanes and their methyl ethers

¹⁷O chemical shifts of axial hydroxyl groups in cyclohexanols are upfield of those of corresponding equatorial groups, but in 5-hydroxy-1,3-dioxanes the opposite is observed: the axial OH resonates downfield of the equatorial OH. The situation is the same in the corresponding methyl ethers and is, thus, not a result of intramolecular hydrogen bonding in the axial 5-hydroxy-1,3-dioxane, but appears to parallel the effect on ¹³C and ¹⁹F shifts observed in corresponding equatorial and axial 5-methyl- and 5-fluoro-1,3-dioxanes, which has been attributed to an upfield shifting effect of the antiperiplanar γ-located heteroatoms. Surprisingly, the reciprocal effect is not seen in the ring ¹⁷O shifts of the 5-hydroxy-1,3-dioxanes. A δ compression shift is seen in the ¹⁷O spectrum of trans-3,3,5-trimethylcyclohexanol (syn-axial OH and CH₃), analogous to the effect earlier reported in ¹³C spectra. Conversion of four of the alcohols to methyl ethers produces a large upfield effect on the ¹⁷O shift, larger in the cyclohexanols than in the 1,3-dioxane-5-ols. Similar upfield shifts have been recorded in the literature; their extent depends on whether the alcohols are primary, secondary or tertiary.     

One new 1,4-napthoquinone derivative from the roots of Juglans mandshurica

A new 1,4-napthoquinone derivative, namely (S)-(-)-3-(8-hydroxy-1,4-dioxo-1,4-dihydro-naphthalen-2-yl)-3-(4-hydroxy-3-methoxyphenyl)-propionic acid methyl ester (1), was isolated from the roots of Juglans mandshurica Maxim. The structure was identified based on HR-ESI-MS, 1D and 2D NMR spectroscopic methods.     

Diverse chemical behaviour of 2-hydroxy-functionalized pyrroline-1-oxide

The reactivity of 2-hydroxy-3,3,5-trimethyl-3,4-dihydro-2H-pyrrole 1-oxide was investigated. The title compound showed unexpected reactivity with several different types of reagents.     

Methods for the synthesis of mono- and polynuclear NH-tetrazoles. (Review)

Data on methods for the synthesis of monocyclic and polynuclear NH-unsubstituted tetrazoles are reviewed.Dedicated to Prof. H. Elguero on the occasion of his 65th birthday.St. Petersburg State Technological Institute (Technical University), St. Petersburg 198013, Russia; Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 867–884, July, 2000.     

The molecular complex of 4-(N-pyridinium)pyridine-N-oxide chloride with tetracyanoethylene in the synthesis of substituted pyridine N-oxides

The structure of the complex of 4-(N-pyridinium)pyridine-N-oxide chloride with tetracyanoethylene was studied by¹³C NMR spectroscopy. The results of the investigation, suggesting the use of this complex in the synthesis of substituted pyridine derivatives, were conformed experimentally by its reaction with oxygen and with nitrogen-containing nucleophiles.Petrozavodsk State University, Petrozavodsk, 185640. St. Petersburg State University, St. Petersburg, 198904. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 184–186, February, 1995. Original article submitted December 24, 1994.     

Ring-ring tautomerism in 1,3-alkanoylhydrazonoximes of acetylacetone

The coexistence in solution of tautomeric isoxazoline and pyrazoline forms of 1,3-alkanoylhydrazonoximes of acetylacetone has been detected and investigated by¹H and¹³C NMR spectroscopic methods. The compounds indicated eliminate hydroxylamine under the action of acid catalysts, forming 1-acyl-3,5-dimethylpyrazoles.Institute of High Molecular Compounds, Russian Academy of Sciences, St. Petersburg 199004, RussiaTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 825–829, June, 2000.     

Michail Vasil'evič Lomonosov

This paper is dedicated to the 300^th anniversary of Michail Vasil'evič Lomonosov, Russiás first world‐renowned scholar. He was educated in Russia and Germany and founded the first chemical laboratory in the Academy of St. Petersburg. There he carried out many quantitative experiments especially in the field of melting glasses. He argued in favor of a corpuscular structure of matter and explained physical and chemical phenomena on the basis of his theory. He also contributed to the humanities by writing numerous papers about the history of the Russian nation and the grammar and the poetics of the Russian language. In his personal life he also wrote himself poems and odes.     

