Synthesis of N-substituted 9-[2-(3,4-methylenedioxyphenyl)-2-oxoethyl]-1,5-dinitro-7,8-benzo-3-azabicyclo[3.3.1]non-7-en-6-ones

Aminomethylation has been accomplished of the anionic Yanovskii adduct of 2,4-dinitronaphthol and 3,4-dimethylenedioxyacetophenone. The structure of the 3-substituted 9-[2-(3,4-methylenedioxyphenyl)-2-oxoethyl]-1,5-dinitro-7,8-benzo-3-azabicylo[3.3.1]non-7-en-6-one was determined by two-dimensional homo-and heteronuclear correlation spectroscopy. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, 1382–1389, September 2007.     

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.     

3-Azabicyclo[3.3.1]nonane Derivatives: IV. Synthesis of Amino Acids with 3-Azabicyclo[3.3.1]nonane Fragment

A series of 1.5-dinitro-3-azabicyclo[3.3.1]non-6-enes was prepared by reduction of 1-R-2,4- and 1-R-3,5-dinitrobenzenes with potassium borohydride followed by Mannich reaction with formaldehyde and amino acids. The molecular structure of (6-bromo-1,5-dinitro-3-azabicyclo[3.3.1]non-6-en-3-yl)acetic acid was studied by X-ray diffraction analysis. The mechanism of decomposition under electron impact was determined for (7-methoxy-1,5-dinitro-3-azabicyclo[3.3.1]non-6-en-3-yl)acetic acid.     

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.     

Chemistry of 1,5-diketones: II. Specificity of transformations of polycyclic 1,5-diketones in acid media

2-(1,3-Diaryl-3-oxopropyl)cyclohexan-1-ones underwent carbo-and heterocyclization in a mixture of acetic acid with acetic anhydride in the presence of perchloric acid. The transformation of 2-(1,3-diaryl-3-oxopropyl)cyclohexan-1-ones into 2,4-diaryl-5,6,7,8-tetrahydrochromenylium salts was shown to involve intermediate 2,4-diarylbicyclo[3.3.1]non-2-en-9-ones. The structure of 2,4-diaryl-substituted bicyclo[3.3.1]non-2-en-9-ones and products of their reactions with halogens and hydroxylamine hydrochloride was confirmed by ¹H and ¹³C NMR spectroscopy.     

Formation of Isomeric 3-Azabicyclo[3.3.1]nonanes in a Reaction of 1-(2-Hydroxyethoxy)-2,4-dinitrobenzene with Sodium Borohydride,Formaldehyde, and Methylamine

Anionic hydride adduct of 1-(2-hydroxyethoxy)-2,4-dinitrobenzene was brought into a double Mannich condensation with formaldehyde and methylamine to furnish a mixture of isomeric 3-azabicyclo[3.3.1]nonanes: 3-methyl-6-(2-hydroxyethoxy)-1,5-dinitro-3-azabicyclo[3.3.1]non-6-ene and 3-methyl-6,6-ethylenedioxy-1,7-dinitro-3-azabicyclo[3.3.1]nonane. By means of NMR spectroscopy, X-ray difraction analysis, and quantum chemistry (PM3) we demonstrated that the spirocyclic isomer had chair-chair conformation with diequatorial orientation of substituents in positions 3 and 7.     

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.     

Reduction of 3-(2-hydroxyethyl)-1,5-dinitro-3-azabicyclo[3.3.1]non-6-ene

Reduction of the nitro groups in 3-(2-hydroxyethyl)-1,5-dinitro-3-azabicyclo[3.3.1]non-6-ene was studied. The structures of the reaction products were confirmed using ¹H and ¹³C NMR spectroscopy.     

