E. N. Alifanova

3-azabicyclo[3.3.1]nonane derivatives: IX. Synthesis and molecular structure of 3-azabicyclo[3.3.1]nonane-1,5-diamines in solution and in solid state

During catalytic reduction with hydrogen on nickel of a series of 3-substituted 1,5-dinitro-3-azabicyclo-[3.3.1]non-6-enes alongside nitro groups reduction occurred also hydrogenation of the double bond. New diamines of the 3-azabicyclo[3.3.1]nonane series were synthesized, and their structure was established by means of IR, 1H and 13C NMR spectroscopy and X-ray diffraction study.

Regioselectivity in the reactions of the acetonate ion with electron-deficient arenes

The reactions of the acetonate ion with 1,3-dinitro-5-X-, 1,3-X2-5-nitro- (X = NO2, CN, COOCH3, CONH2, COO–, and H), and 1,3,5-tricyanobenzenes were studied by 1H NMR and electronic absorption spectroscopy and by quantum-chemical methods. The kinetic factor is decisive for the initial attack of the carbanion on the C(2) atom of unsymmetrical arenes. However, σ-adducts in which a nucleophile is added to the C(4) atom are more stable thermodynamically. In the case of 1,3-X2-5-nitrobenzenes (X = CN, COOCH3, or CONH2), the σ-adducts with the acetonate group in para-position to the X group unexpectedly proved to be very stable. The structures of the σ-adducts based on trinitro- and 1,3-dinitro-5-cyanobenzenes were determined by X-ray diffraction analysis. Quantum-chemical calculations (the AM1 and PM3 semiempirical methods and the density functional method) were used to interpret the reaction regioselectivity and the molecular and electronic structures of the σ-adducts.

Synthesis and Structure of Derivatives of 9-(2-Oxopropyl)-1,5-dinitro-7,8-benzo-3-azabicylo[3.3.1]non-7-en-6-ones

A number of 3-R-9-(2-oxopropyl)-1,5-dinitro-7,8-benzo-3-azsbicyclo[3.3.1]non-7-en-6-ones was synthesized by Mannich reaction involving Yanovsky adduct of 2,4-dinitronaphthol. It was established by molecular spectroscopy and X-ray diffraction analysis that the piperidine ring in these compounds was in the chairconformation with a diequatorial position of the substituent attached to the heteroatom and 2-oxo-propyl group, and the cyclohexenone fragment was in sofaform. By an example of 3-methyl-9-(2-oxopropyl)-1,5-dinitro-7,8-benzo-3-azsbicyclo[3.3.1]non-7-en-6-one the dissociative ionization of bicyclononanes under the electron impact was investigated.

Aminomethylation by Formaldehyde and Primary Amines of Anionic σσ-Adduct Obtained from 2,4-Dinitrophenol and Acetophenone Carbanion

By condensation of 2,4-bis(aci-nitro)-3-(2-phenyl-2-oxoethyl)cyclohex-5-en-1-one with formaldehyde and primary amines a series of N-substituted 9-(2-phenyl-2-oxoethyl)-1,5-dinitro-3-azabicyclo[3.3.1]non-7-en-6-ones was synthesized. With the use of X-ray analysis the cyclohexenone fragment in the 3-(2-bromoethyl)-1,5-dinitro-9-(2-phenyl-2-oxoethyl)-3-azabicyclo[3.3.1]non-7-en-6-ones was established to exist in sofa conformation, and the nitrogen-containing ring to have the chair conformation with equatorial orientation of substituents in 3 and 9 positions. The regio- and stereoselectivity of the reaction under study was interpreted relying on the quantum-chemical calculations by AM1 and PM3 procedures.

VI. Synthesis of heterocyclic analogs of γ-aminobutyric acid from 3,5-dinitrobenzoic acid

A series of 7-carboxy-3-R-1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes was synthesized by reduction of 3,5-dinitrobenzoic acid with sodium borohydride followed by Mannich reaction with formaldehyde and primary amines. The mechanism of decomposition under electron impact of the 3-azabicyclo[3.3.1]nonane was established. Enthalpies of formation of compounds synthesized were calculated by semiempirical PM3 method.

Structure features of ions and ion pairs of nitroarene anionic σ-complexes in aprotic solvents

Abstract The structure of ions and ion pairs of Meisenheimer and Janovsky σ-complexes of 1,3,5-trinitrobenzene has been studied by derivative spectroscopy and semiempirical quantum chemical PM3 and CNDO/S methods. On the base of comparison of theoretical and experimental electronic absorption spectra the three types of co-ordination of anion and cation have been defined. It was established that the structure of ion pairs is determined by the nature of the substituents of the pyramidal unit.

3-Azabicyclo[3.3.1]nonane Derivatives: III. Synthesis of 3-Substituted 9-Acetonyl-1,5-dinitro-3-azabicyclo[3.3.1]-non-6-en-8-ones by Mannich Condensation of the Janovsky σ-Adduct of 2,4-Dinitrophenol with Acetonide Ion

A number of 9-acetonyl-1,5-dinitro-3-azabicyclo[3.3.1]non-6-en-8-one derivatives were synthesized by Mannich condensation of 3-acetonyl-2,4-bis(aci-nitro)cyclohex-5-en-1-one disodium salt with formaldehyde and primary amines.

Synthesis and conformation of 6,8,10-trinitro-1,4-dioxaspiro[4.5]decane

Abstractcis, trans-6,8,10-Trinitro-1,4-dioxaspiro[4.5]decane was synthesized by reduction of the corresponding spirocyclic anionic δ-complex with potassium tetrahydroborate. The molecular structure and the conformation of the title compound were established by X-ray diffraction analysis and1H NMR spectroscopy.

3-Azabicyclo[3.3.1]nonane Derivatives: VIII. Synthesis and Properties of 6(7)-R-3,3-Dimethyl-1,5- dinitro-3-azoniabicyclo[3.3.1]non-6-ene Iodides

N-Alkylation of 6(7)-R-1,5-dinitro-3-methyl-3-azabicyclo[3.3.1]non-6-enes with methyl iodide afforded a series of quaternary ammonium salts whose yield depended on the solvent polarity and character of substituents located in positions 6 or 7 of substrate. The presence of electron-withdrawing groups reduced the yield of the target products compared to unsubstituted compound, whereas the electron-donor substituents increased the yield. As shown by the X-ray diffractionstudy the congormation of the substances was not changed in the course of quaternization. The DTA-TG analysis revealed that in the first stage of thermolysis the 6(7)-R-3,3-dimethyl-1,5-dinitro-3-azoniabicyclo[3.3.1]non-6-ene iodides suffer dealkylation. Two fragmentation paths of compounds synthesized under electron impact were observed: elimination either of methyl iodide or aziridinium cation.

Role of Association of Yanovskii Anionic σ Adducts in Their Oxidation with Quinones

In oxidation of 1,3-dinitro- and 1,3,5-trinitrobenzene acetonate σ adducts (Yanovskii complexes) with sodium, potassium, and tetrabutylammonium cations in acetonitrile and tetrahydrofuran (290-313 K), ion pairs are less reactive than free ions, which is explained by charge redistribution in the ring of the σ adducts, decreasing the electron-donor power of the associated anion. Separation of the apparent rate constants into ionic and ion-pair contributions showed that the reactivity of the ion pairs depends on the radius of their cation. The revealed kinetic regularities are interpreted on the basis of AM1 semiempirical quantum-chemical calculations of the ions and ion pairs with lithium cation.