Reaction of 4,5-Dihydro-1H-pyrazole-3,5,5-tricarboxylic Acids Esters with Halogens

Esters of 4-R-4,5-dihydro-1H-pyrazole-3,5,5-tricarboxylic acids with chlorine yield esters of 4-R-5-chloro-4,5-dihydro-3H-pyrazole-3,3,5-tricarboxylic acids that at thermolysis provide the esters of the corresponding 2-chlorocyclopropanetricarboxylic acid. The same esters react with bromine in dichloromethane at room temperature to give a mixture of esters of the corresponding 1H-pyrazole-3,5-dicarboxylic acids and 5-bromo-4,5-dihydro-3,3,5-tricarboxylic acids. From 5,5-diethyl 3-methyl 4,5-dihydro-1Hpyrazole-3,5,5-tricarboxylate and N-iodosuccinimide or a system iodine-silver trifluoroacetate we obtained 1,1-diethyl 2-methyl 2-iodocyclopropane-1,1,2-tricarboxylate.     

Branched polycyclic tetrazole systems. 1. Synthesis and structure of 2-(5-tetrazolyl)ethyl derivatives of some CH-, OH-, and NH-acids

The cycloaddition of dimethylammonium azide to the nitrile groups of 2-cyanoethyl derivatives of CH-, OH-, and NH-acids leads to open-chain branched structures containing terminal NH-tetrazolyl groups. An x-ray diffraction structural analysis of tris[2-(5-tetrazolyl)ethyl]nitromethane revealed steric access of the equivalent NH-tetrazolyl rings of the branched system. In going from the branched nitrile substrates to the corresponding tetrazoles, the PMR spectra show a breakdown in the resolution of the multiplet components, which had not been observed previously for monocyclic 5-substituted tetrazoles. A dependence was found for the¹³C NMR chemical shifts on the pK_a values, reflecting the NH-acidity of the branched polycyclic tetrazoles in water. Dedicated to the memory of I. N. Goncharova. St. Petersburg State Technological Institute, 198013 St. Petersburg. V. A. éngel'gart Institute of Molecular Biology, Russian Academy of Sciences, 117984 Moscow. L. Ya. Karpov Physics and Chemistry Research Institute, 103062 Moscow. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1494–1501, November, 1997.     

Enantioselective stable isotope analysis (ESIA) of polar herbicides

Assessing the environmental fate of chiral micropollutants such as herbicides is challenging. The complexity of aquatic systems often makes it difficult to obtain hydraulic mass balances, which is a prerequisite when assessing degradation based on concentration data. Elegant alternatives are concentration-independent approaches like compound-specific isotope analysis or enantiospecific concentration analysis. Both detect degradation-induced changes from ratios of molecular species, either isotopologues or enantiomers. A combination of both—enantioselective stable isotope analysis (ESIA)—provides information on ¹³C/¹²C ratios for each enantiomer separately. Recently, Badea et al. demonstrated for the first time ESIA for the insecticide α-hexachlorocyclohexane. The present study enlarges the applicability of ESIA to polar herbicides such as phenoxy acids: 4-CPP ((RS)-2-(4-chlorophenoxy)-propionic acid), mecoprop (2-(4-chloro-2-methylphenoxy)-propionic acid), and dichlorprop (2-(2,4-dichlorophenoxy)-propionic acid). Enantioselective gas chromatography–isotope ratio mass spectrometry was accomplished with derivatization prior to analysis. Precise carbon isotope analysis (2σ?≤?0.5‰) was obtained with ≥7 ng C on column. Microbial degradation of dichlorprop, 2-(2,4-dichlorophenoxy)-propionic acid by Delftia acidovorans MC1 showed pronounced enantiomer fractionation, but no isotope fractionation. In contrast, Badea et al. observed isotope fractionation, but no enantiomeric fractionation. Hence, the two lines of evidence appear to complement each other. They may provide enhanced insight when combined as ESIA.