Study of the bromination of 1,5-dinitro-3-azabicyclo-[3.3.1]non-6-enes

The electrophilic addition of bromine to 3-substituted 1,5-dinitro-3-azabicyclo[3.3.1]non-6-ene in carbon tetrachloride is accompanied by intramolecular 3,7-cyclization with the formation of 6-bromo-3-R-1,5-dinitro-3-azonia-tricyclo[3.3.10^3,7]nonane tribromides. In the bromination of 1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes containing substituents at the double bond, molecular complexes of halogen with the substrate were obtained. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 862–873, June, 2008.     

Reactions of 8-methyl-5-methylsulfanylmethyl-3-thiabicyclo-[3.3.1]non-7-en-6-one at the carbonyl group

The reduction of 8-methyl-5-methylsulfanylmethyl-3-thiabicyclo[3.3.1]non-7-en-6-one with aluminum hydride, lithium tetrahydridoaluminate, or lithium tris(tert-butoxy)hydridoaluminate in tetrahydrofuran gave 8-methyl-5-methylsulfanylmethyl-3-thiabicyclo[3.3.1]non-7-en-6-ol. 8-Methyl-5-methylsulfanylmethyl-3-thiabicyclo[3.3.1]nonan-6-ol was obtained by reduction of the title compound with sodium tetrahydridoborate in pyridine or dimethylformamide. The reaction of 8-methyl-5-methylsulfanylmethyl-3-thiabicyclo[3.3.1]non-7-en-6-one with hydroxylamine hydrochloride afforded the corresponding oxime.     

Selective reduction of 6-substituted 1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes

Reduction of 6-substituted 1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes gives either saturated 1,5-diamino-3-azabicyclo[3.3.1]nonane or unsaturated 1,5-diamino-3-azabicyclo[3.3.1]non-6-enes, depending on the conditions and nature of substituent in the substrate.     

Skeletal rearrangements of <Emphasis Type="Italic">cis</Emphasis>-(-)-7,8-epoxycarveol derivatives promoted by triethylsilyl trifluoromethanesulfonate

Diastereoisomeric couples of (1R,5R,6RS)-2,6-dimethyl-7-oxabicyclo[3.2.1]oct-2-en-6-ylmethanols and their epoxide precursors, (5R,2′RS)-2-methyl-5-(2-methyloxiran-2-yl)cyclohex-2-en-1-ols, in the presence of triethylsilyl trifluoromethanesulfonate underwent [3.2.1]→[3.3.1] skeletal rearrangement with formation of scalemic mixtures of (1R,5R,6R)- and (1R,5R,6S)-2,6-dimethyl-6-triethylsiloxy-8-oxabicyclo[3.3.1]non-2-enes; the (6R)-stereoisomer was isolated as individual substance.     

Chlorination features of 1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes

The electrophilic chlorine addition to 3-substituted 1,5-dinitro-3-azabicyclo[3.3.1]-non-6-enes in the tetrachloromethane is accompanied at an intramolecular 3,7-cyclization giving 6-chloro-3-R-1,5-dinitro-3-azoniatricyclo[3.3.1.03,7]nonane chlorides. The reaction of the tricyclic quaternary ammonium salts with sodium methoxide leads to the formation of dealkylated and dehydrohalogenated products, 3-substituted 8-chloro-1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes, bicyclic products with a halogen atom in an allyl position with respect to the double bond.     

Synthesis of 6,7-benzo-3-borabicyclo[3.3.1]nonane and its 3-aza analog from 2-allylphenyl(diallyl)borane. Intramolecular arylboration of the C=C bond

A method was developed for the synthesis of 6,7-benzo-3-borabicyclo[3.3.1]nonane and 6,7-benzo-3-azabicyclo[3.3.1]nonane derivatives based on intramolecular cyclization of 2-allylphenyl(diallyl)borane. Intramolecular arylboration of the double bond in 1,5-diallyl-2,3-benzo-1-boracyclohexane was carried out for the first time. Conventional oxidation (H₂O₂-OH⁻) of 6,7-benzo-3-methoxy-3-borabicyclo[3.3.1]nonane afforded cis-1,3-di(hydroxymethyl) tetralin. The structure of the latter was established by X-ray diffraction analysis.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 668–672, March, 2005.     

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.     

7-Bromocavernicolenone,a New α-Bromoenone from the Mediterranean Sponge Aplysina (= Verongia) cavernicola. Implied,Unprecedented Involvement of a Halogenated Dopa in the Biogenesis of a Natural Product

A novel, mildly antibacterial, α-bromoenone (7-bromocavernicolenone) has been isolated from the Mediterranean sponge Aplysina (= Verongia) cavernicola. Its structure, 7-bromo-1,5-dihydroxy-2-azabicyclo[3.3.1]non-6-en-3,8-dione ( 3 ), is based on X-ray and NMR analysis and on the observation that acetylation of 3 affords two monoacetates. An unprecedented phenol oxidative biogenetic pathway is suggested leading to 7-bromocavernicolenone via 3-bromotyrosine and 5-bromodopa.     

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.     

3-Azabicyclo[3.3.1]nonane Derivatives: V. Synthesis of 7-Polyfluoroalkoxy-1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes

A number of 7-polyfluoroalkoxy-1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes were synthesized by reduction of 3,5-dinitrophenyl polyfluoroalkyl ethers with sodium tetrahydridoborate, followed by the Mannich reaction with formaldehyde and primary amines.     

The preparation and reactions of 1,3,4,5,6,7,8-heptafluoro-2-naphthyl prop-2-enyl ether: Formation of 1,3,4,5,6,7,8-heptafluoro-1-(prop-2-enyl)naphthalen-2-one and the photolysis and pyrolysis of this ketone [1].

1,3,4,5,6,7,8-Heptafluoro-2-naphthyl prop-2-enyl ether (8) was isomerised in boiling xylene to 1,3,4,5,6,7,8-heptafluoro- 1-(prop-2-enyl)naphthalen-2-one (9). Photolysis of (9) gave 2,5,7-trifluoro-3,4-(tetrafluorobenzo)tricyclo[3.3.1.O^2,7]non-3- en-6-one (11) (by a [2 + 2] addition) and 1,2,7-trifluoro-3,4- (tetrafluorobenzo) tricyclo [3.3.1.O^2,7]non-3-en-8-one (12) (via an initial [3,5] photochemically-allowed sigmatropic shift). Pyrolysis of (9) at 455° also gave (11), while at 490°, both (9) and (11) gave 1-fluorovinyl 4,5,6,7,8-pentafluoro-1-naphthyl ketone (19).     

Synthesis of bridged azabicycles from isoquinolines via a tandem of allylboration and intramolecular metathesis

A method for the synthesis of bridged azabicyclic compounds from isoquinolines was developed. The method is based on a combination of allylboration and ruthenium-catalyzed intramolecular metathesis. Reductive 1,3-diallylation of bromoisoquinolines with triallylborane gave trans-1,3-diallyl-1,2,3,4-tetrahydroisoquinolines. When heated with triallylborane, these compounds yielded mixtures of cis-and trans-isomers in the ratio ∼1: 1. The structure of cis-1,3-diallyl-5-bromo-1,2,3,4-tetrahydroisoquinoline was confirmed by X-ray diffraction analysis. In a similar way, trans-3-allyl-1-vinyl-1,2,3,4-tetrahydroisoquinoline synthesized by sequential vinylation (with vinyllithium) and allylboration of isoquinoline, yielded a mixture of cis-and trans-isomers in the ratio 1.6: 1. Intramolecular metathesis reactions of N-Boc derivatives of cis-isomers in the presence of the Grubbs catalyst (2.0–2.5 mol.%) afforded 7,8-benzo-10-azabicyclo[4.3.1]dec-2-enes or 7,8-benzo-9-azabicyclo[3.3.1]non-2-ene in nearly quantitative yields. Dedicated to Academician V. A. Tartakovsky on the occasion of his 75th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1510–1515, August, 2007.